Cell , IF:41.582 , 2022 Mar , V185 (6) : P967-979.e12 doi: 10.1016/j.cell.2022.01.026
Synthetic mammalian signaling circuits for robust cell population control.
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Primordium Labs, Arcadia, CA 91006, USA.; Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.; Department of Biology, Stanford University, Stanford, CA 94305, USA.; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA. Electronic address: melowitz@caltech.edu.
In multicellular organisms, cells actively sense and control their own population density. Synthetic mammalian quorum-sensing circuits could provide insight into principles of population control and extend cell therapies. However, a key challenge is reducing their inherent sensitivity to "cheater" mutations that evade control. Here, we repurposed the plant hormone auxin to enable orthogonal mammalian cell-cell communication and quorum sensing. We designed a paradoxical population control circuit, termed "Paradaux," in which auxin stimulates and inhibits net cell growth at different concentrations. This circuit limited population size over extended timescales of up to 42 days of continuous culture. By contrast, when operating in a non-paradoxical regime, population control became more susceptible to mutational escape. These results establish auxin as a versatile "private" communication system and demonstrate that paradoxical circuit architectures can provide robust population control.
PMID: 35235768
Trends Plant Sci , IF:18.313 , 2022 Mar , V27 (3) : P227-236 doi: 10.1016/j.tplants.2021.09.008
Auxin's origin: do PILS hold the key?
Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium. Electronic address: kenny.bogaert@ugent.be.; Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB-UGent, Technologiepark 72, B-9052 Ghent, Belgium.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB-UGent, Technologiepark 72, B-9052 Ghent, Belgium.; Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium.
Auxin is a key regulator of many developmental processes in land plants and plays a strikingly similar role in the phylogenetically distant brown seaweeds. Emerging evidence shows that the PIN and PIN-like (PILS) auxin transporter families have preceded the evolution of the canonical auxin response pathway. A wide conservation of PILS-mediated auxin transport, together with reports of auxin function in unicellular algae, would suggest that auxin function preceded the advent of multicellularity. We find that PIN and PILS transporters form two eukaryotic subfamilies within a larger bacterial family. We argue that future functional characterisation of algal PIN and PILS transporters can shed light on a common origin of an auxin function followed by independent co-option in a multicellular context.
PMID: 34716098
Nat Plants , IF:15.793 , 2022 Mar , V8 (3) : P269-280 doi: 10.1038/s41477-022-01111-3
Specification of leaf dorsiventrality via a prepatterned binary readout of a uniform auxin input.
Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland.; Center for Plant Molecular Biology, University of Tubingen, Tubingen, Germany.; NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam.; Center for Plant Molecular Biology, University of Tubingen, Tubingen, Germany. marja.timmermans@zmbp.uni-tuebingen.de.
Developmental boundaries play an important role in coordinating the growth and patterning of lateral organs. In plants, specification of dorsiventrality is critical to leaf morphogenesis. Despite its central importance, the mechanism by which leaf primordia acquire adaxial versus abaxial cell fates to establish dorsiventrality remains a topic of much debate. Here, by combining time-lapse confocal imaging, cell lineage tracing and molecular genetic analyses, we demonstrate that a stable boundary between adaxial and abaxial cell fates is specified several plastochrons before primordium emergence when high auxin levels accumulate on a meristem prepattern formed by the AS2 and KAN1 transcription factors. This occurrence triggers a transient induction of ARF3 and an auxin transcriptional response in AS2-marked progenitors that distinguishes adaxial from abaxial identity. As the primordium emerges, dynamic shifts in auxin distribution and auxin-related gene expression gradually resolve this initial polarity into the stable regulatory network known to maintain adaxial-abaxial polarity within the developing organ. Our data show that spatial information from an AS2-KAN1 meristem prepattern governs the conversion of a uniform auxin input into an ARF-dependent binary auxin response output to specify adaxial-abaxial polarity. Auxin thus serves as a single morphogenic signal that orchestrates distinct, spatially separated responses to coordinate the positioning and emergence of a new organ with its patterning.
PMID: 35318449
Nat Commun , IF:14.919 , 2022 Feb , V13 (1) : P815 doi: 10.1038/s41467-022-28507-1
Defining molecular glues with a dual-nanobody cannabidiol sensor.
Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA.; Department of Biochemistry and Institute for Protein Design, University of Washington, Seattle, WA, 98195, USA.; Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA. nzheng@uw.edu.
"Molecular glue" (MG) is a term coined to describe the mechanism of action of the plant hormone auxin and subsequently used to characterize synthetic small molecule protein degraders exemplified by immune-modulatory imide drugs (IMiDs). Prospective development of MGs, however, has been hampered by its elusive definition and thermodynamic characteristics. Here, we report the crystal structure of a dual-nanobody cannabidiol-sensing system, in which the ligand promotes protein-protein interaction in a manner analogous to auxin. Through quantitative analyses, we draw close parallels among the dual-nanobody cannabidiol sensor, the auxin perception complex, and the IMiDs-bound CRL4(CRBN) E3, which can bind and ubiquitinate "neo-substrates". All three systems, including the recruitment of IKZF1 and CK1alpha to CRBN, are characterized by the lack of ligand binding activity in at least one protein partner and an under-appreciated preexisting low micromolar affinity between the two proteinaceous subunits that is enhanced by the ligand to reach the nanomolar range. These two unifying features define MGs as a special class of proximity inducers distinct from bifunctional compounds and can be used as criteria to guide target selection for future rational discovery of MGs.
PMID: 35145136
Mol Plant , IF:13.164 , 2022 Mar , V15 (3) : P504-519 doi: 10.1016/j.molp.2022.01.004
Wheat breeding history reveals synergistic selection of pleiotropic genomic sites for plant architecture and grain yield.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: liaili@caas.cn.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.; Novogene Bioinformatics Institute, Beijing 100083, China.; Collaborative Innovation Center of Crop Stress Biology & Institute of Plant Stress Biology, School of Life Science, Henan University, Kaifeng 475004, China.; Triticeae Research Institute, Sichuan Agricultural University, Chengdu, Sichuan 611130, China.; The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: xdfu@genetics.ac.cn.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: zhangxueyong@caas.cn.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: malong@caas.cn.
Diversity surveys of crop germplasm are important for gaining insights into the genomic basis for plant architecture and grain yield improvement, which is still poorly understood in wheat. In this study, we exome sequenced 287 wheat accessions that were collected in the past 100 years. Population genetics analysis identified that 6.7% of the wheat genome falls within the selective sweeps between landraces and cultivars, which harbors the genes known for yield improvement. These regions were asymmetrically distributed on the A and B subgenomes with regulatory genes being favorably selected. Genome-wide association study (GWAS) identified genomic loci associated with traits for yield potential, and two underlying genes, TaARF12 encoding an auxin response factor and TaDEP1 encoding the G-protein gamma-subunit, were located and characterized to pleiotropically regulate both plant height and grain weight. Elite single-nucleotide haplotypes with increased allele frequency in cultivars relative to the landraces were identified and found to have accumulated over the course of breeding. Interestingly, we found that TaARF12 and TaDEP1 function in epistasis with the classical plant height Rht-1 locus, leading to propose a "Green Revolution"-based working model for historical wheat breeding. Collectively, our study identifies selection signatures that fine-tune the gibberellin pathway during modern wheat breeding and provides a wealth of genomic diversity resources for the wheat research community.
PMID: 35026438
Dev Cell , IF:12.27 , 2022 Feb , V57 (4) : P526-542.e7 doi: 10.1016/j.devcel.2021.12.019
Dynamic chromatin state profiling reveals regulatory roles of auxin and cytokinin in shoot regeneration.
National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; University of Chinese Academy of Sciences (UCAS), Shanghai 200032, P.R. China.; National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; University of Chinese Academy of Sciences (UCAS), Shanghai 200032, P.R. China.; National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.; National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China. Electronic address: jwwang@sippe.ac.cn.
Shoot regeneration is mediated by the sequential action of two phytohormones, auxin and cytokinin. However, the chromatin regulatory landscapes underlying this dynamic response have not yet been studied. In this study, we jointly profiled chromatin accessibility, histone modifications, and transcriptomes to demonstrate that a high auxin/cytokinin ratio environment primes Arabidopsis shoot regeneration by increasing the accessibility of the gene loci associated with pluripotency and shoot fate determination. Cytokinin signaling not only triggers the commitment of the shoot progenitor at later stages but also allows chromatin to maintain shoot identity genes at the priming stage. Our analysis of transcriptional regulatory dynamics further identifies a catalog of regeneration cis-elements dedicated to cell fate transitions and uncovers important roles of BES1, MYC, IDD, and PIF transcription factors in shoot regeneration. Our results, thus, provide a comprehensive resource for studying cell reprogramming in plants and provide potential targets for improving future shoot regeneration efficiency.
PMID: 35063083
Plant Cell , IF:11.277 , 2022 Mar doi: 10.1093/plcell/koac086
Systems approaches reveal that ABCB and PIN proteins mediate co-dependent auxin efflux.
Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.; Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland.; Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
Members of the B family of membrane-bound ATP-binding cassette (ABC) transporters represent key components of the auxin-efflux machinery in plants. Over the last two decades experimental studies have shown that modifying ABCB expression affects auxin distribution and plant phenotypes. However, precisely how ABCB proteins transport auxin in conjunction with the more widely studied family of PIN-formed (PIN) auxin efflux transporters is unclear, and studies using heterologous systems have produced conflicting results. Here, we integrate ABCB localization data into a multicellular model of auxin transport in the Arabidopsis thaliana root tip to predict how ABCB-mediated auxin transport impacts organ-scale auxin distribution. We use our model to test five potential ABCB-PIN regulatory interactions, simulating the auxin dynamics for each interaction and quantitatively comparing the predictions with experimental images of the DII-VENUS auxin reporter in wild type and abcb single and double loss-of-function mutants. Only specific ABCB-PIN regulatory interactions result in predictions that recreate the experimentally observed DII-VENUS distributions and long-distance auxin transport. Our results suggest that ABCBs enable auxin efflux independently of PINs; however, PIN-mediated auxin efflux is predominantly through a co-dependent efflux where co-localised with ABCBs.
PMID: 35302640
Plant Cell , IF:11.277 , 2022 Mar doi: 10.1093/plcell/koac080
Genetic control of branching patterns in grass inflorescences.
Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132 USA.
Inflorescence branching in the grasses controls the number of florets and hence the number of seeds. Recent data on the underlying genetics come primarily from rice and maize, although new data are accumulating in other systems as well. This review focuses on a window in developmental time from the production of primary branches by the inflorescence meristem through to the production of glumes, which indicate the transition to producing a spikelet. Several major developmental regulatory modules appear to be conserved among most or all grasses. Placement and development of primary branches is controlled by conserved auxin regulatory genes. Subtending bracts are repressed by a network including TASSELSHEATH4, and axillary branch meristems are regulated largely by signaling centers that are adjacent to but not within the meristems themselves. Gradients of SBP-like and APETALA2-like proteins and their microRNA regulators extend along the inflorescence axis and the branches, governing the transition from production of branches to production of spikelets. The relative speed of this transition determines the extent of secondary and higher order branching. This inflorescence regulatory network is modified within individual species, particularly as regards formation of secondary branches. Differences between species are caused both by modifications of gene expression and regulators and by presence or absence of critical genes. The unified networks described here may provide tools for investigating orphan crops and grasses other than the well-studied maize and rice.
PMID: 35258600
Proc Natl Acad Sci U S A , IF:11.205 , 2022 Mar , V119 (11) : Pe2118220119 doi: 10.1073/pnas.2118220119
Proteome-wide cellular thermal shift assay reveals unexpected cross-talk between brassinosteroid and auxin signaling.
Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.; Pelago Bioscience AB, 171 48 Solna, Sweden.; Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.; Department of Biomolecular Medicine, Ghent University, 9052 Ghent, Belgium.; Center for Medical Biotechnology, VIB, 9052 Ghent, Belgium.; VIB Proteomics Core, 9052 Ghent, Belgium.
SignificanceChemical genetics, which investigates biological processes using small molecules, is gaining interest in plant research. However, a major challenge is to uncover the mode of action of the small molecules. Here, we applied the cellular thermal shift assay coupled with mass spectrometry (CETSA MS) to intact Arabidopsis cells and showed that bikinin, the plant-specific glycogen synthase kinase 3 (GSK3) inhibitor, changed the thermal stability of some of its direct targets and putative GSK3-interacting proteins. In combination with phosphoproteomics, we also revealed that GSK3s phosphorylated the auxin carrier PIN-FORMED1 and regulated its polarity that is required for the vascular patterning in the leaf.
PMID: 35254915
Proc Natl Acad Sci U S A , IF:11.205 , 2022 Mar , V119 (10) : Pe2116549119 doi: 10.1073/pnas.2116549119
Auxin methylation by IAMT1, duplicated in the legume lineage, promotes root nodule development in Lotus japonicus.
National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan.; School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan.
Significance IAA carboxyl methyltransferase 1 (IAMT1) converts auxin (IAA) into its methyl ester (MeIAA). IAMT1 is reportedly critical for shoot development of the nonsymbiotic plant Arabidopsis. On the other hand, the function of IAMT1 in roots is unknown. Here, we found that IAMT1 is duplicated in the legume lineage, which evolved root nodule symbiosis. In the model legume Lotus japonicus, one of two paralogs (named IAMT1a) was mainly expressed in root epidermis, but its function is required in the adjacent cell layer, root cortex, where it promotes nodule development. Application of MeIAA, but not IAA, significantly induced NIN, a master regulator of nodule development, without rhizobia. These findings illuminate our understanding of intertissue communication acquired during evolution of root nodule symbiosis.
PMID: 35235457
Proc Natl Acad Sci U S A , IF:11.205 , 2022 Mar , V119 (9) doi: 10.1073/pnas.2105819119
An in-frame deletion mutation in the degron tail of auxin coreceptor IAA2 confers resistance to the herbicide 2,4-D in Sisymbrium orientale.
Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523.; Division CropScience, Weed Control Research, Bayer AG, 65926 Frankfurt, Germany.; School of Agriculture, Food and Wine, University of Adelaide, Adelaide, SA 5064, Australia.; Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523.; Department of Biology, Colorado State University, Fort Collins, CO 80523.; Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO 80523.; Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824.; School of Life Sciences, The University of Warwick, Coventry, CV4 7AL, United Kingdom.; Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523; todd.gaines@colostate.edu.
The natural auxin indole-3-acetic acid (IAA) is a key regulator of many aspects of plant growth and development. Synthetic auxin herbicides such as 2,4-D mimic the effects of IAA by inducing strong auxinic-signaling responses in plants. To determine the mechanism of 2,4-D resistance in a Sisymbrium orientale (Indian hedge mustard) weed population, we performed a transcriptome analysis of 2,4-D-resistant (R) and -susceptible (S) genotypes that revealed an in-frame 27-nucleotide deletion removing nine amino acids in the degron tail (DT) of the auxin coreceptor Aux/IAA2 (SoIAA2). The deletion allele cosegregated with 2,4-D resistance in recombinant inbred lines. Further, this deletion was also detected in several 2,4-D-resistant field populations of this species. Arabidopsis transgenic lines expressing the SoIAA2 mutant allele were resistant to 2,4-D and dicamba. The IAA2-DT deletion reduced binding to TIR1 in vitro with both natural and synthetic auxins, causing reduced association and increased dissociation rates. This mechanism of synthetic auxin herbicide resistance assigns an in planta function to the DT region of this Aux/IAA coreceptor for its role in synthetic auxin binding kinetics and reveals a potential biotechnological approach to produce synthetic auxin-resistant crops using gene-editing.
PMID: 35217601
Curr Biol , IF:10.834 , 2022 Mar doi: 10.1016/j.cub.2022.02.069
Cell-wall damage activates DOF transcription factors to promote wound healing and tissue regeneration in Arabidopsis thaliana.
Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, Almas alle 5, 756 51, Uppsala, Sweden.; Department of Biosciences, Teikyo University, 1-1 Toyosatodai, Utsunomiya 320-8551, Japan.; Independent Junior Research Group - Designer Glycans, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany.; The Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, UK.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.; Independent Junior Research Group - Designer Glycans, Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany; Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA.; Department of Biosciences, Teikyo University, 1-1 Toyosatodai, Utsunomiya 320-8551, Japan; Advanced Instrumental Analysis Center, Teikyo University, 1-1 Toyosatodai, Utsunomiya 320-8551, Japan.; Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, Almas alle 5, 756 51, Uppsala, Sweden. Electronic address: charles.melnyk@slu.se.
Wound healing is a fundamental property of plants and animals that requires recognition of cellular damage to initiate regeneration. In plants, wounding activates a defense response via the production of jasmonic acid and a regeneration response via the hormone auxin and several ethylene response factor (ERF) and NAC domain-containing protein (ANAC) transcription factors. To better understand how plants recognize damage and initiate healing, we searched for factors upregulated during the horticulturally relevant process of plant grafting and found four related DNA binding with one finger (DOF) transcription factors, HIGH CAMBIAL ACTIVITY2 (HCA2), TARGET OF MONOPTEROS6 (TMO6), DOF2.1, and DOF6, whose expression rapidly activated at the Arabidopsis graft junction. Grafting or wounding a quadruple hca2, tmo6, dof2.1, dof6 mutant inhibited vascular and cell-wall-related gene expression. Furthermore, the quadruple dof mutant reduced callus formation, tissue attachment, vascular regeneration, and pectin methylesterification in response to wounding. We also found that activation of DOF gene expression after wounding required auxin, but hormone treatment alone was insufficient for their induction. However, modifying cell walls by enzymatic digestion of cellulose or pectin greatly enhanced TMO6 and HCA2 expression, whereas genetic modifications to the pectin or cellulose matrix using the PECTIN METHYLESTERASE INHIBITOR5 overexpression line or korrigan1 mutant altered TMO6 and HCA2 expression. Changes to the cellulose or pectin matrix were also sufficient to activate the wound-associated ERF115 and ANAC096 transcription factors, suggesting that cell-wall damage represents a common mechanism for wound perception and the promotion of tissue regeneration.
PMID: 35320706
Curr Biol , IF:10.834 , 2022 Mar doi: 10.1016/j.cub.2022.02.073
Auxin boosts energy generation pathways to fuel pollen maturation in barley.
Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umea, Sweden.; Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany; Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria.; Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA.; Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA.; Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany. Electronic address: acosta@mpipz.mpg.de.
Pollen grains become increasingly independent of the mother plant as they reach maturity through poorly understood developmental programs. We report that the hormone auxin is essential during barley pollen maturation to boost the expression of genes encoding almost every step of heterotrophic energy production pathways. Accordingly, auxin is necessary for the flux of sucrose and hexoses into glycolysis and to increase the levels of pyruvate and two tricarboxylic (TCA) cycle metabolites (citrate and succinate). Moreover, bioactive auxin is synthesized by the pollen-localized enzyme HvYUCCA4, supporting that pollen grains autonomously produce auxin to stimulate a specific cellular output, energy generation, that fuels maturation processes such as starch accumulation. Our results demonstrate that auxin can shift central carbon metabolism to drive plant cell development, which suggests a direct mechanism for auxin's ability to promote growth and differentiation.
PMID: 35316655
ISME J , IF:10.302 , 2022 Mar , V16 (3) : P801-811 doi: 10.1038/s41396-021-01133-3
Coordination of root auxin with the fungus Piriformospora indica and bacterium Bacillus cereus enhances rice rhizosheath formation under soil drying.
Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Engineering Research Center of Soil Remediation of Fujian Province University, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Department of Biology, Hong Kong Baptist University, Hong Kong, China.; Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.; Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. wfxu@fafu.edu.cn.
Moderate soil drying (MSD) is a promising agricultural technique that can reduce water consumption and enhance rhizosheath formation promoting drought resistance in plants. The endophytic fungus Piriformospora indica (P. indica) with high auxin production may be beneficial for rhizosheath formation. However, the integrated role of P. indica with native soil microbiome in rhizosheath formation is unclear. Here, we investigated the roles of P. indica and native bacteria on rice rhizosheath formation under MSD using high-throughput sequencing and rice mutants. Under MSD, rice rhizosheath formation was significantly increased by around 30% with P. indica inoculation. Auxins in rice roots and P. indica were responsible for the rhizosheath formation under MSD. Next, the abundance of the genus Bacillus, known as plant growth-promoting rhizobacteria, was enriched in the rice rhizosheath and root endosphere with P. indica inoculation under MSD. Moreover, the abundance of Bacillus cereus (B. cereus) with high auxin production was further increased by P. indica inoculation. After inoculation with both P. indica and B. cereus, rhizosheath formation in wild-type or auxin efflux carrier OsPIN2 complemented line rice was higher than that of the ospin2 mutant. Together, our results suggest that the interaction of the endophytic fungus P. indica with the native soil bacterium B. cereus favors rice rhizosheath formation by auxins modulation in rice and microbes under MSD. This finding reveals a cooperative contribution of P. indica and native microbiota in rice rhizosheath formation under moderate soil drying, which is important for improving water use in agriculture.
PMID: 34621017
New Phytol , IF:10.151 , 2022 Mar doi: 10.1111/nph.18114
Inactivation of the entire Arabidopsis group II GH3s confers tolerance to salinity and water deficit.
Umea Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umea, Sweden.; Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, USA.; Laboratory of Growth Regulators, Faculty of Science, Palacky University and Institute of Experimental Botany of the Czech Academy of Sciences, Slechtitelu 27, Olomouc, Czech Republic.
Indole-3-acetic acid (IAA) controls a plethora of developmental processes. Thus, regulation of their levels is of great relevance for plant performance. Cellular IAA concentration is a result of its transport, biosynthesis and various pathways for IAA inactivation, including oxidation and conjugation. Group II members of the GRETCHEN HAGEN 3 (GH3) gene family code for acyl acid amido synthetases catalysing the conjugation of IAA to amino acids. However, the high level of functional redundancy among them has hampered thorough analysis of their roles in plant development. In this work, we generated an Arabidopsis gh3.1,2,3,4,5,6,9,17 (gh3oct) mutant to knock out the group II GH3 pathway. The gh3oct plants had an elaborated root architecture, were more tolerant to osmotic stresses due to locally increased IAA levels and showed increased tolerance to water deficit. IAA metabolite quantification in gh3oct plants suggested the existence of additional GH3-like enzymes in IAA metabolism. Moreover, our data suggested that oxIAA production depends, at least partly, on the GH3 pathway. Targeted stress-hormone analysis further suggested involvement of ABA in the differential response to salinity of gh3oct plants. Taken together, our data provide new insights into the roles of group II GH3s in IAA metabolism and hormone-regulated plant development.
PMID: 35322877
New Phytol , IF:10.151 , 2022 Mar doi: 10.1111/nph.18111
microRNA172 controls inflorescence meristem size through regulation of APETALA2 in Arabidopsis.
Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, 50829, Germany.; Institute of Systems, Integrative, and Molecular Biology, University of Liverpool, L69 7ZB, United Kingdom.
The APETALA2 (AP2) transcription factor regulates flower development, floral transition and shoot apical meristem (SAM) maintenance in Arabidopsis. AP2 is also regulated at the post-transcriptional level by microRNA172 (miR172), but the contribution of this to SAM maintenance is poorly understood. We generated transgenic plants carrying a form of AP2 that is resistant to miR172 (rAP2) or carrying a wild-type AP2 susceptible to miR172. Phenotypic and genetic analyses were performed on these lines and mir172 mutants to study the role of AP2 regulation by miR172 on meristem size and the rate of flower production. We found that rAP2 enlarges the inflorescence meristem by increasing cell size and cell number. Misexpression of rAP2 from heterologous promoters showed that AP2 acts in the central zone (CZ) and organizing center (OC) to increase SAM size. Furthermore, we found that AP2 is negatively regulated by AUXIN RESPONSE FACTOR 3 (ARF3). However, genetic analyses indicated that ARF3 also influences SAM size and flower production rate independently of AP2. The study identifies miR172/AP2 as a regulatory module controlling inflorescence meristem size and suggests that transcriptional regulation of AP2 by ARF3 fine tunes SAM size determination.
PMID: 35318684
New Phytol , IF:10.151 , 2022 Mar doi: 10.1111/nph.18110
KAI2 regulates seedling development by mediating light-induced remodelling of auxin transport.
School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom.; Plant Genetics, TUM School of Life Sciences, Technical University of Munich (TUM), Emil Ramann Str. 4, 85354, Freising, Germany.; Genetics, Faculty of Biology, LMU Munich, Grosshaderner St. 4, 82152, Martinsried, Germany.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83, Umea, Sweden.; Sainsbury Laboratory Cambridge University, Bateman Street, Cambridge, CB2 1LR, United Kingdom.
Photomorphogenic remodelling of seedling growth is a key developmental transition in the plant life cycle. The alpha/beta-hydrolase signalling protein KARRIKIN-INSENSITIVE2 (KAI2), a close homologue of the strigolactone receptor DWARF14 (D14), is involved in this process, but it is unclear how the effects of KAI2 on development are mediated. Here, using a combination of physiological, pharmacological, genetic and imaging approaches in Arabidopsis thaliana (Heynh.) we show that kai2 phenotypes arise because of a failure to downregulate auxin transport from the seedling shoot apex towards the root system, rather than a failure to respond to light per se. We demonstrate that KAI2 controls the light-induced remodelling of the PIN-mediated auxin transport system in seedlings, promoting a reduction in PIN7 abundance in older tissues, and an increase of PIN1/PIN2 abundance in the root meristem. We show that removing PIN3, PIN4 and PIN7 from kai2 mutants, or pharmacological inhibition of auxin transport and synthesis, is sufficient to suppress most kai2 seedling phenotypes. We conclude that KAI2 regulates seedling morphogenesis by its effects on the auxin transport system. We propose that KAI2 is not required for the light-mediated changes in PIN gene expression but is required for the appropriate changes in PIN protein abundance within cells.
PMID: 35313031
New Phytol , IF:10.151 , 2022 Mar doi: 10.1111/nph.18079
SAV4 is required for ethylene-induced root hair growth through stabilizing PIN2 auxin transporter in Arabidopsis.
School of Life Sciences, Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, Xiamen University, Fujian Province, Xiang'an South Road, Xiamen, 361102, China.
Root hair development is regulated by hormonal and environmental cues, such as ethylene and low phosphate. Auxin efflux carrier PIN2 (PIN-FORMED 2), plays an important role in establishing proper auxin gradient in root tips, which is required for root hair development. Ethylene promotes root hair development through increasing PIN2 abundance in root tips, which subsequently leads to enhanced expression of auxin reporter genes. However, how PIN2 is regulated remains obscure. Here, we report that Arabidopsis thaliana sav4 (Shade Avoidance 4) mutant exhibits defects in ethylene-induced root hair development and establishing proper auxin gradient in root tips. Ethylene treatment increased SAV4 abundance in root tips. SAV4 and PIN2 colocalize to the shootward plasma membrane (PM) of root tip epidermal cells. SAV4 directly interacts with the PIN2 hydrophilic region (PIN2HL), regulates PIN2 abundance on the PM. Vacuolar degradation of PIN2 is suppressed by ethylene, which was weakened in sav4 mutant. Furthermore, SAV4 affects the formation of PIN2 clusters and its lateral diffusion on the PM. In summary, we identified SAV4 as a novel regulator of PIN2 that enhances PIN2 membrane clustering and stability through direct protein-protein interactions. Our study revealed a new layer of regulation on PIN2 dynamics.
PMID: 35274300
New Phytol , IF:10.151 , 2022 Mar doi: 10.1111/nph.18078
Comparative transcriptomics of fungal endophytes in co-culture with their moss host Dicranum scoparium reveals fungal trophic lability and moss unchanged to slightly increased growth rates.
Department of Biology, Duke University, 130 Science Drive, Durham, NC, 27708, USA.; North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy, FL, 32351, USA.; Biodiversity Research Center, Academia Sinica, 128 Academia Road, Section 2, Taipei, 11529, Taiwan.; Soil and Water Sciences Department, University of Florida, 1692 McCarty Drive, Gainesville, FL, 32611, USA.; School of Plant Sciences and Department of Ecology and Evolutionary Biology, University of Arizona, 1140 E. South Campus Drive, Tucson, AZ, 85721, USA.; Department of Ecology and Evolutionary Biology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996, USA.; Department of Agronomy, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan.
Mosses harbor fungi whose interactions within their hosts remain largely unexplored. Trophic ranges of fungal endophytes from the moss Dicranum scoparium were hypothesized to encompass saprotrophism. This moss is an ideal host to study fungal trophic lability because of its natural senescence gradient, and because it can be grown axenically. Dicranum scoparium was co-cultured with each of eight endophytic fungi isolated from naturally occurring D. scoparium. Moss growth rates, and gene expression levels (RNA sequencing) of fungi and D. scoparium, were compared between axenic and co-culture treatments. Functional lability of two fungal endophytes was tested by comparing their RNA expression levels when colonizing living vs dead gametophytes. Growth rates of D. scoparium were unchanged, or increased, when in co-culture. One fungal isolate (Hyaloscyphaceae sp.) that promoted moss growth was associated with differential expression of auxin-related genes. When grown with living vs dead gametophytes, Coniochaeta sp. switched from having upregulated carbohydrate transporter activity to upregulated oxidation-based degradation, suggesting an endophytism to saprotrophism transition. However, no such transition was detected for Hyaloscyphaceae sp. Individually, fungal endophytes did not negatively impact growth rates of D. scoparium. Our results support the long-standing hypothesis that some fungal endophytes can switch to saprotrophism.
PMID: 35263447
New Phytol , IF:10.151 , 2022 Apr , V234 (2) : P494-512 doi: 10.1111/nph.18008
A rice single cell transcriptomic atlas defines the developmental trajectories of rice floret and inflorescence meristems.
Joint International Research Laboratory of Metabolic & Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.; NovelBio Bio-Pharm Technology Co. Ltd, Shanghai, 201114, China.; Crop Breeding & Cultivation Research Institute, Shanghai Academy of Agriculture Sciences, Shanghai, 201403, China.; Max Planck Institute for Plant Breeding Research, Cologne, D50829, Germany.; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SA, 5064, Australia.
Rice inflorescence development determines yield and relies on the activity of axillary meristems (AMs); however, high-resolution analysis of its early development is lacking. Here, we have used high-throughput single-cell RNA sequencing to profile 37 571 rice inflorescence cells and constructed a genome-scale gene expression resource covering the inflorescence-to-floret transition during early reproductive development. The differentiation trajectories of florets and AMs were reconstructed, and discrete cell types and groups of regulators in the highly heterogeneous young inflorescence were identified and then validated by in situ hybridization and with fluorescent marker lines. Our data demonstrate that a WOX transcription factor, DWARF TILLER1, regulates flower meristem activity, and provide evidence for the role of auxin in rice inflorescence branching by exploring the expression and biological role of the auxin importer OsAUX1. Our comprehensive transcriptomic atlas of early rice inflorescence development, supported by genetic evidence, provides single-cell-level insights into AM differentiation and floret development.
PMID: 35118670
New Phytol , IF:10.151 , 2022 Apr , V234 (1) : P149-163 doi: 10.1111/nph.17969
CLAVATA modulates auxin homeostasis and transport to regulate stem cell identity and plant shape in a moss.
School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.; Division of Psychological Medicine & Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics & Genomics, Cardiff University School of Medicine, Heath Park, Cardiff, CF14 4XN, UK.; Laboratory of Growth Regulators, Faculty of Science of Palacky University and Institute of Experimental Botany of the Czech Academy of Sciences, Slechtitelu 27, Olomouc, 78371, Czech Republic.; Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
The CLAVATA pathway is a key regulator of stem cell function in the multicellular shoot tips of Arabidopsis, where it acts via the WUSCHEL transcription factor to modulate hormone homeostasis. Broad-scale evolutionary comparisons have shown that CLAVATA is a conserved regulator of land plant stem cell function, but CLAVATA acts independently of WUSCHEL-like (WOX) proteins in bryophytes. The relationship between CLAVATA, hormone homeostasis and the evolution of land plant stem cell functions is unknown. Here we show that in the moss, Physcomitrella (Physcomitrium patens), CLAVATA affects stem cell activity by modulating hormone homeostasis. CLAVATA pathway genes are expressed in the tip cells of filamentous tissues, regulating cell identity, filament branching, plant spread and auxin synthesis. The receptor-like kinase PpRPK2 plays the major role, and Pprpk2 mutants have abnormal responses to cytokinin, auxin and auxin transport inhibition, and show reduced expression of PIN auxin transporters. We propose a model whereby PpRPK2 modulates auxin gradients in filaments to determine stem cell identity and overall plant form. Our data indicate that CLAVATA-mediated auxin homeostasis is a fundamental property of plant stem cell function, probably exhibited by the last shared common ancestor of land plants.
PMID: 35032334
New Phytol , IF:10.151 , 2022 Mar , V233 (6) : P2397-2404 doi: 10.1111/nph.17946
How is auxin linked with cellular energy pathways to promote growth?
ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA, 6009, Australia.; School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia.
Auxin is the 'growth hormone' and modulation of its concentration correlates with changes in photosynthesis and respiration, influencing the cellular energy budget for biosynthesis and proliferation. However, the relative importance of mechanisms by which auxin directly influences photosynthesis and respiration, or vice versa, are unclear. Here we bring together recent evidence linking auxin with photosynthesis, plastid biogenesis, mitochondrial metabolism and retrograde signalling and through it we propose three hypotheses to test to unify current findings. These require delving into the control of auxin conjugation to primary metabolic intermediates, translational control under auxin regulation and post-translational influences of auxin on primary metabolic processes.
PMID: 34984715
New Phytol , IF:10.151 , 2022 Feb , V233 (4) : P1732-1749 doi: 10.1111/nph.17890
A plastidial retrograde signal potentiates biosynthesis of systemic stress response activators.
Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.; Laboratory of Allergy and Inflammation, Chengdu Third People's Hospital Branch of National Clinical Research Center for Respiratory Disease, Chengdu,, 610031, China.; Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, 55108, USA.
Plants employ an array of intricate and hierarchical signaling cascades to perceive and transduce informational cues to synchronize and tailor adaptive responses. Systemic stress response (SSR) is a recognized complex signaling and response network quintessential to plant's local and distal responses to environmental triggers; however, the identity of the initiating signals has remained fragmented. Here, we show that both biotic (aphids and viral pathogens) and abiotic (high light and wounding) stresses induce accumulation of the plastidial-retrograde-signaling metabolite methylerythritol cyclodiphosphate (MEcPP), leading to reduction of the phytohormone auxin and the subsequent decreased expression of the phosphatase PP2C.D1. This enables phosphorylation of mitogen-activated protein kinases 3/6 and the consequential induction of the downstream events ultimately, resulting in biosynthesis of the two SSR priming metabolites pipecolic acid and N-hydroxy-pipecolic acid. This work identifies plastids as a major initiation site, and the plastidial retrograde signal MEcPP as an initiator of a multicomponent signaling cascade potentiating the biosynthesis of SSR activators, in response to biotic and abiotic triggers.
PMID: 34859454
Cold Spring Harb Perspect Biol , IF:10.005 , 2022 Feb , V14 (2) doi: 10.1101/cshperspect.a039875
Auxin Transporters-A Biochemical View.
Plant Systems Biology, School of Life Sciences, Technical University of Munich, 85354 Freising, Germany.; Department of Plant Science and Landscape Architecture.; Agriculture Biotechnology Center, University of Maryland, College Park, Maryland 20742, USA.
From embryogenesis to fruit formation, almost every aspect of plant development and differentiation is controlled by the cellular accumulation or depletion of auxin from cells and tissues. The respective auxin maxima and minima are generated by cell-to-cell auxin transport via transporter proteins. Differential auxin accumulation as a result of such transport processes dynamically regulates auxin distribution during differentiation. In this review, we introduce all auxin transporter (families) identified to date and discuss the knowledge on prominent family members, namely, the PIN-FORMED exporters, ATP-binding cassette B (ABCB)-type transporters, and AUX1/LAX importers. We then concentrate on the biochemical features of these transporters and their regulation by posttranslational modifications and interactors.
PMID: 34127449
Cold Spring Harb Perspect Biol , IF:10.005 , 2022 Feb , V14 (2) doi: 10.1101/cshperspect.a040089
Modeling Auxin Signaling in Roots: Auxin Computations.
Computational Developmental Biology Group, Utrecht University, Utrecht 3584 CH, The Netherlands.
Auxin signaling and patterning is an inherently complex process, involving polarized auxin transport, metabolism, and signaling, its effect on developmental zones, as well as growth rates, and the feedback between all these different aspects. This complexity has led to an important role for computational modeling in unraveling the multifactorial roles of auxin in plant developmental and adaptive processes. Here we discuss the basic ingredients of auxin signaling and patterning models for root development as well as a series of key modeling studies in this area. These modeling studies have helped elucidate how plants use auxin signaling to compute the size of their root meristem, the direction in which to grow, and when and where to form lateral roots. Importantly, these models highlight how auxin, through patterning of and collaborating with other factors, can fulfill all these roles simultaneously.
PMID: 34001532
Cold Spring Harb Perspect Biol , IF:10.005 , 2022 Mar , V14 (3) doi: 10.1101/cshperspect.a040097
Computational Models of Auxin-Driven Patterning in Shoots.
Department of Computer Science, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
Auxin regulates many aspects of plant development and behavior, including the initiation of new outgrowth, patterning of vascular systems, control of branching, and responses to the environment. Computational models have complemented experimental studies of these processes. We review these models from two perspectives. First, we consider cellular and tissue-level models of interaction between auxin and its transporters in shoots. These models form a coherent body of results exploring different hypotheses pertinent to the patterning of new outgrowth and vascular strands. Second, we consider models operating at the level of plant organs and entire plants. We highlight techniques used to reduce the complexity of these models, which provide a path to capturing the essence of studied phenomena while running simulations efficiently.
PMID: 34001531
Plant Biotechnol J , IF:9.803 , 2022 Mar , V20 (3) : P423-425 doi: 10.1111/pbi.13771
Auxin promotes fiber elongation by enhancing gibberellic acid biosynthesis in cotton.
College of Life Sciences, Shaanxi Normal University, Xi'an, China.
PMID: 34971489
Plant Biotechnol J , IF:9.803 , 2022 Mar , V20 (3) : P526-537 doi: 10.1111/pbi.13734
ZmTE1 promotes plant height by regulating intercalary meristem formation and internode cell elongation in maize.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, Qingdao, Shandong, China.; School of Life Science, Anhui Agricultural University, Hefei, Anhui, China.; Maize Research Institute, Shandong Academy of Agricultural Sciences/National Engineering Laboratory of Wheat and Maize/Key Laboratory of Biology and Genetic Improvement of Maize in Northern Yellow-huai River Plain, Ministry of Agriculture, Jinan, China.; College of Agronomy, Qingdao Agricultural University, Qingdao, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.
Maize height is determined by the number of nodes and the length of internodes. Node number is driven by intercalary meristem formation and internode length by intercalary cell elongation, respectively. However, mechanisms regulating establishment of nodes and internode growth are unclear. We screened EMS-induced maize mutants and identified a dwarf mutant zm66, linked to a single base change in TERMINAL EAR 1 (ZmTE1). Detailed phenotypic analysis revealed that zm66 (zmte1-2) has shorter internodes and increased node numbers, caused by decreased cell elongation and disordered intercalary meristem formation, respectively. Transcriptome analysis showed that auxin signalling genes are also dysregulated in zmte1-2, as are cell elongation and cell cycle-related genes. This argues that ZmTE1 regulates auxin signalling, cell division, and cell elongation. We found that the ZmWEE1 kinase phosphorylates ZmTE1, thus confining it to the nucleus and probably reducing cell division. In contrast, the ZmPP2Ac-2 phosphatase promotes dephosphorylation and cytoplasmic localization of ZmTE1, as well as cell division. Taken together, ZmTE1, a key regulator of plant height, is responsible for maintaining organized formation of internode meristems and rapid cell elongation. ZmWEE1 and ZmPP2Ac-2 might balance ZmTE1 activity, controlling cell division and elongation to maintain normal maize growth.
PMID: 34687251
Plant Biotechnol J , IF:9.803 , 2022 Feb , V20 (2) : P399-408 doi: 10.1111/pbi.13723
Strong and tunable anti-CRISPR/Cas activities in plants.
Instituto de Biologia Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Cientificas (CSIC), Universitat Politecnica de Valencia, Valencia, Spain.
CRISPR/Cas has revolutionized genome engineering in plants. However, the use of anti-CRISPR proteins as tools to prevent CRISPR/Cas-mediated gene editing and gene activation in plants has not been explored yet. This study describes the characterization of two anti-CRISPR proteins, AcrIIA4 and AcrVA1, in Nicotiana benthamiana. Our results demonstrate that AcrIIA4 prevents site-directed mutagenesis in leaves when transiently co-expressed with CRISPR/Cas9. In a similar way, AcrVA1 is able to prevent CRISPR/Cas12a-mediated gene editing. Moreover, using a N. benthamiana line constitutively expressing Cas9, we show that the viral delivery of AcrIIA4 using Tobacco etch virus is able to completely abolish the high editing levels obtained when the guide RNA is delivered with a virus, in this case Potato virus X. We also show that AcrIIA4 and AcrVA1 repress CRISPR/dCas-based transcriptional activation of reporter genes. In the case of AcrIIA4, this repression occurs in a highly efficient, dose-dependent manner. Furthermore, the fusion of an auxin degron to AcrIIA4 results in auxin-regulated activation of a downstream reporter gene. The strong anti-Cas activity of AcrIIA4 and AcrVA1 reported here opens new possibilities for customized control of gene editing and gene expression in plants.
PMID: 34632687
Metab Eng , IF:9.783 , 2022 Mar , V70 : P166-180 doi: 10.1016/j.ymben.2022.01.004
A manipulation of carotenoid metabolism influence biomass partitioning and fitness in tomato.
Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.; Max Planck Institut fur Molekulare Pflanzenphysiologie, Am Muhlenberg1 D-14476, Potsdam-Golm, Germany.; Laboratory of Growth Regulators, Faculty of Science, Palacky University and Institute of Experimental Botany, The Czech Academy of Sciences, Slechtitelu 27, CZ-78371, Olomouc, Czech Republic.; Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia; Max Planck Institut fur Molekulare Pflanzenphysiologie, Am Muhlenberg1 D-14476, Potsdam-Golm, Germany.; Aix-Marseille University, CEA, CNRS UMR7265, BIAM, CEA/Cadarache, F-13108 Saint-Paul-lez-Durance, France.; Institute for Plant Molecular and Cell Biology (IBMCP) UPV-CSIC, 46022, Valencia, Spain.; Max Planck Institut fur Molekulare Pflanzenphysiologie, Am Muhlenberg1 D-14476, Potsdam-Golm, Germany; Boyce Thompson Institute, Cornell University, Ithaca, NY, United States.; Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia; Max Planck Institut fur Molekulare Pflanzenphysiologie, Am Muhlenberg1 D-14476, Potsdam-Golm, Germany. Electronic address: juancamilo.morenobeltran@KAUST.edu.sa.
Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars induced profound metabolic alterations in carotenoid, apocarotenoid and phytohormones pathways. Alterations in isoprenoid- (abscisic acid, gibberellins, cytokinins) and non-isoprenoid (auxin and jasmonic acid) derived hormones together with enhanced xanthophyll content influenced biomass partitioning and abiotic stress tolerance (high light, salt, and drought), and it caused an up to 77% fruit yield increase and enhanced fruit's provitamin A content. In addition, metabolic and hormonal changes led to accumulation of key primary metabolites (e.g. osmoprotectants and antiaging agents) contributing with enhanced abiotic stress tolerance and fruit shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.
PMID: 35031492
Crit Rev Biotechnol , IF:8.429 , 2022 Feb , V42 (1) : P106-124 doi: 10.1080/07388551.2021.1924113
Plant phospholipase D: novel structure, regulatory mechanism, and multifaceted functions with biotechnological application.
National Institute of Plant Genome Research, New Delhi, India.
Phospholipases D (PLDs) are important membrane lipid-modifying enzymes in eukaryotes. Phosphatidic acid, the product of PLD activity, is a vital signaling molecule. PLD-mediated lipid signaling has been the subject of extensive research leading to discovery of its crystal structure. PLDs are involved in the pathophysiology of several human diseases, therefore, viewed as promising targets for drug design. The availability of a eukaryotic PLD crystal structure will encourage PLD targeted drug designing. PLDs have been implicated in plants response to biotic and abiotic stresses. However, the molecular mechanism of response is not clear. Recently, several novel findings have shown that PLD mediated modulation of structural and developmental processes, such as: stomata movement, root growth and microtubule organization are crucial for plants adaptation to environmental stresses. Involvement of PLDs in regulating membrane remodeling, auxin mediated alteration of root system architecture and nutrient uptake to combat nitrogen and phosphorus deficiencies and magnesium toxicity is established. PLDs via vesicle trafficking modulate cytoskeleton and exocytosis to regulate self-incompatibility (SI) signaling in flowering plants, thereby contributes to plants hybrid vigor and diversity. In addition, the important role of PLDs has been recognized in biotechnologically important functions, including oil/TAG synthesis and maintenance of seed quality. In this review, we describe the crystal structure of a plant PLD and discuss the molecular mechanism of catalysis and activity regulation. Further, the role of PLDs in regulating plant development under biotic and abiotic stresses, nitrogen and phosphorus deficiency, magnesium ion toxicity, SI signaling and pollen tube growth and in important biotechnological applications has been discussed.
PMID: 34167393
Plant Physiol , IF:8.34 , 2022 Mar doi: 10.1093/plphys/kiac138
MicroRNA858a, its encoded peptide, and phytosulfokine regulate Arabidopsis growth and development.
CSIR-National Botanical Research Institute, Council of Scientific and Industrial Research (CSIR-NBRI), Rana Pratap Marg, Lucknow-226001, India.; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad- 201002, India.; Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP), Lucknow, India.
Small molecules, such as peptides and miRNAs, are crucial regulators of plant growth. Here, we show the importance of cross-talk between miPEP858a (microRNA858a-encoded peptide)/miR858a and phytosulfokine (PSK4) in regulating plant growth and development in Arabidopsis (Arabidopsis thaliana). Genome-wide expression analysis suggested modulated expression of PSK4 in miR858a mutants and miR858a-overexpressing (miR858aOX) plants. The silencing of PSK4 in miR858aOX plants compromised growth, whereas overexpression of PSK4 in the miR858a mutant rescued the developmental defects. The exogenous application of synthetic PSK4 further complemented the plant development in mutant plants. Exogenous treatment of synthetic miPEP858a in the PSK4 mutant led to clathrin-mediated internalization of the peptide; however, it did not enhance growth as is the case in wild-type plants. We also demonstrated that MYB3 is an important molecular component participating in the miPEP858a/miR858a-PSK4 module. Finally, our work highlights the signaling between miR858a/miPEP858a-MYB3-PSK4 in modulating the expression of key elements involved in auxin responses, leading to the regulation of growth.
PMID: 35325214
Plant Physiol , IF:8.34 , 2022 Mar doi: 10.1093/plphys/kiac133
Pivotal roles of ELONGATED HYPOCOTYL5 in regulation of plant development and fruit metabolism in tomato.
Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.; Key Laboratory of Urban Agriculture Ministry of Agriculture, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240.; Joint Center for Single Cell Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240, China.; Instrumental Analysis Center of Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
The transcription factor ELONGATED HYPOCOTYL5 (HY5) plays critical roles in plant photomorphogenesis. Previous studies on HY5 have mainly focused on the seedling stage in Arabidopsis (Arabidopsis thaliana), and its functions in other plant species have not been well characterized, particularly at adult stages of development. In this report, we investigated the functions of tomato (Solanum lycopersicum) HY5 (SlHY5) from seedlings to adult plants with a focus on fruits. Genome-edited slhy5 mutants exhibited typical compromised photomorphogenesis in response to various light conditions. The slhy5 mutants showed reduced primary root length and secondary root number, which is associated with altered auxin signaling. SlHY5 promoted chlorophyII biosynthesis from seedling to adult stages. Notably, the promotive role of SlHY5 on chlorophyII accumulation was more pronounced on the illuminated side of green fruits than on their shaded side. Consistent with this light-dependent effect, we determined that SlHY5 protein is stabilized by light. Transcriptome and metabolome analyses in fruits revealed that SlHY5 has major functions in the regulation of metabolism, including the biosynthesis of phenylpropanoids and steroidal glycoalkaloids. These data demonstrate that SlHY5 performs both shared and distinct functions in relation to its Arabidopsis counterpart. The manipulation of SlHY5 represents a powerful tool to influence the two vital agricultural traits of seedling fitness and fruit quality in tomato.
PMID: 35312008
Plant Physiol , IF:8.34 , 2022 Mar doi: 10.1093/plphys/kiac099
Maize miR167-ARF3/30-polyamine oxidase 1 module-regulated H2O2 production confers resistance to maize chlorotic mottle virus.
State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing 100193, China.; International Maize and Wheat Improvement Center (CIMMYT), ICRAF Campus, UN Avenue, Gigiri, Nairobi, Kenya.; College of Agronomy, China Agricultural University, Beijing 100193, China.; Department of Plant Pathology, College of Plant Protection, Shandong Agricultural University, Taian 271018, China.; College of Agronomy, Yunnan Agricultural University, Kunming 650201, China.
Maize chlorotic mottle virus (MCMV) is the key pathogen causing maize lethal necrosis (MLN). Due to the sharply increased incidence of MLN in many countries, there is an urgent need to identify resistant lines and uncover the underlying resistance mechanism. Here, we showed that the abundance of maize (Zea mays) microR167 (Zma-miR167) positively modulates the degree of resistance to MCMV. Zma-miR167 directly targets Auxin Response Factor3 (ZmARF3) and ZmARF30, both of which negatively regulate resistance to MCMV. RNA-sequencing coupled with gene expression assays revealed that both ZmARF3 and ZmARF30 directly bind the promoter of Polyamine Oxidase 1 (ZmPAO1) and activate its expression. Knockdown or inhibition of enzymatic activity of ZmPAO1 suppressed MCMV infection. Nevertheless, MCMV-encoded p31 protein directly targets ZmPAO1 and enhances the enzyme activity to counteract Zma-miR167-mediated defense to some degree. We uncovered a role of the Zma-miR167-ZmARF3/30 module for restricting MCMV infection by regulating ZmPAO1 expression, while MCMV employs p31 to counteract this defense.
PMID: 35298645
Plant Physiol , IF:8.34 , 2022 Mar doi: 10.1093/plphys/kiac115
Pleiotropic and Non-redundant Effects of an Auxin Importer in Setaria and Maize.
Donald Danforth Plant Science Center, 975 North Warson Rd, Saint Louis, MO, 63132, USA.; Department of Plant Biology, Ecology, and Evolution, Oklahoma State University, Stillwater, OK 74078, USA.; Division of Biological Sciences, Interdisciplinary Plant Group, and Missouri Maize Center, University of Missouri, 301 Christopher Bond Life Sciences Center, Columbia, MO 65211, USA.
Directional transport of auxin is critical for inflorescence and floral development in flowering plants, but the role of auxin influx carriers (AUX1 proteins) has been largely overlooked. Taking advantage of available AUX1 mutants in green millet (Setaria viridis) and maize (Zea mays), we uncover previously unreported aspects of plant development that are affected by auxin influx, including higher order branches in the inflorescence, stigma branch number, glume (floral bract) development, and plant fertility. However, disruption of auxin flux does not affect all parts of the plant, with little obvious effect on inflorescence meristem size, time to flowering, and anther morphology. In double mutant studies in maize, disruptions of ZmAUX1 also affect vegetative development. A GFP-tagged construct of the Setaria AUX1 protein Sparse Panicle1 (SPP1) under its native promoter showed that SPP1 localizes to the plasma membrane of outer tissue layers in both roots and inflorescences, and accumulates specifically in inflorescence branch meristems, consistent with the mutant phenotype and expected auxin maxima. RNA-seq analysis indicated that most gene expression modules are conserved between mutant and wild-type plants, with only a few hundred genes differentially expressed in spp1 inflorescences. Using CRISPR-Cas9 technology, we disrupted SPP1 and the other four AUX1 homologs in S. viridis. SPP1 has a larger effect on inflorescence development than the others, although all contribute to plant height, tiller formation, and lea, and root development. The AUX1 importers are thus not fully redundant in S. viridis. Our detailed phenotypic characterization plus a stable GFP-tagged line offer tools for future dissection of the function of auxin influx proteins.
PMID: 35285930
Plant Physiol , IF:8.34 , 2022 Feb doi: 10.1093/plphys/kiac084
The BTB-TAZ protein MdBT2 recruits auxin signaling components to regulate adventitious root formation in apple.
State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, Tai-An, 271018, Shandong, China.; Institute of Grape Science and Engineering,College of Horticulture, Qingdao Agricultural University, Qingdao, 266109, China.
Ubiquitination is an important post-translational protein modification. Although BTB and TAZ domain protein 2 (BT2) is involved in many biological processes, its role in apple (Malus domestic) root formation remains unclear. Here, we revealed that MdBT2 inhibits adventitious root (AR) formation through interacting with AUXIN RESPONSE FACTOR8 (MdARF8) and INDOLE-3-ACETIC ACID INDUCIBLE3 (MdIAA3). MdBT2 facilitated MdARF8 ubiquitination and degradation through the 26S proteasome pathway and negatively regulated GRETCHEN HAGEN 3.1 (MdGH3.1) and MdGH3.6 expression. MdARF8 regulates AR formation through inducing transcription of MdGH3s (MdGH3.1, MdGH3.2, MdGH3.5, and MdGH3.6). In addition, MdBT2 facilitated MdIAA3 stability and slightly promoted its interaction with MdARF8. MdIAA3 inhibited AR formation by forming heterodimers with MdARF8 as well as other MdARFs (MdARF5, MdARF6, MdARF7, and MdARF19). Our findings reveal that MdBT2 acts as a negative regulator of AR formation in apple.
PMID: 35218363
Plant Physiol , IF:8.34 , 2022 Feb doi: 10.1093/plphys/kiac046
The CCCH Zinc Finger Protein C3H15 Negatively Regulates Cell Elongation by Inhibiting Brassinosteroid Signaling.
College of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, China.; Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.; Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying 257000, China.; State Key Laboratory of Wheat and Maize Crop Science and College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.; College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China.; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.; Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan 250100, China.; College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China.
Plant CCCH proteins participate in the control of multiple developmental and adaptive processes, but the regulatory mechanisms underlying these processes are not well known. In this study, we showed that the Arabidopsis (Arabidopsis thaliana) CCCH protein C3H15 negatively regulates cell elongation by inhibiting brassinosteroid (BR) signaling. Genetic and biochemical evidence showed that C3H15 functions downstream of the receptor BR INSENSITIVE 1 (BRI1) as a negative regulator in the BR pathway. C3H15 is phosphorylated by the GLYCOGEN SYNTHASE KINASE 3 (GSK3)-like kinase BR-INSENSITIVE 2 (BIN2) at Ser111 in the cytoplasm in the absence of BRs. Upon BR perception, C3H15 transcription is enhanced, and the phosphorylation of C3H15 by BIN2 is reduced. The dephosphorylated C3H15 protein accumulates in the nucleus, where C3H15 regulates transcription via G-rich elements (typically GGGAGA). C3H15 and BRASSINAZOLE RESISTANT 1 (BZR1)/BRI1-EMS-SUPPRESSOR 1 (BES1), two central transcriptional regulators of BR signaling, directly suppress each other and share a number of BR-responsive target genes. Moreover, C3H15 antagonizes BZR1 and BES1 to regulate the expression of their shared cell elongation-associated target gene, SMALL AUXIN-UP RNA 15 (SAUR15). This study demonstrates that C3H15-mediated BR signaling may be parallel to, or even attenuate, the dominant BZR1 and BES1 signaling pathways to control cell elongation. This finding expands our understanding of the regulatory mechanisms underlying BR-induced cell elongation in plants.
PMID: 35139225
Plant Physiol , IF:8.34 , 2022 Feb doi: 10.1093/plphys/kiac041
Cotton long non-coding RNAs regulate cell wall defense genes and strengthen resistance to Verticillium wilt.
State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Sciences, School of Computer and Information Engineering, Henan University, Kaifeng, 475001, Henan, China.; Department of Life Science and Biotechnology, Nanyang Normal University, Nanyang 473000, Henan, China.; Chongqing University of Posts and Telecommunications, College of Bioinformation, Chongqing Key Laboratory of Big Data for Bio Intelligence, Chongqing, China.; Southern Plains Agricultural Research Center, Agricultural Research Service, USDA, College Station, TX 77845, USA.; Kaifeng Academy of Agriculture and Forestry, Kaifeng, China, 475000.; State Key Laboratory of Cotton Biology, Cotton Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Cotton Genetic Improvement, Ministry of Agriculture, Anyang, 455000, Henan, China.
In plants, long non-coding RNAs regulate disease resistance against fungi and other pathogens. However, the specific mechanism behind this regulation remains unclear. In this study, we identified disease resistance-related lncRNAs as well as their regulating genes and assessed their functions by infection of cotton (Gossypium) chromosome segment substitution lines with Verticillium dahliae. Our results demonstrated that lncRNA7 and its regulating gene Pectin methylesterase inhibitor 13 (GbPMEI13) positively regulated disease resistance via the silencing approach, while ectopic overexpression of GbPMEI13 in Arabidopsis (Arabidopsis thaliana) promoted growth and enhanced resistance to V. dahliae. In contrast, lncRNA2 and its regulating gene Polygalacturonase 12 (GbPG12) negatively regulated resistance to V. dahliae. We further found that fungal disease-related agents, including the pectin-derived oligogalacturonide (OG), could down-regulate the expression of lncRNA2 and GbPG12, leading to pectin accumulation. Conversely, OG up-regulated the expression of lncRNA7, which encodes a plant peptide phytosulfokine (PSK-alpha), which was confirmed by lncRNA7 overexpression and UPLC-MS experiments. We showed that PSK-alpha promoted IAA accumulation and activated GbPMEI13 expression through Auxin Response Factor 5 (ARF5). Since it is an inhibitor of pectin methylesterase (PME), GbPMEI13 promotes pectin methylation and therefore increases the resistance to V. dahliae. Consistently, we also demonstrated that GbPMEI13 inhibits the mycelial growth and spore germination of V. dahliae in vitro. In this study, we demonstrated that lncRNA7, lncRNA2, and their regulating genes modulate cell wall defense against V. dahliae via auxin-mediated signaling, providing a strategy for cotton breeding.
PMID: 35134243
Plant Physiol , IF:8.34 , 2022 Feb , V188 (2) : P738-748 doi: 10.1093/plphys/kiab568
Toward synthetic plant development.
Department of Bioengineering, Stanford University, Stanford, California 94305, USA.
The ability to engineer plant form will enable the production of novel agricultural products designed to tolerate extreme stresses, boost yield, reduce waste, and improve manufacturing practices. While historically, plants were altered through breeding to change their size or shape, advances in our understanding of plant development and our ability to genetically engineer complex eukaryotes are leading to the direct engineering of plant structure. In this review, I highlight the central role of auxin in plant development and the synthetic biology approaches that could be used to turn auxin-response regulators into powerful tools for modifying plant form. I hypothesize that recoded, gain-of-function auxin response proteins combined with synthetic regulation could be used to override endogenous auxin signaling and control plant structure. I also argue that auxin-response regulators are key to engineering development in nonmodel plants and that single-cell -omics techniques will be essential for characterizing and modifying auxin response in these plants. Collectively, advances in synthetic biology, single-cell -omics, and our understanding of the molecular mechanisms underpinning development have set the stage for a new era in the engineering of plant structure.
PMID: 34904660
Plant Physiol , IF:8.34 , 2022 Mar , V188 (3) : P1604-1616 doi: 10.1093/plphys/kiab587
Root electrotropism in Arabidopsis does not depend on auxin distribution but requires cytokinin biosynthesis.
Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
Efficient foraging by plant roots relies on the ability to sense multiple physical and chemical cues in soil and to reorient growth accordingly (tropism). Root tropisms range from sensing gravity (gravitropism), light (phototropism), water (hydrotropism), touch (thigmotropism), and more. Electrotropism, also known as galvanotropism, is the phenomenon of aligning growth with external electric fields and currents. Although root electrotropism has been observed in a few species since the end of the 19th century, its molecular and physical mechanisms remain elusive, limiting its comparison with the more well-defined sensing pathways in plants. Here, we provide a quantitative and molecular characterization of root electrotropism in the model system Arabidopsis (Arabidopsis thaliana), showing that it does not depend on an asymmetric distribution of the plant hormone auxin, but instead requires the biosynthesis of a second hormone, cytokinin. We also show that the dose-response kinetics of the early steps of root electrotropism follows a power law analogous to the one observed in some physiological reactions in animals. Future studies involving more extensive molecular and quantitative characterization of root electrotropism would represent a step toward a better understanding of signal integration in plants and would also serve as an independent outgroup for comparative analysis of electroreception in animals and fungi.
PMID: 34893912
Plant Physiol , IF:8.34 , 2022 Mar , V188 (3) : P1686-1708 doi: 10.1093/plphys/kiab565
The positive feedback regulatory loop of miR160-Auxin Response Factor 17-HYPONASTIC LEAVES 1 mediates drought tolerance in apple trees.
State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China.; State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Life Science, Northwest A&F University, Yangling, Shaanxi 712100, China.
Drought stress tolerance is a complex trait regulated by multiple factors. Here, we demonstrate that the miRNA160-Auxin Response Factor 17 (ARF17)-HYPONASTIC LEAVES 1 module is crucial for apple (Malus domestica) drought tolerance. Using stable transgenic plants, we found that drought tolerance was improved by higher levels of Mdm-miR160 or MdHYL1 and by decreased levels of MdARF17, whereas reductions in MdHYL1 or increases in MdARF17 led to greater drought sensitivity. Further study revealed that modulation of drought tolerance was achieved through regulation of drought-responsive miRNA levels by MdARF17 and MdHYL1; MdARF17 interacted with MdHYL1 and bound to the promoter of MdHYL1. Genetic analysis further suggested that MdHYL1 is a direct downstream target of MdARF17. Importantly, MdARF17 and MdHYL1 regulated the abundance of Mdm-miR160. In addition, the Mdm-miR160-MdARF17-MdHYL1 module regulated adventitious root development. We also found that Mdm-miR160 can move from the scion to the rootstock in apple and tomato (Solanum lycopersicum), thereby improving root development and drought tolerance of the rootstock. Our study revealed the mechanisms by which the positive feedback loop of Mdm-miR160-MdARF17-MdHYL1 influences apple drought tolerance.
PMID: 34893896
Plant Physiol , IF:8.34 , 2022 Feb , V188 (2) : P1095-1110 doi: 10.1093/plphys/kiab558
Auxin biosynthesis maintains embryo identity and growth during BABY BOOM-induced somatic embryogenesis.
Bioscience, Wageningen University and Research, Wageningen, 6700 AA, Netherlands.; Laboratory of Molecular Biology, Wageningen University and Research, Wageningen, 6700 AP, Netherlands.; Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, 40-032, Poland.; Enza Zaden Research and Development B.V, Enkhuizen, 1602 DB, The Netherlands.
Somatic embryogenesis is a type of plant cell totipotency where embryos develop from nonreproductive (vegetative) cells without fertilization. Somatic embryogenesis can be induced in vitro by auxins, and by ectopic expression of embryo-expressed transcription factors like the BABY BOOM (BBM) AINTEGUMENTA-LIKE APETALA2/ETHYLENE RESPONSE FACTOR domain protein. These different pathways are thought to converge to promote auxin response and biosynthesis, but the specific roles of the endogenous auxin pathway in somatic embryogenesis induction have not been well-characterized. Here we show that BBM transcriptionally regulates the YUCCA3 (YUC3) and YUC8 auxin biosynthesis genes during BBM-mediated somatic embryogenesis in Arabidopsis (Arabidopsis thaliana) seedlings. BBM induced local and ectopic YUC3 and YUC8 expression in seedlings, which coincided with increased DR5 auxin response and indole-3-acetic acid (IAA) biosynthesis and with ectopic expression of the WOX2 embryo reporter. YUC-driven auxin biosynthesis was required for BBM-mediated somatic embryogenesis, as the number of embryogenic explants was reduced by ca. 50% in yuc3 yuc8 mutants and abolished after chemical inhibition of YUC enzyme activity. However, a detailed YUC inhibitor time-course study revealed that YUC-dependent IAA biosynthesis is not required for the re-initiation of totipotent cell identity in seedlings. Rather, YUC enzymes are required later in somatic embryo development for the maintenance of embryo identity and growth. This study resolves a long-standing question about the role of endogenous auxin biosynthesis in transcription factor-mediated somatic embryogenesis and also provides an experimental framework for understanding the role of endogenous auxin biosynthesis in other in planta and in vitro embryogenesis systems.
PMID: 34865162
Plant Physiol , IF:8.34 , 2022 Feb , V188 (2) : P931-933 doi: 10.1093/plphys/kiab520
TINY ROOT HAIR 1: uncoupling transporter function in auxin-mediated gravitropism and root hair growth.
University of Melbourne, School of BioSciences, Parkville 3010, Australia.
PMID: 34747493
Plant Physiol , IF:8.34 , 2022 Feb , V188 (2) : P1043-1060 doi: 10.1093/plphys/kiab472
Potassium transporter TRH1/KUP4 contributes to distinct auxin-mediated root system architecture responses.
Department of Biotechnology, Agricultural University of Athens, Athens 118 55, Greece.; Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala SE-756 61, Sweden.; Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, Umea SE-901 83, Sweden.; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion GR 70 013, Greece.; Department of Biology, University of Crete, Heraklion GR 71 500, Greece.
In plants, auxin transport and development are tightly coupled, just as hormone and growth responses are intimately linked in multicellular systems. Here we provide insights into uncoupling this tight control by specifically targeting the expression of TINY ROOT HAIR 1 (TRH1), a member of plant high-affinity potassium (K+)/K+ uptake/K+ transporter (HAK/KUP/KT) transporters that facilitate K+ uptake by co-transporting protons, in Arabidopsis root cell files. Use of this system pinpointed specific root developmental responses to acropetal versus basipetal auxin transport. Loss of TRH1 function shows TRHs and defective root gravitropism, associated with auxin imbalance in the root apex. Cell file-specific expression of TRH1 in the central cylinder rescued trh1 root agravitropism, whereas positional TRH1 expression in peripheral cell layers, including epidermis and cortex, restored trh1 defects. Applying a system-level approach, the role of RAP2.11 and ROOT HAIR DEFECTIVE-LIKE 5 transcription factors (TFs) in root hair development was verified. Furthermore, ERF53 and WRKY51 TFs were overrepresented upon restoration of root gravitropism supporting involvement in gravitropic control. Auxin has a central role in shaping root system architecture by regulating multiple developmental processes. We reveal that TRH1 jointly modulates intracellular ionic gradients and cell-to-cell polar auxin transport to drive root epidermal cell differentiation and gravitropic response. Our results indicate the developmental importance of HAK/KUP/KT proton-coupled K+ transporters.
PMID: 34633458
Sci Total Environ , IF:7.963 , 2022 Mar , V810 : P152260 doi: 10.1016/j.scitotenv.2021.152260
Copper oxide (CuO) nanoparticles affect yield, nutritional quality, and auxin associated gene expression in weedy and cultivated rice (Oryza sativa L.) grains.
Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.; The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504, USA; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.; Department of Physics, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.; Department of Plants, Soil, and Climate, Utah State University, 4820 Old Main Hill, Logan, UT 84322, USA.; MSU-DOE - Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA.; Texas A&M Agrilife Research and Extension Centre at Dallas, 17360 Coit Road, TX 75252, USA.; The Connecticut Agricultural Experiment Station, 123 Huntington St., New Haven, CT 06504, USA.; Environmental Science and Engineering Ph.D. Program, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; University of California Center for Environmental Implications of Nanotechnology (UC CEIN), The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, USA. Electronic address: jgardea@utep.edu.
Weedy rice grows competitively with cultivated rice and significantly diminishes rice grain production worldwide. The different effects of Cu-based nanomaterials on the production of weedy and cultivated rice, especially the grain qualities are not known. Grains were collected from weedy and cultivated rice grown for four months in field soil amended with nanoscale CuO (nCuO), bulk CuO (bCuO), and copper sulfate (CuSO4) at 0, 75, 150, 300, and 600 mg Cu/kg soil. Cu translocation, essential element accumulation, yield, sugar, starch, protein content, and the expression of auxin associated genes in grains were determined. The grains of weedy and cultivated rice were differentially impacted by CuO-based compounds. At >/=300 mg/kg, nCuO and bCuO treated rice had no grain production. Treatment at 75 mg/kg significantly decreased grain yield as compared to control with the order: bCuO (by 88.7%) > CuSO4 (by 47.2%) ~ nCuO (by 38.3% only in cultivated rice); at the same dose, the Cu grain content was: nCuO ~ CuSO4 > bCuO > control. In weedy grains, K, Mg, Zn, and Ca contents were decreased by 75 and 150 mg/kg nCuO by up to 47.4%, 34.3%, 37.6%, and 60.0%, but no such decreases were noted in cultivated rice, and Fe content was increased by up to 88.6%, and 53.2%. In rice spikes, nCuO increased Mg, Ca, Fe, and Zn levels by up to 118.1%, 202.6%, 133.8%, and 103.9%, respectively. Nanoscale CuO at 75 and 150 mg/kg upregulated the transcription of an auxin associated gene by 5.22- and 1.38-fold, respectively, in grains of weedy and cultivated rice. The biodistribution of Cu-based compounds in harvested grain was determined by two-photon microscopy. These findings demonstrate a cultivar-specific and concentration-dependent response of rice to nCuO. A potential use of nCuO at 75 and 150 mg/kg in cultivar-dependent delivery system was suggested based on enhanced grain nutritional quality, although the yield was compromised. This knowledge, at the physiological and molecular level, provides valuable information for the future use of Cu-based nanomaterials in sustainable agriculture.
PMID: 34896498
Sci Total Environ , IF:7.963 , 2022 Feb , V806 (Pt 2) : P150592 doi: 10.1016/j.scitotenv.2021.150592
Characterization of bacterial communities isolated from municipal waste compost and screening of their plant-interactive phenotypes.
Department of Biology, UniPD, Padova, Italy; Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE), UniPD, Legnaro, PD, Italy.; Department of Biology, UniPD, Padova, Italy.; Societa Estense Servizi Ambientali S.E.S.A., Este, PD, Italy.; Department of Agronomy Food Natural Resources Animals and Environment (DAFNAE), UniPD, Legnaro, PD, Italy.; Department of Biology, UniPD, Padova, Italy; Botanical Garden, UniPD, Padova, Italy. Electronic address: barbara.baldan@unipd.it.
Four batches of commercial compost obtained from the organic fraction of municipal solid waste were analyzed from chemical and microbiological standpoints. The working hypothesis was that, being this type of compost derived partly from plant waste, it could contain plant-growth promoting bacterial endophytes, prone to be active again upon its usual delivery as fertilizer. Culturable bacteria were isolated at different temperatures, quantified by colony morphology, identified taxonomically by 16S sequencing and screened for plant-growth promoting phenotypes including auxin and siderophore production, phosphate solubilization and peptide mineralization to ammonia. In parallel, the total community was assessed by culture independent DNA metabarcoding. The capability of plants to select, uptake and internally multiply bacteria from these compost samples was analyzed using grapevine in-vitro rooting cuttings from which acquired bacteria were reisolated, quantified and their identities determined as above. Major differences in compost bacterial composition were observed as function of the season, with the winter sample being rather distinct from the summer ones. Bacillales and Actinomycetales dominated the culturable communities while Alteromonadales, Oceanospirillales and Flavobacteriales prevailed in the total community. In spite of the challenging composting cycle conditions, the plant nature of the main input substrates appeared determinant in guaranteeing that 82% of the culturable bacteria were found endowed with one or more of the plant growth-promoting phenotypes tested. Beside its fertilization role, compost proved to be also a potential inoculant carrier for the in-soil delivery of plant beneficial microorganisms. Furthermore, upon an in vitro passage through grapevine plants under axenic conditions, the subsequently recoverable endophyte community yielded also members of the Rhizobiales order which had not been detectable when culturing directly from compost. This observation further suggests that compost-borne plant-interacting taxa could be also rescued from non-culturable states and/or enriched above detectability levels by a contact with their potential host plants.
PMID: 34592304
Curr Opin Plant Biol , IF:7.834 , 2022 Apr , V66 : P102194 doi: 10.1016/j.pbi.2022.102194
Connecting primary and specialized metabolism: Amino acid conjugation of phytohormones by GRETCHEN HAGEN 3 (GH3) acyl acid amido synthetases.
Department of Biology, Washington University in St. Louis, St. Louis, MO 63130 USA. Electronic address: jjez@wustl.edu.
GRETCHEN HAGEN 3 (GH3) acyl acid amido synthetases catalyze the ATP-dependent conjugation of phytohormones with amino acids. Traditionally, GH3 proteins are associated with synthesis of the bioactive jasmonate hormone (+)-7- iso -jasmonoyl-l-isoleucine (JA-Ile) and conjugation of indole-3-acetic acid (IAA) with amino acids that tag the hormone for degradation and/or storage. Modifications of JA and IAA by GH3 acyl acid amido synthetases help maintain phytohormones homeostasis. Recent studies broaden the roles of GH3 proteins to include the regulation of JA biosynthesis; the modification of other auxins (i.e., phenylacetic acid and indole-3-butyric acid); the conjugation of auxinic herbicides, such as 4-dichlorophenoxyacetic acid, 4-(2,4-dichlorophenoxy)butyric acid, and dicamba; and the missing step in the isochorismate pathway for the biosynthesis of salicylic acid. The GH3 protein family joins the growing number of versatile enzyme families that blur the line between primary and specialized metabolism for an increasing range of biology functions.
PMID: 35219141
Curr Opin Plant Biol , IF:7.834 , 2022 Feb , V65 : P102174 doi: 10.1016/j.pbi.2022.102174
Auxin canalization: From speculative models toward molecular players.
Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria; Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences and Faculty of Science of Palacky University, Olomouc, Czech Republic.; Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria.; Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria. Electronic address: jiri.friml@ist.ac.at.
Among the most fascinated properties of the plant hormone auxin is its ability to promote formation of its own directional transport routes. These gradually narrowing auxin channels form from the auxin source toward the sink and involve coordinated, collective polarization of individual cells. Once established, the channels provide positional information, along which new vascular strands form, for example, during organogenesis, regeneration, or leave venation. The main prerequisite of this still mysterious auxin canalization mechanism is a feedback between auxin signaling and its directional transport. This is manifested by auxin-induced re-arrangements of polar, subcellular localization of PIN-FORMED (PIN) auxin exporters. Immanent open questions relate to how position of auxin source and sink as well as tissue context are sensed and translated into tissue polarization and how cells communicate to polarize coordinately. Recently, identification of the first molecular players opens new avenues into molecular studies of this intriguing example of self-organizing plant development.
PMID: 35123880
Curr Opin Plant Biol , IF:7.834 , 2022 Feb , V65 : P102146 doi: 10.1016/j.pbi.2021.102146
Phosphorylation control of PIN auxin transporters.
Plant Systems Biology, School of Life Sciences, Technical University of Munich, Emil-Ramann-Strasse 8, 85354, Freising, Germany.; Plant Systems Biology, School of Life Sciences, Technical University of Munich, Emil-Ramann-Strasse 8, 85354, Freising, Germany. Electronic address: claus.schwechheimer@wzw.tum.de.
The directional transport of the phytohormone auxin is required for proper plant development and tropic growth. Auxin cell-to-cell transport gains directionality through the polar distribution of 'canonical' long PIN-FORMED (PIN) auxin efflux carriers. In recent years, AGC kinases, MAP kinases, Ca(2+)/CALMODULIN-DEPENDENT PROTEIN KINASE-RELATED KINASEs and receptor kinases have been implicated in the control of PIN activity, polarity and trafficking. In this review, we summarize the current knowledge in understanding the posttranslational regulation of PINs by these different protein kinase families. The proposed regulation of PINs by AGC kinases after salt stress and by the stress-activated MAP kinases suggest that abiotic and biotic stress factors may modulate auxin transport and thereby plant growth.
PMID: 34974229
Curr Opin Plant Biol , IF:7.834 , 2022 Feb , V65 : P102115 doi: 10.1016/j.pbi.2021.102115
Cellular and molecular bases of lateral root initiation and morphogenesis.
Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca, 62210, Morelos, Mexico.; Departamento de Biologia Molecular de Plantas, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico (UNAM), Cuernavaca, 62210, Morelos, Mexico. Electronic address: joseph.dubrovsky@ibt.unam.mx.
Lateral root development is essential for the establishment of the plant root system. Lateral root initiation is a multistep process that impacts early primordium morphogenesis and is linked to the formation of a morphogenetic field of pericycle founder cells. Gradual recruitment of founder cells builds this morphogenetic field in an auxin-dependent manner. The complex process of lateral root primordium morphogenesis includes several subprocesses, which are presented in this review. The underlying cellular and molecular mechanisms of these subprocesses are examined.
PMID: 34742019
Curr Opin Plant Biol , IF:7.834 , 2022 Feb , V65 : P102117 doi: 10.1016/j.pbi.2021.102117
Integration of nutrient and water availabilities via auxin into the root developmental program.
Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany.; Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany. Electronic address: vonwiren@ipk-gatersleben.de.
In most soils, the spatial distribution of nutrients and water in the rooting zone of plants is heterogeneous and changes over time. To access localized resources more efficiently, plants induce foraging responses by modulating individual morphological root traits, such as the length of the primary root or the number and length of lateral roots. These adaptive responses require the integration of exogenous and endogenous nutrient- or water-related signals into the root developmental program. Recent studies corroborated a central role of auxin in shaping root architectural traits in response to fluctuating nutrient and water availabilities. In this review, we highlight current knowledge on nutrient- and water-related developmental processes that impact root foraging and involve auxin as a central player. A deeper understanding and exploitation of these auxin-related processes and mechanisms promises advances in crop breeding for higher resource efficiency.
PMID: 34624806
Curr Opin Plant Biol , IF:7.834 , 2022 Feb , V65 : P102111 doi: 10.1016/j.pbi.2021.102111
Hormonal control of cell identity and growth in the shoot apical meristem.
College of Agriculture, South China Agricultural University, 510642, Guangzhou, China; Guangdong Laboratory for Lingnan Modern Agriculture, 510642, Guangzhou, China; Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, CNRS, INRAE, F-69342, Lyon, France.; Laboratoire Reproduction et Developpement des Plantes, Univ Lyon, ENS de Lyon, CNRS, INRAE, F-69342, Lyon, France. Electronic address: teva.vernoux@ens-lyon.fr.
How cells acquire their identities and grow coordinately within a tissue is a fundamental question to understand plant development. In angiosperms, the shoot apical meristem (SAM) is a multicellular tissue containing a stem cell niche, which activity allows for a dynamic equilibrium between maintenance of stem cells and production of differentiated cells that are incorporated in new aerial tissues and lateral organs produced in the SAM. Plant hormones are small-molecule signals controlling many aspects of plant development and physiology. Several hormones are essential regulators of SAM activities. This review highlights current advances that are starting to decipher the complex mechanisms underlying the hormonal control of cell identity and growth in the SAM.
PMID: 34543915
Free Radic Biol Med , IF:7.376 , 2022 Mar , V182 : P192-205 doi: 10.1016/j.freeradbiomed.2022.02.034
Heme oxygenase-nitric oxide crosstalk-mediated iron homeostasis in plants under oxidative stress.
Department of Botany, Gargi College, University of Delhi, India. Electronic address: singh.neha.du@gmail.com.; Laboratory of Plant Physiology and Biochemistry, Department of Botany, University of Delhi, Delhi, 110007, India. Electronic address: bhatlasc@gmail.com.
Plant growth under abiotic stress conditions significantly enhances intracellular generation of reactive oxygen species (ROS). Oxidative status of plant cells is directly affected by the modulation of iron homeostasis. Among mammals and plants, heme oxygenase-1 (HO-1) is a well-known antioxidant enzyme. It catalyzes oxygenation of heme, thereby producing Fe(2+), CO and biliverdin as byproducts. The antioxidant potential of HO-1 is primarily due to its catalytic reaction byproducts. Biliverdin and bilirubin possess conjugated pi-electrons which escalate the ability of these biomolecules to scavenge free radicals. CO also enhances the ROS scavenging ability of plants cells by upregulating catalase and peroxidase activity. Enhanced expression of HO-1 in plants under oxidative stress accompanies sequestration of iron in specialized iron storage proteins localized in plastids and mitochondria, namely ferritin for Fe(3+) storage and frataxin for storage of Fe-S clusters, respectively. Nitric oxide (NO) crosstalks with HO-1 at multiple levels, more so in plants under oxidative stress, in order to maintain intracellular iron status. Formation of dinitrosyl-iron complexes (DNICs) significantly prevents Fenton reaction during oxidative stress. DNICs also release NO upon dissociation in target cells over long distance in plants. They also function as antioxidants against superoxide anions and lipidic free radicals. A number of NO-modulated transcription factors also facilitate iron homeostasis in plant cells. Plants facing oxidative stress exhibit modulation of lateral root formation by HO-1 through NO and auxin-dependent pathways. The present review provides an in-depth analysis of the structure-function relationship of HO-1 in plants and mammals, correlating them with their adaptive mechanisms of survival under stress.
PMID: 35247570
Plant Cell Environ , IF:7.228 , 2022 Mar doi: 10.1111/pce.14316
A novel calmodulin-interacting Domain of Unknown Function 506 protein represses root hair elongation in Arabidopsis.
Noble Research Institute LLC, Ardmore, Oklahoma, USA.
Domain of Unknown Function 506 proteins are ubiquitous in plants. The phosphorus (P) stress-inducible REPRESSOR OF EXCESSIVE ROOT HAIR GROWTH1 (AtRXR1) gene encodes the first characterized DUF506. AtRXR1 inhibits root hair elongation by interacting with RabD2c GTPase. However, functions of other P-responsive DUF506 genes are still missing. Here, we selected two additional P-inducible DUF506 genes for further investigation. The expression of both genes was induced by auxin. Under P-stress, At3g07350 gene expressed ubiquitously in seedlings, whereas At1g62420 (AtRXR3) expression was strongest in roots. AtRXR3 overexpressors and knockouts had shorter and longer root hairs, respectively. A functional AtRXR3-green fluorescent protein fusion localized to root epidermal cells. Chromatin immunoprecipitation and quantitative reverse-transcriptase-polymerase chain reaction revealed that AtRXR3 was transcriptionally activated by RSL4. Bimolecular fluorescence complementation and calmodulin (CaM)-binding assays showed that AtRXR3 interacted with CaM in the presence of Ca(2+) . Moreover, cytosolic Ca(2+) ([Ca(2+) ]cyt ) oscillations in root hairs of rxr3 mutants exhibited elevated frequencies and dampened amplitudes compared to those of wild type. Thus, AtRXR3 is another DUF506 protein that attenuates P-limitation-induced root hair growth through mechanisms that involve RSL4 and interaction with CaM to modulate tip-focused [Ca(2+) ]cyt oscillations.
PMID: 35312071
Plant Cell Environ , IF:7.228 , 2022 Feb doi: 10.1111/pce.14290
Jasmonic acid coordinates with light, glucose and auxin signalling in regulating branching angle of Arabidopsis lateral roots.
National Institute of Plant Genome Research, New Delhi, India.
The role of jasmonates (JAs) in primary root growth and development and in plant response to external stimuli is already known. However, its role in lateral root (LR) development remains to be explored. Our work identified methyl jasmonate (MeJA) as a key phytohormone in determining the branching angle of Arabidopsis LRs. MeJA inclines the LRs to a more vertical orientation, which was dependent on the canonical JAR1-COI1-MYC2,3,4 signalling. Our work also highlights the dual roles of light in governing LR angle. Light signalling enhances JA biosynthesis, leading to erect root architecture; whereas, glucose (Glc) induces wider branching angles. Combining physiological and molecular assays, we revealed that Glc antagonises the MeJA response via TARGET OF RAPAMYCIN (TOR) signalling. Moreover, physiological assays using auxin mutants, MYC2-mediated transcriptional activation of LAZY2, LAZY4 and auxin biosynthetic gene CYP79B2, and asymmetric distribution of DR5::GFP and PIN2::GFP pinpointed the role of an intact auxin machinery required by MeJA for vertical growth of LRs. We also demonstrated that light perception and signalling are indispensable for inducing vertical angles by MeJA. Thus, our investigation highlights antagonism between light and Glc signalling and how they interact with JA-auxin signals to optimise the branching angle of LRs.
PMID: 35147228
Plant Cell Environ , IF:7.228 , 2022 Mar , V45 (3) : P771-788 doi: 10.1111/pce.14266
Genetic and molecular mechanisms underlying root architecture and function under heat stress-A hidden story.
Department of Agronomy, Kansas State University, Manhattan, Kansas, USA.
Heat stress events are resulting in a significant negative impact on global food production. The dynamics of cellular, molecular and physiological homoeostasis in aboveground parts under heat stress are extensively deciphered. However, root responses to higher soil/air temperature or stress signalling from shoot to root are limited. Therefore, this review presents a holistic view of root physio-morphological and molecular responses to adapt under hotter environments. Heat stress reprogrammes root cellular machinery, including crosstalk between genes, phytohormones, reactive oxygen species (ROS) and antioxidants. Spatio-temporal regulation and long-distance transport of phytohormones, such as auxin, cytokinin and abscisic acid (ABA) determine the root growth and development under heat stress. ABA cardinally integrates a signalling pathway involving heat shock factors, heat shock proteins and ROS to govern heat stress responses. Additionally, epigenetic modifications by transposable elements, DNA methylation and acetylation also regulate root growth under heat stress. Exogenous application of chemical compounds or biological agents such as ascorbic acid, metal ion chelators, fungi and bacteria can alleviate heat stress-induced reduction in root biomass. Future research should focus on the systemic effect of heat stress from shoot to root with more detailed investigations to decipher the molecular cues underlying the roots architecture and function.
PMID: 35043409
Plant Cell Environ , IF:7.228 , 2022 Feb , V45 (2) : P572-590 doi: 10.1111/pce.14229
Insights into ROS-dependent signalling underlying transcriptomic plant responses to the herbicide 2,4-D.
Departamento de Bioquimica, Biologia Celular y Molecular de Plantas, EEZ, CSIC, Granada, Spain.; Bioinformatics Unit, IPBLN, CSIC, Granada, Spain.; Plataforma Andaluza de Bioinformatica-SCBI, Universidad de Malaga, Malaga, Spain.; Department Ciencies Agraries i del Medi Natural, Universitat Jaume I, Castello de la Plana, Spain.; Departamento de Biologia Molecular y Bioquimica, Ciencias, Univ. de Malaga, Malaga, Spain.; Institute for Mediterranean and Subtropical Horticulture "La Mayora" (IHSM-UMA-CSIC), Malaga, Spain.; Instituto de Biologia Molecular y Celular de Plantas (CSIC-Univ. Valencia), CPI Edificio 8E, Valencia, Spain.
The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) functions as an agronomic weed control herbicide. High concentrations of 2,4-D induce plant growth defects, particularly leaf epinasty and stem curvature. Although the 2,4-D triggered reactive oxygen species (ROS) production, little is known about its signalling. In this study, by using a null mutant in peroxisomal acyl CoA oxidase 1 (acx1-2), we identified acyl-coenzyme A oxidase 1 (ACX1) as one of the main sources of ROS production and, in part, also causing the epinastic phenotype following 2,4-D application. Transcriptomic analyses of wild type (WT) plants after treatment with 2,4-D revealed a ROS-related peroxisomal footprint in early plant responses, while other organelles, such as mitochondria and chloroplasts, are involved in later responses. Interestingly, a group of 2,4-D-responsive ACX1-dependent transcripts previously associated with epinasty is related to auxin biosynthesis, metabolism, and signalling. We found that the auxin receptor auxin signalling F-box 3 (AFB3), a component of Skp, Cullin, F-box containing complex (SCF) (ASK-cullin-F-box) E3 ubiquitin ligase complexes, which mediates auxin/indole acetic acid (AUX/IAA) degradation by the 26S proteasome, acts downstream of ACX1 and is involved in the epinastic phenotype induced by 2,4-D. We also found that protein degradation associated with ubiquitin E3-RING and E3-SCF-FBOX in ACX1-dependent signalling in plant responses to 2,4-D is significantly regulated over longer treatment periods.
PMID: 34800292
Plant Cell Environ , IF:7.228 , 2022 Mar , V45 (3) : P969-984 doi: 10.1111/pce.14230
The volatile cedrene from Trichoderma guizhouense modulates Arabidopsis root development through auxin transport and signalling.
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement and MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China.; Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Rhizosphere microorganisms interact with plant roots by producing chemical signals that regulate root development. However, the distinct bioactive compounds and signal transduction pathways remain to be identified. Here, we showed that sesquiterpenes are the main volatile compounds produced by plant-beneficial Trichoderma guizhouense NJAU4742. Inhibition of sesquiterpene biosynthesis eliminated the promoting effect of this strain on root growth, indicating its involvement in plant-fungus cross-kingdom signalling. Sesquiterpene component analysis identified cedrene, a highly abundant sesquiterpene in strain NJAU4742, to stimulate plant growth and root development. Genetic analysis and auxin transport inhibition showed that the TIR1 and AFB2 auxin receptors, IAA14 auxin-responsive protein, and ARF7 and ARF19 transcription factors affected the response of lateral roots to cedrene. Moreover, the AUX1 auxin influx carrier and PIN2 efflux carrier were also found to be indispensable for cedrene-induced lateral root formation. Confocal imaging showed that cedrene affected the expression of pPIN2:PIN2:GFP and pPIN3:PIN3:GFP, which might be related to the effect of cedrene on root morphology. These results suggested that a novel sesquiterpene molecule from plant-beneficial T. guizhouense regulates plant root development through the transport and signalling of auxin.
PMID: 34800291
Plant Cell Environ , IF:7.228 , 2022 Feb , V45 (2) : P496-511 doi: 10.1111/pce.14216
(+)-Catechin, epicatechin and epigallocatechin gallate are important inducible defensive compounds against Ectropis grisescens in tea plants.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China.; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, China.
The tea plant, Camellia sinensis (L.) O. Kuntze, is an economically important, perennial woody plant rich in catechins. Although catechins have been reported to play an important role in plant defences against microbes, their roles in the defence of tea plants against herbivores remain unknown. In this study, we allowed the larvae of Ectropis grisescens, a leaf-feeding pest, to feed on the plants, and alternatively, we wounded the plants and then treated them with E. grisescens oral secretions (WOS). Both approaches triggered jasmonic acid-, ethylene- and auxin-mediated signalling pathways; as a result, plants accumulated three catechin compounds: (+)-catechin, epicatechin and epigallocatechin. Not only was the mass of E. grisescens larvae fed on plants previously infested with E. grisescens or treated with WOS significantly lower than that of larvae fed on controls, but also artificial diet supplemented with epicatechin, (+)-catechin or epigallocatechin gallate reduced larval growth rates. In addition, the exogenous application of jasmonic acid, ethylene or auxin induced the biosynthesis of the three catechins, which, in turn, enhanced the resistance of tea plants to E. grisescens, leading to the coordination of the three signalling pathways. Our results suggest that the three catechins play an important role in the defences of tea plants against E. grisescens.
PMID: 34719788
Plant Cell Environ , IF:7.228 , 2022 Mar , V45 (3) : P955-968 doi: 10.1111/pce.14210
Auxin-mediated regulation of arbuscular mycorrhizal symbiosis: A role of SlGH3.4 in tomato.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, China.; Guangdong Key Laboratory for New Technology Research of Vegetables, Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, China.; Zhejiang Institute of Subtropical Crops, Zhejiang Academy of Agricultural Sciences, Wenzhou, Zhejiang, China.; Key Laboratory of Tobacco Genetic Improvement and Biotechnology, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, Shandong, China.; Department of Ecological Environment and Soil Science, Nanjing Institute of Vegetable Science, Nanjing, Jiangsu, China.; College of Horticulture Technology, Suzhou Polytechnic Institute of Agriculture, Suzhou, Jiangsu, China.
Most land plants can establish symbiosis with arbuscular mycorrhizal (AM) fungi to increase fitness to environmental challenges. The development of AM symbiosis is controlled by intricate procedures involving all phytohormones. However, the mechanisms underlying the auxin-mediated regulation of AM symbiosis remains largely unknown. Here, we report that AM colonisation promotes auxin response and indole-3-acetic acid (IAA) accumulation, but downregulates IAA biosynthesis genes in tomato (Solanum lycopersicum). External IAA application modulates the AM symbiosis by promoting arbuscule formation at low concentrations but repressing it at high concentrations. An AM-induced GH3 gene, SlGH3.4, encoding a putative IAA-amido synthetase, negatively regulates mycorrhization via maintaining cellular auxin homoeostasis. Loss of SlGH3.4 function increased free IAA content and arbuscule incidence, while constitutively overexpressing SlGH3.4 in either tomato or rice resulted in decreased IAA content, total colonisation level and arbuscule abundance in mycorrhizal roots. Several auxin-inducible expansin genes involved in AM formation or resistance to pathogen infection were upregulated in slgh3.4 mycorrhizal roots but downregulated in the SlGH3.4-overexpressing plants. Taken together, our results highlight a positive correlation between the endogenous IAA content and mycorrhization level, particularly arbuscule incidence, and suggest that the SlGH3.4-mediated auxin homoeostasis and regulation of expansin genes is involved in finely tuning the AM development.
PMID: 34713922
Plant Cell Environ , IF:7.228 , 2022 Mar , V45 (3) : P871-883 doi: 10.1111/pce.14137
ABA regulation of root growth during soil drying and recovery can involve auxin response.
Fujian Provincial Key Laboratory of Plant Functional Biology and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.; College of Agriculture, Yangzhou University, Yangzhou, China.; Lancaster Environment Centre, Lancaster University, Lancaster, UK.
Abscisic acid (ABA) plays an important role in plant adaptation to water deficits, but its role in regulating root growth (primary root elongation and lateral root number) during different drought-phases remains unclear. Here, we exposed wild-type (WT) and ABA-deficient (not) tomato plants to three continuous drought-phases (moderate drying: day 0-21; severe drying: day 22-47 and re-watering: day 48-51). It was found that WT increased primary root growth during moderate drying; maintained more lateral roots, and greater primary root and total root length under severe drying; and produced more roots after re-watering. After RNA-Seq analysis, we found that the auxin-related genes in root showed different expression patterns between WT and not under drying or re-watering. Further, exogenous supply of IAA partially recovered the root growth of ABA-deficient not plants under three continuous drought-phases. Our results suggested that ABA regulation of tomato root growth during soil drying and recovery can involve auxin response.
PMID: 34176142
Microbiol Spectr , IF:7.171 , 2022 Feb , V10 (1) : Pe0034521 doi: 10.1128/spectrum.00345-21
Functional Genetic Diversity and Plant Growth Promoting Potential of Polyphosphate Accumulating Bacteria in Soil.
Division of Microbial Technology, CSIR-National Botanical Research Institute, Lucknow, India.; Academy of Scientific and Innovative Research, AcSIR, Ghaziabad, India.; Department of Botany, Kumaun University, Nainital, India.; Computational Biology Laboratory, Genetics and Biotechnology Division, CSIR-National Botanical Research Institute, Lucknow, India.
Polyphosphate (polyP) accumulation is an important trait of microorganisms. Implication of polyP accumulating bacteria (PAB) in enhanced biological phosphate removal, heavy metal sequestration, and dissolution of dental enamel is well studied. Phosphorous (P) accumulated within microbial biomass also regulates labile P in soil; however, abundance and diversity of the PAB in soil is still unexplored. Present study investigated the genetic and functional diversity of PAB in rhizosphere soil. Here, we report the abundance of Pseudomonas spp. as high PAB in soil, suggesting their contribution to global P cycling. Additional subset analysis of functional genes i.e., polyphosphate kinase (ppk) and exopolyphosphatase (ppx) in all PAB, indicates their significance in bacterial growth and metabolism. Distribution of functional genes in phylogenetic tree represent a more biologically realistic discrimination for the two genes. Distribution of ppx gene disclosed its phylogenetic conservation at species level, however, clustering of ppk gene of similar species in different clades illustrated its environmental condition mediated modifications. Selected PAB showed tolerance to abiotic stress and strong correlation with plant growth promotary (PGP) traits viz. phosphate solubilization, auxin and siderophore production. Interaction of PAB with A. thaliana enhanced the growth and phosphate status of the plant under salinity stress, suggestive of their importance in P cycling and stress alleviation. IMPORTANCE Study discovered the abundance of Pseudomonas genera as a high phosphate accumulator in soil. The presence of functional genes (polyphosphate kinase [ppk] and exopolyphosphatase [ppx]) in all PAB depicts their importance in polyphosphate metabolism in bacteria. Genetic and functional diversity reveals conservation of the ppx gene at species level. Furthermore, we found a positive correlation between PAB and plant growth promotary traits, stress tolerance, and salinity stress alleviation in A. thaliana.
PMID: 35196785
Chemosphere , IF:7.086 , 2022 Feb : P134044 doi: 10.1016/j.chemosphere.2022.134044
Increasing atmospheric CO2 differentially supports arsenite stress mitigating impact of arbuscular mycorrhizal fungi in wheat and soybean plants.
Laboratory for Integrated Molecular Plant Physiology Research (IMPRES), Department of Biology, University of Antwerp, Antwerp, Belgium; Department of Botany and Microbiology, Faculty of Science, Beni-Suef University, 62521, Beni-Suef, Egypt.; Department of Agricultural Microbiology, Faculty of Agriculture, Mansoura University, Mansoura, 35516, Egypt.; Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia.; Department of Biological Sciences, College of Science, King Faisal University, Al-Ahsa, 31982, Saudi Arabia; Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, 12613, Egypt.; Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia.; Department of Biological Sciences, College of Science, King Faisal University, Al-Ahsa, 31982, Saudi Arabia.; Laboratory for Integrated Molecular Plant Physiology Research (IMPRES), Department of Biology, University of Antwerp, Antwerp, Belgium.; Department of Agronomy, Faculty of Agriculture, Mansoura University, Mansoura, 35516, Egypt. Electronic address: salahco_2010@mans.edu.eg.
Arbuscular mycorrhizal fungi (AMF) are beneficial for the plant growth under heavy metal stress. Such beneficial effect is improved by elevated CO2 (eCO2). However, the mechanisms by which eCO2 improves AMF symbiotic associations under arsenite (As(III)) toxicity are hardly studied. Herein, we compared these regulatory mechanisms in species from two agronomical important plant families - grasses (wheat) and legumes (soybean). As(III) decreased plant growth (i.e., 53.75 and 60.29% of wheat and soybean, respectively) and photosynthesis. It also increased photorespiration and oxidative injury in both species, but soybean was more sensitive to oxidative stress as indicated by higher H2O2 accumulation and oxidation of protein and lipid. eCO2 significantly improved AMF colonization by increasing auxin levels, which induced high carotenoid cleavage dioxygenase (CCDs) activity, particularly in soybean roots. The improved sugar metabolism in plant shoots by co-application of eCO2 and As(III) allocated more sugars to roots sequentially. Sugar accumulation in plant roots is further induced by AMF, resulting in more C skeletons to produce organic acids, which are effectively exudated into the soil to reduce As(III) uptake. Exposure to eCO2 reduced oxidative damage and this mitigation was stronger in soybean. This could be attributed to a greater reduction in photorespiration as well as a stronger antioxidant and detoxification defence systems. The grass/legume-specificity was supported by principal component analysis, which revealed that soybean was more affected by As(III) stress and more responsive to AMF and eCO2. This study provided a mechanistic understanding of the impact of AMF, eCO2 and their interaction on As-stressed grass and legume plants, allowing better practical strategies to mitigate As(III) phytotoxicity.
PMID: 35202662
J Integr Plant Biol , IF:7.061 , 2022 Mar doi: 10.1111/jipb.13256
Testing the polar auxin transport model with a selective plasma membrane H(+) -ATPase inhibitor.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.; Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.; Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.; Department of Dermatology, Peking University First Hospital, Beijing, 10034, China.; Iomics Biosciences Inc., Beijing, 100102, China.; College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Auxin is unique among plant hormones in that its function requires polarized transport across plant cells. A chemiosmotic model was proposed to explain how polar auxin transport is derived by the H+ gradient across the plasma membrane established by plasma membrane H+-ATPases (PM H+-ATPases). However, a classical genetic approach by mutations in PM H+-ATPase members did not result in the ablation of polar auxin distribution, possibly due to functional redundancy in this gene family. To confirm the crucial role of PM H+-ATPases in the polar auxin transport model (PATM), we employed a chemical genetic approach. Through a chemical screen, we identified protonstatin-1 (PS-1), a selective small-molecule inhibitor of PM H+-ATPase activity that inhibits auxin transport. Assays with transgenic plants and yeast strains showed that the activity of PM H+-ATPases affects auxin uptake as well as acropetal and basipetal polar auxin transport. We propose that PS-1 can be used as a tool to interrogate the function of PM H+-ATPases. Our results support the chemiosmotic model in which PM H+-ATPase itself plays a fundamental role in polar auxin transport. This article is protected by copyright. All rights reserved.
PMID: 35352470
J Integr Plant Biol , IF:7.061 , 2022 Mar doi: 10.1111/jipb.13243
BYPASS1-LIKE regulates lateral root initiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis.
Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.; College of Life Science and Technology, Gansu Agricultural University, Lanzhou, 730070, China.; School of Forestry, Beijing Forestry University, Beijing, 100083, China.
Auxin and auxin-mediated signaling pathways are known to regulate lateral root development. Although exocytic vesicle trafficking plays an important role in recycling the PIN-FORMED (PIN) auxin efflux carriers and in polar auxin transport during lateral root formation, the mechanistic details of these processes are not well understood. Here, we demonstrate that BYPASS1-LIKE (B1L) regulates lateral root initiation via exocytic vesicular trafficking-mediated PIN recycling in Arabidopsis thaliana. b1l mutants contained significantly more lateral roots than the wild type, primarily due to increased lateral root primordium initiation. Furthermore, the auxin signal was stronger in stage I lateral root primordia of b1l than in those of the wild type. Treatment with exogenous auxin and an auxin transport inhibitor indicated that the lateral root phenotype of b1l could be attributed to higher auxin levels and that B1L regulates auxin efflux. Indeed, compared to the wild type, C-terminally GFP-tagged PIN1 and PIN3 accumulated at higher levels in b1l lateral root primordia. B1L interacts with the exocyst, and b1l shows defective PIN exocytosis. These observations indicate that B1L interacts with the exocyst to regulate PIN-mediated polar auxin transport and lateral root initiation in Arabidopsis. This article is protected by copyright. All rights reserved.
PMID: 35249253
J Integr Plant Biol , IF:7.061 , 2022 Feb doi: 10.1111/jipb.13237
Symplastic communication in the root cap directs auxin distribution to modulate root development.
College of Life Sciences, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; The Department of Plant Systems Physiology, Radboud University, Netherlands.
Root cap not only protects root meristem, but also detects and transduces the signals of environmental changes to affect root development. The symplastic communication is an important way for plants to transduce signals to coordinate the development and physiology in response to the changing enviroments. However, it is unclear how the symplastic communication between root cap cells affects root growth. Here we exploit an inducible system to specifically block the symplastic communication in the root cap. Transient blockage of plasmodesmata (PD) in differentiated collumella cells severely impairs the root development in Arabidopsis, in particular in the stem cell niche and the proximal meristem. The neighboring stem cell niche is the region that is most sensitive to the disrupted symplastic communication and responds rapidly via the alteration of auxin distribution. In the later stage, the cell division in proximal meristem is inhibited, presumably due to the reduced auxin level in the root cap. Our results reveal the essential role of the differentiated collumella cells in the root cap mediated signaling system that directs root development. This article is protected by copyright. All rights reserved.
PMID: 35199475
J Integr Plant Biol , IF:7.061 , 2022 Feb , V64 (2) : P371-392 doi: 10.1111/jipb.13225
Auxin signaling: Research advances over the past 30 years.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China.; Institute of Science and Technology (IST), Klosterneuburg, 3400, Austria.
Auxin, one of the first identified and most widely studied phytohormones, has been and will remain a hot topic in plant biology. After more than a century of passionate exploration, the mysteries of its synthesis, transport, signaling, and metabolism have largely been unlocked. Due to the rapid development of new technologies, new methods, and new genetic materials, the study of auxin has entered the fast lane over the past 30 years. Here, we highlight advances in understanding auxin signaling, including auxin perception, rapid auxin responses, TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes (TIR1/AFBs)-mediated transcriptional and non-transcriptional branches, and the epigenetic regulation of auxin signaling. We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals. In addition, we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling, which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development. The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field, leading to an increasingly deeper, more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.
PMID: 35018726
J Integr Plant Biol , IF:7.061 , 2022 Mar , V64 (3) : P771-786 doi: 10.1111/jipb.13218
Regulation of cytokinin biosynthesis using PtRD26pro -IPT module improves drought tolerance through PtARR10-PtYUC4/5-mediated reactive oxygen species removal in Populus.
National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.; Department of Biology, Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China.
Drought is a critical environmental factor which constrains plant survival and growth. Genetic engineering provides a credible strategy to improve drought tolerance of plants. Here, we generated transgenic poplar lines expressing the isopentenyl transferase gene (IPT) under the driver of PtRD26 promoter (PtRD26pro -IPT). PtRD26 is a senescence and drought-inducible NAC transcription factor. PtRD26pro -IPT plants displayed multiple phenotypes, including improved growth and drought tolerance. Transcriptome analysis revealed that auxin biosynthesis pathway was activated in the PtRD26pro -IPT plants, leading to an increase in auxin contents. Biochemical analysis revealed that ARABIDOPSIS RESPONSE REGULATOR10 (PtARR10), one of the type-B ARR transcription factors in the cytokinin pathway, was induced in PtRD26pro -IPT plants and directly regulated the transcripts of YUCCA4 (PtYUC4) and YUCCA5 (PtYUC5), two enzymes in the auxin biosynthesis pathway. Overexpression of PtYUC4 enhanced drought tolerance, while simultaneous silencing of PtYUC4/5 evidently attenuated the drought tolerance of PtRD26pro -IPT plants. Intriguingly, PtYUC4/5 displayed a conserved thioredoxin reductase activity that is required for drought tolerance by deterring reactive oxygen species accumulation. Our work reveals the molecular basis of cytokinin and auxin interactions in response to environmental stresses, and shed light on the improvement of drought tolerance without a growth penalty in trees by molecular breeding.
PMID: 34990062
J Exp Bot , IF:6.992 , 2022 Mar doi: 10.1093/jxb/erac119
Impaired auxin signaling increases vein and stomatal density but reduces hydraulic efficiency and ultimately net photosynthesis.
Departamento de Biologia Vegetal, Universidade Federal de Vicosa, Vicosa, 36570-900, Brazil.; Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC, 27695, USA.
Auxins are known to regulate xylem development in plants, however, their effects on water transport efficiency are poorly known. Here we used tomato plants of the diageotropica mutant (dgt), which has impaired function of a Cyclophilin 1 cis/trans isomerase involved in auxin signaling, and its corresponding wild type (WT) to explore its effects on plant hydraulics and leaf gas exchange. The xylem conduits of dgt showed a reduced hydraulically-weighted vessel diameter (Dh) (24-43%) and conduit number (25-58%) in petioles and stems, resulting in lower theoretical hydraulic conductivities (Kt); on the other hand, no changes in root Dh and Kt were observed. The measured stem and leaf hydraulic conductances of dgt agreed with the Kt values and were lower (up to 81%) as well; however, despite dgt and WT showed similar root Dh and Kt, the measured root hydraulic conductance of dgt was 75% lower. The dgt mutation increased the vein and stomata density, which could potentially increase photosynthesis. Nevertheless, even presenting the same photosynthetic capacity of WT plants, the dgt showed a photosynthetic rate c. 25% lower, coupled with a stomatal conductance reduction of 52%. These results clearly demonstrate that increases in Dv and Ds only result in higher leaf gas exchange when accompanied by higher hydraulic efficiency.
PMID: 35312771
J Exp Bot , IF:6.992 , 2022 Mar doi: 10.1093/jxb/erac111
Phytomelatonin as a central molecule in plant disease resistance.
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, Hainan province, 570228, China.; Department of Cellular and Structural Biology, UT Health San Antonio, Long School of Medicine, San Antonio, TX, USA.
Melatonin is an essential phytohormone in the regulation of many plant processes, including both during plant development and in response to stress. Pathogen infections cause serious damage to plants and reduce agricultural production. Recent studies indicate that melatonin plays important roles in alleviating bacterial, fungal and viral diseases in plants and post-harvest fruits. Herein, we summarize information related to the effects of melatonin on plant disease resistance. Melatonin, reactive oxygen species (ROS) and reactive nitrogen species (RNS) form a complex loop during plant-pathogen interaction to regulate plant disease resistance. Moreover, melatonin also has crosstalk with other phytohormones including salicylic acid (SA), jasmonic acid (JA), auxin, abscisic acid (ABA) which further activates plant defense genes. Melatonin not only plays an important role in plant immunity, but also in alleviating pathogen pathogenicity. We also summarize the known processes by which melatonin mediates pathogen pathogenicity via negatively regulating the expression levels of genes related to cell viability as well as virulence-related genes. The multiple mechanisms underlying melatonin influences on both plant immunity and pathogen pathogenicity support the recognition of the essential nature of melatonin in plant-pathogen interactions, highlighting phytomelatonin as a critical molecule in plant immune responses.
PMID: 35298631
J Exp Bot , IF:6.992 , 2022 Mar doi: 10.1093/jxb/erac088
Cytokinin oxidase/dehydrogenase family genes exhibit functional divergence and overlap in rice growth and development, especially in control of tillering.
College of Agriculture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.; Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture, Nanjing 210095, People's Republic of China.; Collaborative Innovation Center for Modern Crop Production co-sponsored by Province and Ministry, Nanjing 210095, People's Republic of China.
Cytokinins play key roles in plant growth and development; hence, cytokinin biosynthesis and degradation have been extensively studied. Cytokinin oxidase/dehydrogenases (CKXs) are a group of enzymes that regulate oxidative cleavage to maintain cytokinin homeostasis. In rice, 11 OsCKX genes have been identified to date; however, most of their functions remain unknown. Here, we comprehensively analyzed the expression patterns and functions of OsCKX genes. Using CRISPR/Cas9 technology, we constructed mutants of all OsCKX genes to determine the functions of OsCKXs in rice development. The results revealed that the single osckx and higher-order osckx4 osckx9 mutant lines showed functional overlap and subfunctionalization. Notably, the osckx1 osckx2 and osckx4 osckx9 double mutants displayed contrasting phenotypic changes in tiller number and panicle size compared to the wild type. Moreover, we identified several genes with significantly altered expression in osckx4 and osckx9 single and double mutant plants. Many differentially expressed genes were found to be associated with auxin and cytokinin pathways. Additionally, the cytokinins in osckx4 osckx9 mutants were increased compared to the wild type. Overall, our findings provide new insights into the functions of OsCKX genes in rice growth and may be used as a foundation for future studies aimed at improving rice yield.
PMID: 35247044
J Exp Bot , IF:6.992 , 2022 Mar doi: 10.1093/jxb/erac083
Nitrate-dependent regulation of miR444-OsMADS27 signaling cascade controls root development in rice.
National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore 560065, India.; SASTRA University, Thirumalaisamudram, Thanjavur 613401, India.
Nitrate is an important nutrient and a key signaling molecule for plant development. A number of transcription factors involved in the process of nitrate response and their regulatory mechanisms have been identified. However, little is known about the nitrate sensor transcription factors and their regulatory mechanisms among crop plants. In this study, we identified functions of a nitrate-responsive miR444:MADS-box transcription factor OsMADS27 module and its downstream targets mediating rice root growth and stress responses. Transgenic rice plants expressing miR444 target mimic improved rice root growth. Although miR444 has the potential to target multiple genes, we identified OsMADS27 as the major miR444 target that regulates the expression of nitrate transporters, as well as several key genes including expansins and those associated with auxin signaling promote root growth. In agreement with this, overexpression of miRNA-resistant OsMADS27 improved root development and tolerance to stresses, while its silencing suppressed root growth. OsMADS27-mediated a robust stress tolerance in plants through its ability to bind to the promoters of specific stress regulators as observed in ChIP-Seq analysis. Our results provide evidence of nitrate-dependent miR444-OsMADS27 signaling cascade involved in the regulation of rice root growth as well as its surprising role in stress responses.
PMID: 35243491
J Exp Bot , IF:6.992 , 2022 Feb doi: 10.1093/jxb/erac074
Serratia marcescens PLR enhances lateral root formation through supplying PLR-derived auxin and enhancing auxin biosynthesis in Arabidopsis.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China.; Peking University Institute of Advanced Agricultural Sciences, Weifang, China.; Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, China.; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
Plant-growth-promoting rhizobacteria (PGPR) refer to bacteria that colonize the rhizosphere and contribute to plant growth or stress tolerance. To further understand the molecular mechanism of symbiosis of plants-PGPRs, we performed a high-throughput single colony screening from rhizosphere, and uncovered a bacterium (named promoting lateral root, PLR) that significantly promotes Arabidopsis lateral root formation. By 16S rDNA sequencing, PLR was identified as a novel sub-species of Serratia marcescens. RNA-seq analysis of Arabidopsis integrated with phenotypic verification of auxin signaling mutants demonstrated that the promotion effect of PLR on lateral root formation is dependent on auxin signaling. Furthermore, PLR enhanced the tryptophan-dependent IAA synthesis by inducing multiple auxin synthesis genes in Arabidopsis. Genome-wide sequencing of PLR integrated with the identification of IAA and its precursors in PLR exudates showed that tryptophan treatment significantly enhanced the ability of PLR to produce IAA and its precursors IPA and IAM. Interestingly, PLR induced multiple nutrient (N, P, K, S) transporter genes in an auxin-independent manner. In summary, this study provides evidence to show how PLR enhances plant growth through finely tuning auxin biosynthesis and signaling in Arabidopsis, implying a potential application of PLR in crop yield improvement through accelerating root development.
PMID: 35196372
J Exp Bot , IF:6.992 , 2022 Feb doi: 10.1093/jxb/erac059
Ammonium transporters cooperatively regulate rice crown root formation responding to ammonium nitrogen.
MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River and State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.
Crown roots (CRs) are major components of rice root system and develop at the basal node of the shoot, and CR development is largely influenced by environmental factors. Ammonium nitrogen is known to impact plant root development through ammonium transporter AMTs, but it remains unclear whether ammonium and AMTs play roles in rice CR formation. In this study, we revealed a significant role of ammonium, rather than nitrate, in regulating rice CR development. High ammonium supply increases CR formation but inhibits CR elongation. Genetic evidence showed that the regulation of ammonium in CR development relies on ammonium uptake mediated jointly by OsAMT1;1, OsAMT1;2; OsAMT1;3, and OsAMT2;1, but not on root acidification in which ammonium uptake resulted. OsAMTs are also needed for glutamine-induced CR formation. Furthermore, we showed that auxin efflux carriers PINs-dependent polar auxin transport acts downstream of ammonium uptake and assimilation to activate local auxin signaling at CR primordium, in turn promoting CR formation. Taken together, our results highlight a critical role of OsAMTs in cooperatively regulating CR formation through regulating auxin transport under N-rich condition.
PMID: 35176162
J Exp Bot , IF:6.992 , 2022 Feb doi: 10.1093/jxb/erac050
ORESARA 15, a PLATZ transcription factor, controls root meristem size through auxin and cytokinin signaling-related pathways.
Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea.; Center for Plant Aging Research, Institute for Basic Science, Daegu 42988, Republic of Korea.; Department of Biological Sciences, Chungnam National University, Daejeon 34134, Republic of Korea.; School of Biological Sciences, Seoul National University, Seoul 08826, Republic of Korea.; New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Korea.
An optimal size of postembryonic root apical meristem (RAM) is achieved by a balance between cell division and differentiation. Despite extensive research, molecular mechanisms underlying the coordination of cell division and differentiation are still fragmentary. Here, we report that ORESARA 15 (ORE15), an Arabidopsis PLATZ transcription factor preferentially expressed in the RAM, determines RAM size. The primary root length, RAM size, cell division rate, and stem cell niche activity were reduced in an ore15 loss-of-function mutant but enhanced in an activation-tagged line overexpressing ORE15 compared with the wild type. ORE15 forms mutually positive and negative feedback loops with auxin and cytokinin signaling, respectively. Collectively, our findings imply that ORE15 controls the RAM size by mediating the antagonistic interaction between auxin and cytokinin signaling-related pathways.
PMID: 35139177
J Exp Bot , IF:6.992 , 2022 Feb doi: 10.1093/jxb/erac036
FRAGILE CULM 18 encodes a UDP-glucuronic acid decarboxylase required for xylan biosynthesis and plant growth in rice.
Rice Research Institute, Shenyang Agricultural University, Shenyang, China.; Jinzhou Academy of Science and Technology, Jinzhou, China.
Although UDP-glucuronic acid decarboxylases (UXSs) have been well studied to catalyze the conversion of UDP-glucuronic acid into UDP-xylose, their biological roles in grasses remains largely unknown. The rice (Oryza sativa) genome contains six UXSs, but none of them has been genetically characterized. Here, we reported on the characterization of a novel rice fragile culm mutant, fc18, which exhibited brittleness with altered cell wall and pleiotropic defects in growth. Map-based cloning and transgenic analyses revealed that the FC18 encodes a cytosol-localized OsUXS3 and is widely expressed with higher levels in xylan-rich tissues. Monosaccharide analysis showed that the xylose level decreased in fc18, and cell wall fractions determinations confirmed that the xylan content in fc18 declined, suggesting that UDP-xylose from FC18 participates in xylan biosynthesis. Moreover, the fc18 mutant displayed defective cellulose properties, which led to an enhancement in biomass saccharification. Furthermore, genes involved in sugar metabolism and phytohormone signal transduction were largely altered in fc18. Consistently, the fc18 mutant exhibited significantly reduced free auxin (indole-3-acetic acid, IAA) content and lower expression levels of PIN family genes compared to wild-type. Our work underpins the physiological roles of FC18/UXS3 in xylan biosynthesis, cellulose deposition, and plant growth in rice.
PMID: 35104839
J Exp Bot , IF:6.992 , 2022 Mar , V73 (5) : P1327-1343 doi: 10.1093/jxb/erab504
Lysophosphatidic acid acyltransferases: a link with intracellular protein trafficking in Arabidopsis root cells?
CNRS, University of Bordeaux, Laboratoire de Biogenese Membranaire, UMR 5200, 33140 Villenave d'Ornon, France.; LEB Aquitaine Transfert-ADERA, INRA Bordeaux Aquitaine, 33140 Villenave d'Ornon, France.; Plant Cell Biology, Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.; Bordeaux Imaging Center, UMS 3420 CNRS, US004 INSERM, University of Bordeaux, 33000 Bordeaux, France.
Phosphatidic acid (PA) and lysophosphatidic acid acyltransferases (LPAATs) might be critical for the secretory pathway. Four extra-plastidial LPAATs (LPAAT2, 3, 4, and 5) were identified in Arabidopsis thaliana. These AtLPAATs display a specific enzymatic activity converting lysophosphatidic acid to PA and are located in the endomembrane system. We investigate a putative role for AtLPAATs 3, 4, and 5 in the secretory pathway of root cells through genetical (knockout mutants), biochemical (activity inhibitor, lipid analyses), and imaging (live and immuno-confocal microscopy) approaches. Treating a lpaat4;lpaat5 double mutant with the LPAAT inhibitor CI976 produced a significant decrease in primary root growth. The trafficking of the auxin transporter PIN2 was disturbed in this lpaat4;lpaat5 double mutant treated with CI976, whereas trafficking of H+-ATPases was unaffected. The lpaat4;lpaat5 double mutant is sensitive to salt stress, and the trafficking of the aquaporin PIP2;7 to the plasma membrane in the lpaat4;lpaat5 double mutant treated with CI976 was reduced. We measured the amounts of neo-synthesized PA in roots, and found a decrease in PA only in the lpaat4;lpaat5 double mutant treated with CI976, suggesting that the protein trafficking impairment was due to a critical PA concentration threshold.
PMID: 34982825
Development , IF:6.868 , 2022 Mar , V149 (5) doi: 10.1242/dev.200079
High temperature perception in leaves promotes vascular regeneration and graft formation in distant tissues.
Department of Plant Biology, Swedish University of Agricultural Sciences, Ulls grand 1, 765 51 Uppsala, Sweden.; Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, 8092 Zurich, Switzerland.; Institute of Agricultural and Nutritional Sciences, Faculty of Natural Sciences III, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 5, 06120 Halle (Saale), Germany.; RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan.; Department of Biological Sciences, Faculty of Science, The University of Tokyo, Tokyo 113-8654, Japan.
Cellular regeneration in response to wounding is fundamental to maintain tissue integrity. Various internal factors including hormones and transcription factors mediate healing, but little is known about the role of external factors. To understand how the environment affects regeneration, we investigated the effects of temperature upon the horticulturally relevant process of plant grafting. We found that elevated temperatures accelerated vascular regeneration in Arabidopsis thaliana and tomato grafts. Leaves were crucial for this effect, as blocking auxin transport or mutating PHYTOCHROME INTERACTING FACTOR 4 (PIF4) or YUCCA2/5/8/9 in the cotyledons abolished the temperature enhancement. However, these perturbations did not affect grafting at ambient temperatures, and temperature enhancement of callus formation and tissue adhesion did not require PIF4, suggesting leaf-derived auxin specifically enhanced vascular regeneration in response to elevated temperatures. We also found that elevated temperatures accelerated the formation of inter-plant vascular connections between the parasitic plant Phtheirospermum japonicum and host Arabidopsis, and this effect required shoot-derived auxin from the parasite. Taken together, our results identify a pathway whereby local temperature perception mediates long distance auxin signaling to modify regeneration, grafting and parasitism. This article has an associated 'The people behind the papers' interview.
PMID: 35217857
Hortic Res , IF:6.793 , 2022 Feb doi: 10.1093/hr/uhac032
Physiological, biochemical, and molecular aspects of grafting in fruit trees.
Horticultural Sciences Department, University of Florida, Gainesville, FL 32607 USA.
Grafting is a widely used practice for asexual propagation of fruit trees. Many physiological, biochemical, and molecular changes occur upon grafting that can influence important horticultural traits. This technology has many advantages, including avoidance of juvenility, modifying the scion architecture, improving productivity, adapting scion cultivars to unfavourable environmental conditions, and developing traits in resistance to insect pests, bacterial and fungal diseases. A limitation of grafting is scion-rootstock incompatibility. It may be caused by many factors, including insufficient genetic proximity, physiological or biochemical factors, lignification at the graft union, poor graft architecture, insufficient cell recognition between union tissues, and metabolic differences in the scion and the rootstock. Plant hormones, like auxin, ethylene (ET), cytokinin (CK), gibberellin (GA), abscisic acid (ABA), and jasmonic acid (JA) orchestrate several crucial physiological and biochemical processes happening at the site of the graft union. Additionally, epigenetic changes at the union affect chromatin architecture by DNA methylation, histone modification, and the action of small RNA molecules. The mechanism triggering these effects likely is affected by hormonal crosstalk, protein and small molecules movement, nutrients uptake, and transport in the grafted trees. This review provides an overview of the basis of physiological, biochemical, and molecular aspects of fruit tree grafting between scion and rootstock.
PMID: 35184166
Cells , IF:6.6 , 2022 Mar , V11 (5) doi: 10.3390/cells11050863
Insights into the Histone Acetylation-Mediated Regulation of the Transcription Factor Genes That Control the Embryogenic Transition in the Somatic Cells of Arabidopsis.
Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, 40-007 Katowice, Poland.; Centre for Bioinformatics and Data Analysis, Medical University of Bialystok, 15-269 Bialystok, Poland.
Somatic embryogenesis (SE), which is a process that involves the in vitro-induced embryogenic reprogramming of plant somatic cells, requires dynamic changes in the cell transcriptome. These changes are fine-tuned by many genetic and epigenetic factors, including posttranslational histone modifications such as histone acetylation. Antagonistically acting enzymes, histone acetyltransferases (HATs) and deacetylases (HDACs), which control histone acetylation in many developmental processes, are believed to control SE. However, the function of specific HAT/HDACs and the genes that are subjected to histone acetylation-mediated regulation during SE have yet to be revealed. Here, we present the global and gene-specific changes in histone acetylation in Arabidopsis explants that are undergoing SE. In the TSA (trichostatin A)-induced SE, we demonstrate that H3 and H4 acetylation might control the expression of the critical transcription factor (TF) genes of a vital role in SE, including LEC1, LEC2 (LEAFY COTYLEDON 1; 2), FUS3 (FUSCA 3) and MYB118 (MYB DOMAIN PROTEIN 118). Within the HATs and HDACs, which mainly positively regulate SE, we identified HDA19 as negatively affecting SE by regulating LEC1, LEC2 and BBM. Finally, we provide some evidence on the role of HDA19 in the histone acetylation-mediated regulation of LEC2 during SE. Our results reveal an essential function of histone acetylation in the epigenetic mechanisms that control the TF genes that play critical roles in the embryogenic reprogramming of plant somatic cells. The results implicate the complexity of Hac-related gene regulation in embryogenic induction and point to differences in the regulatory mechanisms that are involved in auxin- and TSA-induced SE.
PMID: 35269485
mSystems , IF:6.496 , 2022 Mar : Pe0009122 doi: 10.1128/msystems.00091-22
Transcriptional Profiles of a Foliar Fungal Endophyte (Pestalotiopsis, Ascomycota) and Its Bacterial Symbiont (Luteibacter, Gammaproteobacteria) Reveal Sulfur Exchange and Growth Regulation during Early Phases of Symbiotic Interaction.
School of Plant Sciences, The University of Arizonagrid.134563.6, Tucson, Arizona, USA.; Department of Pediatrics, School of Medicine, University of California, La Jolla, California, USA.; Hexagon Bio, Menlo Park, California, USA.; Department of Plant Pathology and Environmental Microbiology, Pennsylvania State Universitygrid.29857.31, Pennsylvania, USA.; Department of Ecology and Evolutionary Biology, The University of Arizonagrid.134563.6, Tucson, Arizona, USA.
Symbiosis with bacteria is widespread among eukaryotes, including fungi. Bacteria that live within fungal mycelia (endohyphal bacteria) occur in many plant-associated fungi, including diverse Mucoromycota and Dikarya. Pestalotiopsis sp. strain 9143 is a filamentous ascomycete isolated originally as a foliar endophyte of Platycladus orientalis (Cupressaceae). It is infected naturally with the endohyphal bacterium Luteibacter sp. strain 9143, which influences auxin and enzyme production by its fungal host. Previous studies have used transcriptomics to examine similar symbioses between endohyphal bacteria and root-associated fungi such as arbuscular mycorrhizal fungi and plant pathogens. However, currently there are no gene expression studies of endohyphal bacteria of Ascomycota, the most species-rich fungal phylum. To begin to understand such symbioses, we developed methods for assessing gene expression by Pestalotiopsis sp. and Luteibacter sp. when grown in coculture and when each was grown axenically. Our assays showed that the density of Luteibacter sp. in coculture was greater than in axenic culture, but the opposite was true for Pestalotiopsis sp. Dual-transcriptome sequencing (RNA-seq) data demonstrate that growing in coculture modulates developmental and metabolic processes in both the fungus and bacterium, potentially through changes in the balance of organic sulfur via methionine acquisition. Our analyses also suggest an unexpected, potential role of the bacterial type VI secretion system in symbiosis establishment, expanding current understanding of the scope and dynamics of fungal-bacterial symbioses. IMPORTANCE Interactions between microbes and their hosts have important outcomes for host and environmental health. Foliar fungal endophytes that infect healthy plants can harbor facultative endosymbionts called endohyphal bacteria, which can influence the outcome of plant-fungus interactions. These bacterial-fungal interactions can be influential but are poorly understood, particularly from a transcriptome perspective. Here, we report on a comparative, dual-RNA-seq study examining the gene expression patterns of a foliar fungal endophyte and a facultative endohyphal bacterium when cultured together versus separately. Our findings support a role for the fungus in providing organic sulfur to the bacterium, potentially through methionine acquisition, and the potential involvement of a bacterial type VI secretion system in symbiosis establishment. This work adds to the growing body of literature characterizing endohyphal bacterial-fungal interactions, with a focus on a model facultative bacterial-fungal symbiosis in two species-rich lineages, the Ascomycota and Proteobacteria.
PMID: 35293790
Plant J , IF:6.417 , 2022 Feb doi: 10.1111/tpj.15710
NS encodes an auxin transporter that regulates the 'numerous spines' trait in cucumber (Cucumis sativus) fruit.
Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Fruit spine is an important agronomic trait in cucumber and the "numerous spines (ns)" cucumber varieties are popular in Europe and West Asia. Although the classical genetic locus of ns was reported more than two decades ago, the NS gene has not been cloned yet. In this study, nine genetic loci for the different densities of fruit spines were identified by a genome-wide association study. Among the nine loci, fsdG2.1 was closely associated with the classical genetic locus ns, which harbors a candidate gene Csa2G264590. Overexpression of Csa2G264590 resulted in lower fruit spine density, and the knockout mutant generated by CRISPR/Cas9 displayed an increased spine density, demonstrating that the Csa2G264590 gene is NS. NS is specifically expressed in the fruit peel and spine. Genetic analysis showed that NS regulates fruit spine development independently of the tuberculate gene, Tu, which regulates spine development on tubercules; the cucumber glabrous mutants csgl1 and csgl3 are epistatic to ns. Furthermore, we found that auxin levels in the fruit peel and spine were significantly lower in the knockout mutant ns-cr. Moreover, RNA-sequencing showed that the plant hormone signal transduction pathway was enriched. Notably, most of the auxin responsive Aux/IAA family genes were downregulated in ns-cr. Haplotype analysis showed that the non-functional haplotype of NS exists exclusively in the Eurasian cucumber backgrounds. Taken together, the cloning of NS gene provides new insights into the regulatory network of fruit spine development.
PMID: 35181968
Plant J , IF:6.417 , 2022 Feb , V109 (4) : P980-991 doi: 10.1111/tpj.15609
Genetic variations in ZmSAUR15 contribute to the formation of immature embryo-derived embryonic calluses in maize.
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Maize Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
The ability of immature maize (Zea mays) embryos to form embryonic calluses (ECs) is highly genotype dependent, which limits transgenic breeding development in maize. Here, we report the association map-based cloning of ZmSAUR15 using an association panel (AP) consisting of 309 inbred lines with diverse formation abilities for ECs. We demonstrated that ZmSAUR15, which encodes a small auxin-upregulated RNA, acts as a negative effector in maize EC induction. Polymorphisms in the ZmSAUR15 promoter that influence the expression of ZmSAUR15 transcripts modulate the EC induction capacity in maize. ZmSAUR15 is involved in indole-3-acetic acid biosynthesis and cell division in immature embryo-derived callus. The ability of immature embryos to induce EC formation can be improved by the knockout of ZmSAUR15, which consequently increases the callus regeneration efficiency. Our study provides new insights into overcoming the genotypic limitations associated with EC formation and improving genetic transformation in maize.
PMID: 34822726
Org Lett , IF:6.005 , 2022 Mar , V24 (8) : P1616-1619 doi: 10.1021/acs.orglett.2c00121
Photoassisted Cross-Coupling Reaction of alpha-Chlorocarbonyl Compounds with Arylboronic Acids.
Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan.; Division of Applied Chemistry, Okayama University, Tsushimanaka, Okayama 700-8530, Japan.
A Suzuki-Miyaura cross-coupling reaction of alpha-chloroacetates or alpha-chloroacetamides with arylboronic acids is made possible by visible-light irradiation. This reaction provides a useful method for the synthesis of alpha-arylacetates and alpha-arylacetamides from chlorides under mild reaction conditions. An indole-3-acetic acid derivative that is the key intermediate of the plant hormone auxin can be synthesized from 1-Boc-indole in two steps by combining an iridium-catalyzed C-H borylation and a palladium-catalyzed cross-coupling reaction.
PMID: 35191697
Int J Mol Sci , IF:5.923 , 2022 Mar , V23 (6) doi: 10.3390/ijms23063090
BoPEP4, a C-Terminally Encoded Plant Elicitor Peptide from Broccoli, Plays a Role in Salinity Stress Tolerance.
Department of Biotechnology, College of Life Science, Northeast Agricultural University, Harbin 150030, China.
Plant peptide hormones play various roles in plant development, pathogen defense and abiotic stress tolerance. Plant elicitor peptides (Peps) are a type of damage-associated molecular pattern (DAMP) derived from precursor protein PROPEPs. In this study, we identified nine PROPEP genes in the broccoli genome. qRT-PCR analysis indicated that the expression levels of BoPROPEPs were induced by NaCl, ABA, heat, SA and P. syringae DC3000 treatments. In order to study the functions of Peps in salinity stress response, we synthesized BoPep4 peptide, the precursor gene of which, BoPROPEP4, was significantly responsive to NaCl treatment, and carried out a salinity stress assay by exogenous application of BoPep4 in broccoli sprouts. The results showed that the application of 100 nM BoPep4 enhanced tolerance to 200 mM NaCl in broccoli by reducing the Na(+)/K(+) ratio and promoting accumulation of wax and cutin in leaves. Further RNA-seq analysis identified 663 differentially expressed genes (DGEs) under combined treatment with BoPep4 and NaCl compared with NaCl treatment, as well as 1776 genes differentially expressed specifically upon BoPep4 and NaCl treatment. GO and KEGG analyses of these DEGs indicated that most genes were enriched in auxin and ABA signal transduction, as well as wax and cutin biosynthesis. Collectively, this study shows that there was crosstalk between peptide hormone BoPep4 signaling and some well-established signaling pathways under salinity stress in broccoli sprouts, which implies an essential function of BoPep4 in salinity stress defense.
PMID: 35328511
Int J Mol Sci , IF:5.923 , 2022 Mar , V23 (6) doi: 10.3390/ijms23062936
The Photoperiod Stress Response in Arabidopsis thaliana Depends on Auxin Acting as an Antagonist to the Protectant Cytokinin.
Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universitat Berlin, D-14195 Berlin, Germany.; Laboratory of Growth Regulators, Faculty of Science, Palacky University & Institute of Experimental Botany, The Czech Academy of Sciences, Slechtitelu 27, CZ-783 71 Olomouc, Czech Republic.
Fluctuating environmental conditions trigger adaptive responses in plants, which are regulated by phytohormones. During photoperiod stress caused by a prolongation of the light period, cytokinin (CK) has a protective function. Auxin often acts as an antagonist of CK in developmental processes and stress responses. Here, we investigated the regulation of the photoperiod stress response in Arabidopsis thaliana by auxin and its interaction with CK. Transcriptome analysis revealed an altered transcript abundance of numerous auxin metabolism and signaling genes after photoperiod stress treatment. The changes appeared earlier and were stronger in the photoperiod-stress-sensitive CK receptor mutant arabidopsis histidine kinase 2 (ahk2),3 compared to wild-type plants. The concentrations of indole-3-acetic acid (IAA), IAA-Glc and IAA-Asp increased in both genotypes, but the increases were more pronounced in ahk2,3. Genetic analysis revealed that the gain-of-function YUCCA 1 (YUC1) mutant, yuc1D, displayed an increased photoperiod stress sensitivity. In contrast, a loss of the auxin receptors TRANSPORT-INHIBITOR-RESISTANT 1 (TIR1), AUXIN SIGNALING F-BOX 2 (AFB2) and AFB3 in wild-type and ahk2,3 background caused a reduced photoperiod stress response. Overall, this study revealed that auxin promotes response to photoperiod stress antagonizing the protective CK.
PMID: 35328357
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (5) doi: 10.3390/ijms23052696
Thidiazuron Promotes Leaf Abscission by Regulating the Crosstalk Complexities between Ethylene, Auxin, and Cytokinin in Cotton.
Engineering Research Center of Plant Growth Regulator, Ministry of Education/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China.; Institute of Agricultural Information, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.; High Latitude Crops Institute, Shanxi Agriculture University, Datong 037008, China.
Thidiazuron (TDZ) is widely used as a defoliant to induce leaf abscission in cotton. However, the underlying molecular mechanism is still unclear. In this study, RNA-seq and enzyme-linked immunosorbent assays (ELISA) were performed to reveal the dynamic transcriptome profiling and the change of endogenous phytohormones upon TDZ treatment in leaf, petiole, and abscission zone (AZ). We found that TDZ induced the gene expression of ethylene biosynthesis and signal, and promoted ethylene accumulation earlier in leaf than that in AZ. While TDZ down-regulated indole-3-acetic acid (IAA) biosynthesis genes mainly in leaf and IAA signal and transport genes. Furthermore, the IAA content reduced more sharply in the leaf than that in AZ to change the auxin gradient for abscission. TDZ suppressed CTK biosynthesis genes and induced CTK metabolic genes to reduce the IPA accumulation for the reduction of ethylene sensitivity. Furthermore, TDZ regulated the gene expression of abscisic acid (ABA) biosynthesis and signal and induced ABA accumulation between 12-48 h, which could up-regulate ABA response factor genes and inhibit IAA transporter genes. Our data suggest that TDZ orchestrates metabolism and signal of ethylene, auxin, and cytokinin, and also the transport of auxin in leaf, petiole, and AZ, to control leaf abscission.
PMID: 35269837
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (5) doi: 10.3390/ijms23052472
Combined BSA-Seq Based Mapping and RNA-Seq Profiling Reveal Candidate Genes Associated with Plant Architecture in Brassica napus.
National Center of Rapeseed Improvement in Wuhan, National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Plant architecture involves important agronomic traits affecting crop yield, resistance to lodging, and fitness for mechanical harvesting in Brassica napus. Breeding high-yield varieties with plant architecture suitable for mechanical harvesting is the main goal of rapeseed breeders. Here, we report an accession of B. napus (4942C-5), which has a dwarf and compact plant architecture in contrast to cultivated varieties. A BC8 population was constructed by crossing a normal plant architecture line, 8008, with the recurrent parent 4942C-5. To investigate the molecular mechanisms underlying plant architecture, we performed phytohormone profiling, bulk segregant analysis sequencing (BSA-Seq), and RNA sequencing (RNA-Seq) in BC8 plants with contrasting plant architecture. Genetic analysis indicated the plant architecture traits of 4942C-5 were recessive traits controlled by multiple genes. The content of auxin (IAA), gibberellin (GA), and abscisic acid (ABA) differed significantly between plants with contrasting plant architecture in the BC8 population. Based on BSA-Seq analysis, we identified five candidate intervals on chromosome A01, namely those of 0 to 6.33 Mb, 6.45 to 6.48 Mb, 6.51 to 6.53 Mb, 6.77 to 6.79 Mb, and 7 to 7.01 Mb regions. The RNA-Seq analysis revealed a total of 4378 differentially expressed genes (DEGs), of which 2801 were up-regulated and 1577 were down-regulated. There, further analysis showed that genes involved in plant hormone biosynthesis and signal transduction, cell structure, and the phenylpropanoid pathway might play a pivotal role in the morphogenesis of plant architecture. Association analysis of BSA-Seq and RNA-Seq suggested that seven DEGs involved in plant hormone signal transduction and a WUSCHEL-related homeobox (WOX) gene (BnaA01g01910D) might be candidate genes responsible for the dwarf and compact phenotype in 4942C-5. These findings provide a foundation for elucidating the mechanisms underlying rapeseed plant architecture and should contribute to breed new varieties suitable for mechanization.
PMID: 35269615
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23042361
Maize Transcription Factor ZmARF4 Confers Phosphorus Tolerance by Promoting Root Morphological Development.
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Wenjiang 611130, China.; Maize Research Institute, Sichuan Agricultural University, Wenjiang 611130, China.; Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Wenjiang 611130, China.; Triticeae Research Institute and Key Lab for Major Crop Diseases, Sichuan Agricultural University, Wenjiang 611130, China.
Plant growth and development are closely related to phosphate (Pi) and auxin. However, data regarding auxin response factors (ARFs) and their response to phosphate in maize are limited. Here, we isolated ZmARF4 in maize and dissected its biological function response to Pi stress. Overexpression of ZmARF4 in Arabidopsis confers tolerance of Pi deficiency with better root morphology than wild-type. Overexpressed ZmARF4 can partially restore the absence of lateral roots in mutant arf7 arf19. The ZmARF4 overexpression promoted Pi remobilization and up-regulated AtRNS1, under Pi limitation while it down-regulated the expression of the anthocyanin biosynthesis genes AtDFR and AtANS. A continuous detection revealed higher activity of promoter in the Pi-tolerant maize P178 line than in the sensitive 9782 line under low-Pi conditions. Meanwhile, GUS activity was specifically detected in new leaves and the stele of roots in transgenic offspring. ZmARF4 was localized to the nucleus and cytoplasm of the mesophyll protoplast and interacted with ZmILL4 and ZmChc5, which mediate lateral root initiation and defense response, respectively. ZmARF4 overexpression also conferred salinity and osmotic stress tolerance in Arabidopsis. Overall, our findings suggest that ZmARF4, a pleiotropic gene, modulates multiple stress signaling pathways, and thus, could be a candidate gene for engineering plants with multiple stress adaptation.
PMID: 35216479
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23042228
Salicylic Acid in Root Growth and Development.
Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia.; Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia.
In plants, salicylic acid (SA) is a hormone that mediates a plant's defense against pathogens. SA also takes an active role in a plant's response to various abiotic stresses, including chilling, drought, salinity, and heavy metals. In addition, in recent years, numerous studies have confirmed the important role of SA in plant morphogenesis. In this review, we summarize data on changes in root morphology following SA treatments under both normal and stress conditions. Finally, we provide evidence for the role of SA in maintaining the balance between stress responses and morphogenesis in plant development, and also for the presence of SA crosstalk with other plant hormones during this process.
PMID: 35216343
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23042210
BnERF114.A1, a Rapeseed Gene Encoding APETALA2/ETHYLENE RESPONSE FACTOR, Regulates Plant Architecture through Auxin Accumulation in the Apex in Arabidopsis.
State Key Laboratory of Stress Biology for Arid Areas, Northwest A&F University, Xianyang 712100, China.; Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan 430062, China.
Plant architecture is crucial for rapeseed breeding. Here, we demonstrate the involvement of BnERF114.A1, a transcription factor for ETHYLENE RESPONSE FACTOR (ERF), in the regulation of plant architecture in Brassica napus. BnERF114.A1 is a member of the ERF family group X-a, encoding a putative 252-amino acid (aa) protein, which harbours the AP2/ERF domain and the conserved CMX-1 motif. BnERF114.A1 is localised to the nucleus and presents transcriptional activity, with the functional region located at 142-252 aa of the C-terminus. GUS staining revealed high BnERF114.A1 expression in leaf primordia, shoot apical meristem, leaf marginal meristem, and reproductive organs. Ectopic BnERF114.A1 expression in Arabidopsis reduced plant height, increased branch and silique number per plant, and improved seed yield per plant. Furthermore, in Arabidopsis, BnERF114.A1 overexpression inhibited indole-3-acetic acid (IAA) efflux, thus promoting auxin accumulation in the apex and arresting apical dominance. Therefore, BnERF114.A1 probably plays an important role in auxin-dependent plant architecture regulation.
PMID: 35216327
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23042091
Global N(6)-Methyladenosine Profiling Revealed the Tissue-Specific Epitranscriptomic Regulation of Rice Responses to Salt Stress.
Institute of Crop Sciences, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; College of Agronomy, Anhui Agricultural University, Hefei 230036, China.; National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya 572024, China.
N(6)-methyladenosine (m(6)A) methylation represents a new layer of the epitranscriptomic regulation of plant development and growth. However, the effects of m(6)A on rice responses to environmental stimuli remain unclear. In this study, we performed a methylated-RNA immunoprecipitation sequencing analysis and compared the changes in m(6)A methylation and gene expression in rice under salt stress conditions. Salt stress significantly increased the m(6)A methylation in the shoots (p value < 0.05). Additionally, 2537 and 2304 differential m(6)A sites within 2134 and 1997 genes were identified in the shoots and roots, respectively, under salt stress and control conditions. These differential m(6)A sites were largely regulated in a tissue-specific manner. A unique set of genes encoding transcription factors, antioxidants, and auxin-responsive proteins had increased or decreased m(6)A methylation levels only in the shoots or roots under salt stress, implying m(6)A may mediate salt tolerance by regulating transcription, ROS homeostasis, and auxin signaling in a tissue-specific manner. Integrating analyses of m(6)A modifications and gene expression changes revealed that m(6)A changes regulate the expression of genes controlling plant growth, stress responses, and ion transport under saline conditions. These findings may help clarify the regulatory effects of m(6)A modifications on rice salt tolerance.
PMID: 35216209
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23042073
Transcriptomic Analysis Suggests Auxin Regulation in Dorsal-Ventral Petal Asymmetry of Wild Progenitor Sinningia speciosa.
Department of Life Science, National Taiwan University, Taipei 10617, Taiwan.; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.; Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei 10617, Taiwan.; Institute of Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
The establishment of dorsal-ventral (DV) petal asymmetry is accompanied by differential growth of DV petal size, shape, and color differences, which enhance ornamental values. Genes involved in flower symmetry in Sinningia speciosa have been identified as CYCLOIDEA (SsCYC), but which gene regulatory network (GRN) is associated with SsCYC to establish DV petal asymmetry is still unknown. To uncover the GRN of DV petal asymmetry, we identified 630 DV differentially expressed genes (DV-DEGs) from the RNA-Seq of dorsal and ventral petals in the wild progenitor, S. speciosa 'ES'. Validated by qRT-PCR, genes in the auxin signaling transduction pathway, SsCYC, and a major regulator of anthocyanin biosynthesis were upregulated in dorsal petals. These genes correlated with a higher endogenous auxin level in dorsal petals, with longer tube length growth through cell expansion and a purple dorsal color. Over-expression of SsCYC in Nicotiana reduced petal size by regulating cell growth, suggesting that SsCYC also controls cell expansion. This suggests that auxin and SsCYC both regulate DV petal asymmetry. Transiently over-expressed SsCYC, however, could not activate most major auxin signaling genes, suggesting that SsCYC may not trigger auxin regulation. Whether auxin can activate SsCYC or whether they act independently to regulate DV petal asymmetry remains to be explored in the future.
PMID: 35216188
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (4) doi: 10.3390/ijms23041933
Auxin/Cytokinin Antagonistic Control of the Shoot/Root Growth Ratio and Its Relevance for Adaptation to Drought and Nutrient Deficiency Stresses.
Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546, USA.
The hormones auxin and cytokinin regulate numerous aspects of plant development and often act as an antagonistic hormone pair. One of the more striking examples of the auxin/cytokinin antagonism involves regulation of the shoot/root growth ratio in which cytokinin promotes shoot and inhibits root growth, whereas auxin does the opposite. Control of the shoot/root growth ratio is essential for the survival of terrestrial plants because it allows growth adaptations to water and mineral nutrient availability in the soil. Because a decrease in shoot growth combined with an increase in root growth leads to survival under drought stress and nutrient limiting conditions, it was not surprising to find that auxin promotes, while cytokinin reduces, drought stress tolerance and nutrient uptake. Recent data show that drought stress and nutrient availability also alter the cytokinin and auxin signaling and biosynthesis pathways and that this stress-induced regulation affects cytokinin and auxin in the opposite manner. These antagonistic effects of cytokinin and auxin suggested that each hormone directly and negatively regulates biosynthesis or signaling of the other. However, a growing body of evidence supports unidirectional regulation, with auxin emerging as the primary regulatory component. This master regulatory role of auxin may not come as a surprise when viewed from an evolutionary perspective.
PMID: 35216049
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (3) doi: 10.3390/ijms23031915
Screening of Differentially Expressed Genes and Localization Analysis of Female Gametophyte at the Free Nuclear Mitosis Stage in Pinus tabuliformis Carr.
College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.; College of Horticulture, Jilin Agriculture University, Changchun 130118, China.
Female sterility is a common phenomenon in the plant world, and systematic research has not been carried out in gymnosperms. In this study, the ovules of No. 28 sterile line and No. 15 fertile line Pinus tabuliformis were used as materials, and a total of 18 cDNA libraries were sequenced by the HiSeqTM 4000 platform to analyze the differentially expressed genes (DEGs) and simple sequence repeats (SSRs) between the two lines. In addition, this study further analyzed the DEGs involved in the signal transduction of plant hormones, revealing that the signal pathways related to auxin, cytokinin, and gibberellin were blocked in the sterile ovule. Additionally, real-time fluorescent quantitative PCR verified that the expression trend of DEGs related to plant hormones was consistent with the results of high-throughput sequencing. Frozen sections and fluorescence in situ hybridization (FISH) were used to study the temporal and spatial expression patterns of PtRab in the ovules of P. tabuliformis. It was found that PtRab was significantly expressed in female gametophytes and rarely expressed in the surrounding diploid tissues. This study further explained the molecular regulation mechanism of female sterility in P. tabuliformis, preliminarily mining the key factors of ovule abortion in gymnosperms at the transcriptional level.
PMID: 35163836
Int J Mol Sci , IF:5.923 , 2022 Feb , V23 (3) doi: 10.3390/ijms23031810
Phytoplasma Infection Blocks Starch Breakdown and Triggers Chloroplast Degradation, Leading to Premature Leaf Senescence, Sucrose Reallocation, and Spatiotemporal Redistribution of Phytohormones.
Molecular Plant Pathology Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA.; Electron and Confocal Microscopy Unit, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA.
Witches'-broom (WB, excessive initiation, and outgrowth of axillary buds) is one of the remarkable symptoms in plants caused by phytoplasmas, minute wall-less intracellular bacteria. In healthy plants, axillary bud initiation and outgrowth are regulated by an intricate interplay of nutrients (such as sugars), hormones, and environmental factors. However, how these factors are involved in the induction of WB by phytoplasma is poorly understood. We postulated that the WB symptom is a manifestation of the pathologically induced redistribution of sugar and phytohormones. Employing potato purple top phytoplasma and its alternative host tomato (Solanum lycopersicum), sugar metabolism and transportation, and the spatiotemporal distribution of phytohormones were investigated. A transmission electron microscopy (TEM) analysis revealed that starch breakdown was inhibited, resulting in the degradation of damaged chloroplasts, and in turn, premature leaf senescence. In the infected source leaves, two marker genes encoding asparagine synthetase (Sl-ASN) and trehalose-6-phosphate synthase (Sl-TPS) that induce early leaf senescence were significantly up-regulated. However, the key gibberellin biosynthesis gene that encodes ent-kaurene synthase (Sl-KS) was suppressed. The assessment of sugar content in various infected tissues (mature leaves, stems, roots, and leaf axils) indicated that sucrose transportation through phloem was impeded, leading to sucrose reallocation into the leaf axils. Excessive callose deposition and the resulting reduction in sieve pore size revealed by aniline blue staining and TEM provided additional evidence to support impaired sugar transport. In addition, a spatiotemporal distribution study of cytokinin and auxin using reporter lines detected a cytokinin signal in leaf axils where the axillary buds initiated. However, the auxin responsive signal was rarely present in such leaf axils, but at the tips of the newly elongated buds. These results suggested that redistributed sucrose as well as cytokinin in leaf axils triggered the axillary bud initiation, and auxin played a role in the bud elongation. The expression profiles of genes encoding squamosa promoter-binding proteins (Sl-SBP1), and BRANCHED1 (Sl-BRC1a and Sl-BRC1b) that control axillary bud release, as determined by quantitative reverse transcription (qRT)-PCR, indicated their roles in WB induction. However, their interactions with sugars and cytokinins require further study. Our findings provide a comprehensive insight into the mechanisms by which phytoplasmas induce WB along with leaf chlorosis, little leaf, and stunted growth.
PMID: 35163732
Front Bioeng Biotechnol , IF:5.89 , 2022 , V10 : P837965 doi: 10.3389/fbioe.2022.837965
Process Engineering of Biopharmaceutical Production in Moss Bioreactors via Model-Based Description and Evaluation of Phytohormone Impact.
Plant Biotechnology, Faculty of Biology, University of Freiburg, Freiburg, Germany.; Institute of Process Engineering in Life Sciences III Bioprocess Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
The moss Physcomitrella is an interesting production host for recombinant biopharmaceuticals. Here we produced MFHR1, a synthetic complement regulator which has been proposed for the treatment of diseases associated to the complement system as part of human innate immunity. We studied the impact of different operation modes for the production process in 5 L stirred-tank photobioreactors. The total amount of recombinant protein was doubled by using fed-batch or batch compared to semi-continuous operation, although the maximum specific productivity (mg MFHR1/g FW) increased just by 35%. We proposed an unstructured kinetic model which fits accurately with the experimental data in batch and semi-continuous operation under autotrophic conditions with 2% CO2 enrichment. The model is able to predict recombinant protein production, nitrate uptake and biomass growth, which is useful for process control and optimization. We investigated strategies to further increase MFHR1 production. While mixotrophic and heterotrophic conditions decreased the MFHR1-specific productivity compared to autotrophic conditions, addition of the phytohormone auxin (NAA, 10 microM) to the medium enhanced it by 470% in shaken flasks and up to 230% and 260%, in batch and fed-batch bioreactors, respectively. Supporting this finding, the auxin-synthesis inhibitor L-kynurenine (100 microM) decreased MFHR1 production significantly by 110% and 580% at day 7 and 18, respectively. Expression analysis revealed that the MFHR1 transgene, driven by the Physcomitrella actin5 (PpAct5) promoter, was upregulated 16 h after NAA addition and remained enhanced over the whole process, whereas the auxin-responsive gene PpIAA1A was upregulated within the first 2 hours, indicating that the effect of auxin on PpAct5 promoter-driven expression is indirect. Furthermore, the day of NAA supplementation was crucial, leading to an up to 8-fold increase of MFHR1-specific productivity (0.82 mg MFHR1/g fresh weight, 150 mg accumulated over 7 days) compared to the productivity reported previously. Our findings are likely to be applicable to other plant-based expression systems to increase biopharmaceutical production and yields.
PMID: 35252145
Front Plant Sci , IF:5.753 , 2022 , V13 : P833747 doi: 10.3389/fpls.2022.833747
ARF6s Identification and Function Analysis Provide Insights Into Flower Development of Punica granatum L.
Co-innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.; College of Forestry, Nanjing Forestry University, Nanjing, China.
Based on the genome and small-RNA sequencing of pomegranate, miRNA167 and three target genes PgARF6 were identified in "Taishanhong" genome. Three PgARF6 genes and their corresponding protein sequences, expression patterns in pomegranate flower development and under exogenous hormones treatments were systematically analyzed in this paper. We found that PgARF6s are nuclear proteins with conserved structures. However, PgARF6s had different protein structures and expression profiles in pomegranate flower development. At the critical stages of pomegranate ovule sterility (8.1-14.0 mm), the expression levels of PgARF6s in bisexual flowers were lower than those in functional male flowers. Interestingly, PgARF6c expression level was significantly higher than PgARF6a and PgARF6b. Under the treatment of exogenous IBA and 6-BA, PgARF6s were down-regulated, and the expression of PgARF6c was significantly inhibited. PgmiR167a and PgmiR167d had the binding site on PgARF6 genes sequences, and PgARF6a has the directly targeted regulatory relationship with PgmiR167a in pomegranate. At the critical stage of ovule development (8.1-12.0 mm), exogenous IBA and 6-BA promoted the content of GA and ZR accumulation, inhibited BR accumulation. There was a strong correlation between the expression of PgARF6a and PgARF6b. Under exogenous hormone treatment, the content of ZR, BR, GA, and ABA were negatively correlated with the expressions of PgARF6 genes. However, JA was positively correlated with PgARF6a and PgARF6c under IBA treatment. Thus, our results provide new evidence for PgARF6 genes involving in ovule sterility in pomegranate flowers.
PMID: 35321445
Front Plant Sci , IF:5.753 , 2022 , V13 : P798580 doi: 10.3389/fpls.2022.798580
Transcriptomic Analysis Revealed Reactive Oxygen Species Scavenging Mechanisms Associated With Ferrous Iron Toxicity in Aromatic Keteki Joha Rice.
Department of Life Science and Bioinformatics, Assam University, Silchar, India.; Plant Molecular Biology Laboratory, Department of Botany, Gauhati University, Guwahati, India.; Department of Botany, Pragjyotish College, Guwahati, India.; Department of Botany, Guwahati College, Guwahati, India.; Department of Biochemistry, Central University of Rajasthan, Ajmer, India.
Lowland acidic soils with water-logged regions are often affected by ferrous iron (Fe(2+)) toxicity, a major yield-limiting factor of rice production. Under severe Fe(2+) toxicity, reactive oxygen species (ROS) are crucial, although molecular mechanisms and associated ROS homeostasis genes are still unknown. In this study, a comparative RNA-Seq based transcriptome analysis was conducted to understand the Fe(2+) toxicity tolerance mechanism in aromatic Keteki Joha. About 69 Fe homeostasis related genes and their homologs were identified, where most of the genes were downregulated. Under severe Fe(2+) toxicity, the biosynthesis of amino acids, RNA degradation, and glutathione metabolism were induced, whereas phenylpropanoid biosynthesis, photosynthesis, and fatty acid elongation were inhibited. The mitochondrial iron transporter (OsMIT), vacuolar iron transporter 2 (OsVIT2), ferritin (OsFER), vacuolar mugineic acid transporter (OsVMT), phenolic efflux zero1 (OsPEZ1), root meander curling (OsRMC), and nicotianamine synthase (OsNAS3) were upregulated in different tissues, suggesting the importance of Fe retention and sequestration for detoxification. However, several antioxidants, ROS scavenging genes and abiotic stress-responsive transcription factors indicate ROS homeostasis as one of the most important defense mechanisms under severe Fe(2+) toxicity. Catalase (CAT), glutathione (GSH), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) were upregulated. Moreover, abiotic stress-responsive transcription factors, no apical meristem (NAC), myeloblastosis (MYB), auxin response factor (ARF), basic helix-loop-helix (bZIP), WRKY, and C2H2-zinc finger protein (C2H2-ZFP) were also upregulated. Accordingly, ROS homeostasis has been proposed as an essential defense mechanism under such conditions. Thus, the current study may enrich the understanding of Fe-homeostasis in rice.
PMID: 35283928
Front Plant Sci , IF:5.753 , 2022 , V13 : P770284 doi: 10.3389/fpls.2022.770284
Triploid Hybrid Vigor in Above-Ground Growth and Methane Fermentation Efficiency of Energy Willow.
Institute of Plant Biology, Biological Research Centre, Eotvos Lorand Research Network (ELKH), Szeged, Hungary.; Department of Plant Biology, University of Szeged, Szeged, Hungary.; Department of Biological Resources, Centre for Agricultural Research, Agricultural Institute, Martonvasar, Hungary.; Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia.; UBM Feed Zrt. Pilisvorosvar, Hungary.; Department of Biotechnology, University of Szeged, Szeged, Hungary.
Hybrid vigor and polyploidy are genetic events widely utilized to increase the productivity of crops. Given that bioenergy usage needs to be expanded, we investigated triploid hybrid vigor in terms of the biology of biomass-related willow traits and their relevance to the control of biomethane production. To produce triploid hybrid genotypes, we crossed two female diploid Swedish cultivars (Inger, Tordis) with two male autotetraploid willow (Salix viminalis) variants (PP-E7, PP-E15). Field studies at two locations and in two successive years recorded considerable midparent heterosis (MPH%) in early shoot length that ranged between 11.14 and 68.85% and in the growth rate between 34.12 and 97.18%. The three triploid hybrids (THs) developed larger leaves than their parental cultivars, and the MPH% for their CO2 assimilation rate varied between 0.84 and 25.30%. The impact of hybrid vigor on the concentrations of plant hormones in these TH genotypes reflected essentially different hormonal statuses that depended preferentially on maternal parents. Hybrid vigor was evinced by an elevated concentration of jasmonic acid in shoot meristems of all the three THs (MPH:29.73; 67.08; 91.91%). Heterosis in auxin-type hormones, such as indole-3-acetic acid (MPH:207.49%), phenylacetic acid (MPH:223.51%), and salicylic acid (MPH:27.72%) and benzoic acid (MPH:85.75%), was detectable in the shoots of TH21/2 plants. These hormones also accumulated in their maternal Inger plants. Heterosis in cytokinin-type hormones characterized the shoots of TH3/12 and TH17/17 genotypes having Tordis as their maternal parent. Unexpectedly, we detected abscisic acid as a positive factor in the growth of TH17/17 plants with negative MPH percentages in stomatal conductance and a lower CO2 assimilation rate. During anaerobic digestion, wood raw materials from the triploid willow hybrids that provided positive MPH% in biomethane yield (6.38 and 27.87%) showed negative MPH in their acid detergent lignin contents (from -8.01 to -14.36%). Altogether, these insights into controlling factors of above-ground growth parameters of willow genotypes support the utilization of triploid hybrid vigor in willow breeding to expand the cultivation of short rotation energy trees for renewable energy production.
PMID: 35283877
Front Plant Sci , IF:5.753 , 2022 , V13 : P821563 doi: 10.3389/fpls.2022.821563
Biological Functions of Strigolactones and Their Crosstalk With Other Phytohormones.
Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China.
Phytohormones are small chemicals critical for plant development and adaptation to a changing environment. Strigolactones (SLs), carotenoid-derived small signalling molecules and a class of phytohormones, regulate multiple developmental processes and respond to diverse environmental signals. SLs also coordinate adjustments in the balance of resource distribution by strategic modification of the plant development, allowing plants to adapt to nutrient deficiency. Instead of operating independently, SL interplays with abscisic acid, cytokinin, auxin, ethylene, and some other plant phytohormones, forming elaborate signalling networks. Hormone signalling crosstalk in plant development and environmental response may occur in a fully concerted manner or as a cascade of sequential events. In many cases, the exact underlying mechanism is unclear because of the different effects of phytohormones and the varying backgrounds of their actions. In this review, we systematically summarise the synthesis, signal transduction, and biological functions of SLs and further highlight the significance of crosstalk between SLs and other phytohormones during plant development and resistance to ever-changing environments.
PMID: 35283865
Front Plant Sci , IF:5.753 , 2022 , V13 : P837130 doi: 10.3389/fpls.2022.837130
Deciphering Novel Transcriptional Regulators of Soybean Hypocotyl Elongation Based on Gene Co-expression Network Analysis.
College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.; State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China.; Academy for Advanced Interdisciplinary Studies, Henan University, Kaifeng, China.
Hypocotyl elongation is the key step of soybean seed germination, as well an important symbol of seedling vitality, but the regulatory mechanisms remain largely elusive. To address the problem, bioinformatics approaches along with the weighted gene co-expression network analysis (WGCNA) were carried out to elucidate the regulatory networks and identify key regulators underlying soybean hypocotyl elongation at transcriptional level. Combining results from WGCNA, yeast one hybridization, and phenotypic analysis of transgenic plants, a cyan module significantly associated with hypocotyl elongation was discerned, from which two novel regulatory submodules were identified as key candidates underpinning soybean hypocotyl elongation by modulating auxin and light responsive signaling pathways. Taken together, our results constructed the regulatory network and identified novel transcriptional regulators of soybean hypocotyl elongation based on WGCNA, which provide new insights into the global regulatory basis of soybean hypocotyl elongation and offer potential targets for soybean improvement to acquire cultivars with well-tuned hypocotyl elongation and seed germination vigor.
PMID: 35273629
Front Plant Sci , IF:5.753 , 2021 , V12 : P767044 doi: 10.3389/fpls.2021.767044
Auxin-Glucose Conjugation Protects the Rice (Oryza sativa L.) Seedlings Against Hydroxyurea-Induced Phytotoxicity by Activating UDP-Glucosyltransferase Enzyme.
Division of Applied Life Science (BK 21 Four), Gyeongsang National University, Jinju, South Korea.; Department of Biotechnology, PSGR Krishnammal College for Women, Coimbatore, India.; Institute of Agriculture and Life Science (IALS), Gyeongsang National University, Jinju, South Korea.; Department of Smart Agro-Industry, Gyeongsang National University, Jinju, South Korea.; Division of Plant Sciences, University of Missouri, Columbia, MO, United States.
Hydroxyurea (HU) is the replication stress known to carry out cell cycle arrest by inhibiting ribonucleotide reductase (RNR) enzyme upon generating excess hydrogen peroxide (H2O2) in plants. Phytohormones undergo synergistic and antagonistic interactions with reactive oxygen species (ROS) and redox signaling to protect plants against biotic and abiotic stress. Therefore, in this study, we investigated the protective role of Indole-3-acetic acid (IAA) in mitigating HU-induced toxicity in rice seedlings. The results showed that IAA augmentation improved the growth of the seedlings and biomass production by maintaining photosynthesis metabolism under HU stress. This was associated with reduced H2O2 and malondialdehyde (MDA) contents and improved antioxidant enzyme [superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD)] activity that was significantly affected under HU stress. Furthermore, we showed that the HU stress-induced DNA damage leads to the activation of uridine 5'-diphosphate-glucosyltransferase (UGT), which mediates auxin homeostasis by catalyzing IAA-glucose conjugation in rice. This IAA-glucose conjugation upregulates the RNR, transcription factor 2 (E2F2), cyclin-dependent kinase (CDK), and cyclin (CYC) genes that are vital for DNA replication and cell division. As a result, perturbed IAA homeostasis significantly enhanced the key phytohormones, such as abscisic acid (ABA), salicylic acid (SA), cytokinin (CTK), and gibberellic acid (GA), that alter plant architecture by improving growth and development. Collectively, our results contribute to a better understanding of the physiological and molecular mechanisms underpinning improved growth following the HU + IAA combination, activated by phytohormone and ROS crosstalk upon hormone conjugation via UGT.
PMID: 35251058
Front Plant Sci , IF:5.753 , 2022 , V13 : P818233 doi: 10.3389/fpls.2022.818233
Transcriptomic and Physiological Analysis Reveals the Responses to Auxin and Abscisic Acid Accumulation During Vaccinium corymbosum Flower Bud and Fruit Development.
College of Chemistry and Life Sciences, Zhejiang Normal University, Zhejiang, China.; Zhejiang Provincial Key Laboratory of Biotechnology on Specialty Economic Plants, Zhejiang Normal University, Zhejiang, China.
Blueberry (Vaccinium corymbosum) is reputed as a rich source of health-promoting phytonutrients, which contributes to its burgeoning consumer demand and production. However, blueberries are much smaller and have lower yields than most domesticated berries, and the inherent regulatory mechanisms remain elusive. In this study, the cytological and physiological changes, as well as comparative transcriptomic analysis throughout flower and fruit development in the southern highbush blueberry cultivar 'O'Neal' were performed. 'O'Neal' hypanthium and fruit exhibited a distinctive cell proliferation pattern, and auxin accumulation was unusual throughout development, while abscisic acid (ABA) levels rapidly increased in association with anthocyanin accumulation, total phenolic reduction and fruit maturation. Transcriptomic data showed that many differentially expressed genes (DEGs) were specifically expressed at each flower bud and fruit developmental stage. Further weighted gene co-expression network analysis (WGCNA) revealed numerous DEGs that correlated with the cell numbers of outer mesocarp and columella, showed two distinctive expression patterns. Most of the DEGs involved in auxin biosynthesis, transportation and signal transduction were upregulated, and this upregulation was accompanied by cell expansion, and flower bud and fruit development. However, individual members of VcSAUR50 and VcIAA9 families might be insensitive to auxin, suggesting that these genes play a distinctive role in the growth and development of blueberry fruits. These results will support future research to better understand the flower and fruit development of southern highbush blueberry.
PMID: 35242154
Front Plant Sci , IF:5.753 , 2022 , V13 : P828923 doi: 10.3389/fpls.2022.828923
Transcriptomic Variations and Network Hubs Controlling Seed Size and Weight During Maize Seed Development.
Henan Provincial Key Laboratory of Maize Biology, Institute of Cereal Crops, Henan Academy of Agricultural Sciences, Zhengzhou, China.; Institute of Industrial Crops, Henan Academy of Agricultural Sciences, Zhengzhou, China.; State Kay Laboratory of Agro-biotechnology and Key Laboratory of Pest Monitoring and Green Management-MOA, China Agricultural University, Beijing, China.; Henan Maize Engineering Technology Joint Center, Henan Agricultural University, Zhengzhou, China.
To elucidate the mechanisms underlying seed development in maize, comprehensive RNA-seq analyses were conducted on Zhengdan1002 (ZD1002), Zhengdan958 (ZD958), and their parental lines during seven seed developmental stages. We found that gene expression levels were largely nonadditive in hybrids and that cis-only or trans x cis pattern played a large role in hybrid gene regulation during seed developmental stage. Weighted gene co-expression network (WGCNA) analysis showed that 36 modules were highly correlated (r = -0.90-0.92, p < 0.05) with kernel weight, length, and width during seed development. Forty-five transcription factors and 38 ribosomal protein genes were identified as major hub genes determining seed size/weight. We also described a network hub, Auxin Response Factor 12 of maize (ZmARF12), a member of a family of transcription factor that mediate gene expression in response to auxin, potentially links auxin signal pathways, cell division, and the size of the seeds. The ZmARF12 mutant exhibited larger seed size and higher grain weight. ZmARF12 transcription was negatively associated with cell division during seed development, which was confirmed by evaluating the yield of protoplasts that isolated from the kernels of the mutant and other inbred lines. Transient knock-down of ZmARF12 in maize plants facilitated cell expansion and division, whereas transient silencing of its potential interactor ZmIAA8 impaired cell division. ZmIAA8 expression was repressed in the ZmARF12 over-expressed protoplasts. The mutant phenotype and the genetics studies presented here illustrated evidence that ZmARF12 is a cell division repressor, and potentially determines the final seed size.
PMID: 35237291
Front Plant Sci , IF:5.753 , 2022 , V13 : P809435 doi: 10.3389/fpls.2022.809435
Comprehensive Analysis of Long Non-coding RNA Modulates Axillary Bud Development in Tobacco (Nicotiana tabacum L.).
China Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute of China National Tobacco Corporation (CNTC), Zhengzhou, China.; China Tobacco Hunan Industrial Co., Ltd., Changsha, China.
Long non-coding RNAs (lncRNAs) regulate gene expression and are crucial for plant growth and development. However, the mechanisms underlying the effects of activated lncRNAs on axillary bud development remain largely unknown. By lncRNA transcriptomes of axillary buds in topped and untopped tobacco plants, we identified a total of 13,694 lncRNAs. LncRNA analysis indicated that the promoted growth of axillary bud by topping might be partially ascribed to the genes related to hormone signal transduction and glycometabolism, trans-regulated by differentially expressed lncRNAs, such as MSTRG.52498.1, MSTRG.60026.1, MSTRG.17770.1, and MSTRG.32431.1. Metabolite profiling indicated that auxin, abscisic acid and gibberellin were decreased in axillary buds of topped tobacco lines, while cytokinin was increased, consistent with the expression levels of related lncRNAs. MSTRG.52498.1, MSTRG.60026.1, MSTRG.17770.1, and MSTRG.32431.1 were shown to be influenced by hormones and sucrose treatments, and were associated with changes of axillary bud growth in the overexpression of NtCCD8 plants (with reduced axillary buds) and RNA interference of NtTB1 plants (with increased axillary buds). Moreover, MSTRG.28151.1 was identified as the antisense lncRNA of NtTB1. Silencing of MSTRG.28151.1 in tobacco significantly attenuated the expression of NtTB1 and resulted in larger axillary buds, suggesting the vital function of MSTRG.28151.1 axillary bud developmen by NtTB1. Our findings shed light on lncRNA-mRNA interactions and their functional roles in axillary bud growth, which would improve our understanding of lncRNAs as important regulators of axillary bud development and plant architecture.
PMID: 35237286
Front Plant Sci , IF:5.753 , 2022 , V13 : P809723 doi: 10.3389/fpls.2022.809723
Physio-Morphological, Biochemical and Transcriptomic Analyses Provide Insights Into Drought Stress Responses in Mesona chinensis Benth.
Guangxi Key Laboratory of Medicinal Resources Protection and Genetic Improvement, Guangxi Botanical Garden of Medicinal Plants, Nanning, China.; Guangxi Engineering Research Center of TCM Resource Intelligent Creation, Guangxi Botanical Garden of Medicinal Plants, Nanning, China.
Drought stress affects the normal growth and development of Mesona chinensis Benth (MCB), which is an important medicinal and edible plant in China. To investigate the physiological and molecular mechanisms of drought resistance in MCB, different concentrations of polyethylene glycol 6000 (PEG6000) (0, 5, 10, and 15%) were used to simulate drought conditions in this study. Results showed that the growth of MCB was significantly limited under drought stress conditions. Drought stress induced the increases in the contents of Chla, Chlb, Chla + b, soluble protein, soluble sugar, and soluble pectin and the activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), hydrogen peroxide (H2O2), and malondialdehyde (MDA). Transcriptome analysis revealed 3,494 differentially expressed genes (DEGs) (1,961 up-regulated and 1,533 down-regulated) between the control and 15% PEG6000 treatments. These DEGs were identified to be involved in the 10 metabolic pathways, including "plant hormone signal transduction," "brassinosteroid biosynthesis," "plant-pathogen interaction," "MAPK signaling pathway-plant," "starch and sucrose metabolism," "pentose and glucuronate interconversions," "phenylpropanoid biosynthesis," "galactose metabolism," "monoterpenoid biosynthesis," and "ribosome." In addition, transcription factors (TFs) analysis showed 8 out of 204 TFs, TRINITY_DN3232_c0_g1 [ABA-responsive element (ABRE)-binding transcription factor1, AREB1], TRINITY_DN4161_c0_g1 (auxin response factor, ARF), TRINITY_DN3183_c0_g2 (abscisic acid-insensitive 5-like protein, ABI5), TRINITY_DN28414_c0_g2 (ethylene-responsive transcription factor ERF1b, ERF1b), TRINITY_DN9557_c0_g1 (phytochrome-interacting factor, PIF3), TRINITY_DN11435_c1_g1, TRINITY_DN2608_c0_g1, and TRINITY_DN6742_c0_g1, were closely related to the "plant hormone signal transduction" pathway. Taken together, it was inferred that these pathways and TFs might play important roles in response to drought stress in MCB. The current study provided important information for MCB drought resistance breeding in the future.
PMID: 35222473
Front Plant Sci , IF:5.753 , 2022 , V13 : P804716 doi: 10.3389/fpls.2022.804716
Salt-Specific Gene Expression Reveals Elevated Auxin Levels in Arabidopsis thaliana Plants Grown Under Saline Conditions.
Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom.; Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, South Africa.; Center for Complex Network Intelligence, Tsinghua Laboratory of Brain and Intelligence, Department of Computer Science, Tsinghua University, Beijing, China.; Center for Complex Network Intelligence, Tsinghua Laboratory of Brain and Intelligence, Department of Biomedical Engineering, Tsinghua University, Beijing, China.; Center for Systems Biology Dresden (CSBD), Dresden, Germany.; International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.; Laboratory of Growth Regulators, Institute of Experimental Botany of the Czech Academy of Sciences and Faculty of Science of Palacky University, Olomouc, Czechia.; Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy.
Soil salinization is increasing globally, driving a reduction in crop yields that threatens food security. Salinity stress reduces plant growth by exerting two stresses on plants: rapid shoot ion-independent effects which are largely osmotic and delayed ionic effects that are specific to salinity stress. In this study we set out to delineate the osmotic from the ionic effects of salinity stress. Arabidopsis thaliana plants were germinated and grown for two weeks in media supplemented with 50, 75, 100, or 125 mM NaCl (that imposes both an ionic and osmotic stress) or iso-osmolar concentrations (100, 150, 200, or 250 mM) of sorbitol, that imposes only an osmotic stress. A subsequent transcriptional analysis was performed to identify sets of genes that are differentially expressed in plants grown in (1) NaCl or (2) sorbitol compared to controls. A comparison of the gene sets identified genes that are differentially expressed under both challenge conditions (osmotic genes) and genes that are only differentially expressed in plants grown on NaCl (ionic genes, hereafter referred to as salt-specific genes). A pathway analysis of the osmotic and salt-specific gene lists revealed that distinct biological processes are modulated during growth under the two conditions. The list of salt-specific genes was enriched in the gene ontology (GO) term "response to auxin." Quantification of the predominant auxin, indole-3-acetic acid (IAA) and IAA biosynthetic intermediates revealed that IAA levels are elevated in a salt-specific manner through increased IAA biosynthesis. Furthermore, the expression of NITRILASE 2 (NIT2), which hydrolyses indole-3-acetonitile (IAN) into IAA, increased in a salt-specific manner. Overexpression of NIT2 resulted in increased IAA levels, improved Na:K ratios and enhanced survival and growth of Arabidopsis under saline conditions. Overall, our data suggest that auxin is involved in maintaining growth during the ionic stress imposed by saline conditions.
PMID: 35222469
Front Plant Sci , IF:5.753 , 2022 , V13 : P790563 doi: 10.3389/fpls.2022.790563
Multi-Omic Investigation of Low-Nitrogen Conditional Resistance to Clubroot Reveals Brassica napus Genes Involved in Nitrate Assimilation.
IGEPP, INRAE, Institut Agro, Universite de Rennes 1, Le Rheu, France.; P2M2 PRP, BIA, INRAE, Le Rheu, France.
Nitrogen fertilization has been reported to influence the development of clubroot, a root disease of Brassicaceae species, caused by the obligate protist Plasmodiophora brassicae. Our previous works highlighted that low-nitrogen fertilization induced a strong reduction of clubroot symptoms in some oilseed rape genotypes. To further understand the underlying mechanisms, the response to P. brassicae infection was investigated in two genotypes "Yudal" and HD018 harboring sharply contrasted nitrogen-driven modulation of resistance toward P. brassicae. Targeted hormone and metabolic profiling, as well as RNA-seq analysis, were performed in inoculated and non-inoculated roots at 14 and 27 days post-inoculation, under high and low-nitrogen conditions. Clubroot infection triggered a large increase of SA concentration and an induction of the SA gene markers expression whatever the genotype and nitrogen conditions. Overall, metabolic profiles suggested that N-driven induction of resistance was independent of SA signaling, soluble carbohydrate and amino acid concentrations. Low-nitrogen-driven resistance in "Yudal" was associated with the transcriptional regulation of a small set of genes, among which the induction of NRT2- and NR-encoding genes. Altogether, our results indicate a possible role of nitrate transporters and auxin signaling in the crosstalk between plant nutrition and partial resistance to pathogens.
PMID: 35222461
Front Plant Sci , IF:5.753 , 2022 , V13 : P753264 doi: 10.3389/fpls.2022.753264
Mung Bean (Vigna radiata L.) Source Leaf Adaptation to Shading Stress Affects Not Only Photosynthetic Physiology Metabolism but Also Control of Key Gene Expression.
College of Agronomy, Shenyang Agricultural University, Shenyang, China.; State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy, Northwest A&F University, Yangling, China.
Shading stress strongly limits the effective growth of plants. Understanding how plant morphogenesis and physiological adaptation are generated in response to the reduced low light conditions is important for food crop development. In this study, two mung bean (Vigna radiata L.) cultivars, namely, Xilv 1 and Yulv 1, were grown in the field to explore the effects of shading stress on their growth. The results of morphology, physiology, and biochemistry analyses showed that the shading stress significantly weakened the leaf photosynthetic capacity as measured by the decreased net photosynthetic rate, stomatal conductance, and transpiration rate and increased intercellular CO2 concentration. These responses resulted in plant morphological characteristics that increased the light energy absorption in low light conditions. Such variations occurred due to the leaf anatomical structure with destroyed palisade tissues and spongy tissues. Under shading stress, Yulv 1 showed higher physiological metabolic intensity than Xilv 1, which was related to changes in chlorophyll (Chl), such as Chl a and b, and Chl a/b ratio. Compared with normal light conditions, the Chl fluorescence values, photosynthetic assimilation substances, and enzyme activities in mung bean plants under shading stress were reduced to different extent. In addition, the relative expression levels of VrGA2ox, VrGA20ox1, VrGA3ox1, VrROT3, and VrBZR1, which are related to endogenous hormone in mung bean leaves, were upregulated by shading stress, further leading to the improvements in the concentrations of auxin, gibberellins (GAs), and brassinolide (BR). Combined with the morphological, physiological, and molecular responses, Yulv 1 has stronger tolerance and ecological adaptability to shading stress than Xilv 1. Therefore, our study provides insights into the agronomic traits and gene expressions of mung bean cultivars to enhance their adaptability to the shading stress.
PMID: 35185974
Front Plant Sci , IF:5.753 , 2021 , V12 : P826584 doi: 10.3389/fpls.2021.826584
Genome-Wide Association Analysis Coupled With Transcriptome Analysis Reveals Candidate Genes Related to Salt Stress in Alfalfa (Medicago sativa L.).
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
Salt stress is the main abiotic factor affecting alfalfa yield and quality. However, knowledge of the genetic basis of the salt stress response in alfalfa is still limited. Here, a genome-wide association study (GWAS) involving 875,023 single-nucleotide polymorphisms (SNPs) was conducted on 220 alfalfa varieties under both normal and salt-stress conditions. Phenotypic analysis showed that breeding status and geographical origin play important roles in the alfalfa salt stress response. For germination ability under salt stress, a total of 15 significant SNPs explaining 9%-14% of the phenotypic variation were identified. For tolerance to salt stress in the seedling stage, a total of 18 significant SNPs explaining 12%-23% of the phenotypic variation were identified. Transcriptome analysis revealed 2,097 and 812 differentially expressed genes (DEGs) that were upregulated and 2,445 and 928 DEGs that were downregulated in the leaves and roots, respectively, under salt stress. Among these DEGs, many encoding transcription factors (TFs) were found, including MYB-, CBF-, NAC-, and bZIP-encoding genes. Combining the results of our GWAS analysis and transcriptome analysis, we identified a total of eight candidate genes (five candidate genes for tolerance to salt stress and three candidate genes for germination ability under salt stress). Two SNPs located within the upstream region of MsAUX28, which encodes an auxin response protein, were significantly associated with tolerance to salt stress. The two significant SNPs within the upstream region of MsAUX28 existed as three different haplotypes in this panel. Hap 1 (G/G, A/A) was under selection in the alfalfa domestication and improvement process.
PMID: 35185967
Front Plant Sci , IF:5.753 , 2021 , V12 : P807710 doi: 10.3389/fpls.2021.807710
Plant Responses Underlying Timely Specialized Metabolites Induction of Brassica Crops.
Mision Biologica de Galicia (MBG-CSIC), Pontevedra, Spain.; Department of Plant Biology, Faculty of Biology, Institute of Biotechnology and Biomedicine, University of Valencia, Valencia, Spain.; Department of Plant Sciences, University of California, Davis, Davis, CA, United States.; DynaMo Center of Excellence, University of Copenhagen, Frederiksberg, Denmark.
A large subset of plant stress-signaling pathways, including those related with chemical defense production, exhibit diurnal or circadian oscillations. However the extent to which diurnal or circadian time influences the stress mediated accumulation of plant specialized metabolites remains largely unknown. Because plant responses to physical stress (e.g., wounding) is considered a common component of mounting a response against a broad range of environmental stresses, including herbivory, we have utilized mechanical wounding as the stress stimulus to determine the direct contribution of time of day on the induced defenses of Brassica crops. We analyzed glucosinolates (GSLs) from leaves of broccoli (Brassica oleracea) and turnip greens (Brassica rapa) following exposure to mechanical wounding at dawn (ZT0), mid-day (ZT4), and dusk (ZT8). Several GSLs differentially accumulated and their changes depended upon the time of day at wounding was performed. This response varied considerably between species. In a parallel experiment, we investigated whether diurnal activation of Brassica phytochemicals in response to wounding might prime plants against herbivore attack. Results showed that maximal response of plant chemical defense against larvae of the generalist pest Mamestra brassicae occurred at ZT0 in broccoli and ZT8 in turnip greens. Metabolome analysis for global trends of time dependent compounds showed that sulfur-containing phytochemicals, GSL hydrolysis products, auxin-signaling components, and other metabolites activators of plant disease resistance (nicotinamide and pipecolate) had important contributions to the responses of M. brassicae feeding behavior in broccoli at morning. Overall, the findings in this study highlight a significant role for time of day in the wound stress responsive metabolome, which can in turn affect plant-herbivore interactions.
PMID: 35185956
Front Plant Sci , IF:5.753 , 2021 , V12 : P794582 doi: 10.3389/fpls.2021.794582
S-Nitrosation of E3 Ubiquitin Ligase Complex Components Regulates Hormonal Signalings in Arabidopsis.
Instituto de Investigaciones Biologicas, UE-CONICET-UNMDP, Facultad de Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina.; Instituto de Fisiologia, Biologia Molecular y Neurociencias (IFIBYNE), CONICET-UBA, Buenos Aires, Argentina.; Servicio de Proteomica, Centro de Biologia Molecular "Severo Ochoa", CSIC-UAM, Madrid, Spain.; Unidad de Investigacion, Hospital Universitario Santa Cristina, Instituto de Investigacion Sanitaria Princesa (IIS-IP), Madrid, Spain.; Molecular Signal Processing Department, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), Germany.; KWS Gateway Research Center, LLC., BRDG Park at The Danforth Plant Science Center, St. Louis, MO, United States.; Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA, United States.
E3 ubiquitin ligases mediate the last step of the ubiquitination pathway in the ubiquitin-proteasome system (UPS). By targeting transcriptional regulators for their turnover, E3s play a crucial role in every aspect of plant biology. In plants, SKP1/CULLIN1/F-BOX PROTEIN (SCF)-type E3 ubiquitin ligases are essential for the perception and signaling of several key hormones including auxins and jasmonates (JAs). F-box proteins, TRANSPORT INHIBITOR RESPONSE 1 (TIR1) and CORONATINE INSENSITIVE 1 (COI1), bind directly transcriptional repressors AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) and JASMONATE ZIM-DOMAIN (JAZ) in auxin- and JAs-depending manner, respectively, which permits the perception of the hormones and transcriptional activation of signaling pathways. Redox modification of proteins mainly by S-nitrosation of cysteines (Cys) residues via nitric oxide (NO) has emerged as a valued regulatory mechanism in physiological processes requiring its rapid and versatile integration. Previously, we demonstrated that TIR1 and Arabidopsis thaliana SKP1 (ASK1) are targets of S-nitrosation, and these NO-dependent posttranslational modifications enhance protein-protein interactions and positively regulate SCF(TIR1) complex assembly and expression of auxin response genes. In this work, we confirmed S-nitrosation of Cys140 in TIR1, which was associated in planta to auxin-dependent developmental and stress-associated responses. In addition, we provide evidence on the modulation of the SCF(COI1) complex by different S-nitrosation events. We demonstrated that S-nitrosation of ASK1 Cys118 enhanced ASK1-COI1 protein-protein interaction. Overexpression of non-nitrosable ask1 mutant protein impaired the activation of JA-responsive genes mediated by SCF(COI1) illustrating the functional relevance of this redox-mediated regulation in planta. In silico analysis positions COI1 as a promising S-nitrosation target, and demonstrated that plants treated with methyl JA (MeJA) or S-nitrosocysteine (NO-Cys, S-nitrosation agent) develop shared responses at a genome-wide level. The regulation of SCF components involved in hormonal perception by S-nitrosation may represent a key strategy to determine the precise time and site-dependent activation of each hormonal signaling pathway and highlights NO as a pivotal molecular player in these scenarios.
PMID: 35185952
Genomics , IF:5.736 , 2022 Mar , V114 (2) : P110271 doi: 10.1016/j.ygeno.2022.110271
Transcriptome profiling reveals major structural genes, transcription factors and biosynthetic pathways involved in leaf senescence and nitrogen remobilization in rainfed spring wheat under different nitrogen fertilization rates.
State Key Laboratory of Arid Land Crop Science, Lanzhou, China; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; CSIR-Plant Genetic Resources Research Institute (PGRRI), P. O. Box 7, Bunso, Ghana.; State Key Laboratory of Arid Land Crop Science, Lanzhou, China; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China. Electronic address: lill@gsau.edu.cn.; State Key Laboratory of Arid Land Crop Science, Lanzhou, China; College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China.; Department of Crop Science, Faculty of Agriculture, Food and Consumer Sciences, University for Development Studies, P. O Box TL 1882, Tamale, Ghana.
The present study was undertaken to profile transcriptional changes in flag leaves between anthesis and end of grain filling stages of rainfed spring wheat cultivar under varying nitrogen (N) application rates: 0 kg/ha (NN), 52.5 kg/ha (LN), and 210 kg/ha (HN). A total of 4485 and 4627 differentially expressed genes (DEGs) were detected in LN and HN, respectively. The differential application of N altered several pathways; including plant hormone signal transduction, mitogen-activated protein kinase signaling pathway-plant, photosynthesis, phenylpropanoid biosynthesis and ATP-binding cassette transporters. Jasmonic acid, abscisic acid, salicylic acid and brassinosteroid related genes promoted leaf senescence in NN or LN, whereas auxin, gibberellin acid and cytokinins genes inhibited leaf senescence in HN. Major transcription factors: auxin/indole-3-acetic acid (AUX/IAA), no apical meristem (NAC) and WRKY expressed higher in either HN or LN than NN. The DEGs, pathways and transcription factors provide valuable insight for manipulation of leaf senescence and N remobilization in wheat.
PMID: 35065192
Microbiol Res , IF:5.415 , 2022 May , V258 : P126976 doi: 10.1016/j.micres.2022.126976
Pythium oligandrum in plant protection and growth promotion: Secretion of hydrolytic enzymes, elicitors and tryptamine as auxin precursor.
Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic. Electronic address: katerina.belonoznikova@natur.cuni.cz.; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic. Electronic address: veronika.hyskova@natur.cuni.cz.; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic. Electronic address: josef.chmelik@natur.cuni.cz.; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic. Electronic address: daniel.kavan@natur.cuni.cz.; Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojova 313, 165 00 Praha 6, Czech Republic. Electronic address: cerovska@ueb.cas.cz.; Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Praha 2, Czech Republic. Electronic address: helena.ryslava@natur.cuni.cz.
Pythium is a genus of parasitic oomycetes which target plants and both nonvertebrate and vertebrate animals, including fish and mammalian species. However, several Pythium spp., such as P. oligandrum, function as mycoparasites of pathogenic fungi, bacteria, and oomycetes in soil and thus as advantageous biocontrol agents. This review primarily focuses on biochemical processes underlying their positive effects. For example, P. oligandrum degrades host cell wall polysaccharides using chitinases, cellulases, endo-beta-1,3-glucanases, and various exoglycosidases. Proteases from various classes also participate in the cell wall hydrolysis. All these processes can modify cell surface structures and help Pythium spp. compete for space and nutrition. Accordingly, enzyme secretion most likely plays a key role in plant root colonisation. Plant-P. oligandrum interactions, nevertheless, do not involve tissue injury but instead activate plant defence mechanisms, thereby strengthening future plant responses to pathogen attacks. Priming induces the phenylpropanoid and terpenoid pathways and thus synthesis of secondary metabolites, including lignin, for cell wall fortification and other metabolic adjustments. Such metabolic changes are mediated by elicitins, cell wall glycoproteins and oligandrins produced by P. oligandrum. As homologous proteins of beta-cinnamomin from Phytophthora cinnamomi with similar essential amino acids for sterol binding, oligandrins stand out for their structure, which they share with cell wall glycoproteins, albeit without the Ser-Thr-rich O-glycosylated domain for cell wall attachment. P. oligandrum also provides plant with tryptamine used for auxin synthesis, promoting plant growth. Overall, in addition to discussing plant metabolic and phytohormonal changes after P. oligandrum inoculation, we review data on P. oligandrum applications as researchers increasingly search for effective and environmentally friendly ways to protect crops. In this context, P. oligandrum emerges as a highly suitable biotechnological solution.
PMID: 35158298
J Agric Food Chem , IF:5.279 , 2022 Mar , V70 (9) : P2777-2788 doi: 10.1021/acs.jafc.1c07224
Regulatory Mechanism of the Constitutive Photomorphogenesis 9 Signalosome Complex in Response to Abiotic Stress in Plants.
College of Life Science, Key Laboratory of Straw Biology and Higher Value Application, Ministry of Education, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China.; School of Public Health, Jilin Medical University, Jilin, Jilin 132013, People's Republic of China.; Food Science and Engineering, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China.; College of Food and Biotechnology, Changchun Polytechnic, Changchun, Jilin 130033, People's Republic of China.; College of Resources and Environment, Jilin Agricultural University, Changchun, Jilin 130118, People's Republic of China.
The constitutive photomorphogenesis 9 (COP9) signalosome (CSN) is a highly conserved protein complex that regulates signaling pathways in plants under abiotic stress. We discuss the potential molecular mechanisms of CSN under abiotic stress, including oxidative stress with reactive oxygen species signaling, salt stress with jasmonic acid, gibberellic acid, and abscisic acid signaling, high-temperature stress with auxin signaling, and optical radiation with DNA damage and repair response. We conclude that CSN likely participates in affecting antioxidant biosynthesis and hormone signaling by targeting receptors, kinases, and transcription factors in response to abiotic stress, which potentially provides valuable information for engineering stress-tolerant crops.
PMID: 35199516
J Agric Food Chem , IF:5.279 , 2022 Mar , V70 (8) : P2545-2553 doi: 10.1021/acs.jafc.1c07750
Dicationic Herbicidal Ionic Liquids Comprising Two Active Ingredients Exhibiting Different Modes of Action.
Department of Chemical Technology, Poznan University of Technology, Poznan 60-965, Poland.; Institute of Plant Protection - National Research Institute, Poznan 60-318, Poland.
In the framework of this study, dicationic herbicidal ionic liquids (HILs) containing tetramethylene-1,4-bis(decyldimethylammonium) and dodecylmethylene-1,12-bis(decyldimethylammonium), including two different herbicidal anions exhibiting different modes of action, were synthesized and characterized. One herbicide incorporated into the HILs was a tribenuron-methyl belonging to ALS inhibitors, while the second herbicidal anion was a synthetic auxin that acts as a growth regulator, namely 2,4-dichlorophenoxyacetate (2,4-D), 2-(2,4-dichlorophenoxy)propionate, (2,4-DP), 2,4,5-trichlorophenoxyacetate (2,4,5-T), 4-chloro-2-methylphenoxyacetiate (MCPA), 2-(4-chloro-2-methylphenoxy)propionate (MCPP), and 4-chlorophenoxyacetate (4-CPA). The obtained products were found to be unstable and decomposed, which can be attributed to the presence of an additional methyl group within the sulfonylurea bridge of the tribenuron-methyl. The synthesized HILs exhibited good affinity with polar and semipolar solvents, with ethyl acetate and hexane as the only solvents that did not dissolve the HILs. Greenhouse tests demonstrated that most of the obtained HILs were more effective than the reference herbicide containing tribenuron-methyl. The length of the alkyl chain in the cation also influenced the effectiveness of the HILs. Better effects were observed for dodecylmethylene-1,12-bis(decyldimethylammonium) cations compared to tetramethylene-1,4-bis(decyldimethylammonium). Therefore, the novel dicatonic HILs showed to integrate the advent of the combination of the different herbicides into a single molecule, enhance herbicidal efficacy, and reduce the risk of weed resistance due to the various modes of action of the applied treatment.
PMID: 35170944
Front Mol Biosci , IF:5.246 , 2022 , V9 : P826990 doi: 10.3389/fmolb.2022.826990
The Photoreaction of the Proton-Pumping Rhodopsin 1 From the Maize Pathogenic Basidiomycete Ustilago maydis.
Institute of Experimental Physics, Genetic Biophysics, Freie Universitat Berlin, Berlin, Germany.; Institute of Experimental Physics, Experimental Molecular Biophysics, Freie Universitat Berlin, Berlin, Germany.; Department of Biotechnology and Biophysics, Biocenter, Julius Maximilian University of Wurzburg, Wurzburg, Germany.
Microbial rhodopsins have recently been discovered in pathogenic fungi and have been postulated to be involved in signaling during the course of an infection. Here, we report on the spectroscopic characterization of a light-driven proton pump rhodopsin (UmRh1) from the smut pathogen Ustilago maydis, the causative agent of tumors in maize plants. Electrophysiology, time-resolved UV/Vis and vibrational spectroscopy indicate a pH-dependent photocycle. We also characterized the impact of the auxin hormone indole-3-acetic acid that was shown to influence the pump activity of UmRh1 on individual photocycle intermediates. A facile pumping activity test was established of UmRh1 expressed in Pichia pastoris cells, for probing proton pumping out of the living yeast cells during illumination. We show similarities and distinct differences to the well-known bacteriorhodopsin from archaea and discuss the putative role of UmRh1 in pathogenesis.
PMID: 35281268
Plant Methods , IF:4.993 , 2022 Mar , V18 (1) : P38 doi: 10.1186/s13007-022-00864-4
MultipleXLab: A high-throughput portable live-imaging root phenotyping platform using deep learning and computer vision.
Laboratory of Plant Cell and Developmental Biology (LPCDB), Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.; Ipsumio B.V., High Tech Campus, 5656, Eindhoven, AE, Netherlands.; Sensors Lab, Advanced Membranes and Porous Materials Center (AMPMC), Computer, Electrical and Mathematical Science and Engineering (CEMSE), KAUST, Thuwal, Saudi Arabia.; Laboratory of Plant Cell and Developmental Biology (LPCDB), Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia. Ikram.Blilou@kaust.edu.sa.
BACKGROUND: Profiling the plant root architecture is vital for selecting resilient crops that can efficiently take up water and nutrients. The high-performance imaging tools available to study root-growth dynamics with the optimal resolution are costly and stationary. In addition, performing nondestructive high-throughput phenotyping to extract the structural and morphological features of roots remains challenging. RESULTS: We developed the MultipleXLab: a modular, mobile, and cost-effective setup to tackle these limitations. The system can continuously monitor thousands of seeds from germination to root development based on a conventional camera attached to a motorized multiaxis-rotational stage and custom-built 3D-printed plate holder with integrated light-emitting diode lighting. We also developed an image segmentation model based on deep learning that allows the users to analyze the data automatically. We tested the MultipleXLab to monitor seed germination and root growth of Arabidopsis developmental, cell cycle, and auxin transport mutants non-invasively at high-throughput and showed that the system provides robust data and allows precise evaluation of germination index and hourly growth rate between mutants. CONCLUSION: MultipleXLab provides a flexible and user-friendly root phenotyping platform that is an attractive mobile alternative to high-end imaging platforms and stationary growth chambers. It can be used in numerous applications by plant biologists, the seed industry, crop scientists, and breeding companies.
PMID: 35346267
Plant Methods , IF:4.993 , 2022 Feb , V18 (1) : P17 doi: 10.1186/s13007-022-00850-w
Optimized synthesis of layered double hydroxide lactate nanosheets and their biological effects on Arabidopsis seedlings.
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, 570228, Hainan, China.; College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.; Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.; Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.; College of Environment, Beijing Forestry University, Beijing, 100083, China.; Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, 570228, Hainan, China. ylwan@hainanu.edu.cn.; College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China. ylwan@hainanu.edu.cn.
BACKGROUND: Layered double hydroxide lactate nanosheets (LDH-lactate-NS) are powerful carriers for delivering macro-molecules into intact plant cells. In the past few years, some studies have been carried out on DNA/RNA transformation and plant disease resistance, but little attention has been paid to these factors during LDH-lactate-NS synthesis and delamination, nor has their relationship to the DNA adsorption capacity or transformation efficiency of plant cells been considered. RESULTS: Since the temperature during delamination alters particle sizes and zeta potentials of LDH-lactate-NS products, we compared the LDH-lactate-NS stability, DNA adsorption rate and delivery efficiency of fluorescein isothiocyanate isomer I (FITC) of them, found that the LDH-lactate-NS obtained at 25 degrees C has the best characters for delivering biomolecules into plant cell. To understand the potential side effects and cytotoxicity of LDH-lactate-NS to plants, we compared the root growth rate between the Arabidopsis thaliana seedlings grown in the culture medium with 1-300 mug/mL LDH-lactate-NS and equivalent raw material, Mg(lactate)2 and Al (lactate)3. Phenotypic analysis showed LDH in a range of 1-300 mug/mL can enhance the root elongation, whereas the same concentration of raw materials dramatically inhibited root elongation, suggesting the nanocrystallization has a dramatical de-toxic effect to Mg(lactate)2 and Al (lactate)3. Since enhancing of root elongation by LDH is an unexpected phenomenon, we further designed experiments to investigate influence of LDH to Arabidopsis seedlings. We further used the gravitropic bending test, qRT-PCR analysis of auxin transport proteins, non-invasive micro-test technology and liquid chromatography-mass spectrometry to investigate the auxin transport and distribution in Arabidopsis root. Results indicated that LDH-lactate-NS affect root growth by increasing the polar auxin transport. CONCLUSIONS: Optimal synthesized LDH-lactate-NS can delivery biomolecules into intact plant cells with high efficiency and low cytotoxity. The working solution of LDH-lactate-NS can promote root elongation via increase the polar auxin transport in Arabidopsis roots.
PMID: 35144635
Plant Cell Physiol , IF:4.927 , 2022 Feb , V63 (2) : P265-278 doi: 10.1093/pcp/pcab169
NARROW AND DWARF LEAF 1, the Ortholog of Arabidopsis ENHANCER OF SHOOT REGENERATION1/DORNROSCHEN, Mediates Leaf Development and Maintenance of the Shoot Apical Meristem in Oryza sativa L.
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 Japan.; Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka, 411-8540 Japan.; Graduate School of Agricultural Regional Vitalization, Kibi International University, Minamiawaji, Hyogo, 656-0484 Japan.; Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577 Japan.; Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Hokkaido, 060-0810 Japan.
The molecular basis for leaf development, a major focus in developmental biology, remains unclear in the monocotyledonous grass, rice (Oryza sativa). Here, we performed a mutant screen in rice and identified an AP2-type transcription factor family protein, NARROW AND DWARF LEAF1 (NDL1). NDL1 is the ortholog of Arabidopsis thaliana (subsequently called Arabidopsis) ENHANCER OF SHOOT REGENERATION1 (ESR1)/DORNROSCHEN (DRN) and mediates leaf development and maintenance of the shoot apical meristem (SAM). Loss of function of NDL1 results in bladeless leaves and SAMs that are flat, rather than dome-shaped, and lack cell proliferation activity. This loss of function also causes reduced auxin signaling. Moreover, as is the case with Arabidopsis ESR1/DRN, NDL1 plays crucial roles in shoot regeneration. Importantly, we found that NDL1 is not expressed in the SAM but is expressed in leaf primordia. We propose that NDL1 cell autonomously regulates leaf development, but non-cell autonomously regulates SAM maintenance in rice.
PMID: 35166362
Plant Cell Physiol , IF:4.927 , 2022 Feb doi: 10.1093/pcp/pcac017
Warm Temperature Promotes Shoot Regeneration in Arabidopsis thaliana.
RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan.; Department of Biological Sciences, Faculty of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.; Institut de Biologie Moleculaire des Plantes, 12 rue du General Zimmer, Strasbourg 67084, France.; Department of Biology, Faculty of Science, Niigata University, Ikarashi, Niigata 950-2181, Japan.; College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.; UMR5004 Biochimie et Physiologie Moleculaire des Plantes, Universite de Montpellier, CNRS, INRAE, Institut Agro, 2 place Pierre Viala, Montpellier 34060, France.; Leibniz-Institut fur Gemuse- und Zierpflanzenbau (IGZ) e.V., Theodor-Echtermeyer-Weg 1, Grossbeeren 14979, Germany.
Many plants are able to regenerate upon cutting, and this process can be enhanced in vitro by incubating explants on hormone-supplemented media. While such protocols have been used for decades, little is known about the molecular details of how incubation conditions influence their efficiency. In this study, we find that warm temperature promotes both callus formation and shoot regeneration in Arabidopsis thaliana. We show that such an increase in shoot regenerative capacity at higher temperatures correlates with the enhanced expression of several regeneration-associated genes, such as CUP-SHAPED COTYLEDON 1 (CUC1) encoding a transcription factor involved in shoot meristem formation and YUCCAs (YUCs) encoding auxin biosynthesis enzymes. ChIP-sequencing analyses further reveal that the histone variant H2A.Z is enriched on these loci at 17 degrees C, while its occupancy is reduced by an increase in ambient temperature to 27 degrees C. Moreover, we provide genetic evidence to demonstrate that H2A.Z acts as a repressor of de novo shoot organogenesis, since H2A.Z-depleted mutants display enhanced shoot regeneration. This study thus uncovers a new chromatin-based mechanism that influences hormone-induced regeneration and additionally highlights incubation temperature as a key parameter for optimizing in vitro tissue culture.
PMID: 35157760
Plant Cell Physiol , IF:4.927 , 2022 Mar , V63 (3) : P384-400 doi: 10.1093/pcp/pcac004
Diminished Auxin Signaling Triggers Cellular Reprogramming by Inducing a Regeneration Factor in the Liverwort Marchantia polymorpha.
Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan.; Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba, 278-8510 Japan.; RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, 230-0045 Japan.; Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Aichi, 444-8585 Japan.; Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan.
Regeneration in land plants is accompanied by the establishment of new stem cells, which often involves reactivation of the cell division potential in differentiated cells. The phytohormone auxin plays pivotal roles in this process. In bryophytes, regeneration is enhanced by the removal of the apex and repressed by exogenously applied auxin, which has long been proposed as a form of apical dominance. However, the molecular basis behind these observations remains unexplored. Here, we demonstrate that in the liverwort Marchantia polymorpha, the level of endogenous auxin is transiently decreased in the cut surface of decapitated explants, and identify by transcriptome analysis a key transcription factor gene, LOW-AUXIN RESPONSIVE (MpLAXR), which is induced upon auxin reduction. Loss of MpLAXR function resulted in delayed cell cycle reactivation, and transient expression of MpLAXR was sufficient to overcome the inhibition of regeneration by exogenously applied auxin. Furthermore, ectopic expression of MpLAXR caused cell proliferation in normally quiescent tissues. Together, these data indicate that decapitation causes a reduction of auxin level at the cut surface, where, in response, MpLAXR is up-regulated to trigger cellular reprogramming. MpLAXR is an ortholog of Arabidopsis ENHANCER OF SHOOT REGENERATION 1/DORNROSCHEN, which has dual functions as a shoot regeneration factor and a regulator of axillary meristem initiation, the latter of which requires a low auxin level. Thus, our findings provide insights into stem cell regulation as well as apical dominance establishment in land plants.
PMID: 35001102
Plant Cell Physiol , IF:4.927 , 2022 Mar , V63 (3) : P305-316 doi: 10.1093/pcp/pcab172
Auxin Efflux Transporters OsPIN1c and OsPIN1d Function Redundantly in Regulating Rice (Oryza sativa L.) Panicle Development.
College of Agriculture, Nanjing Agricultural University, No.1 Weigang, Nanjing 210095, People's Republic of China.; Key Laboratory of Crop Physiology Ecology and Production Management, Ministry of Agriculture, No.1 Weigang, Nanjing 210095, People's Republic of China.; Collaborative Innovation Center for Modern Crop Production co-sponsored by Province and Ministry, Nanjing Agricultural University, No.1 Weigang, Nanjing 210095, People's Republic of China.
The essential role of auxin in plant growth and development is well known. Pathways related to auxin synthesis, transport and signaling have been extensively studied in recent years, and the PIN-FORMED (PIN) protein family has been identified as being pivotal for polar auxin transport and distribution. However, research focused on the functional characterization of PIN proteins in rice is still lacking. In this study, we investigated the expression and function of OsPIN1c and OsPIN1d in the japonica rice variety (Nipponbare) using gene knockout and high-throughput RNA sequencing analysis. The results showed that OsPIN1c and OsPIN1d were mainly expressed in young panicles and exhibited a redundant function. Furthermore, OsPIN1c or OsPIN1d loss-of-function mutants presented a mild phenotype compared with the wild type. However, in addition to significantly decreased plant height and tiller number, panicle development was severely disrupted in double-mutant lines of OsPIN1c and OsPIN1d. Severe defects included smaller inflorescence meristem and panicle sizes, fewer primary branches, elongated bract leaves, non-degraded hair and no spikelet growth. Interestingly, ospin1cd-3, a double-mutant line with functional retention of OsPIN1d, showed milder defects than those observed in other mutants. Additionally, several critical regulators of reproductive development, such as OsPID, LAX1, OsMADS1 and OsSPL14/IPA1, were differentially expressed in ospin1c-1 ospin1d-1, supporting the hypothesis that OsPIN1c and OsPIN1d are involved in regulating panicle development. Therefore, this study provides novel insights into the auxin pathways that regulate plant reproductive development in monocots.
PMID: 34888695
Pest Manag Sci , IF:4.845 , 2022 Mar doi: 10.1002/ps.6863
Soybean Dose-Response to 2,4-D and Dicamba at Vegetative and Reproductive Growth Stages.
Former Graduate Student, Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS, 39762, United States of America.; Research Technician, Department of Agronomy and Horticulture, University of Nebraska-Lincoln, West Central Research and Extension Center, North Platte, NE, 69101, United States of America.; Former Graduate Student, Department of Agronomy and Horticulture, University of Nebraska-Lincoln, West Central Research and Extension Center, North Platte, NE, 69101, United States of America.; Endowed Chair, Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS, 39762, United States of America.; Extension Specialist, Department of Agronomy and Horticulture, University of Nebraska-Lincoln, West Central Research and Extension Center, North Platte, NE, 69101, United States of America.; Department of Plant and Soil Sciences, Mississippi State University, Mississippi State, MS, 39762, United States of America.; Commercial Agronomist, Corteva Agriscience, Wilmington, DE, 19805, United States of America.; Extension Weed Scientist, Department of Crop, Soil and Environmental Sciences, University of Arkansas, Lonoke, AR, 72086, United States of America.
PMID: 35254733
Appl Environ Microbiol , IF:4.792 , 2022 Mar , V88 (6) : Pe0216021 doi: 10.1128/aem.02160-21
Phloroglucinol Promotes Fucoxanthin Synthesis by Activating the cis-Zeatin and Brassinolide Pathways in Thalassiosira pseudonana.
College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, China.; School of Marine Sciences, Ningbo University, Ningbo, China.; Affiliated Hospital of Medical School of Ningbo University, Ningbo, China.
Phloroglucinol improves shoot formation and somatic embryogenesis in several horticultural and grain crops, but its function in microalgae remains unclear. Here, we found that sufficiently high concentrations of phloroglucinol significantly increased fucoxanthin synthesis, growth, and photosynthetic efficiency in the microalga Thalassiosira pseudonana. These results suggested that the role of phloroglucinol is conserved across higher plants and microalgae. Further analysis showed that, after phloroglucinol treatment, the contents of cis-zeatin and brassinolide in T. pseudonana increased significantly, while the contents of trans-zeatin, N(6)-isopentenyladenine (iP), auxin, and gibberellin were unaffected. Indeed, functional studies showed that the effects of cis-zeatin and brassinolide in T. pseudonana were similar to those of phloroglucinol. Knockout of key enzyme genes in the cis-zeatin synthesis pathway of T. pseudonana or treatment of T. pseudonana with a brassinolide synthesis inhibitor (brassinazole) significantly reduced growth and fucoxanthin content in T. pseudonana, and phloroglucinol treatment partially alleviated these inhibitory effects. However, phloroglucinol treatment was ineffective when the cis-zeatin and brassinolide pathways were simultaneously inhibited. These results suggested that the cis-zeatin and brassinolide signaling pathways are independent regulators of fucoxanthin synthesis in T. pseudonana and that phloroglucinol affects both pathways. Thus, this study not only characterizes the mechanism by which phloroglucinol promotes fucoxanthin synthesis but also demonstrates the roles of cis-zeatin and brassinolide in T. pseudonana. IMPORTANCE Here, we demonstrate that phloroglucinol, a growth promoter in higher plants, also increases growth and fucoxanthin synthesis in the microalga Thalassiosira pseudonana and therefore may have substantial practical application for industrial fucoxanthin production. Phloroglucinol treatment also induced the synthesis of cis-zeatin and brassinolide in T. pseudonana, and the cis-zeatin and brassinolide signaling pathways were implicated in the phloroglucinol-driven increases in T. pseudonana growth and fucoxanthin synthesis. Thus, our work clarified the molecular mechanism of phloroglucinol promoting the growth and fucoxanthin synthesis of Thalassiosira pseudonana and suggested that cis-zeatin and brassinolide, in addition to phloroglucinol, have potential utility as inducers of increased microalgal fucoxanthin production.
PMID: 35108066
Plant Sci , IF:4.729 , 2022 May , V318 : P111238 doi: 10.1016/j.plantsci.2022.111238
Glutamate: A multifunctional amino acid in plants.
Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan. Electronic address: ming@gate.sinica.edu.tw.
Glutamate (Glu) is a versatile metabolite and a signaling molecule in plants. Glu biosynthesis is associated with the primary nitrogen assimilation pathway. The conversion between Glu and 2-oxoglutarate connects Glu metabolism to the tricarboxylic acid cycle, carbon metabolism, and energy production. Glu is the predominant amino donor for transamination reactions in the cell. In addition to protein synthesis, Glu is a building block for tetrapyrroles, glutathione, and folate. Glu is the precursor of gamma-aminobutyric acid that plays an important role in balancing carbon/nitrogen metabolism and various cellular processes. Glu can conjugate to the major auxin indole 3-acetic acid (IAA), and IAA-Glu is destined for oxidative degradation. Glu also conjugates with isochorismate for the production of salicylic acid. Accumulating evidence indicates that Glu functions as a signaling molecule to regulate plant growth, development, and defense responses. The ligand-gated Glu receptor-like proteins (GLRs) mediate some of these responses. However, many of the Glu signaling events are GLR-independent. The receptor perceiving extracellular Glu as a danger signal is still unknown. In addition to GLRs, Glu may act on receptor-like kinases or receptor-like proteins to trigger immune responses. Glu metabolism and Glu signaling may entwine to regulate growth, development, and defense responses in plants.
PMID: 35351313
Plant Sci , IF:4.729 , 2022 May , V318 : P111221 doi: 10.1016/j.plantsci.2022.111221
Maize GSK3-like kinase ZmSK2 is involved in embryonic development.
State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.; State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China. Electronic address: zhaoqian@cau.edu.cn.
Grain size and weight are closely related to the yield of cereal crops. Abnormal development of the embryo, an important part of the grain, not only affects crop yield but also impacts next-generation survival. Here, we found that maize GSK3-like kinase ZmSK2, a homolog of BIN2 in Arabidopsis, is involved in embryonic development. ZmSK2 overexpression resulted in severe BR defective phenotypes and arrested embryonic development at the transition stage, while the zmsk2 knockout lines showed enlarged embryos. ZmSK2 interacts with Aux/IAA-transcription factor 28 (ZmIAA28), a negative regulator of auxin signaling, and the interaction region is the auxin degron "GWPPV" motif of ZmIAA28 domain II. Coexpression of ZmSK2 with ZmIAA28 increased the accumulation of ZmIAA28 in maize protoplasts, which may have been due to phosphorylation by ZmSK2. In conclusion, this study reveals the function of ZmSK2 in maize embryonic development and proposes that ZmSK2-ZmIAA28 may be another link in the signaling pathway that integrates BR and auxin.
PMID: 35351312
Plant Sci , IF:4.729 , 2022 May , V318 : P111220 doi: 10.1016/j.plantsci.2022.111220
Transcriptome analysis reveals that cytokinins inhibit adventitious root formation through the MdRR12-MdCRF8 module in apple rootstock.
College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: keli505@163.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 2826267803@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 2987827737@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 3361604145@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 835734450@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 794700190@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: 2654669505@qq.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: mjp588@163.com.; College of Horticulture, Yangling Sub-Center of National Center for Apple Improvement, Northwest A&F University, Yangling 712100, Shannxi, P.R. China. Electronic address: afant@nwsuaf.edu.cn.
Adventitious root (AR) formation is great significance for apple rootstock breeding. Transcriptome analyses were performed with cytokinins (CTKs) signal treatments to analyze the mechanism of AR formation. The results showed that 6-benzyadenine (6-BA) treatment inhibited AR formation. Histological analysis also observed that AR primordium cell formation was significantly suppressed by 6-BA treatment; the ratio of auxin/cytokinins exhibited the lowest values at 1 and 3 day (d) in the 6-BA treatment group. Furthermore, the differentially expressed genes were divided into five categories, including auxin, cytokinins, other hormones, cell cycle, and carbohydrate metabolism pathways. Due to the study of cytokinins signal treatment, it is important to understand the particular module mediated by the cytokinins pathway. The expression level of MdRR12 (a family member of B-type cytokinins-responsive factors) was significantly upregulated at 3 d by 6-BA treatment. Compared to the wild type, the 35S::MdRR12 transgenic tobaccos suppressed AR formation. The promoter sequence of MdCRF8 contains AGATT motif elements that respond to MdRR12. RNA-seq and RT-qPCR assays predicted cytokinins response factor (MdCRF8) to be a downstream gene regulated by MdRR12. The activity of the pro-MdCRF8-GUS promoter was obviously induced by 6-BA treatment and inhibited by lovastatin (Lov) treatment. Yeast one-hybrid, dual-luciferase reporter, and GUS coexpression assays revealed that MdRR12 could directly bind to the MdCRF8 promoter. Additionally, 35S::MdCRF8 transgenic tobaccos also blocked AR growth. Compared to the wild type, 35S::MdRR12 and 35S::MdCRF8 transgenic tobaccos enhanced sensitivity to cytokinins. Thus, we describe that MdRR12 and MdCRF8 function as integrators of cytokinins signals that affect cell cycle- and carbohydrate metabolism-related genes to regulate cell fate transition during AR formation. On the basis of these results, we concluded that the MdRR12-MdCRF8 module is involved in the negative regulation of AR formation in apple rootstock and can potentially be applied in agriculture using genetic approaches.
PMID: 35351311
Plant Sci , IF:4.729 , 2022 May , V318 : P111219 doi: 10.1016/j.plantsci.2022.111219
Hydrogen sulfide inhibits the abscission of tomato pedicel through reconstruction of a basipetal auxin gradient.
School of Life Science, Shanxi University, Taiyuan 030006, China; Shanxi Key Laboratory for Research and Development of Regional Plants, Taiyuan 030006, China.; School of Life Science, Shanxi University, Taiyuan 030006, China; Shanxi Key Laboratory for Research and Development of Regional Plants, Taiyuan 030006, China. Electronic address: peiyanxi@sxu.edu.cn.
Abscission is an important developmental process and an essential agricultural trait. Auxin and ethylene are two phytohormones with important roles in the complex, but still elusive signaling network of abscission. Here, we found that hydrogen sulfide (H2S), a newly identified gasotransmitter, inhibits the initiation of tomato pedicel abscission. The underlying mechanism was explored through transcriptome profile analysis in various pedicel tissues with or without H2S treatment in the early abscission stage. The data suggested that H2S strongly influences the global transcription of pedicel tissues, exerts differential expression regulation along the pedicel, and markedly influences both the auxin and ethylene signaling pathways. Computational analysis revealed that H2S reconstructs a basipetal auxin gradient along the pedicel at 4 h after treatment; this finding was further substantiated by the GUS-staining results of DR5::GUS pedicels. The inhibitory effect of H2S to the ethylene signaling pathway might be an indirect action. Moreover, the subtilisin-like proteinase family members involved in the release of peptide signal molecules are critical components of the abscission signaling network downstream of auxin and ethylene.
PMID: 35351302
Plant Sci , IF:4.729 , 2022 Mar , V316 : P111175 doi: 10.1016/j.plantsci.2021.111175
LsRGL1 controls the bolting and flowering times of lettuce by modulating the gibberellin pathway.
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, 100193, China.; Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, College of Horticulture, China Agricultural University, Beijing, 100193, China. Electronic address: wangq@cau.edu.cn.
Bolting, which is a serious problem during lettuce (Lactuca sativa L.) production, is responsible for substantial annual yield and quality losses. Gibberellin plays a critical role in the regulation of lettuce bolting. Additionally, DELLA proteins negatively regulate the gibberellin signaling pathway. However, it is unclear if DELLA proteins are involved in the regulation of lettuce bolting. Therefore, in this study, we identified four DELLA-encoding genes in lettuce, including LsRGL1, which was highly expressed in the stem and negatively correlated with bolting. Knocking down this gene in lettuce promoted bolting, whereas its overexpression inhibited bolting and the biosynthesis of gibberellin and auxin. A transcriptome analysis revealed that genes involved in gibberellin and auxin biosynthesis and flowering were affected in the LsRGL1-overexpressing lines. The yeast two-hybrid and yeast one-hybrid assay results indicated that LsRGL1 can interact with LsGA3ox and the LsYUC4 promoter region. Considered together, the results of this study suggest LsRGL1 negatively regulates lettuce bolting. Furthermore, its function may depend on modifications to gibberellin and auxin levels mediated at the transcript and protein levels.
PMID: 35151458
Front Genet , IF:4.599 , 2022 , V13 : P805347 doi: 10.3389/fgene.2022.805347
Identification and Characterization of Key Genes Responsible for Weedy and Cultivar Growth Types in Soybean.
Department of Agriculture and Life Industry, Kangwon National University, Chuncheon, South Korea.; Department of Agricultural Biotechnology/National Academy of Agricultural Science, Rural Development Administration, Jeonju, South Korea.
In cultivated plants, shoot morphology is an important factor that influences crop economic value. However, the effects of gene expression patterns on shoot morphology are not clearly understood. In this study, the molecular mechanism behind shoot morphology (including leaf, stem, and node) was analyzed using RNA sequencing to compare weedy (creeper) and cultivar (stand) growth types obtained in F7 derived from a cross of wild and cultivated soybeans. A total of 12,513 (in leaves), 14,255 (in stems), and 11,850 (in nodes) differentially expressed genes were identified among weedy and cultivar soybeans. Comparative transcriptome and expression analyses revealed 22 phytohormone-responsive genes. We found that GIBBERELLIN 2-OXIDASE 8 (GA2ox), SPINDLY (SPY), FERONIA (FER), AUXIN RESPONSE FACTOR 8 (ARF8), CYTOKININ DEHYDROGENASE-1 (CKX1), and ARABIDOPSIS HISTIDINE KINASE-3 (AHK3), which are crucial phytohormone response genes, were mainly regulated in the shoot of weedy and cultivar types. These results indicate that interactions between phytohormone signaling genes regulate shoot morphology in weedy and cultivar growth type plants. Our study provides insights that are useful for breeding and improving crops to generate high-yield soybean varieties.
PMID: 35281824
Front Genet , IF:4.599 , 2022 , V13 : P822516 doi: 10.3389/fgene.2022.822516
Identification of Candidate Genes for Salinity and Anaerobic Tolerance at the Germination Stage in Rice by Genome-Wide Association Analyses.
Institute of Crop Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China.; College of Agronomy, Anhui Agricultural University, Hefei, China.; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.; Department of Plant Breeding and Genetics, The University of Haripur, Haripur, Pakistan.; Department of Biotechnology, COMSATS University Islamabad-Abbottabad Campus, Abbottabad, Pakistan.; National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences, Sanya, China.
Multiple stress tolerance at the seed germination stage is crucial for better crop establishment in the direct-seeded rice ecosystem. Therefore, identifying rice genes/quantitative trait loci (QTLs) associated with salinity and anaerobic tolerance at the germination stage is a prerequisite for adaptive breeding. Here, we studied 498 highly diverse rice accessions Xian (Indica) and Geng (Japonica), and six traits that are highly associated with salinity and anaerobic tolerance at germination stage were measured. A high-density 2.8M Single Nucleotide Polymorphisms (SNP) genotype map generated from the 3,000 Rice Genomes Project (3KRGP) was used for mapping through a genome-wide association study. In total, 99 loci harboring 117 QTLs were detected in different populations, 54, 21, and 42 of which were associated with anaerobic, salinity, and combined (anaerobic and salinity) stress tolerance. Nineteen QTLs were close to the reported loci for abiotic stress tolerance, whereas two regions on chromosome 4 (qSGr4a/qCL4c/qRI4d and qAGr4/qSGr4b) and one region on chromosome 10 (qRI10/qCL10/ qSGr10b/qBM10) were associated with anaerobic and salinity related traits. Further haplotype analysis detected 25 promising candidates genes significantly associated with the target traits. Two known genes (OsMT2B and OsTPP7) significantly associated with grain yield and its related traits under saline and anaerobic stress conditions were identified. In this study, we identified the genes involved in auxin efflux (Os09g0491740) and transportation (Os01g0976100), whereas we identified multistress responses gene OsMT2B (Os01g0974200) and a major gene OsTPP7 (Os09g0369400) involved in anaerobic germination and coleoptile elongation on chromosome 9. These promising candidates provide valuable resources for validating potential salt and anaerobic tolerance genes and will facilitate direct-seeded rice breeding for salt and anaerobic tolerance through marker-assisted selection or gene editing.
PMID: 35281797
Plant Cell Rep , IF:4.57 , 2022 Mar doi: 10.1007/s00299-022-02849-y
MusaATAF2-like protein regulates shoot development and multiplication by inducing cytokinin hypersensitivity and flavonoid accumulation in banana plants.
Plant Cell Culture Technology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India.; Homi Bhabha National Institute, Mumbai, India.; Department of Biotechnology, University of Mumbai, Mumbai, India.; Plant Biotechnology and Secondary Metabolites Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India.; Plant Cell Culture Technology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India. trgana@barc.gov.in.; Homi Bhabha National Institute, Mumbai, India. trgana@barc.gov.in.
KEY MESSAGE: Senescence-associated transcription factor ATAF2 regulates cytokinin signalling and in vitro shoot multiplication in banana plants. MusaATAF2-like protein is a stress-related NAC transcription factor of banana. It regulates senescence in rooted banana plants. During the early stages of plant development under in vitro conditions, the presence of 6-benzylaminopurine leads to vigorous shoot multiplication. The major contributor to plant shoot multiplication is auxin to cytokinin ratio and their signalling components. The LC-MS analysis of transgenic banana plants overexpressing MusaATAF2 indicated significantly higher cytokinin content and remarkably lower auxin content. Auxin transport has been reported to be inhibited by flavonoids. Their significantly higher abundance in the shoot tissues in transgenic lines suggested potential negative regulation of auxin signalling in transgenic plants. Enhanced shoot multiplication in transgenic lines was further corroborated by reduced transcript abundance of type-A Arabidopsis response regulator-like genes (inhibitors of cytokinin signalling pathway) and higher expression of Arabidopsis histidine kinase-like genes and type-B Arabidopsis response regulator-like genes (positive regulators of cytokinin signalling pathway) in transgenic lines. Altogether, the data concludes that MusaATAF2 induces cytokinin hypersensitivity in banana shoots by modulating/regulating the cytokinin signalling components and flavonoids content.
PMID: 35244754
Molecules , IF:4.411 , 2022 Mar , V27 (6) doi: 10.3390/molecules27061804
Changes in Endogenous Phytohormones of Gerbera jamesonii Axillary Shoots Multiplied under Different Light Emitting Diodes Light Quality.
Department of Ornamental Plants and Garden Art, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, 29 Listopada 54, 31-425 Krakow, Poland.; Department of Developmental Biology, The Franciszek Gorski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Krakow, Poland.
Light quality is essential in in vitro cultures for morphogenesis process. Light emitting diodes system (LED) allows adjustment as desired and the most appropriate light spectrum. The study analyzed the influence of different LED light quality on the balance of endogenous phytohormones and related compounds (PhRC) in in vitro multiplied axillary shoots of Gerbera jamesonii. Over a duration of 40 days, the shoots were exposed to 100% red light, 100% blue light, red and blue light at a 7:3 ratio with control fluorescent lamps. Every 10 days plant tissues were tested for their PhRC content with the use of an ultra-high performance liquid chromatography (UHPLC). Shoots' morphometric features were analyzed after a multiplication cycle. We identified 35 PhRC including twelve cytokinins, seven auxins, nine gibberellins, and seven stress-related phytohormones. Compounds content varied from 0.00052 nmol/g to 168.15 nmol/g of dry weight (DW). The most abundant group were stress-related phytohormones (particularly benzoic and salicylic acids), and the least abundant were cytokinins (about 370 times smaller content). LED light did not disturb the endogenous phytohormone balance, and more effectively mitigated the stress experienced by in vitro grown plants than the fluorescent lamps. The stress was most effectively reduced under the red LED. Red and red:blue light lowered tissue auxin levels. Blue LED light lowered the shoot multiplication rate and their height, and induced the highest content of gibberellins at the last stage of the culture.
PMID: 35335168
Sci Rep , IF:4.379 , 2022 Mar , V12 (1) : P4750 doi: 10.1038/s41598-022-08558-6
Terrestrial arthropods broadly possess endogenous phytohormones auxin and cytokinins.
Department of Biological Resource Science, Faculty of Agriculture, Saga University, Saga, 840-8502, Japan. tokudam@cc.saga-u.ac.jp.; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, 890-0065, Japan. tokudam@cc.saga-u.ac.jp.; Department of Food and Life Sciences, Ibaraki University, Ami, Ibaraki, 300-0393, Japan.; Department of Biological Resource Science, Faculty of Agriculture, Saga University, Saga, 840-8502, Japan.; The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, 890-0065, Japan.; Present address: Koshi Research Station, Institute for Plant Protection, NARO, Kumamoto, 861-1192, Japan.
Some herbivorous insects possess the ability to synthesize phytohormones and are considered to use them for manipulating their host plants, but how these insects acquired the ability remains unclear. We investigated endogenous levels of auxin (IAA) and cytokinins (iP and tZ), including their ribosides (iPR and tZR), in various terrestrial arthropod taxa. Surprisingly, IAA was detected in all arthropods analysed. In contrast, tZ and/or tZR was detected only in some taxa. Endogenous levels of IAA were not significantly different among groups with different feeding habits, but gall inducers possessed significantly higher levels of iPR, tZ and tZR. Ancestral state reconstruction of the ability to synthesize tZ and tZR revealed that the trait has only been acquired in taxa containing gall inducers. Our results strongly suggest critical role of the cytokinin synthetic ability in the evolution of gall-inducing habit and IAA has some function in arthropods.
PMID: 35306514
Sci Rep , IF:4.379 , 2022 Mar , V12 (1) : P3595 doi: 10.1038/s41598-022-07637-y
Expression profiling of TaARGOS homoeologous drought responsive genes in bread wheat.
Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan. kashif_ahmed01@yahoo.com.; Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan.; National Agricultural Research Centre (NARC), Islamabad, Pakistan.; College of Agriculture, Nanjing Agricultural University, Najing, China.
Drought tolerant germplasm is needed to increase crop production, since water scarcity is a critical bottleneck in crop productivity worldwide. Auxin Regulated Gene involved in Organ Size (ARGOS) is a large protein family of transcription factors that plays a vital role in organ size, plant growth, development, and abiotic stress responses in plants. Although, the ARGOS gene family has been discovered and functionalized in a variety of crop plants, but a comprehensive and systematic investigation of ARGOS genes in locally used commercial wheat cultivars is still yet to be reported. The relative expression of three highly conserved TaARGOS homoeologous genes (TaARGOS-A, TaARGOS-B, TaARGOS-D) was studied in three drought-tolerant (Pakistan-2013, NARC-2009 and NR-499) and three sensitive (Borlaug-2016, NR-514 and NR-516) wheat genotypes under osmotic stress, induced by PEG-6000 at 0 (exogenous control), 2, 4, 6, and 12 h. The normalization of target genes was done using beta-actin as endogenous control, whereas DREB3, as a marker gene was also transcribed, reinforcing the prevalence of dehydration in all stress treatments. Real-time quantitative PCR revealed that osmotic stress induced expression of the three TaARGOS transcripts in different wheat seedlings at distinct timepoints. Overall, all genes exhibited significantly higher expression in the drought-tolerant genotypes as compared to the sensitive ones. For instance, the expression profile of TaARGOS-A and TaARGOS-D showed more than threefold increase at 2 h and six to sevenfold increase after 4 h of osmotic stress. However, after 6 h of osmotic stress these genes started to downregulate, and the lowest gene expression was noticed after 12 h of osmotic stress. Among all the homoeologous genes, TaARGOS-D, in particular, had a more significant influence on controlling plant growth and drought tolerance as it showed the highest expression. Altogether, TaARGOSs are involved in seedling establishment and overall plant growth. In addition, the tolerant group of genotypes had a much greater relative fold expression than the sensitive genotypes. Ultimately, Pakistan-2013 showed the highest relative expression of the studied genes than other genotypes which shows its proficiency to mitigate osmotic stress. Therefore, it could be cultivated in arid and semi-arid regions under moisture-deficient regimes. These findings advocated the molecular mechanism and regulatory roles of TaARGOS genes in plant growth and osmotic stress tolerance in contrasting groups of wheat genotypes, accompanied by the genetic nature of identified genotypes in terms of their potential for drought tolerance.
PMID: 35246579
Plant Physiol Biochem , IF:4.27 , 2022 Mar , V179 : P78-89 doi: 10.1016/j.plaphy.2022.03.022
Ultrastructural and hormonal changes related to harmaline-induced treatment in Arabidopsis thaliana (L.) Heynh. root meristem.
Departamento de Bioloxia Vexetal e Ciencias do Solo, Facultade de Bioloxia, Universidade de Vigo, Campus Lagoas-Marcosende s/n, 36310, Vigo, Spain.; Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Universita Statale di Milano, Via Celoria n masculine2, 20133, Milano, Italy.; Departamento de Bioloxia Vexetal e Ciencias do Solo, Facultade de Bioloxia, Universidade de Vigo, Campus Lagoas-Marcosende s/n, 36310, Vigo, Spain. Electronic address: adela@uvigo.es.
Harmaline is an indole alkaloid with demonstrated phytotoxicity and recognized pharmacological applications. However, no information is available concerning its mode of action on plant metabolism. Therefore, the present work evaluated bioherbicide mode of action of harmaline on plant metabolism of Arabidopsis thaliana (L.) Heynh. Harmaline induced a strong inhibitory activity on root growth of treated seedlings, reaching IC50 and IC80 values of 14 and 29 muM, respectively. Treated roots were shorter and thicker than control and were characterized by a shorter root meristem size and an increase of root hairs production. Harmaline induced ultrastructural changes such as increment of cell wall thickness, higher density and condensation of mitochondria and vacuolization, appearance of cell wall deposits, increment of Golgi secretory activity and higher percentage of aberrant nuclei. The ethylene inhibitor AgNO3 reversed high root hair appearance and increment of root thickness, and pTCSn::GFP transgenic line showed fluorescence cytokinin signal in stele zone after harmaline treatment that was absent in control, whereas the auxin signal in the transgenic line DR5 was significantly reduced by the treatment. All these results suggest that the mode of action of harmaline could be involving auxin, ethylene and cytokinin synergic/antagonistic action.
PMID: 35325658
Plant Physiol Biochem , IF:4.27 , 2022 Feb , V175 : P1-11 doi: 10.1016/j.plaphy.2022.02.002
Loss-of-function mutations in the ERF96 gene enhance iron-deficient tolerance in Arabidopsis.
School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China.; State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, 230036, China.; School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China. Electronic address: jiangli@ustc.edu.cn.
Iron is an essential micronutrient for plant growth and development. Here we provide evidence for a role of ERF96 in iron-deficiency response in Arabidopsis thaliana. The ERF96-loss-of-function mutants were found to be more tolerant to iron-deficiency stress than wild type (WT) and to have higher iron and chlorophyll content. Further studies showed that the transcriptional levels of iron-uptake related genes IRT1, FRO2, AHA2, FIT and bHLH38 in mutants were significantly higher than in WT under iron deficiency. Comparative transcriptome analysis suggested that the differentially expressed genes (DEGs) between ERF96-loss-of-function mutant and WT under iron deficiency were mainly enriched in iron uptake and chlorophyll degradation. According to the specific analysis of these two kinds of DEGs, the expression of iron uptake and transport related genes in ERF96-loss-of-function mutant was higher and the expression of chlorophyll degradation related genes was lower under iron deficiency. Furthermore, loss-of-function of ERF96 influenced the plant hormone, especially auxin and ethylene signal transduction. Altogether, our results demonstrate that loss-of-function of ERF96 increased Fe uptake and chlorophyll level through ethylene and auxin signal pathway in the regulation of iron-deficiency response in Arabidopsis.
PMID: 35158317
Environ Sci Pollut Res Int , IF:4.223 , 2022 Feb , V29 (6) : P9232-9247 doi: 10.1007/s11356-021-16246-7
Amelioration of sodium and arsenic toxicity in Salvinia natans L. with 2,4-D priming through physiological responses.
Plant Physiology, Biochemistry and Plant Molecular Biology Research Unit, Department of Botany, University of Kalyani, Kalyani, 74 1235, Nadia, W.B., India.; Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka, 1207, Bangladesh. mhzsauag@yahoo.com.; Plant Physiology, Biochemistry and Plant Molecular Biology Research Unit, Department of Botany, University of Kalyani, Kalyani, 74 1235, Nadia, W.B., India. mkadak09@gmail.com.
Sodium (Na) and arsenic (As) toxicity were monitored by hyperaccumulation of metals in Salvinia natans L. with 2,4-dichlorophenoxyacetic acid (2,4-D) induction. Salvinia was recorded with significant bioaccumulation of those metals with de-folding of cellular attributes in sustenance under toxic environment. 2,4-D priming has revised the growth components like net assimilation rate and relative water content to register initial plants' survival against Na and As. Proline biosynthesis supported in the maintenance of osmotic adjustment and plants sustained better activity through subdued electrolytic leakage. Oxidative stress due to both Na and As exposure is responsible for induction under significant moderation of lipid peroxidation and protein carbonization by 2,4-D application was evident to release the stress from metal and metalloids. Reactive oxygen species (ROS) like superoxide and hydrogen peroxide accumulation were monitored with activity of NADP(H)-oxidase. However, it was downregulated by 2,4-D to check the oxidative damages. Superoxide dismutase and peroxidases were significantly moderated to reduce the oxidative degradation for both metals with 2,4-D induction. Glutathione metabolism and recycling of ascorbate with monodehydroascorbate activity were other features to maintain the redox homeostasis for metal toxicity. At the molecular level, polymorphic variations of concern genes in redox cascades demarked significantly for those two metals and established the biomarker for those metals, respectively. As a whole, the biocompatibility of auxin herbicide in Salvinia may raise the possibility for auxin metabolism and thereby, the bioaccumulation to Na and As vis-a-vis tolerance for ecological safety is established.
PMID: 34495473
BMC Plant Biol , IF:4.215 , 2022 Mar , V22 (1) : P149 doi: 10.1186/s12870-022-03539-3
miR390 family of Cymbidium goeringii is involved in the development of reproductive organs in transgenic Arabidopsis.
College of Landscape Architecture, Nanjing Forestry University, 210037, Nanjing, Jiangsu Province, China.; Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, 310021, Hangzhou, Zhejiang Province, China.; College of Landscape Architecture, Nanjing Forestry University, 210037, Nanjing, Jiangsu Province, China. hufengrong2003@sina.com.
BACKGROUND: miR390s is an ancient family with a high level of conservation among plant miRNAs. Through the auxin signal transduction pathway, miR390 participates in diverse biological processes of plant growth and development. As an important Chinese traditional orchid, Cymbidium goeringii has unique flower shape and elegant fragrance. But its development has been greatly restricted because of the low flower bud differentiation and the difficult reproduction. This study aims to provide guidance for the role of cgo-miR390 in reproductive organ development to enhance the ornamental and economic value of Cymbidium. RESULTS: MIR390a, MIR390b and MIR390c of C. goeringii were cloned, and their length ranged from 130 to 150 nt. Each precursor sequence of cgo-miR390 contains 2 to 3 mature miRNAs. Three kinds of cgo-miR390s displayed distinct temporal and spatial expression patterns during floral development in C. goeringii. The overexpression of MIR390s alters morphology and function of stamens and pistils in Arabidopsis, such as enlargement of anther aspect ratio and separation of stylar and stigmas, which affects the development of fruits and seeds. In particular, the pollen amount decreased and the seed abortion rate increased in cgo-MIR390c-overexpressed plants. CONCLUSIONS: cgo-miR390 family affected the development of reproductive organs in transgenic Arabidopsis. The study provides references for the genetic improvement for orchid with potentially great economic benefit.
PMID: 35346036
BMC Plant Biol , IF:4.215 , 2022 Mar , V22 (1) : P133 doi: 10.1186/s12870-022-03524-w
Wound-induced signals regulate root organogenesis in Arabidopsis explants.
Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Korea.; Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon, 34113, Korea.; Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology, Daejeon, 34113, Korea.; Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 34141, Korea. hyojunlee@kribb.re.kr.; Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology, Daejeon, 34113, Korea. hyojunlee@kribb.re.kr.
BACKGROUND: Reactive oxygen species (ROS) and calcium ions (Ca(2+)) are representative signals of plant wound responses. Wounding triggers cell fate transition in detached plant tissues and induces de novo root organogenesis. While the hormonal regulation of root organogenesis has been widely studied, the role of early wound signals including ROS and Ca(2+) remains largely unknown. RESULTS: We identified that ROS and Ca(2+) are required for de novo root organogenesis, but have different functions in Arabidopsis explants. The inhibition of the ROS and Ca(2+) signals delayed root development in detached leaves. Examination of the auxin signaling pathways indicated that ROS and Ca(2+) did not affect auxin biosynthesis and transport in explants. Additionally, the expression of key genes related to auxin signals during root organogenesis was not significantly affected by the inhibition of ROS and Ca(2+) signals. The addition of auxin partially restored the suppression of root development by the ROS inhibitor; however, auxin supplementation did not affect root organogenesis in Ca(2+)-depleted explants. CONCLUSIONS: Our results indicate that, while both ROS and Ca(2+) are key molecules, at least in part of the auxin signals acts downstream of ROS signaling, and Ca(2+) acts downstream of auxin during de novo root organogenesis in leaf explants.
PMID: 35317749
BMC Plant Biol , IF:4.215 , 2022 Mar , V22 (1) : P112 doi: 10.1186/s12870-022-03459-2
Transcriptome analysis reveals key developmental and metabolic regulatory aspects of oil palm (Elaeis guineensis Jacq.) during zygotic embryo development.
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, College of Horticulture, Hainan University, Haikou, 570228, China.; Coconut Research Institute, Chinese Academy of Tropical Agricultural Sciences / Hainan Key Laboratory of Tropical Oil Crops Biology, Wenchang, 571339, China.; Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, College of Horticulture, Hainan University, Haikou, 570228, China. chenping08213@163.com.; Coconut Research Institute, Chinese Academy of Tropical Agricultural Sciences / Hainan Key Laboratory of Tropical Oil Crops Biology, Wenchang, 571339, China. jeromejeyakumarj@gmail.com.
BACKGROUND: Oil palm is the most efficient oil-producing crop in the world, and the yield of palm oil is associated with embryonic development. However, a comprehensive understanding of zygotic embryo development at the molecular level remains elusive. In order to address this issue, we report the transcriptomic analysis of zygotic embryo development in oil palm, specifically focusing on regulatory genes involved in important biological pathways. RESULTS: In this study, three cDNA libraries were prepared from embryos at S1 (early-stage), S2 (middle-stage), and S3 (late-stage). There were 16,367, 16,500, and 18,012 genes characterized at the S1, S2, and S3 stages of embryonic development, respectively. A total of 1522, 2698, and 142 genes were differentially expressed in S1 vs S2, S1 vs S3, and S2 vs S3, respectively. Using Gene Ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis to identify key genes and pathways. In the hormone signaling pathway, genes related to auxin antagonize the output of cytokinin which regulates the development of embryo meristem. The genes related to abscisic acid negatively regulating the synthesis of gibberellin were strongly up-regulated in the mid-late stage of embryonic development. The results were reported the early synthesis and mid-late degradation of sucrose, as well as the activation of the continuous degradation pathway of temporary starch, providing the nutrients needed for differentiation of the embryonic cell. Moreover, the transcripts of genes involved in fatty acid synthesis were also abundantly accumulated in the zygotic embryos. CONCLUSION: Taken together, our research provides a new perspective on the developmental and metabolic regulation of zygotic embryo development at the transcriptional level in oil palm.
PMID: 35279075
BMC Plant Biol , IF:4.215 , 2022 Mar , V22 (1) : P110 doi: 10.1186/s12870-022-03470-7
Maize plant architecture trait QTL mapping and candidate gene identification based on multiple environments and double populations.
College of Bioscience, Jilin Agricultural University, Changchun, 130118, China.; College of Agriculture, Jilin Agricultural University, Changchun, 130118, China.; College of Agriculture, Jilin Agricultural University, Changchun, 130118, China. 1533104768@qq.com.
BACKGROUND: The plant architecture traits of maize determine the yield. Plant height, ear position, leaf angle above the primary ear and internode length above the primary ear together determine the canopy structure and photosynthetic efficiency of maize and at the same time affect lodging and disease resistance. A flat and tall plant architecture confers an obvious advantage in the yield of a single plant but is not conducive to dense planting and results in high rates of lodging; thus, it has been gradually eliminated in production. Although using plants that are too compact, short and density tolerant can increase the yield per unit area to a certain extent, the photosynthetic efficiency of such plants is low, ultimately limiting yield increases. Genetic mapping is an effective method for the improvement of plant architecture to identify candidate genes for regulating plant architecture traits. RESULTS: To find the best balance between the yield per plant and the yield per unit area of maize, in this study, the F2:3 pedigree population and a RIL population with the same male parent were used to identify QTL for plant height (PH), ear height (EH), leaf angle and internode length above the primary ear (LAE and ILE) in Changchun and Gongzhuling for 5 consecutive years (2016-2020). A total of 11, 13, 23 and 13 QTL were identified for PH, EH, LAE, and ILE, respectively. A pleiotropic consistent QTL for PH overlapped with that for EH on chromosome 3, with a phenotypic variation explanation rate from 6.809% to 21.96%. In addition, there were major consistent QTL for LAE and ILE, and the maximum phenotypic contribution rates were 24.226% and 30.748%, respectively. Three candidate genes were mined from the three consistent QTL regions and were involved in the gibberellin-activated signal pathway, brassinolide signal transduction pathway and auxin-activated signal pathway, respectively. Analysis of the expression levels of the three genes showed that they were actively expressed during the jointing stage of vigorous maize growth. CONCLUSIONS: In this study, three consistent major QTL related to plant type traits were identified and three candidate genes were screened. These results lay a foundation for the cloning of related functional genes and marker-assisted breeding of related functional genes.
PMID: 35277127
Tree Physiol , IF:4.196 , 2022 Feb , V42 (2) : P317-324 doi: 10.1093/treephys/tpab110
Auxin concentration and xylem production of Pinus massoniana in a subtropical forest in south China.
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe, Guangzhou 510650, China.; Center for Plant Ecology, Core Botanical Garden, Chinese Academy of Sciences, 723 Xingke Road, Tianhe, Guangzhou 510650, China.; University of Chinese Academy of Sciences, 19(A) Yuquan Road, Shijingshan, Beijing 100049, China.; Departement des Sciences Fondamentales, Universite du Quebec a Chicoutimi, 555 boulevard de l'Universite Chicoutimi, QC G7H 2B1, Canada.; Key Laboratory of Geospatial Technology for Middle and Lower Yellow River Regions, Henan University, 1 Jinming Road, Kaifeng Henan 475004, China.
Auxin is involved in various developmental processes of plants, including cell division in cambium and xylem differentiation. However, most studies linking auxin and xylem cell production are performed in environments with a strong seasonality (i.e., temperate and boreal climates). The temporal dynamics of auxin and cambial activity of subtropical trees remain basically unknown. In this study, we sampled four microcores weekly in three individuals of Chinese red pine (Pinus massoniana Lamb.) from February to December 2015-16 to compare xylem formation with auxin concentration in subtropical China. During the entire period of sampling, the number of cambial cells varied from 2 to 7, while the number of cells in the enlarging zone ranged from 1 to 4 and from 1 to 5 in the wall-thickening zone. In 2015, the average auxin concentration was 3.46 ng g-1, with 33 xylem cells being produced at the end of the year. In 2016, a lower auxin concentration (2.59 ng g-1) corresponded to a reduced annual xylem production (13.7 cells). No significant relationship between auxin concentration and number of xylem cells in differentiation was found at the weekly scale. Unlike in boreal and temperate forests, the lack of wood formation seasonality in subtropical forests makes it more difficult to reveal the relationship between auxin concentration and number of xylem cells in differentiation at the intra-annual scale. The frequent and repeated samplings might have reduced auxin concentration in the developing cambium and xylem, resulting in a lower xylem cell production.
PMID: 34505152
Tree Physiol , IF:4.196 , 2022 Feb , V42 (2) : P391-410 doi: 10.1093/treephys/tpab102
The meristem-associated endosymbiont Methylorubrum extorquens DSM13060 reprograms development and stress responses of pine seedlings.
Ecology and Genetics Research Unit, University of Oulu, Paavo Havaksentie J1, FI-90014 Oulu, Finland.; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8, FI-00014 Helsinki, Finland.; Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig, Germany.; Institute of Molecular Biology and Genetics of NASU, Acad. Zabolotnoho str., 150 03680 Kyiv, Ukraine.; Weiden am See, Burgenland 7121, Austria.; Production Systems, Tree Breeding, Natural Resources Institute Finland LUKE, FI-57200 Savonlinna, Finland.
Microbes living in plant tissues-endophytes-are mainly studied in crop plants where they typically colonize the root apoplast. Trees-a large carbon source with a high capacity for photosynthesis-provide a variety of niches for endophytic colonization. We have earlier identified a new type of plant-endophyte interaction in buds of adult Scots pine, where Methylorubrum species live inside the meristematic cells. The endosymbiont Methylorubrum extorquens DSM13060 significantly increases needle and root growth of pine seedlings without producing plant hormones, but by aggregating around host nuclei. Here, we studied gene expression and metabolites of the pine host induced by M. extorquens DSM13060 infection. Malic acid was produced by pine to potentially boost M. extorquens colonization and interaction. Based on gene expression, the endosymbiont activated the auxin- and ethylene (ET)-associated hormonal pathways through induction of CUL1 and HYL1, and suppressed salicylic and abscisic acid signaling of pine. Infection by the endosymbiont had an effect on pine meristem and leaf development through activation of GLP1-7 and ALE2, and suppressed flowering, root hair and lateral root formation by downregulation of AGL8, plantacyanin, GASA7, COW1 and RALFL34. Despite of systemic infection of pine seedlings by the endosymbiont, the pine genes CUL1, ETR2, ERF3, HYL, GLP1-7 and CYP71 were highly expressed in the shoot apical meristem, rarely in needles and not in stem or root tissues. Low expression of MERI5, CLH2, EULS3 and high quantities of ononitol suggest that endosymbiont promotes viability and protects pine seedlings against abiotic stress. Our results indicate that the endosymbiont positively affects host development and stress tolerance through mechanisms previously unknown for endophytic bacteria, manipulation of plant hormone signaling pathways, downregulation of senescence and cell death-associated genes and induction of ononitol biosynthesis.
PMID: 34328183
Mol Plant Microbe Interact , IF:4.171 , 2022 Mar , V35 (3) : P215-229 doi: 10.1094/MPMI-05-21-0118-R
Bradyrhizobium japonicum IRAT FA3 Alters Arabidopsis thaliana Root Architecture via Regulation of Auxin Efflux Transporters PIN2, PIN3, PIN7, and ABCB19.
Department of Microbiology and Plant Pathology, University of California-Riverside, Riverside, CA 92521, U.S.A.
Beneficial rhizobacteria can stimulate changes in plant root development. Although root system growth is mediated by multiple factors, the regulated distribution of the phytohormone auxin within root tissues plays a principal role. Auxin transport facilitators help to generate the auxin gradients and maxima that determine root structure. Here, we show that the plant-growth-promoting rhizobacterial strain Bradyrhizobium japonicum IRAT FA3 influences specific auxin efflux transporters to alter Arabidopsis thaliana root morphology. Gene expression profiling of host transcripts in control and B. japonicum-inoculated roots of the wild-type A. thaliana accession Col-0 confirmed upregulation of PIN2, PIN3, PIN7, and ABCB19 with B. japonicum and identified genes potentially contributing to a diverse array of auxin-related responses. Cocultivation of the bacterium with loss-of-function auxin efflux transport mutants revealed that B. japonicum requires PIN3, PIN7, and ABCB19 to increase lateral root development and utilizes PIN2 to reduce primary root length. Accelerated lateral root primordia production due to B. japonicum was not observed in single pin3, pin7, or abcb19 mutants, suggesting independent roles for PIN3, PIN7, and ABCB19 during the plant-microbe interaction. Our work demonstrates B. japonicum's influence over host transcriptional reprogramming during plant interaction with this beneficial microbe and the subsequent alterations to root system architecture.[Formula: see text] Copyright (c) 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
PMID: 34941379
Microorganisms , IF:4.128 , 2022 Feb , V10 (2) doi: 10.3390/microorganisms10020365
Control of Fungal Diseases and Fruit Yield Improvement of Strawberry Using Bacillus velezensis CE 100.
Department of Chemical Engineering, University of California, Davis, CA 95616, USA.; Department of Plant Sciences, University of California, Davis, CA 95616, USA.; Department of Forest Resources, Chonnam National University, Gwangju 61186, Korea.; Division of Agricultural and Biological Chemistry, Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju 61186, Korea.
Due to the increasing health and environmental risks associated with the use of fungicides in agriculture, alternatives-such as using plant growth-promoting bacteria (PGPB) to suppress phytopathogens-that simultaneously improve plant yield, are important. This study evaluated the biocontrol efficiency of Bacillus velezensis CE100 against Macrophomina phaseolina and Fusarium oxysporum f. sp. fragariae, the respective causal agents for charcoal rot and fusarium wilt diseases in strawberry, and its potential to enhance strawberry growth and fruit production. B. velezensis CE 100 produced fungal cell wall-degrading enzymes, chitinases, and beta-1,3-glucanases; and inhibited the mycelial growth of M. phaseolina and F. oxysporum f. sp. fragariae by 64.7% and 55.2%, respectively. The mycelia of both phytopathogenic fungi showed severe swelling and rupturing of the hyphae compared to the smooth, normal growth in the control group. Moreover, B. velezensis CE100 produced up to 2.8 units/mL of indole-3-acetic acid (IAA) during incubation and enhanced root biomass in strawberries. Consequently, B. velezensis CE 100 not only increased the fruit yield of strawberries by controlling the fungal diseases but also through enhancing plant growth. The findings of this study indicate that B. velezensis CE100 could be a safe, ecofriendly biocontrol alternative to chemical fungicides in strawberry production.
PMID: 35208819
Genes (Basel) , IF:4.096 , 2022 Mar , V13 (3) doi: 10.3390/genes13030515
High Resistance to Quinclorac in Multiple-Resistant Echinochloa colona Associated with Elevated Stress Tolerance Gene Expression and Enriched Xenobiotic Detoxification Pathway.
Department of Crop, Soil, and Environmental Sciences, University of Arkansas, Fayetteville, AR 72704, USA.; Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634, USA.; Genomics and Bioinformatics Facility, Clemson University, Clemson, SC 29634, USA.; Center for Human Genetics, Clemson University, Greenwood, SC 29646, USA.; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA.
Echinochloa colona and other species in this genus are a threat to global rice production and food security. Quinclorac, an auxin mimic, is a common herbicide for grass weed control in rice, and Echinochloa spp. have evolved resistance to it. The complete mode of quinclorac action and subsequent evolution of resistance is not fully understood. We analyzed the de novo transcriptome of multiple-herbicide-resistant (ECO-R) and herbicide-susceptible genotypes in response to quinclorac. Several biological processes were constitutively upregulated in ECO-R, including carbon metabolism, photosynthesis, and ureide metabolism, indicating improved metabolic efficiency. The transcriptional change in ECO-R following quinclorac treatment indicates an efficient response, with upregulation of trehalose biosynthesis, which is also known for abiotic stress mitigation. Detoxification-related genes were induced in ECO-R, mainly the UDP-glycosyltransferase (UGT) family, most likely enhancing quinclorac metabolism. The transcriptome data also revealed that many antioxidant defense elements were uniquely elevated in ECO-R to protect against the auxin-mediated oxidative stress. We propose that upon quinclorac treatment, ECO-R detoxifies quinclorac utilizing UGT genes, which modify quinclorac using the sufficient supply of UDP-glucose from the elevated trehalose pathway. Thus, we present the first report of upregulation of trehalose synthesis and its association with the herbicide detoxification pathway as an adaptive mechanism to herbicide stress in Echinochloa, resulting in high resistance.
PMID: 35328069
Genes (Basel) , IF:4.096 , 2022 Mar , V13 (3) doi: 10.3390/genes13030469
Effect of the PmARF6 Gene from Masson Pine (Pinus massoniana) on the Development of Arabidopsis.
Key Laboratory of Forestry Genetics & Biotechnology of Ministry of Education, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.; Wenzhou Key laboratory of Resource Plant Innovation and Utilization, Zhejiang Institute of Subtropical Crops, Wenzhou 325005, China.
Masson pine (Pinus massoniana) is a core industrial tree species that is used for afforestation in southern China. Previous studies have shown that Auxin Response Factors (ARFs) are involved in the growth and development of various species, but the function of ARFs in Masson pine is unclear. In this research, we cloned and identified Masson pine ARF6 cDNA (PmARF6). The results showed that PmARF6 encodes a protein of 681 amino acids that is highly expressed in female flowers. Subcellular analysis showed that the PmARF6 protein occurred predominantly in the nucleus and cytomembrane of Masson pine cells. Compared with wild-type (WT) Arabidopsis, transgenic Arabidopsis plants overexpressing PmARF6 had fewer rosette leaves, and their flower development was slower. These results suggest that overexpression of PmARF6 may inhibit the flower and leaf development of Masson pine and provide new insights into the underlying developmental mechanism.
PMID: 35328022
Genes (Basel) , IF:4.096 , 2022 Feb , V13 (3) doi: 10.3390/genes13030441
Transcriptome Profiling Reveals Role of MicroRNAs and Their Targeted Genes during Adventitious Root Formation in Dark-Pretreated Micro-Shoot Cuttings of Tetraploid Robinia pseudoacacia L.
National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design (BAICFTBMD), Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.; School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen 518055, China.; School of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.; University of Chinese Academy of Sciences, Beijing 100049, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China.; School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.; Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing 100083, China.
Tetraploid Robinia pseudoacacia L. is a difficult-to-root species, and is vegetatively propagated through stem cuttings. Limited information is available regarding the adventitious root (AR) formation of dark-pretreated micro-shoot cuttings. Moreover, the role of specific miRNAs and their targeted genes during dark-pretreated AR formation under in vitro conditions has never been revealed. The dark pretreatment has successfully promoted and stimulated adventitious rooting signaling-related genes in tissue-cultured stem cuttings with the application of auxin (0.2 mg L(-1) IBA). Histological analysis was performed for AR formation at 0, 12, 36, 48, and 72 h after excision (HAE) of the cuttings. The first histological events were observed at 36 HAE in the dark-pretreated cuttings; however, no cellular activities were observed in the control cuttings. In addition, the present study aimed to uncover the role of differentially expressed (DE) microRNAs (miRNAs) and their targeted genes during adventitious root formation using the lower portion (1-1.5 cm) of tetraploid R. pseudoacacia L. micro-shoot cuttings. The samples were analyzed using Illumina high-throughput sequencing technology for the identification of miRNAs at the mentioned time points. Seven DE miRNA libraries were constructed and sequenced. The DE number of 81, 162, 153, 154, 41, 9, and 77 miRNAs were upregulated, whereas 67, 98, 84, 116, 19, 16, and 93 miRNAs were downregulated in the following comparisons of the libraries: 0-vs-12, 0-vs-36, 0-vs-48, 0-vs-72, 12-vs-36, 36-vs-48, and 48-vs-72, respectively. Furthermore, we depicted an association between ten miRNAs (novel-m0778-3p, miR6135e.2-5p, miR477-3p, miR4416c-5p, miR946d, miR398b, miR389a-3p, novel m0068-5p, novel-m0650-3p, and novel-m0560-3p) and important target genes (auxin response factor-3, gretchen hagen-9, scarecrow-like-1, squamosa promoter-binding protein-like-12, small auxin upregulated RNA-70, binding protein-9, vacuolar invertase-1, starch synthase-3, sucrose synthase-3, probable starch synthase-3, cell wall invertase-4, and trehalose phosphatase synthase-5), all of which play a role in plant hormone signaling and starch and sucrose metabolism pathways. The quantitative polymerase chain reaction (qRT-PCR) was used to validate the relative expression of these miRNAs and their targeted genes. These results provide novel insights and a foundation for further studies to elucidate the molecular factors and processes controlling AR formation in woody plants.
PMID: 35327995
Plant Genome , IF:4.089 , 2022 Mar : Pe20199 doi: 10.1002/tpg2.20199
Differential gene expression in tall fescue tissues in response to water deficit.
Dep. of Plant and Soil Sciences, Univ. of Kentucky, Lexington, KY, 40546-0312, USA.; Dep. of Plant Pathology, Univ. of Kentucky, Lexington, KY, 40546-0312, USA.; USDA-ARS, Forage-Animal Production Research Unit, Lexington, KY, 40546-0091, USA.
Tall fescue (Festuca arundinacea Schreb.) is a popular pasture and turf grass particularly known for drought resistance, allowing for its persistence in locations that are unfavorable for other cool-season grasses. Also, its seed-borne fungal symbiont (endophyte) Epichloe coenophiala, which resides in the crown and pseudostem, can be a contributing factor in its drought tolerance. Because it contains the apical meristems, crown survival under drought stress is critical to plant survival as well as the endophyte. In this study, we subjected tall fescue plants with their endophyte to water-deficit stress or, as controls with normal watering, then compared plant transcriptome responses in four vegetative tissues: leaf blades, pseudostem, crown, and roots. A transcript was designated a differentially expressed gene (DEG) if it exhibited at least a twofold expression difference between stress and control samples with an adjusted p value of .001. Pathway analysis of the DEGs across all tissue types included photosynthesis, carbohydrate metabolism, phytohormone biosynthesis and signaling, cellular organization, and a transcriptional regulation. While no specific pathway was observed to be differentially expressed in the crown, genes encoding auxin response factors, nuclear pore anchors, structural maintenance of chromosomes, and class XI myosin proteins were more highly differentially expressed in crown than in the other vegetative tissues, suggesting that regulation in expression of these genes in the crown may aid in survival of the meristems in the crown.
PMID: 35322562
Plant Mol Biol , IF:4.076 , 2022 Mar doi: 10.1007/s11103-022-01258-9
TOPLESS in the regulation of plant immunity.
415, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.; 415, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India. ashis_nandi@mail.jnu.ac.in.
KEY MESSAGE: This review presents the multiple ways how topless and topless-related proteins regulate defense activation in plants and help in optimizing the defense-growth tradeoff. Eukaryotic gene expression is tightly regulated at various levels by hormones, transcription regulators, post-translational modifications, and transcriptional coregulators. TOPLESS (TPL)/TOPLESS-related (TPR) corepressors regulate gene expression by interacting with other transcription factors. TPRs regulate auxin, gibberellins, jasmonic acid, strigolactone, and brassinosteroid signaling in plants. In general, except for GA, TPLs suppress these signaling pathways to prevent unwanted activation of hormone signaling. The association of TPL/TPRs in these hormonal signaling reflects a wide role of this class of corepressors in plants' normal and stress physiology. The involvement of TPL in immune responses was first demonstrated a decade ago as a repressor of DND1 and DND2 that are negative regulators of plant immune response. Over the last decade, several research groups have established a larger role of TPL/TPRs in plant immunity during both pattern- and effector-triggered immunity. Very recent research unraveled the significant involvement of TPRs in balancing the growth and defense trade-off. TPRs, along with proteasomal degradation complex, miRNA, and phasiRNA, suppress the activation of autoimmunity in plants under normal conditions and promote defense under pathogen attack.
PMID: 35347548
Plant Mol Biol , IF:4.076 , 2022 Mar doi: 10.1007/s11103-022-01255-y
Eucalyptus grandis AUX/INDOLE-3-ACETIC ACID 13 (EgrIAA13) is a novel transcriptional regulator of xylogenesis.
School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, VIC, 3363, Australia. nadeeshani.karannagoda@agriculture.vic.gov.au.; Centre for AgriBioscience, Agriculture Victoria, AgriBio, Bundoora, Victoria, 3083, Australia. nadeeshani.karannagoda@agriculture.vic.gov.au.; School of Ecosystem and Forest Sciences, The University of Melbourne, Creswick, VIC, 3363, Australia.; Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa.; Laboratoire de Recherche en Sciences Vegetales, Universite de Toulouse III, CNRS, UPS, UMR 5546, 24 Chemin de Borde Rouge, 31320, Castanet-Tolosan, France.
KEY MESSAGE: Our Induced Somatic Sector Analysis and protein-protein interaction experiments demonstrate that Eucalyptus grandis IAA13 regulates xylem fibre and vessel development, potentially via EgrIAA13 modules involving ARF2, ARF5, ARF6 and ARF19. Auxin is a crucial phytohormone regulating multiple aspects of plant growth and differentiation, including regulation of vascular cambium activity, xylogenesis and its responsiveness towards gravitropic stress. Although the regulation of these biological processes greatly depends on auxin and regulators of the auxin signalling pathway, many of their specific functions remain unclear. Therefore, the present study aims to functionally characterise Eucalyptus grandis AUX/INDOLE-3-ACETIC ACID 13 (EgrIAA13), a member of the auxin signalling pathway. In Eucalyptus and Populus, EgrIAA13 and its orthologs are preferentially expressed in the xylogenic tissues and downregulated in tension wood. Therefore, to further investigate EgrIAA13 and its function during xylogenesis, we conducted subcellular localisation and Induced Somatic Sector Analysis experiments using overexpression and RNAi knockdown constructs of EgrIAA13 to create transgenic tissue sectors on growing stems of Eucalyptus and Populus. Since Aux/IAAs interact with Auxin Responsive Factors (ARFs), in silico predictions of IAA13-ARF interactions were explored and experimentally validated via yeast-2-hybrid experiments. Our results demonstrate that EgrIAA13 localises to the nucleus and that downregulation of EgrIAA13 impedes Eucalyptus xylem fibre and vessel development. We also observed that EgrIAA13 interacts with Eucalyptus ARF2, ARF5, ARF6 and ARF19A. Based on these results, we conclude that EgrIAA13 is a regulator of Eucalyptus xylogenesis and postulate that the observed phenotypes are likely to result from alterations in the auxin-responsive transcriptome via IAA13-ARF modules such as EgrIAA13-EgrARF5. Our results provide the first insights into the regulatory role of EgrIAA13 during xylogenesis.
PMID: 35292886
Plant Mol Biol , IF:4.076 , 2022 Mar doi: 10.1007/s11103-022-01254-z
Transcriptome analysis of a near-isogenic line and its recurrent parent reveals the role of Pup1 QTL in phosphorus deficiency tolerance of rice at tillering stage.
Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India. sureshkumar3_in@yahoo.co.uk.; Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.; Decode Genomics Private Limited, New Delhi, India.; Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.; Indian Council of Agricultural Research, New Delhi, India.
Phosphorus (P) is essential for cellular processes like respiration, photosynthesis, biosynthesis of membrane phospholipids, etc. To cope with P deficiency stress, plants adopt reprograming of the expression of genes involved in different metabolic/signaling pathways for survival, growth, and development. Plants use transcriptional, post-transcriptional, and/or post-translational machinery to achieve P homeostasis. Several transcription factors (TFs), miRNAs, and P transporters play important roles in P deficiency tolerance; however, the underlying mechanisms responsible for P deficiency tolerance remain poorly understood. Studies on P starvation/deficiency responses in plants at early (seedling) stage of growth have been reported but only a few of them focused on molecular responses of the plant at advanced (tillering or reproductive) stage of growth. To decipher the strategies adopted by rice at tillering stage under P deficiency stress, a pair of contrasting genotypes [Pusa-44 (a high-yielding, P deficiency sensitive cultivar) and its near-isogenic line (NIL-23, P deficiency tolerant) for Pup1 QTL] was used for morphophysiological, biochemical, and molecular analyses. Comparative analyses of shoot and root tissues from 45-day-old plants grown hydroponically under P sufficient (16 ppm) or P deficient (4 ppm) medium confirmed some of the known morphophysiological responses. Moreover, RNA-seq analysis revealed the important roles of phosphate transporters, TFs, auxin-responsive proteins, modulation in the cell wall, fatty acid metabolism, and chromatin architecture/epigenetic modifications in providing P deficiency tolerance to NIL-23, which were brought in due to the introgression of the Pup1 QTL in Pusa-44. This study provides insights into the molecular functions of Pup1 for P deficiency tolerance, which might be utilized to improve P-use efficiency of rice for better productivity in P deficient soils. KEY MESSAGE: Introgression of Pup1 QTL in high-yielding rice cultivar modulates mainly phosphate transporters, TFs, auxin-responsive proteins, cell wall structure, fatty acid metabolism, and chromatin architecture/epigenetic modifications at tillering stage of growth under phosphorus deficiency stress.
PMID: 35275352
Plant Mol Biol , IF:4.076 , 2022 Feb , V108 (3) : P257-275 doi: 10.1007/s11103-021-01238-5
CIN-like TCP13 is essential for plant growth regulation under dehydration stress.
Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science (CSRS), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan. kaoru.urano@riken.jp.; Institute of Agrobiological Sciences, NARO 3-1-3 Kannondai, Tsukuba, Ibaraki, 305-8604, Japan. kaoru.urano@riken.jp.; Plant Biotechnology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan.; Bioorganic Research Institute, Suntory Foundation for Life Sciences, Seikacho, Kyoto, 619-0284, Japan.; INRAE, Universite de Bordeaux, UMR1332 Biologie du Fruit Et Pathologie, 33882, Villenave d'Ornon Cedex, France.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium.; VIB Center for Plant Systems Biology, 9052, Ghent, Belgium.; Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8657, Japan.; Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science (CSRS), 3-1-1 Koyadai, Tsukuba, Ibaraki, 305-0074, Japan. kazuo.shinozaki@riken.jp.
KEY MESSAGE: A dehydration-inducible Arabidopsis CIN-like TCP gene, TCP13, acts as a key regulator of plant growth in leaves and roots under dehydration stress conditions. Plants modulate their shape and growth in response to environmental stress. However, regulatory mechanisms underlying the changes in shape and growth under environmental stress remain elusive. The CINCINNATA (CIN)-like TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) family of transcription factors (TFs) are key regulators for limiting the growth of leaves through negative effect of auxin response. Here, we report that stress-inducible CIN-like TCP13 plays a key role in inducing morphological changes in leaves and growth regulation in leaves and roots that confer dehydration stress tolerance in Arabidopsis thaliana. Transgenic Arabidopsis plants overexpressing TCP13 (35Spro::TCP13OX) exhibited leaf rolling, and reduced leaf growth under osmotic stress. The 35Spro::TCP13OX transgenic leaves showed decreased water loss from leaves, and enhanced dehydration tolerance compared with their control counterparts. Plants overexpressing a chimeric repressor domain SRDX-fused TCP13 (TCP13pro::TCP13SRDX) showed severely serrated leaves and enhanced root growth. Transcriptome analysis of TCP13pro::TCP13SRDX transgenic plants revealed that TCP13 affects the expression of dehydration- and abscisic acid (ABA)-regulated genes. TCP13 is also required for the expression of dehydration-inducible auxin-regulated genes, INDOLE-3-ACETIC ACID5 (IAA5) and LATERAL ORGAN BOUNDARIES (LOB) DOMAIN 1 (LBD1). Furthermore, tcp13 knockout mutant plants showed ABA-insensitive root growth and reduced dehydration-inducible gene expression. Our findings provide new insight into the molecular mechanism of CIN-like TCP that is involved in both auxin and ABA response under dehydration stress.
PMID: 35050466
Phytochemistry , IF:4.072 , 2022 Feb , V194 : P113039 doi: 10.1016/j.phytochem.2021.113039
The GH3 amidosynthetases family and their role in metabolic crosstalk modulation of plant signaling compounds.
Department of Biochemistry, Nicolaus Copernicus University in Torun, Lwowska 1, 87-100, Torun, Poland.; Department of Biochemistry, Nicolaus Copernicus University in Torun, Lwowska 1, 87-100, Torun, Poland. Electronic address: maciejost@umk.pl.
The Gretchen Hagen 3 (GH3) genes encoding proteins belonging to the ANL superfamily are widespread in the plant kingdom. The ANL superfamily consists of three groups of adenylating enzymes: aryl- and acyl-CoA synthetases, firefly luciferase, and amino acid-activating adenylation domains of the nonribosomal peptide synthetases (NRPS). GH3s are cytosolic, acidic amidosynthetases of the firefly luciferase group that conjugate auxins, jasmonates, and benzoate derivatives to a wide group of amino acids. In contrast to auxins, which amide conjugates mainly serve as a storage pool of inactive phytohormone or are involved in the hormone degradation process, conjugation of jasmonic acid (JA) results in biologically active phytohormone jasmonyl-isoleucine (JA-Ile). Moreover, GH3s modulate salicylic acid (SA) concentration by conjugation of its precursor, isochorismate. GH3s, as regulators of the phytohormone level, are crucial for normal plant development as well as plant defense response to different abiotic and biotic stress factors. Surprisingly, recent studies indicate that FIN219/JAR1/GH3.11, one of the GH3 proteins, may act not only as an enzyme but is also able to interact with tau-class glutathione S-transferase (GSTU) and constitutive photomorphogenic 1 (COP1) proteins and regulate light and stress signaling pathways. The aim of this work is to summarize our current knowledge of the GH3 family.
PMID: 34861536
Phytopathology , IF:4.025 , 2022 Mar : PPHYTO05210189R doi: 10.1094/PHYTO-05-21-0189-R
The Role of the Wheat Reduced height (Rht)-DELLA Mutants and Associated Hormones in Infection by Claviceps purpurea, the Causal Agent of Ergot.
National Institute of Agricultural Botany, Cambridge CB3 0LE, United Kingdom.; Instituto de Biologia Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas, Universidad Politecnica de Valencia, Valencia 46022, Spain.
Partial resistance to the biotrophic fungal pathogen Claviceps purpurea, causal agent of ergot, has been found that colocates with mutant alleles of the wheat Reduced height (Rht) loci on chromosomes 4B and 4D. These Rht loci represent the wheat orthologs of the Arabidopsis Della genes. To investigate the role of the Rht mutant DELLA proteins in ergot resistance, we assessed C. purpurea infection in wheat near-isogenic lines (NILs) carrying the gibberellic acid (GA)-insensitive semidwarf alleles Rht-B1b and Rht-D1b and the severe dwarf alleles Rht-B1c and Rht-D1c. NILs of the GA-sensitive alleles Rht8 (chromosome 2D) and Rht12 (chromosome 5A) were also included. A general trend toward increased resistance to C. purpurea, with smaller and lighter sclerotia, was observed on the NILs Rht-B1b, Rht-D1b, Rht-B1c, and Rht-D1c, and also on Rht8. Levels of the bioactive GA4 and the auxin indole-3-acetic acid increased after inoculation with C. purpurea, following similar patterns and implicating a potential auxin-mediated induction of GA biosynthesis. In contrast, jasmonic acid (JA) levels fell in the parental lines 'Mercia' and 'Maris Huntsman' after inoculation with C. purpurea, but increased in all the Rht-mutant NILs. Inoculation with C. purpurea did not show any informative changes in the levels of salicylic acid. Our results suggest that GA-mediated degradation of the DELLA proteins and down-regulation of JA-signaling pathways supports infection of wheat by C. purpurea. As these responses are generally associated with necrotrophic fungal pathogens, we propose that the biotroph C. purpurea may have a necrotrophic growth stage.
PMID: 34698539
BMC Genomics , IF:3.969 , 2022 Feb , V23 (1) : P109 doi: 10.1186/s12864-022-08341-x
Combined transcriptomic and metabolomic analysis reveals the potential mechanism of seed germination and young seedling growth in Tamarix hispida.
College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.; Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Xinjiang Production and Construction Corps, College of Life Sciences, Tarim University, Alar, 843300, China.; Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China.; Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China. qinrui@scuec.edu.cn.; Hubei Provincial Key Laboratory for Protection and Application of Special Plant Germplasm in Wuling Area of China, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China. liuhong@scuec.edu.cn.; College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. yaojlmy@mail.hzau.edu.cn.
BACKGROUND: Seed germination is a series of ordered physiological and morphogenetic processes and a critical stage in plant life cycle. Tamarix hispida is one of the most salt-tolerant plant species; however, its seed germination has not been analysed using combined transcriptomics and metabolomics. RESULTS: Transcriptomic sequencing and widely targeted metabolomics were used to detect the transcriptional metabolic profiles of T. hispida at different stages of seed germination and young seedling growth. Transcriptomics showed that 46,538 genes were significantly altered throughout the studied development period. Enrichment study revealed that plant hormones, such as auxin, ABA, JA and SA played differential roles at varying stages of seed germination and post-germination. Metabolomics detected 1022 metabolites, with flavonoids accounting for the highest proportion of differential metabolites. Combined analysis indicated that flavonoid biosynthesis in young seedling growth, such as rhoifolin and quercetin, may improve the plant's adaptative ability to extreme desert environments. CONCLUSIONS: The differential regulation of plant hormones and the accumulation of flavonoids may be important for the seed germination survival of T. hispida in response to salt or arid deserts. This study enhanced the understanding of the overall mechanism in seed germination and post-germination. The results provide guidance for the ecological value and young seedling growth of T. hispida.
PMID: 35135479
BMC Genomics , IF:3.969 , 2022 Feb , V23 (1) : P95 doi: 10.1186/s12864-021-08251-4
Dissection of canopy layer-specific genetic control of leaf angle in Sorghum bicolor by RNA sequencing.
Department of Agronomy, Iowa State University, Ames, IA, 50011, USA.; Present address: Bayer Crop Science, Chesterfield, MO, USA.; Corn Insects and Crop Genetics Research, USDA-ARS, Ames, IA, 50011, USA.; Department of Statistics, Iowa State University, Ames, IA, 50011, USA.; Department of Agronomy, Iowa State University, Ames, IA, 50011, USA. mgsalas@iastate.edu.
BACKGROUND: Leaf angle is an important plant architecture trait, affecting plant density, light interception efficiency, photosynthetic rate, and yield. The "smart canopy" model proposes more vertical leaves in the top plant layers and more horizontal leaves in the lower canopy, maximizing conversion efficiency and photosynthesis. Sorghum leaf arrangement is opposite to that proposed in the "smart canopy" model, indicating the need for improvement. Although leaf angle quantitative trait loci (QTL) have been previously reported, only the Dwarf3 (Dw3) auxin transporter gene, colocalizing with a major-effect QTL on chromosome 7, has been validated. Additionally, the genetic architecture of leaf angle across canopy layers remains to be elucidated. RESULTS: This study characterized the canopy-layer specific transcriptome of five sorghum genotypes using RNA sequencing. A set of 284 differentially expressed genes for at least one layer comparison (FDR < 0.05) co-localized with 69 leaf angle QTL and were consistently identified across genotypes. These genes are involved in transmembrane transport, hormone regulation, oxidation-reduction process, response to stimuli, lipid metabolism, and photosynthesis. The most relevant eleven candidate genes for layer-specific angle modification include those homologous to genes controlling leaf angle in rice and maize or genes associated with cell size/expansion, shape, and cell number. CONCLUSIONS: Considering the predicted functions of candidate genes, their potential undesirable pleiotropic effects should be further investigated across tissues and developmental stages. Future validation of proposed candidates and exploitation through genetic engineering or gene editing strategies targeted to collar cells will bring researchers closer to the realization of a "smart canopy" sorghum.
PMID: 35114939
Plants (Basel) , IF:3.935 , 2022 Mar , V11 (6) doi: 10.3390/plants11060775
Synergistic Modulation of Seed Metabolites and Enzymatic Antioxidants Tweaks Moisture Stress Tolerance in Non-Cultivated Traditional Rice Genotypes during Germination.
Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore 641003, India.; School of Agriculture and Biosciences, Karunya Institute of Technology and Sciences, Karunya Nagar, Coimbatore 641114, India.; Department of Plant Breeding and Genetics, Agricultural College & Research Institute, Tamil Nadu Agricultural University, Killikulam 628252, India.; Crop Production Division, ICAR-National Rice Research Institute, Cuttack 753006, India.; Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore 641003, India.; Department of Food Science and Nutrition, College of Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.; Department of Biology, College of Science and Humanities in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia.; Department of Physical Sport Science, College of Education, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.; Department of Biotechnology, Faculty of Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia.
Traditional rice landraces are treasures for novel genes to develop climate-resilient cultivars. Seed viability and germination determine rice productivity under moisture stress. The present study evaluated 100 rice genotypes, including 85 traditional landraces and 15 improved cultivars from various agro-ecological zones of Tamil Nadu, along with moisture-stress-susceptible (IR 64) and moisture-stress-tolerant (IR 64 Drt1) checks. The landraces were screened over a range of osmotic potentials, namely (-) 1.0 MPa, (-) 1.25 MPa and (-) 1.5 MPa, for a period of 5 days in PEG-induced moisture stress. Physio-morphological traits, such as rate of germination, root and shoot length, vigor index, R/S ratio and relative water content (RWC), were assessed during early moisture stress at the maximum OP of (-) 1.5 MPa. The seed macromolecules, phytohormones (giberellic acid, auxin (IAA), cytokinin and abscisic acid), osmolytes and enzymatic antioxidants (catalase and superoxide dismutase) varied significantly between moisture stress and control treatments. The genotype Kuliyadichan registered more IAA and giberellic acid (44% and 35%, respectively, over moisture-stress-tolerant check (IR 64 Drt1), whereas all the landraces showed an elevated catalase activity, thus indicating that the tolerant landraces effectively eliminate oxidative damages. High-performance liquid chromatography analysis showed a reduction in cytokinin and an increase in ABA level under induced moisture stress. Hence, the inherent moisture-stress tolerance of six traditional landraces, such as Kuliyadichan, Rajalakshmi, Sahbhagi Dhan, Nootripathu, Chandaikar and Mallikar, was associated with metabolic responses, such as activation of hydrolytic enzymes, hormonal crosstalk, ROS signaling and antioxidant enzymes (especially catalase), when compared to the susceptible check, IR 64. Hence, these traditional rice landraces can serve as potential donors for introgression or pyramiding moisture-stress-tolerance traits toward developing climate-resilient rice cultivars.
PMID: 35336657
Plants (Basel) , IF:3.935 , 2022 Mar , V11 (6) doi: 10.3390/plants11060743
5-Aminolevulinic Acid and 24-Epibrassinolide Improve the Drought Stress Resilience and Productivity of Banana Plants.
Agricultural Botany Department, Faculty of Agriculture, Mansoura University, Mansoura 35516, Egypt.; Horticulture Department, Faculty of Desert and Environmental Agriculture, Matrouh University, Fouka 51511, Egypt.; Agricultural Botany Department, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt.; Department of Plant Physiology, Institute of Biology, Warsaw University of Life Sciences SGGW, 02-776 Warsaw, Poland.; Institute of Technology and Life Sciences, National Research Institute, Falenty, Al.Hrabska 3, 05-090 Pruszkow, Poland.; Technological Institute of Sonora, 818 South Ferbero 5th Street, Ciudad Obregon 85000, Mexico.; Department of Bioengineering, West Pomeranian University of Technology, 71-434 Szczecin, Poland.; Water Relations and Field Irrigation Department, Agricultural and Biological Research Institute, National Research Center, Giza 12622, Egypt.; Soil, Water and Environment Research Institute (SWERI), Agricultural Research Center, Giza 12619, Egypt.; Department of Horticulture, Faculty of Agriculture, Tanta University, Tanta 31527, Egypt.
Plant growth, development, and productivity are adversely affected under drought conditions. Previous findings indicated that 5-aminolevulinic acid (ALA) and 24-epibrassinolide (EBL) play an important role in the plant response to adverse environmental conditions. This study demonstrated the role of ALA and EBL on oxidative stress and photosynthetic capacity of drought-stressed 'Williams' banana grown under the Egyptian semi-arid conditions. Exogenous application of either ALA or EBL at concentrations of 15, 30, and 45 mg.L(-1) significantly restored plant photosynthetic activity and increased productivity under reduced irrigation; this was equivalent to 75% of the plant's total water requirements. Both compounds significantly reduced drought-induced oxidative damages by increasing antioxidant enzyme activities (superoxide dismutase 'SOD', catalase 'CAT', and peroxidase 'POD') and preserving chloroplast structure. Lipid peroxidation, electrolyte loss and free non-radical H2O2 formation in the chloroplast were noticeably reduced compared to the control, but chlorophyll content and photosynthetic oxygen evolution were increased. Nutrient uptake, auxin and cytokinin levels were also improved with the reduced abscisic acid levels. The results indicated that ALA and EBL could reduce the accumulation of reactive oxygen species and maintain the stability of the chloroplast membrane structure under drought stress. This study suggests that the use of ALA or EBL at 30 mg.L(-1) can promote the growth, productivity and fruit quality of drought-stressed banana plants.
PMID: 35336624
Plants (Basel) , IF:3.935 , 2022 Mar , V11 (6) doi: 10.3390/plants11060721
Auxin-Producing Bacteria from Duckweeds Have Different Colonization Patterns and Effects on Plant Morphology.
Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA.; Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA.; Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
The role of auxin in plant-microbe interaction has primarily been studied using indole-3-acetic acid (IAA)-producing pathogenic or plant-growth-promoting bacteria. However, the IAA biosynthesis pathway in bacteria involves indole-related compounds (IRCs) and intermediates with less known functions. Here, we seek to understand changes in plant response to multiple plant-associated bacteria taxa and strains that differ in their ability to produce IRCs. We had previously studied 47 bacterial strains isolated from several duckweed species and determined that 79% of these strains produced IRCs in culture, such as IAA, indole lactic acid (ILA), and indole. Using Arabidopsis thaliana as our model plant with excellent genetic tools, we performed binary association assays on a subset of these strains to evaluate morphological responses in the plant host and the mode of bacterial colonization. Of the 21 tested strains, only four high-quantity IAA-producing Microbacterium strains caused an auxin root phenotype. Compared to the commonly used colorimetric Salkowski assay, auxin concentration determined by LC-MS was a superior indicator of a bacteria's ability to cause an auxin root phenotype. Studies with the auxin response mutant axr1-3 provided further genetic support for the role of auxin signaling in mediating the root morphology response to IAA-producing bacteria strains. Interestingly, our microscopy results also revealed new evidence for the role of the conserved AXR1 gene in endophytic colonization of IAA-producing Azospirillum baldaniorum Sp245 via the guard cells.
PMID: 35336603
Plants (Basel) , IF:3.935 , 2022 Mar , V11 (5) doi: 10.3390/plants11050707
Red Light and Glucose Enhance Cytokinin-Mediated Bud Initial Formation in Physcomitrium patens.
School of Biological Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar 752050, Odisha, India.; Homi Bhabha National Institute (HBNI), Training School Complex, Anushakti Nagar, Mumbai 400094, Maharashtra, India.
Growth and development of Physcomitrium patens is endogenously regulated by phytohormones such as auxin and cytokinin. Auxin induces the transition of chloronema to caulonema. This transition is also regulated by additional factors such as quantity and quality of light, carbon supply, and other phytohormones such as strigolactones and precursors of gibberrelic acid. On the other hand, cytokinins induce the formation of bud initials following caulonema differentiation. However, the influence of external factors such as light or nutrient supply on cytokinin-mediated bud initial formation has not been demonstrated in Physcomitrium patens. This study deals with the effect of light quality and nutrient supply on cytokinin-mediated bud initial formation. Bud initial formation has been observed in wild type plants in different light conditions such as white, red, and blue light in response to exogenously supplied cytokinin as well as glucose. In addition, budding assay has been demonstrated in the cry1a mutant of Physcomitrium in different light conditions. The results indicate that carbon supply and red light enhance the cytokinin response, while blue light inhibits this process in Physcomitrium.
PMID: 35270177
Plants (Basel) , IF:3.935 , 2022 Mar , V11 (5) doi: 10.3390/plants11050683
Gene Expression Analysis of Potato (Solanum tuberosum L.) Lipoxygenase Cascade and Oxylipin Signature under Abiotic Stress.
Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, P.O. Box 30, 420111 Kazan, Russia.
The metabolism of polyunsaturated fatty acids through the lipoxygenase-catalyzed step and subsequent reactions is referred to as the lipoxygenase (LOX) pathway. The components of this system, such as jasmonates, are involved in growth, development and defense reactions of plants. In this report, we focus on dynamics of expression of different LOX pathway genes and activities of target enzymes with three abiotic stress factors: darkness, salinity and herbicide toxicity. To obtain a more complete picture, the expression profiles of marker genes for salicylic acid, abscisic acid, ethylene, auxin and gibberellin-dependent signaling systems under the same stresses were also analyzed. The gene expression in Solanum tuberosum plants was analyzed using qRT-PCR, and we found that the LOX-cascade-related genes responded to darkness, salinity and herbicide toxicity in different ways. We detected activation of a number of 9-LOX pathway genes; however, in contrast to studies associated with biotic stress (infection), the 9-divinyl ether synthase branch of the LOX cascade was inhibited under all three stresses. GC-MS analysis of the oxylipin profiles also showed the main activity of the 9-LOX-cascade-related enzymes after treatment with herbicide and darkness.
PMID: 35270153
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (5) doi: 10.3390/plants11050664
In Silico Genome-Wide Characterisation of the Lipid Transfer Protein Multigenic Family in Sunflower (H. annuus L.).
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy.
The sunflower (Helianthus annuus L.) is among the most widely cultivated crops in the world due to the oilseed production. Lipid transfer proteins (LTPs) are low molecular mass proteins encoded by a broad multigenic family in higher plants, showing a vast range of functions; these proteins have not been characterised in sunflower at the genomic level. In this work, we exploited the reliable genome sequence of sunflower to identify and characterise the LTP multigenic family in H. annuus. Overall, 101 sunflower putative LTP genes were identified using a homology search and the HMM algorithm. The selected sequences were characterised through phylogenetic analysis, exon-intron organisation, and protein structural motifs. Sunflower LTPs were subdivided into four clades, reflecting their genomic and structural organisation. This gene family was further investigated by analysing the possible duplication origin of genes, which showed the prevalence of tandem and whole genome duplication events, a result that is in line with polyploidisation events that occurred during sunflower genome evolution. Furthermore, LTP gene expression was evaluated on cDNA libraries constructed on six sunflower tissues (leaf, root, ligule, seed, stamen, and pistil) and from roots treated with stimuli mimicking biotic and abiotic stress. Genes encoding LTPs belonging to three out of four clades responded specifically to external stimuli, especially to abscisic acid, auxin, and the saline environment. Interestingly, genes encoding proteins belonging to one clade were expressed exclusively in sunflower seeds. This work is a first attempt of genome-wide identification and characterisation of the LTP multigenic family in a plant species.
PMID: 35270134
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (5) doi: 10.3390/plants11050650
Throttling Growth Speed: Evaluation of aux1-7 Root Growth Profile by Combining D-Root system and Root Penetration Assay.
Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, 165 02 Prague, Czech Republic.; Department of Experimental Plant Biology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic.; Department of Functional and Evolutionary Ecology, Molecular Systems Biology (MoSys), Faculty of Life Sciences, University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.; Vienna Metabolomics Center (VIME), University of Vienna, Djerassiplatz 1, 1030 Wien, Austria.
Directional root growth control is crucial for plant fitness. The degree of root growth deviation depends on several factors, whereby exogenous growth conditions have a profound impact. The perception of mechanical impedance by wild-type roots results in the modulation of root growth traits, and it is known that gravitropic stimulus influences distinct root movement patterns in concert with mechanoadaptation. Mutants with reduced shootward auxin transport are described as being numb towards mechanostimulus and gravistimulus, whereby different growth conditions on agar-supplemented medium have a profound effect on how much directional root growth and root movement patterns differ between wild types and mutants. To reduce the impact of unilateral mechanostimulus on roots grown along agar-supplemented medium, we compared the root movement of Col-0 and auxin resistant 1-7 in a root penetration assay to test how both lines adjust the growth patterns of evenly mechanostimulated roots. We combined the assay with the D-root system to reduce light-induced growth deviation. Moreover, the impact of sucrose supplementation in the growth medium was investigated because exogenous sugar enhances root growth deviation in the vertical direction. Overall, we observed a more regular growth pattern for Col-0 but evaluated a higher level of skewing of aux1-7 compared to the wild type than known from published data. Finally, the tracking of the growth rate of the gravistimulated roots revealed that Col-0 has a throttling elongation rate during the bending process, but aux1-7 does not.
PMID: 35270119
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (5) doi: 10.3390/plants11050618
The Effects of Exogenous Salicylic Acid on Endogenous Phytohormone Status in Hordeum vulgare L. under Salt Stress.
Faculty of Agriculture, Duzce University, 81620 Duzce, Turkey.; Laboratory of Growth Regulators, Faculty of Science, Palacky University and Institute of Experimental Botany, The Czech Academy of Sciences, CZ-78371 Olomouc, Czech Republic.; Faculty of Science, Karadeniz Technical University, 61080 Trabzon, Turkey.
Acclimation to salt stress in plants is regulated by complex signaling pathways involving endogenous phytohormones. The signaling role of salicylic acid (SA) in regulating crosstalk between endogenous plant growth regulators' levels was investigated in barley (Hordeum vulgare L. 'Ince'; 2n = 14) leaves and roots under salt stress. Salinity (150 and 300 mM NaCl) markedly reduced leaf relative water content (RWC), growth parameters, and leaf water potential (LWP), but increased proline levels in both vegetative organs. Exogenous SA treatment did not significantly affect salt-induced negative effects on RWC, LWP, and growth parameters but increased the leaf proline content of plants under 150 mM salt stress by 23.1%, suggesting that SA enhances the accumulation of proline, which acts as a compatible solute that helps preserve the leaf's water status under salt stress. Changes in endogenous phytohormone levels were also investigated to identify agents that may be involved in responses to increased salinity and exogenous SA. Salt stress strongly affected endogenous cytokinin (CK) levels in both vegetative organs, increasing the concentrations of CK free bases, ribosides, and nucleotides. Indole-3-acetic acid (IAA, auxin) levels were largely unaffected by salinity alone, especially in barley leaves, but SA strongly increased IAA levels in leaves at high salt concentration and suppressed salinity-induced reductions in IAA levels in roots. Salt stress also significantly increased abscisic acid (ABA) and ethylene levels; the magnitude of this increase was reduced by treatment with exogenous SA. Both salinity and SA treatment reduced jasmonic acid (JA) levels at 300 mM NaCl but had little effect at 150 mM NaCl, especially in leaves. These results indicate that under high salinity, SA has antagonistic effects on levels of ABA, JA, ethylene, and most CKs, as well as basic morphological and physiological parameters, but has a synergistic effect on IAA, which was well exhibited by principal component analysis (PCA).
PMID: 35270088
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (5) doi: 10.3390/plants11050580
Comparisons of Anatomical Characteristics and Transcriptomic Differences between Heterografts and Homografts in Pyrus L.
Qingdao Key Laboratory of Genetic Improvement and Breeding in Horticultural Plants, Engineering Laboratory of Genetic Improvement of Horticultural Crops of Shandong Province, College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China.; Haidu College, Qingdao Agricultural University, Laiyang 265200, China.
Pear (Pyrus L.) is an important temperate fruit worldwide, and grafting is widely used in pear vegetative propagation. However, the mechanisms of graft healing or incompatibility remain poorly understood in Pyrus. To study the differences in graft healing in Pyrus, the homograft "Qingzhen D1/Qingzhen D1" and the heterograft "QAUP-1/Qingzhen D1" as compatibility and incompatibility combinations were compared. Anatomical differences indicated the healing process was faster in homografts than in heterografts. During the healing process, four critical stages in graft union formation were identified in the two types of grafts. The expression of the genes associated with hormone signaling (auxin and cytokinins), and lignin biosynthesis was delayed in the healing process of heterografts. In addition, the PbBglu13 gene, encoded beta-glucosidase, was more highly up-regulated in heterografts than in homografts to promote healing. Meanwhile, the most of DEGs related starch and sucrose metabolism were found to be up-regulated in heterografts; those results indicated that cellulose and sugar signals were also involved in graft healing. The results of this study improved the understanding of the differences in the mechanisms of graft healing between homografts and heterografts.
PMID: 35270050
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (4) doi: 10.3390/plants11040561
Electrophysiological, Morphologic, and Transcriptomic Profiling of the Ogura-CMS, DGMS and Maintainer Broccoli Lines.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Ministry of Agriculture, #12 Zhong Guan Cun Nandajie Street, Beijing 100081, China.; China Vegetable Biotechnology (Shouguang) Co., Ltd., Shouguang 262700, China.; Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
To better serve breeding of broccoli, the electrophysiological, morphological and transcriptomic profiling of the isogenic Ogura-CMS, DGMS and their maintainer fertile lines, were carried out by scanning electron microscopy, investigation of agronomic traits and RNA-sequencing analysis. The agronomic traits of plant height, length of the largest leaf, plant spread angle, single head weight, head width and stem diameter showed stronger performance in Ogura-CMS broccoli than in DGMS line or maintainer fertile line. However, the Ogura-CMS broccoli was poorer in the seed yield and seed germination than in the DGMS line and maintainer fertile line. Additionally, the DGMS broccoli had longer maturation and flowering periods than the Ogura-CMS and maintainer fertile lines. There were obvious differences in the honey gland, happening in the male sterility and fertile lines of broccoli. Additionally, the mechanism regulating Ogura-CMS and DGMS in broccoli was investigated using florets transcriptome analyses of the Ogura-CMS, DGMS and maintainer fertile lines. As a result, a total of 2670 differentially expressed genes (DEGs) were detected, including 1054 up- and 1616 downregulated genes in the Ogura-CMS and DGMS lines compared to the maintainer fertile line. A number of functionally known genes involved in plant hormones (auxin, salicylic acid and brassinosteroid), five Mitochondrial Oxidative Phosphorylation (OXPHOS) genes of atp8, LOC106319879, LOC106324734, LOC106314622 and LOC106298585, and three upregulated genes (Lhcb1, Lhcb3 and Lhcb5) associated with the photosynthesis-antenna protein pathway, were obviously detected to be highly associated with reproductive development including flowering time, maturity and reproductive period in the Ogura-CMS and DGMS broccoli comparing to their maintainer fertile line. Our research would provide a comprehensive foundation for understanding the differences of electrophysiological, morphological and transcriptomic profiles in the Ogura-CMS, DGMS and maintainer broccoli, and as well as being beneficial to exploring the mechanism of male sterility in Brassica crops.
PMID: 35214894
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (4) doi: 10.3390/plants11040538
Identification of One Major QTL and a Novel Gene OsIAA17q5 Associated with Tiller Number in Rice Using QTL Analysis.
Division of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu 41566, Korea.; Crop Breeding Division, National Institute of Crop Science, Rural Development Administration, Wanju 55365, Korea.; Coastal Agriculture Research Institute, Kyungpook National University, Daegu 41566, Korea.; Biosafety Division, National Institute of Agricultural Science, Jeonju 54874, Korea.; School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Korea.
Rice tillers are one of the most important traits for the yield and development of rice, although little is known about its mode of inheritance. Tiller numbers were recorded every 7 days a total of nine times, starting 30 days after transplantation. Quantitative trait locus (QTL) based analysis on a set of double haploid population derivatives of a cross between the Cheongcheong and Nagdong varieties identified a major effect of locus RM18130-RM3381 on chromosome 5, which was expressed in eight different growth stages. Within the target region RM18130-RM3381 (physical distance: 2.08 Mb), 61 candidate genes were screened by annotation. Among the candidate genes, Os05g0230700 (named OsIAA17q5), which belongs to the family of auxin-responsive genes, was selected as a target. Auxin promotes cell division and meristem maintenance and is an effective plant regulator which influences plant growth and development by altering the expression of various genes. OsIAA17q5 is expected to control the number of tillers. The present study provides further understanding of the basic genetic mechanisms that selectively express the control of tiller numbers in different growth stages, as well as provides valuable information for future research aimed at cloning the target gene. These results may contribute to developing a comprehensive understanding of the basic genetic processes regulating the developmental behavior of tiller numbers in rice.
PMID: 35214873
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (4) doi: 10.3390/plants11040498
Interaction between Growth Regulators Controls In Vitro Shoot Multiplication in Paulownia and Selection of NaCl-Tolerant Variants.
Central Laboratory of Genetic Engineering, Botany and Microbiology Department, Faculty of Science, Sohag University, Sohag 82524, Egypt.; Biology Department, Faculty of Science, Jazan University, Jazan 82817, Saudi Arabia.; Plant Pathology Research Institute, Agricultural Research Center, Giza 12619, Egypt.; Botany and Microbiology Department, Faculty of Science, South Valley University, Qena 83523, Egypt.
The interaction between cytokinin, auxin and GA controlled in vitro shoot multiplication in paulownia was influenced by a medium water potential (Psi) modulation, where it was modulated using different textures or strengths of MS medium, media of different types (MS, WPM, SH and B5) or NaCl incorporation. The interaction between 2 mg/L BAP and 0.1 mg/L NAA expressed the highest shoot number on each media type, but it was better with media of lower water potential (MS and WPM), and MS medium was the best. Psi of full-strength semisolid MS medium expressed the highest shoot multiplication. The opposite was detected when Psi of MS medium was changed using half- or double-strength MS. Psi of full-strength MS medium in semisolid form resulted in a valuable interaction between 2 mg/L BAP, 0.1 mg/L NAA and 0.1 mg/L GA, leading to efficient shoot formation, and it was associated with an increase in internode length and decrease in stem diameter, which facilitated obtaining synseeds with a high ability to convert. High genetic variation was recorded under long-term culture (14 subcultures). Polymorphism using the ISSR technique was higher than that of RAPD. A further increase in polymorphism was detected when NaCl was used, where five salt-tolerant lines were selected. Some salt-tolerant-selected lines showed one or more amplification products of a specific molecular weight that did not appear in the control. For example, with OPA-07 and OPG-02 RAPD primers, all the salt-tolerant-selected lines showed the appearance of amplification fragments (610 bp and 300 bp, respectively) that were not detected in control.
PMID: 35214831
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (4) doi: 10.3390/plants11040472
Identification of Peanut Aux/IAA Genes and Functional Prediction during Seed Development and Maturation.
State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, China.; College of Agronomy, Shandong Agricultural University, Tai'an 271018, China.; College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.
Auxin-responsive genes AUX/IAA are important during plant growth and development, but there are few relevant reports in peanut. In this study, 44 AhIAA genes were identified from cultivated peanut, of which 31 genes were expressed in seed at varying degrees. AhIAA-3A, AhIAA-16A and AhIAA-15B were up-regulated, while AhIAA-11A, AhIAA-5B and AhIAA-14B were down-regulated with seed development and maturation. The expression patterns of seven genes, AhIAA-1A, AhIAA-4A, AhIAA-10A, AhIAA-20A, AhIAA-1B, AhIAA-4B and AhIAA-19B, were consistent with the change trend of auxin, and expression in late-maturing variety LM was significantly higher than that in early-maturing EM. Furthermore, allelic polymorphism analysis of AhIAA-1A and AhIAA-1B, which were specifically expressed in seeds, showed that three SNP loci in 3'UTR of AhIAA-1A could effectively distinguish the EM- and LM- type germplasm, providing a basis for breeding markers development. Our results offered a comprehensive understanding of Aux/IAA genes in peanut and provided valuable clues for further investigation of the auxin signal transduction pathway and auxin regulation mechanism in peanut.
PMID: 35214804
Plants (Basel) , IF:3.935 , 2022 Feb , V11 (3) doi: 10.3390/plants11030454
Functional Antagonism of WRI1 and TCP20 Modulates GH3.3 Expression to Maintain Auxin Homeostasis in Roots.
School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.; Kentucky Tobacco Research and Development Center, Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546, USA.
Auxin is a well-studied phytohormone, vital for diverse plant developmental processes. The GH3 genes are one of the major auxin responsive genes, whose expression changes lead to modulation of plant development and auxin homeostasis. However, the transcriptional regulation of these GH3 genes remains largely unknown. WRI1 is an essential transcriptional regulator governing plant fatty acid biosynthesis. Recently, we identified that the expression of GH3.3 is increased in the roots of wri1-1 mutant. Nevertheless, in this study we found that AtWRI1 did not activate or repress the promoter of GH3.3 (proGH3.3) despite of its binding to proGH3.3. Cross-family transcription factor interactions play pivotal roles in plant gene regulatory networks. To explore the molecular mechanism by which WRI1 controls GH3.3 expression, we screened an Arabidopsis transcription factor library and identified TCP20 as a novel AtWRI1-interacting regulator. The interaction between AtWRI1 and TCP20 was further verified by several approaches. Importantly, we found that TCP20 directly regulates GH3.3 expression via binding to TCP binding element. Furthermore, AtWRI1 repressed the TCP20-mediated transactivation of proGH3.3. EMSAs demonstrated that AtWRI1 antagonized TCP20 from binding to proGH3.3. Collectively, we provide new insights that WRI1 attenuates GH3.3 expression through interaction with TCP20, highlighting a new mechanism that contributes to fine-tuning auxin homeostasis.
PMID: 35161435
Gene , IF:3.688 , 2022 May , V823 : P146320 doi: 10.1016/j.gene.2022.146320
Tomato zonate spot virus induced hypersensitive resistance via an auxin-related pathway in pepper.
Institute of Biotechnology and Germplasm Resources, Yunnan Academy of Agricultural Sciences, Yunnan ProvincialKey Laboratory of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resource and GermplasmInnovation, Ministry of Agriculture, KunmingYunnan 650204, China.; Kunming Institute of Botany, Chinese Academy of Science, Kunming Yunnan 650201, China.; Institute of Biotechnology and Germplasm Resources, Yunnan Academy of Agricultural Sciences, Yunnan ProvincialKey Laboratory of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resource and GermplasmInnovation, Ministry of Agriculture, KunmingYunnan 650204, China; Life Science College, Southwest Forestry University, Kunming Yunnan 650224, China.; Life Science College, Southwest Forestry University, Kunming Yunnan 650224, China.; Yunnan University of Chinese Medicine, Kunming Yunnan 650500, China.
Tomato zonate spotvirus (TZSV) often incurs significant losses in many food and ornamental crops in Yunnan province, China, and the surrounding areas. The pepper (Capsicum chinensePI152225)can develop hypersensitive resistance following infection with TZSV, through an as yet unknown mechanism. The transcriptome dataset showed a total of 45.81 GB of clean data were obtained from six libraries, and the average percentage of the reads mapped to the pepper genome was over 90.00 %. A total of 1403 differentially expressed genes (DEGs) were obtained after TZSV infection, including 825significantly up-regulated genes and 578 down-regulated genes. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that most up-regulated DEGs were involved in basal defenses. RT-qPCR, and virus induced gene silencing (VIGS) were used preliminarily to identifyBBC_22506 and BBC_18917, among total of 71 differentially expressed genes (DEGs), that play a key role in mediating the auxin-induced signaling pathway that might take part in hypersensitive response (HR) conferred resistance to viral infection in pepper (PI152225) byTZSV. This is the first study on the mechanism of auxin resistance, involved in defense responses of pepper against viral diseases, which lay the foundation for further study on the pathogenic mechanism of TZSV, as well as the mechanism of resistance to TZSV, in peppers.
PMID: 35218893
J Plant Physiol , IF:3.549 , 2022 Feb , V269 : P153594 doi: 10.1016/j.jplph.2021.153594
Auxin transport in developing protophloem: A case study in canalization.
Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland.; Department of Plant Molecular Biology, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland. Electronic address: christian.hardtke@unil.ch.
Spatiotemporal cues orchestrate the development of organs and cellular differentiation in multicellular organisms. For instance, in the root apical meristem an auxin gradient patterns the transition from stem cell maintenance to transit amplification and eventual differentiation. Among the proximal tissues generated by this growth apex, the early, so-called protophloem, is the first tissue to differentiate. This observation has been linked to increased auxin activity in the developing protophloem sieve element cell files as compared to the neighboring tissues. Here we review recent progress in the characterization of the unique mechanism by which auxin canalizes its activity in the developing protophloem and fine-tunes its own transport to guide proper timing of protophloem sieve element differentiation.
PMID: 34953411
Protoplasma , IF:3.356 , 2022 Mar , V259 (2) : P327-342 doi: 10.1007/s00709-021-01647-9
A positive response of ginger root zone and rhizome development to suitable sowing depth.
College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China.; Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Tai'an, 271018, China.; Key Laboratory of Biology of Horticultural Crops in Huanghuai Region, Ministry of Agriculture and Rural Affairs, Tai'an, 271018, China.; State Key Laboratory of Crop Biology, Tai'an, 271018, China.; School of Environment, Tsinghua University, Beijing, 100084, China.; College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, China. xukun@sdau.edu.cn.; Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Tai'an, 271018, China. xukun@sdau.edu.cn.; Key Laboratory of Biology of Horticultural Crops in Huanghuai Region, Ministry of Agriculture and Rural Affairs, Tai'an, 271018, China. xukun@sdau.edu.cn.; State Key Laboratory of Crop Biology, Tai'an, 271018, China. xukun@sdau.edu.cn.
Sowing depth significantly affects ginger (Zingiber officinale Roscoe) yields, and sowing depth can affect rhizosphere community structure through root exudates. However, the relationship between the reaction process in root zone and ginger rhizome development is unclear. In this study, we investigated the rhizome and root development and rhizosphere environment at different sowing depths (2 cm (SD2), 5 cm (SD5), and 10 cm (SD10)). It was found that SD10 significantly increased ginger yield, which is related to the development of vascular bundles and the expression of aquaporin. PLS-PM analysis found that root length, root absorption capacity, and soil enzymes have the strongest correlation with yield, while root diameter is negatively correlated with yield. Under SD10, the increase of auxin and ethylene content together with the expression of ARF7, LBD16, and PIN1 promoted the development of lateral roots. In addition, SD10 increased the secretion of root organic acids, amino acids, and carbohydrates, which in turn promoted the development of rhizosphere bacteria. The promotion of SD10 on nitrogen cycle and nitrogen fixation ability in turn promoted the development of ginger.
PMID: 34075471
AoB Plants , IF:3.276 , 2022 Feb , V14 (1) : Pplab075 doi: 10.1093/aobpla/plab075
AtANN1 and AtANN2 are involved in phototropism of etiolated hypocotyls of Arabidopsis by regulating auxin distribution.
Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China.; Department of Agricultural and Animal Engineering, Cangzhou Vocation College of Technology, Cangzhou 061001, China.
Phototropism is an essential response in some plant organs and features several signalling molecules involved in either photo-sensing or post-sensing responses. Annexins are involved in regulating plant growth and its responses to various stimuli. Here, we provide novel data showing that two members of the Annexin family in Arabidopsis thaliana, AtANN1 and AtANN2, may be involved in the phototropism of etiolated hypocotyls. In wild type, unilateral blue light (BL) induced a strong phototropic response, while red light (RL) only induced a weak response. The responses of single- or double-null mutants of the two annexins, including atann1, atann2 and atann1/atann2, were significantly weaker than those observed in wild type, indicating the involvement of AtANN1 and AtANN2 in BL-induced phototropism. Unilateral BL induced asymmetric distribution of DR5-GFP and PIN3-GFP fluorescence in hypocotyls; notably, fluorescent intensity on the shaded side was markedly stronger than that on the illuminated side. In etiolated atann1, atann2 or atann1/atann2 hypocotyls, unilateral BL-induced asymmetric distributions of DR5-GFP and PIN3-GFP were weakened or impaired. Herein, we suggest that during hypocotyls phototropic response, AtANN1 and AtANN2 may be involved in BL-stimulated signalling by regulating PIN3-charged auxin transport.
PMID: 35079328
G3 (Bethesda) , IF:3.154 , 2022 Mar doi: 10.1093/g3journal/jkac057
Genome-wide analysis of AAAG and ACGT cis- elements in Arabidopsis thaliana reveals their involvement with genes downregulated under jasmonic acid response in an orientation independent manner.
Department of Biological Sciences, Birla Institute of Technology and Science- Pilani, K.K. Birla Goa campus, Zuarinagar, Goa 403726, India.; Department of Biological Sciences, Birla Institute of Technology and Science- Pilani, Pilani, Jhunjhunu, Rajasthan 333031, India.; Department of Computer Science and Information Systems, Birla Institute of Technology and Science- Pilani, K.K. Birla Goa campus, Zuarinagar, Sancoale, Goa 403726, India.; Institute of Biosciences and Technology,Shri Ramswaroop Memorial University, Lucknow-Deva Road, Barabanki, Uttar Pradesh 225003, India.
Cis-regulatory elements are regions of non-coding DNA that regulate the transcription of neighboring genes. The study of cis-element architecture that functions in transcription regulation are essential. AAAG and ACGT are a class of cis-regulatory elements, known to interact with Dof and bZIP transcription factors respectively, and are known to regulate the expression of auxin response, gibberellin response, floral development, light response, seed storage proteins genes, biotic and abiotic stress genes in plants. Analysisof the frequency of occurrence of AAAG and ACGT motifs from varying spacer lengths (0 to 30 base pair) between these two motifs in both possible orientations-AAAG (N) ACGT and ACGT (N) AAAG, in the promoters and genome of Arabidopsis thaliana which indicated preferred orientation of AAAG (N) ACGT over ACGT (N) AAAG across the genome and in promoters. Further, microarray analysis revealed the involvement of these motifs in the genes downregulated under jasmonic acid response in an orientation-independent manner. These results were further confirmed by the transient expression studies with promoter-reporter cassettes carrying AAAG and ACGT motifs in both orientations. Furthermore, cluster analysis on genes with AAAG (N) ACGT and ACGT (N) AAAG motifs orientations revealed clusters of genes to be involved in ABA signaling, transcriptional regulation, DNA binding, and metal ion binding. These findings can be utilized in designing synthetic promoters for the development of stress-tolerant transgenic plants and also provides an insight into the roles of these motifs in transcriptional regulation.
PMID: 35302624
Funct Plant Biol , IF:3.101 , 2022 Feb , V49 (3) : P245-258 doi: 10.1071/FP21288
Nitric oxide is involved in hydrogen sulfide-induced adventitious rooting in tomato (Solanum lycopersicum).
College of Horticulture, Gansu Agricultural University, 1 Yinmen Village, Anning District, Lanzhou 730070, China.
Nitric oxide (NO) and hydrogen sulfide (H2 S) are signalling molecules that regulate adventitious rooting in plants. However, little is known about the cross-talk between NO and H2 S during adventitious rooting. Tomato (Solanum lycopersicum L.) explants were used to investigate the roles of and relationships between NO and H2 S during rooting. Effects of the NO donor sodium nitroprusside (SNP) and the H2 S donor sodium hydrosulfide (NaHS) on adventitious rooting were dose-dependent, and the greatest biological responses were observed under 25muM SNP and 50muM NaHS. The positive effect of NaHS was reversed by the NO scavenger 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), indicating that the H2 S-induced response was partially NO-dependent. Peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD) activities significantly increased by SNP and NaHS treatment, and indoleacetic acid oxidase (IAAO) activity and the O2 - and H2 O2 content significantly decreased by SNP and NaHS treatment. SNP and NaHS treatment also increased the content of soluble sugar and protein and indole-3-acetic acid (IAA). cPTIO significantly mitigated the increases in POD, PPO and SOD activity and soluble sugar, protein and IAA content induced by NaHS. SNP and NaHS upregulated the expression of auxin-related genes (ARF4 and ARF16 ), cell cycle-related genes (CYCD3 , CYCA3 and CDKA1 ), and antioxidant-related genes (TPX2 , SOD and POD ); whereas cPTIO significantly inhibited the increase in the expression of these genes induced by NaHS. Overall, these results show that NO may be involved in H2 S-induced adventitious rooting by regulating the activity of rooting-related enzymes, the expression of related genes, and the content of various nutrients.
PMID: 34991782
Plant Biol (Stuttg) , IF:3.081 , 2022 Mar doi: 10.1111/plb.13417
Hydrogen sulphide (H2 S) in the hidden half: Role in root growth, stress signalling and rhizospheric interactions.
Microbiology Laboratory, Department of Botany, University of North Bengal, Darjeeling, India.; Plant Biochemistry Laboratory, Department of Botany, University of North Bengal, Darjeeling, India.; Department of Biology, Faculty of Science, College of Haql, University of Tabuk, Tabuk, Saudi Arabia.; Department of Botany, Jangipur College, University of Kalyani, Jangipur, India.
Apart from nitric oxide (NO) and carbon monoxide (CO), hydrogen sulphide (H2 S) has emerged as a potential gasotransmitter that has regulatory roles in root differentiation, proliferation and stress signalling. H2 S metabolism in plants exhibits spatio-temporal differences that are intimately associated with sulphide signalling in the cytosol and other subcellular components, e.g. chloroplast and mitochondria. H2 S biosynthesis in plant organs uses both enzymatic and non-enzymatic pathways. H2 S generation in roots and aerial organs is modulated by developmental phase and changes in environmental stimuli. H2 S has an influential role in root development and in the nodulation process. Studies have revealed that H2 S is a part of the auxin and NO signalling pathways in roots, which induce lateral root formation. At the molecular level, exogenous application of H2 S regulates expression of several transcription factors, viz. LBD (Lateral organ Boundaries Domain), MYB (myeloblastosis) and AP2/ERF (Apetala 2/ Ethylene Response Factor), which stimulate upregulation of PpLBD16 (Lateral organ boundaries domain 16), thereby significantly increasing the number of lateral roots. Concomitantly, H2 S acts as a crucial signalling molecule in roots during various abiotic stresses, e.g. drought, salinity heavy metals (HMs), etc., and augments stress tolerance in plants. Interestingly, extensive crosstalk exists between H2 S, NO, ABA, calcium and ethylene during stress, which escalate plant defence and regulate plant growth and productivity. Hence, the present review will elaborate the role of H2 S in root development, stress alleviation, legume-Rhizobium symbiosis and rhizosphere signalling. The review also examines the mechanism of H2 S-mediated abiotic stress mitigation and cross-talk with other signaling molecules.
PMID: 35334141
PeerJ , IF:2.984 , 2022 , V10 : Pe12892 doi: 10.7717/peerj.12892
Micropropagation of pokeweed (Phytolacca americana L.) and comparison of phenolic, flavonoid content, and antioxidant activity between pokeweed callus and other parts.
Salt-Tolerant Rice Research Group, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand.; Department of Pharmacognosy and Toxicology, Faculty of Pharmaceutical Science, Khon Kaen University, Khon Kaen, Thailand.
Background: Pokeweed (Phytolacca americana L.) is regarded as an invasive plant in many parts of the world but possesses therapeutic characteristics used for antitumor and rheumatism treatment. This study investigated the effects of auxins and four explants on pokeweed callus induction. The effects of cytokinins and combinations between cytokinins and NAA on shoot and root induction were also studied. TPC, TFC and antioxidant activity of calli were screened and compared with other pokeweed plant parts. Methods: Four explants were used to induce callus using 2,4-D and IBA at 1, 2, 3 and 4 mg/l for each auxin. Direct shoot organogenesis from nodal explants was investigated using BAP, kinetin and TDZ (1, 2 and 4 mg/l for each cytokinin). Combined effects between cytokinins and NAA at 0.1, 0.2 and 0.3 mg/l were further simultaneously estimated with root induction. Calli derived from the leaves were compared with other plant parts for TPC, TFC and antioxidant activity using the Folin-Ciocalteu, AlCl3 colorimetric assay and DPPH assays, respectively. Results: Results showed that MS medium containing 2 mg/l 2,4-D induced callus formation on leaf explants that provided highest fresh and dry weights. Three types of synthetic cytokinins as kinetin, TDZ and BAP were used for direct shoot organogenesis from pokeweed nodes. MS medium containing 2 mg/l kinetin was effective in stimulating normal shoots, with the largest number of shoots and leaves and the longest shoots. The combination between cytokinins and NAA showed no positive effect on shoot and root induction from pokeweed nodal explants. For TPC and TFC determination, pokeweed seeds and leaves possessed the highest phenolic and flavonoid contents, respectively. Highest phenolic content of pokeweed seeds led to lowest IC50 by DPPH assay. Phenolic content was higher than flavonoid content. Conclusion: Results suggested promising conditions for callus induction. Leaf explants cultured on MS medium with 2 mg/l 2,4-D and nodal explants cultured on MS medium with 2 mg/l kinetin provided the largest number of normal shoots and leaves. NAA did not show positive effects on shoot and root induction when combined with cytokinins. Chemical constituent screening indicated that seeds and leaves provided highest TPC and TFC, respectively, while pokeweed calli contained higher phenolic than flavonoid content. This is the first report describing chemical constituent screening and antioxidant activity of calli and other parts of the pokeweed plant. Results provided significant information to further enhance bioactive compound contents of pokeweed calli using elicitation methods.
PMID: 35186483
PeerJ , IF:2.984 , 2022 , V10 : Pe12854 doi: 10.7717/peerj.12854
The effect of 2,4-dichlorophenoxyacetic acid on the production of oat (Avena sativa L.) doubled haploid lines through wide hybridization.
Instytut Fizjologii Roslin im. Franciszka Gorskiego PAN, Krakow, Polska.
Background: Development of new cultivars is one of the vital options for adapting agriculture to climate change, and the production of doubled haploid (DH) plants can make a significant contribution to accelerating the breeding process. Oat is one of the cereals with particular health benefits, but it unfortunately still remains recalcitrant to haploidization. Our previous studies have clearly demonstrated that post-pollination with hormone treatment is a key step in haploid production through wide hybridization and indicated it as the most effective method for this species. Therefore, we subsequently addressed the problem of the influence of 2,4-dichlorophenoxyacetic acid (2,4-D) concentration on consecutive stages of DH production. Methods: Twenty-nine genotypes were tested, 9,465 florets were pollinated with maize pollen 2 days after emasculation and then treated with 2,4-D at 50 mg/L and 100 mg/L. Results: The applied treatments did not reveal any differences in the number of obtained haploid embryos. However, almost twice as many haploid plants formed on MS medium after applying a higher auxin concentration and 20% more successfully acclimatized. Moreover, 100 mg/L 2,4-D treatment resulted in twice as many DH lines that produced almost three times more seeds compared to 50 mg/L treatment. Nevertheless, the results have confirmed the existence of strong genotypic variation, which may significantly limit the development of an effective and economically feasible method that could be incorporated into breeding programs.
PMID: 35178299
J Plant Res , IF:2.629 , 2022 Mar , V135 (2) : P351-360 doi: 10.1007/s10265-022-01374-z
Effects of different photoperiods on flower opening, flower closing and circadian expression of clock-related genes in Iris domestica and I. dichotoma.
Department of Landscape Architecture, Beijing Forestry University, No. 35 Tsinghua East Road, Haidian District, Beijing, China.; Department of Landscape Architecture, Beijing Forestry University, No. 35 Tsinghua East Road, Haidian District, Beijing, China. gaoyk@bjfu.edu.cn.
The circadian clock can entrain to forced light-dark cycles by adjusting the phases and periods of flower opening and closing in ephemeral flowers. The responses of circadian rhythms to the same light conditions differ from species. However, the differences in internal genetic mechanisms underlying the different responses between species remain unclear. Iris domestica and I. dichotoma have ephemeral flowers and significantly divergent flower opening and closing times. The effects of different photoperiods (continuous darkness, 4L20D, 8L16D, 12L12D, 16L8D, 20L4D and continuous white light) on flower opening and closing, and expression patterns of seven genes (CRYPTOCHROME 1, PHYTOCHROME B, LATE ELONGATED HYPOCOTYL, PSEUDO RESPONSE REGULATOR 95, PHYTOCHROME INTERACTING FACTOR 4-like, SMUX AUXIN UP RNA 64-like and senescence-associated gene 39-like) involved in the circadian regulation of flower opening and closing were compared between I. domestica and I. dichotoma. Flower opening and closing in the two species exhibited circadian rhythms under continuous darkness (DD), but showed arrhythmia in continuous white light (LL). In the two species, keeping robust rhythms, strong synchronicity, rapid progressions of flower opening and closing and reaching full opening stage required a dark period longer than 4 h. In light-dark cycles with dark periods longer than 4 h, flower opening and closing times of the two species delayed with the delay of dawn, and the degree to which flower opening time varies with the time of dawn was greater in I. dichotoma than in I. domestica. The arrhythmia of flower opening and closing under 20L4D and LL would result from the arrhythmic output signals rather than arrhythmia of oscillators and photoreceptors. The different responses of the two species to the change of photoperiods would be caused by the transcriptional differences of genes in the output pathway of circadian clock system rather than in the input pathway or oscillators.
PMID: 35157159
Arch Microbiol , IF:2.552 , 2022 Feb , V204 (3) : P181 doi: 10.1007/s00203-022-02768-2
A new endophytic fungus CJAN1179 isolated from the Cholistan desert promotes lateral root growth in Arabidopsis and produces IAA through tryptophan-dependent pathway.
Chemistry Department, The Islamia University of Bahawalpur, Bahawalpur, 63000, Pakistan.; INRES, Molecular Phytomedicine, Rheinische Friedrich-Wilhelms-University Bonn, Karlrobert-Kreiten-Str. 13, 53115, Bonn, Germany.; Institute of Biochemistry, Biotechnology and Bioinformatics, The Islamia University of Bahawalpur, Baghdad Ul Jadeed Campus, Bahawalpur, 63000, Pakistan.; Department of Botany, The Islamia University of Bahawalpur, Bahawalpur, 63000, Pakistan.; INRES, Molecular Phytomedicine, Rheinische Friedrich-Wilhelms-University Bonn, Karlrobert-Kreiten-Str. 13, 53115, Bonn, Germany. sylvia.schleker@uni-bonn.de.
Fungi, important for growth of plants in arid lands, are expected to be involved in novel biochemical activities during fungal-plant interactions. We isolated 150 fungi associated with rhizosphere and root endosphere of two perennial grasses, Cymbopogon jwarancusa and Panicum antidotale, from Cholistan desert. The isolates were screened for their impact on plant growth and development using Arabidopsis thaliana (Col-0) as a model system. A root-endophytic fungus CJAN1179 from C. jwarancusa showed the highest plant growth-promoting effects. The most remarkable was enhanced number of lateral roots (3.1-fold). CJAN1179 produced indole-3-acetic acid (IAA) particularly in the presence of tryptophan. ITS sequence and phylogenetic analysis characterisation suggested the fungus to be a new species within Sordariomycetidae. CJAN1179 appears to promote plant growth by secreting IAA using tryptophan as a precursor. This fungus can be further explored for its suitability to promote growth of commercially important crops, particularly in arid regions.
PMID: 35175443
Braz J Microbiol , IF:2.476 , 2022 Mar , V53 (1) : P281-288 doi: 10.1007/s42770-021-00651-8
Stimulatory effects of defective and effective 3-indoleacetic acid-producing bacterial strains on rice in an advanced stage of its vegetative cycle.
Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropedica, RJ, 23.891-000, Brazil.; Departamento de Ciencias Do Solo, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropedica, RJ, 23890-000, Brazil.; Departamento de Ciencias Ambientais E Florestais, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropedica, RJ, 23890-000, Brazil.; Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropedica, RJ, 23890-000, Brazil.; Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropedica, RJ, 23.891-000, Brazil. ederson.jesus@embrapa.br.
The production of 3-indoleacetic acid (IAA) by plant growth-promoting bacteria (PGPR) stimulates root development and plant growth. In addition, morphological changes such as an increased root ramification and root hair production improves nutrient absorption and biomass accumulation. The objective of this work was to evaluate the effect of IAA-producing strains on rice in an advanced stage of its vegetative cycle. Rice was inoculated with Gluconacetobacter diazotrophicus PAL 5 and its lao- mutant, deficient in auxin production, Azospirillum baldaniorum Sp 245, and Escherichia coli DH10b. Both the mutant and wild-type G. diazotrophicus stimulated root elongation, area, volume, and diameter. However, the lao- mutant strain was the only one capable of increasing the number of roots. In turn, inoculation with A. baldaniorum had no significant effect on plant development. The inoculation with E. coli led to changes in root volume, area, and diameter, and a response that may be related to the stress caused by its presence. We conclude that the inoculation with G. diazotrophicus stimulates the root system's growth independently of their IAA production ability, suggesting that a metabolite other than IAA is responsible for this effect at advanced stages of the rice's vegetative cycle.
PMID: 35060090
Virus Genes , IF:2.332 , 2022 Feb , V58 (1) : P1-14 doi: 10.1007/s11262-021-01881-6
The interplay of plant hormonal pathways and geminiviral proteins: partners in disease development.
Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, -110021, India.; Department of Botany, Bhagat Singh Government P.G. College, Jaora, Ratlam, Madhya Pradesh, 457226, India.; Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, -110021, India. indasgup@south.du.ac.in.
Viruses belonging to the family Geminiviridae infect plants and are responsible for a number of diseases of crops in the tropical and sub-tropical regions of the World. The innate immune response of the plant assists in its defense against such viral pathogens by the recognition of pathogen/microbe-associated molecular patterns through pattern-recognition receptors. Phytohormone signalling pathways play a vital role in plant defense responses against these devastating viruses. Geminiviruses, however, have developed counter-defense strategies that prevail over the above defense pathways. The proteins encoded by geminiviruses act as suppressors of plant immunity by interacting with the signalling components of several hormones. In this review we focus on the molecular interplay of phytohormone pathways and geminiviral infection and try to find interesting parallels with similar mechanisms known in other plant-infecting viruses and strengthen the argument that this interplay is necessary for disease development.
PMID: 35034268
Mol Biol Rep , IF:2.316 , 2022 Mar doi: 10.1007/s11033-022-07354-9
Phosphorus homeostasis: acquisition, sensing, and long-distance signaling in plants.
Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India.; ICAR- Indian Agricultural Statistical Research Institute, New Delhi, India.; Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India. arunatyagi19@yahoo.com.
Phosphorus (P), an essential nutrient required by plants often becomes the limiting factor for plant growth and development. Plants employ various mechanisms to sense the continuously changing P content in the soil. Transcription factors, such as SHORT ROOT (SHR), AUXIN RESPONSE FACTOR19 (ARF19), and ETHYLENE-INSENSITIVE3 (EIN3) regulate the growth of primary roots, root hairs, and lateral roots under low P. Crop improvement strategies under low P depend either on improving P acquisition efficiency or increasing P utilization. The various phosphate transporters (PTs) are involved in the uptake and transport of P from the soil to various plant cellular organelles. A plethora of regulatory elements including transcription factors, microRNAs and several proteins play a critical role in the regulation of coordinated cellular P homeostasis. Among these, the well-established P starvation signaling pathway comprising of central transcriptional factor phosphate starvation response (PHR), microRNA399 (miR399) as a long-distance signal molecule, and PHOSPHATE 2 (PHO2), an E2 ubiquitin conjugase is crucial in the regulation of phosphorus starvation responsive genes. Under PHR control, several classes of PHTs, microRNAs, and proteins modulate root architecture, and metabolic processes to enable plants to adapt to low P. Even though sucrose and inositol phosphates are known to influence the phosphorus starvation response genes, the exact mechanism of regulation is still unclear. In this review, a basic understanding of P homeostasis under low P in plants and all the above aspects are discussed.
PMID: 35318578
Mol Biol Rep , IF:2.316 , 2022 Mar , V49 (3) : P1973-1984 doi: 10.1007/s11033-021-07011-7
The SAUR gene family in coffee: genome-wide identification and gene expression analysis during somatic embryogenesis.
Central Laboratory of Molecular Biology, Department of Chemistry, Federal University of Lavras (UFLA), Lavras, MG, 37200000, Brazil.; Brazilian Agricultural Research Corporation (Embrapa Tabuleiros Costeiros), Aracaju, SE, 49025040, Brazil.; Central Laboratory of Molecular Biology, Department of Chemistry, Federal University of Lavras (UFLA), Lavras, MG, 37200000, Brazil. luciano@ufla.br.
BACKGROUND: Small auxin-up RNA (SAUR) genes form a wide family supposedly involved in different physiological and developmental processes in plants such as leaf senescence, auxin signaling and transport, hypocotyl development and tolerance to abiotic stresses. The transcription of SAUR genes is quickly induced by auxins, a group of phytohormones of major importance on embryo development. To better understand the distribution and expression profile of such still not explored family in Coffea sp., especially during the development of somatic embryogenesis (SE), SAUR members were characterized in silico using the available Coffea canephora genome data and analyzed for gene expression by RT-qPCR in C. arabica embryogenic samples. METHODS AND RESULTS: Over C. canephora genome 31 CcSAURs were distributed by 11 chromosomes. Out of these 31 gene members, 5 SAURs were selected for gene expression analysis in C. arabica embryogenic materials. CaSAUR12 and CaSAUR18 were the members highly expressed through almost all plant materials. The other genes had more expression in at least one of the developing embryo stages or plantlets. The CaSAUR12 was the only member to exhibit an increased expression in both non-embryogenic calli and the developing embryo stages. CONCLUSION: The identification of SAUR family on C. canephora genome followed by the analysis of gene expression profile across coffee somatic embryogenesis process on C. arabica represents a further additional step towards a better comprehension of molecular components acting on SE. Along with new research about this gene family such knowledge may support studies about clonal propagation methods via somatic embryogenesis to help the scientific community towards improvements into coffee crop.
PMID: 35034287
Evodevo , IF:2.25 , 2022 Mar , V13 (1) : P8 doi: 10.1186/s13227-022-00192-7
Fossils and plant evolution: structural fingerprints and modularity in the evo-devo paradigm.
Department of Biological Sciences, California Polytechnic State University Humboldt, Arcata, CA, 95521, USA. mihai@humboldt.edu.; Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA.; Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA.
Fossils constitute the principal repository of data that allow for independent tests of hypotheses of biological evolution derived from observations of the extant biota. Traditionally, transformational series of structure, consisting of sequences of fossils of the same lineage through time, have been employed to reconstruct and interpret morphological evolution. More recently, a move toward an updated paradigm was fueled by the deliberate integration of developmental thinking in the inclusion of fossils in reconstruction of morphological evolution. The vehicle for this is provided by structural fingerprints-recognizable morphological and anatomical structures generated by (and reflective of) the deployment of specific genes and regulatory pathways during development. Furthermore, because the regulation of plant development is both modular and hierarchical in nature, combining structural fingerprints recognized in the fossil record with our understanding of the developmental regulation of those structures produces a powerful tool for understanding plant evolution. This is particularly true when the systematic distribution of specific developmental regulatory mechanisms and modules is viewed within an evolutionary (paleo-evo-devo) framework. Here, we discuss several advances in understanding the processes and patterns of evolution, achieved by tracking structural fingerprints with their underlying regulatory modules across lineages, living and fossil: the role of polar auxin regulation in the cellular patterning of secondary xylem and the parallel evolution of arborescence in lycophytes and seed plants; the morphology and life history of early polysporangiophytes and tracheophytes; the role of modularity in the parallel evolution of leaves in euphyllophytes; leaf meristematic activity and the parallel evolution of venation patterns among euphyllophytes; mosaic deployment of regulatory modules and the diverse modes of secondary growth of euphyllophytes; modularity and hierarchy in developmental regulation and the evolution of equisetalean reproductive morphology. More generally, inclusion of plant fossils in the evo-devo paradigm has informed discussions on the evolution of growth patterns and growth responses, sporophyte body plans and their homology, sequences of character evolution, and the evolution of reproductive systems.
PMID: 35236418
Plant Signal Behav , IF:2.247 , 2022 Feb doi: 10.1080/15592324.2022.2031784
The epigenetic regulator ULTRAPETALA1 suppresses de novo root regeneration from Arabidopsis leaf explants.
Key Laboratory of Saline-Alkali Vegetation Ecology Restoration Ministry of Education, Northeast Forestry University, Harbin, China.; College of Life Science, Institute of Genetics, Northeast Forestry University, Harbin, China.; Lushan Botanical Garden, Chinese Academy of Sciences, Jiujiang, China.
Plants have the potency to regenerate adventitious roots from aerial organs after detachment. In Arabidopsis thaliana, de novo root regeneration (DNRR) from leaf explants is triggered by wounding signaling that rapidly induces the expression of the ETHYLENE RESPONSE FACTOR (ERF) transcription factors ERF109 and ABR1 (ERF111). In turn, the ERFs promote the expression of ASA1, an essential enzyme of auxin biosynthesis, which contributes to rooting by providing high levels of auxin near the wounding side of the leaf. Here, we show that the loss of the epigenetic regulator ULTRAPETALA1 (ULT1), which interacts with Polycomb and Trithorax Group proteins, accelerates and reinforces adventitious root formation. Expression of ERF109 and ASA1 was increased in ult1 mutants, whereas ABR1 was not significantly changed. Cultivation of explants on media with exogenous auxin equates adventitious root formation in wild-type with ult1 mutants, suggesting that ULT1 negatively regulates DNRR by suppressing auxin biosynthesis. Based on these findings, we propose that ULT1 is involved in a novel mechanism that prevents overproliferation of adventitious roots during DNRR.
PMID: 35164655
J Environ Sci Health B , IF:1.99 , 2022 Feb : P1-10 doi: 10.1080/03601234.2022.2028528
Searching for biomarkers of early detection of 2,4-D effects in a native tree species from the Brazilian Cerrado biome.
Ciencia e Tecnologia - Campus Rio Verde, Instituto Federal Goiano de Educacao, Rio Verde, Goias, Brazil.; Laboratorio de Estudo de Plantas sob Estresse, Universidade de Sao Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba, Sao Paulo, Brazil.; Ciencia e Tecnologia Goiano - Campus Morrinhos, Instituto Federal de Educacao, Morrinhos, Goias, Brazil.; Nucleo de Pesquisa em Ecologia, Instituto de Botanica, Sao Paulo, Sao Paulo, Brazil.
Biodiversity in the Brazilian Cerrado biome has been declining sharply with the continued expansion of agriculture and the excessive use of herbicides. Thus, the aim of this study was to evaluate the morphophysiological and biochemical responses in Dipteryx alata plants to various doses of the herbicide 2,4-D. Specific biomarkers that characterize the phytoindicator potential of this species were determined. Gas exchange, chlorophyll a fluorescence, photosynthetic pigments, and the activities of antioxidant enzymes and cellulase were performed after 24, 96 and/or 396 hours after 2,4-D application (HAA). The herbicide caused higher antioxidant enzymatic activity 24 HAA and damage to the photosynthetic machinery after 96 HAA. Reduction in gas exchange, chlorophyll content, and photochemical traits were observed. Increased respiratory rates, non-photochemical quenching, and carotenoid concentrations in 2,4-D-treated plants were important mechanisms in the defense against the excess energy absorbed. Furthermore, the absence of leaf symptoms suggested tolerance of D. alata to 2,4-D. Nevertheless, changes in the photosynthetic and biochemical metabolism of D. alata are useful as early indicators of herbicide contamination, especially in the absence of visual symptoms. These results are important for early monitoring of plants in conserved areas and for preventing damage to sensitive species.
PMID: 35114885
Appl Plant Sci , IF:1.936 , 2022 Jan-Feb , V10 (1) : Pe11454 doi: 10.1002/aps3.11454
A protocol for the generation of Arachis hypogaea composite plants: A valuable tool for the functional study of mycorrhizal symbiosis.
Ciencias Agrogenomicas, Escuela Nacional de Estudios Superiores Unidad Leon Universidad Nacional Autonoma de Mexico (UNAM), Leon, C.P. 37689 Guanajuato Mexico.; Departamento de Genomica Alimentaria Universidad de La Cienega del Estado de Michoacan de Ocampo, Sahuayo, C.P. 59103 Michoacan de Ocampo Mexico.
Premise: Agrobacterium rhizogenes-induced hairy root systems are one of the most preferred and versatile systems for the functional characterization of genes. The use of hairy root systems is a rapid and convenient alternative for studying root biology, biotic and abiotic stresses, and root symbiosis in in vitro recalcitrant legume species such as Arachis hypogaea. Methods and Results: We present a rapid, simplified method for the generation of composite A. hypogaea plants with transgenic hairy roots. We demonstrate a technique of hairy root induction mediated by A. rhizogenes from young A. hypogaea shoots. The efficacy of the system for producing transgenic roots is demonstrated using an enhanced green fluorescent protein (eGFP) expression vector. Furthermore, the application of the system for studying root branching is shown using the auxin-responsive marker DR5 promoter fused to beta-glucuronidase (GUS). Finally, the success of the hairy root system for root symbiotic studies is illustrated by inoculating hairy roots with arbuscular mycorrhizal fungi. Conclusions: In this study, we have developed a rapid, efficient, and cost-effective composite plant protocol for A. hypogaea that is particularly effective for root-related studies and for the validation of candidate genes in A. hypogaea during mycorrhizal symbiosis.
PMID: 35228912
Biochem Genet , IF:1.89 , 2022 Feb , V60 (1) : P127-152 doi: 10.1007/s10528-021-10093-4
Identification and Expression Analysis of miR160 and Their Target Genes in Cucumber.
School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, 453003, China.; Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, 453003, China.; School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, 453003, China. sunyd2001@163.com.; Henan Province Engineering Research Center of Horticultural Plant Resource Utilization and Germplasm Enhancement, Xinxiang, 453003, China. sunyd2001@163.com.; Institute of Horticulture, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China.
miR160 plays a crucial role in various biological processes by regulating their target gene auxin response factor (ARF) in plants. However, little is known about miR160 and ARF in cucumber fruit expansion. Here, 4 Csa-MIR160 family members and 17 CsARFs were identified through a genome-wide search. Csa-miR160 showed a closer relationship with those in melon. Phylogenetic analysis revealed that CsARFs were divided into four classes and most of CsARFs presented a closer evolutionary relationship with those from tomato. Putative cis-elements analysis predicted that Csa-MIR160 and CsARFs were involved in light, phytohormone and stress response, which proved that they might take part in light, phytohormone and stress signaling pathway by the miR160-ARF module. In addition, CsARF5, CsARF11, CsARF13 and CsARF14 were predicted as the target genes of Csa-miR160. qRT-PCR revealed that Csa-miR160 and their target gene CsARFs were differentially expressed in differential cucumber tissues and developmental stages. Csa-miR160d was only expressed in the expanded cucumber fruit. CsARF5, CsARF11 and CsARF13 exhibited the lower expression in the expanded fruit than those in the ovary, while, CsARF14 showed the reverse trend. Our results suggested that Csa-miR160d might play a crucial role in cucumber fruit expansion by negatively targeting CsARF5, CsARF11 and CsARF13. This is the first genome-wide analysis of miR160 in cucumber. These findings provide useful information and resources for further studying the role of miR160 and ARF in cucumber fruit expansion.
PMID: 34117971