Nat Commun , IF:14.919 , 2021 Aug , V12 (1) : P4804 doi: 10.1038/s41467-021-24883-2
Warm temperature triggers JOX and ST2A-mediated jasmonate catabolism to promote plant growth.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB Center for Plant Systems Biology, Ghent, Belgium.; Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.; Goettingen Service Unit for Metabolomics and Lipidomics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.; State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Key Laboratory of Crop Genomics and Genetic Improvement (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, China.; Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research RAS, Pushchino, Russia.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. Ive.DeSmet@psb.vib-ugent.be.; VIB Center for Plant Systems Biology, Ghent, Belgium. Ive.DeSmet@psb.vib-ugent.be.
Plants respond to warm temperature by increased elongation growth of organs to enhance cooling capacity. Phytohormones, such as auxin and brassinosteroids, regulate this growth process. However, our view on the players involved in warm temperature-mediated growth remains fragmentary. Here, we show that warm temperature leads to an increased expression of JOXs and ST2A, genes controlling jasmonate catabolism. This leads to an elevated 12HSO4-JA level and consequently to a reduced level of bioactive jasmonates. Ultimately this results in more JAZ proteins, which facilitates plant growth under warm temperature conditions. Taken together, understanding the conserved role of jasmonate signalling during thermomorphogenesis contributes to ensuring food security under a changing climate.
PMID: 34376671
Biol Rev Camb Philos Soc , IF:12.82 , 2021 Aug doi: 10.1111/brv.12785
What do we know about growth of vessel elements of secondary xylem in woody plants?
Polish Academy of Sciences Botanical Garden - Centre for Biological Diversity Conservation in Powsin, Prawdziwka 2, 02-973, Warsaw, Poland.; Institute of Biology, University of Opole, Oleska 22, 45-052, Opole, Poland.
Despite extensive knowledge about vessel element growth and the determination of the axial course of vessels, these processes are still not fully understood. They are usually explained as resulting primarily from hormonal regulation in stems. This review focuses on an increasingly discussed aspect - mechanical conditions in the vascular cambium. Mechanical conditions in cambial tissue are important for the growth of vessel elements, as well as other cambial derivatives. In relation to the type of stress acting on cambial cells (compressive versus tensile stress) we: (i) discuss the shape of the enlarging vessel elements observed in anatomical sections; (ii) present hypotheses regarding the location of intrusive growth of vessel elements and cambial initials; (iii) explain the relationship between the growth of vessel elements and fibres; and (iv) consider the effect of mechanical stress in determining the course of a vessel. We also highlight the relationship between mechanical stress and transport of the most extensively studied plant hormone - auxin. We conclude that the integration of a biomechanical factor with the commonly acknowledged hormonal regulation could significantly enhance the analysis of the formation of vessel elements as well as entire vessels, which transport water and minerals in numerous plant species.
PMID: 34374202
Dev Cell , IF:12.27 , 2021 Aug , V56 (15) : P2176-2191.e10 doi: 10.1016/j.devcel.2021.07.005
A reflux-and-growth mechanism explains oscillatory patterning of lateral root branching sites.
Computational Developmental Biology, Department of Biology, Utrecht University, Utrecht, the Netherlands.; Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium; VIB Center for Plant Systems Biology, Ghent, Belgium.; Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University, Wageningen, the Netherlands; Rijk Zwaan Breeding B.V., Department of Biotechnology, Eerste Kruisweg 9, 4793 RS Fijnaart, the Netherlands.; Computational Developmental Biology, Department of Biology, Utrecht University, Utrecht, the Netherlands. Electronic address: k.h.w.j.tentusscher@uu.nl.
Modular, repetitive structures are a key component of complex multicellular body plans across the tree of life. Typically, these structures are prepatterned by temporal oscillations in gene expression or signaling. Although a clock-and-wavefront mechanism was identified and plant leaf phyllotaxis arises from a Turing-type patterning for vertebrate somitogenesis and arthropod segmentation, the mechanism underlying lateral root patterning has remained elusive. To resolve this enigma, we combined computational modeling with in planta experiments. Intriguingly, auxin oscillations automatically emerge in our model from the interplay between a reflux-loop-generated auxin loading zone and stem-cell-driven growth dynamics generating periodic cell-size variations. In contrast to the clock-and-wavefront mechanism and Turing patterning, the uncovered mechanism predicts both frequency and spacing of lateral-root-forming sites to positively correlate with root meristem growth. We validate this prediction experimentally. Combined, our model and experimental results support that a reflux-and-growth patterning mechanism underlies lateral root priming.
PMID: 34343477
Plant Cell , IF:11.277 , 2021 Aug doi: 10.1093/plcell/koab207
CALCIUM-DEPENDENT PROTEIN KINASE 29 modulates PIN-FORMED polarity and Arabidopsis development via its own phosphorylation code.
Department of Biological Sciences, Seoul National University, Seoul 08826, Korea.
PIN-FORMED (PIN)-mediated polar auxin transport is involved in key developmental processes in plants. Various internal and external cues influence plant development via the modulation of intracellular PIN polarity and, thus, the direction of polar auxin transport, but the mechanisms underlying these processes remain largely unknown. PIN proteins harbor a hydrophilic loop (HL) that has important regulatory functions; here, we used the HL as bait in protein pulldown screening for modulators of intracellular PIN trafficking in Arabidopsis thaliana. CPK29, a Ca2+-dependent protein kinase, was identified and shown to phosphorylate specific target residues on the PIN-HL that were not phosphorylated by other kinases. Furthermore, loss of CPK29 or mutations of the phospho-target residues in PIN-HLs significantly compromised intracellular PIN trafficking and polarity, causing defects in PIN-mediated auxin redistribution and biological processes such as lateral root formation, root twisting, hypocotyl gravitropism, phyllotaxis, and reproductive development. These findings indicate that CPK29 directly interprets Ca2+ signals from internal and external triggers, resulting in the modulation of PIN trafficking and auxin responses.
PMID: 34402905
Proc Natl Acad Sci U S A , IF:11.205 , 2021 Aug , V118 (35) doi: 10.1073/pnas.2101526118
ENHANCED GRAVITROPISM 2 encodes a STERILE ALPHA MOTIF-containing protein that controls root growth angle in barley and wheat.
Institute of Crop Sciences and Resource Conservation, Crop Functional Genomics, University of Bonn, 53113 Bonn, Germany.; Department of Agricultural and Food Sciences, University of Bologna, 40127 Bologna, Italy.; Institute of Phytopathology, Research Centre for BioSystems, Land Use and Nutrition, Justus-Liebig-University Giessen, 35392 Giessen, Germany.; Cologne Center for Genomics, University of Cologne, 50931 Cologne, Germany.; Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, 06466 Seeland, Germany.; Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Forschungszentrum Juelich GmbH, 52425 Julich, Germany.; Institute of Crop Sciences and Resource Conservation, Crop Bioinformatics, University of Bonn, 53115 Bonn, Germany.; German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig, 04103 Leipzig, Germany.; John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.; Department of Agricultural and Food Sciences, University of Bologna, 40127 Bologna, Italy; hochhold@uni-bonn.de silvio.salvi@unibo.it.; Institute of Crop Sciences and Resource Conservation, Crop Functional Genomics, University of Bonn, 53113 Bonn, Germany; hochhold@uni-bonn.de silvio.salvi@unibo.it.
The root growth angle defines how roots grow toward the gravity vector and is among the most important determinants of root system architecture. It controls water uptake capacity, nutrient use efficiency, stress resilience, and, as a consequence, yield of crop plants. We demonstrated that the egt2 (enhanced gravitropism 2) mutant of barley exhibits steeper root growth of seminal and lateral roots and an auxin-independent higher responsiveness to gravity compared to wild-type plants. We cloned the EGT2 gene by a combination of bulked-segregant analysis and whole genome sequencing. Subsequent validation experiments by an independent CRISPR/Cas9 mutant allele demonstrated that egt2 encodes a STERILE ALPHA MOTIF domain-containing protein. In situ hybridization experiments illustrated that EGT2 is expressed from the root cap to the elongation zone. We demonstrated the evolutionary conserved role of EGT2 in root growth angle control between barley and wheat by knocking out the EGT2 orthologs in the A and B genomes of tetraploid durum wheat. By combining laser capture microdissection with RNA sequencing, we observed that seven expansin genes were transcriptionally down-regulated in the elongation zone. This is consistent with a role of EGT2 in this region of the root where the effect of gravity sensing is executed by differential cell elongation. Our findings suggest that EGT2 is an evolutionary conserved regulator of root growth angle in barley and wheat that could be a valuable target for root-based crop improvement strategies in cereals.
PMID: 34446550
Curr Biol , IF:10.834 , 2021 Aug doi: 10.1016/j.cub.2021.07.075
Auxin requirements for a meristematic state in roots depend on a dual brassinosteroid function.
Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.; Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel.; Lorey I. Lokey Interdisciplinary Center for Life Sciences and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel.; Laboratory of Growth Regulators, Institute of Experimental Botany, Czech Academy of Sciences and Palacky University, Olomouc, Czech Republic.; Faculty of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel. Electronic address: sigal@technion.ac.il.
Root meristem organization is maintained by an interplay between hormone signaling pathways that both interpret and determine their accumulation and distribution. The interacting hormones Brassinosteroids (BR) and auxin control the number of meristematic cells in the Arabidopsis root. BR was reported both to promote auxin signaling input and to repress auxin signaling output. Whether these contradicting molecular outcomes co-occur and what their significance in meristem function is remain unclear. Here, we established a dual effect of BR on auxin, with BR simultaneously promoting auxin biosynthesis and repressing auxin transcriptional output, which is essential for meristem maintenance. Blocking BR-induced auxin synthesis resulted in rapid BR-mediated meristem loss. Conversely, plants with reduced BR levels were resistant to a critical loss of auxin biosynthesis, maintaining their meristem morphology. In agreement, injured root meristems, which rely solely on local auxin synthesis, regenerated when both auxin and BR synthesis were inhibited. Use of BIN2 as a tool to selectively inhibit BR signaling yielded meristems with distinct phenotypes depending on the perturbed tissue: meristem reminiscent either of BR-deficient mutants or of high BR exposure. This enabled mapping of the BR-auxin interaction that maintains the meristem to the outer epidermis and lateral root cap tissues and demonstrated the essentiality of BR signaling in these tissues for meristem response to BR. BR activity in internal tissues however, proved necessary to control BR levels. Together, we demonstrate a basis for inter-tissue coordination and how a critical ratio between these hormones determines the meristematic state.
PMID: 34418341
Curr Biol , IF:10.834 , 2021 Aug , V31 (15) : P3365-3373.e7 doi: 10.1016/j.cub.2021.05.036
Cytokinins initiate secondary growth in the Arabidopsis root through a set of LBD genes.
Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00014, Finland; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland.; Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00014, Finland; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland. Electronic address: xin.wang@helsinki.fi.; Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00014, Finland; Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland. Electronic address: aripekka.mahonen@helsinki.fi.
During primary growth, plant tissues increase their length, and as these tissues mature, they initiate secondary growth to increase thickness.(1) It is not known what activates this transition to secondary growth. Cytokinins are key plant hormones regulating vascular development during both primary and secondary growth. During primary growth of Arabidopsis roots, cytokinins promote procambial cell proliferation(2)(,)(3) and vascular patterning together with the hormone auxin.(4-7) In the absence of cytokinins, secondary growth fails to initiate.(8) Enhanced cytokinin levels, in turn, promote secondary growth.(8)(,)(9) Despite the importance of cytokinins, little is known about the downstream signaling events in this process. Here, we show that cytokinins and a few downstream LATERAL ORGAN BOUNDARIES DOMAIN (LBD) family of transcription factors are rate-limiting components in activating and further promoting secondary growth in Arabidopsis roots. Cytokinins directly activate transcription of two homologous LBD genes, LBD3 and LBD4. Two other homologous LBDs, LBD1 and LBD11, are induced only after prolonged cytokinin treatment. Our genetic studies revealed a two-stage mechanism downstream of cytokinin signaling: while LBD3 and LBD4 regulate activation of secondary growth, LBD1, LBD3, LBD4, and LBD11 together promote further radial growth and maintenance of cambial stem cells. LBD overexpression promoted rapid cell growth followed by accelerated cell divisions, thus leading to enhanced secondary growth. Finally, we show that LBDs rapidly inhibit cytokinin signaling. Together, our data suggest that the cambium-promoting LBDs negatively feed back into cytokinin signaling to keep root secondary growth in balance.
PMID: 34129827
J Hazard Mater , IF:10.588 , 2021 Aug , V415 : P124907 doi: 10.1016/j.jhazmat.2020.124907
Hydrogen sulfide (H2S) underpins the beneficial silicon effects against the copper oxide nanoparticles (CuO NPs) phytotoxicity in Oryza sativa seedlings.
Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, UP, India.; Plant Physiology Laboratory, Department of Botany, C.M.P. Degree College, A Constituent Post Graduate College of University of Allahabad, Prayagraj 211002, India.; Department of Chemistry and Biochemistry, The University of Texas at El Paso, 500 West University Ave., El Paso, TX 79968, United States.; Amity Institute of Organic Agriculture, Amity University Uttar Pradesh, Sector-125, Noida 201313, India.; Department of Biotechnology, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, UP, India. Electronic address: shiveshs@mnnit.ac.in.; Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry, Cell and Molecular Biology of Plants, Estacion Experimental del Zaidin, Spanish National Research Council (CSIC), C/ Profesor Albareda, 1, 18008 Granada, Spain.
Nanoparticle-pollution has associated severe negative effects on crop productivity. Hence, methods are needed to alleviate nano-toxicity in crop plants. The present study aims to evaluate if the exogenous hydrogen sulfide (H2S) application in combination with silicon (Si) could palliate the harmful effects of copper oxide nanoparticles (CuO NPs). Fifteen day-old rice (Oryza sativa L.) seedlings were used as a model plant. The results indicate that simultaneous exogenous addition of 10muM Si and 100muM NaHS (as an H2S donor) provided tolerance and enhanced defence mechanism of the rice seedlings against 100muM CuO NPs. Thus, it was observed in terms of their growth, photosynthetic pigments, antioxidant enzyme activities, the content of non-enzymatic components, chlorophyll fluorescence and up-regulation of antioxidant genes. Si and NaHS stimulated gene expression of silicon (Lsi1 and Lsi2) and auxin (PIN5 and PIN10) transporters. Taken together, data indicate that H2S underpins the beneficial Si effects in rice seedlings against the oxidative stress triggers by CuO NPs, and stimulation of enzymatic components of the ascorbate-glutathione cycle being the main factor for the beneficial effects triggered by the couple of Si and H2S. Therefore, it could be concluded that the simultaneous application of Si and H2S promote the resilience of the rice seedlings against the oxidative stress induced by CuO NPs.
PMID: 34088169
New Phytol , IF:10.151 , 2021 Aug doi: 10.1111/nph.17702
The leaf polarity factors SGS3 and YABBYs regulate style elongation through auxin signaling in Mimulus lewisii.
Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA.; College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.; College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China.; Qinghai Key Laboratory of Genetics and Physiology of Vegetables, Qinghai University, Xining, 810008, China.; Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA.
Style length is a major determinant of breeding strategies in flowering plants and can vary dramatically between and within species. However, little is known about the genetic and developmental control of style elongation. We characterized the role of two classes of leaf adaxial-abaxial polarity factors, SUPPRESSOR OF GENE SILENCING3 (SGS3) and the YABBY family transcription factors, in the regulation of style elongation in Mimulus lewisii. We also examined the spatiotemporal patterns of auxin response during style development. Loss of SGS3 function led to reduced style length via limiting cell division, and downregulation of YABBY genes by RNA interference resulted in shorter styles by decreasing both cell division and cell elongation. We discovered an auxin response minimum between the stigma and ovary during early stages of pistil development that marks style differentiation. Subsequent redistribution of auxin response to this region correlated with style elongation. Auxin response was substantially altered when both SGS3 and YABBY functions were disrupted. We suggest that auxin signaling plays a central role in style elongation and that how auxin signaling controls the different cell division and elongation patterns underpinning natural style length variation is a major question for future research.
PMID: 34449905
New Phytol , IF:10.151 , 2021 Aug doi: 10.1111/nph.17687
Osmotic stress represses root growth by modulating the transcriptional regulation of PIN-FORMED3.
State Key Laboratory of Hybrid Rice, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, 430072, China.
Osmotic stress influences root system architecture, and polar auxin transport (PAT) is well-established to regulate root growth and development. However, how PAT responds to osmotic stress at the molecular level remains poorly understood. In this study, we explored whether and how the auxin efflux carrier PIN-FORMED3 (PIN3) participates in osmotic stress-induced root growth inhibition in Arabidopsis (Arabidopsis thaliana). We observed that osmotic stress induces a HD-ZIP II transcription factor-encoding gene HOMEODOMAIN ARABIDOPSIS THALIANA2 (HAT2) expression in roots. The hat2 loss-of-function mutant is less sensitive to osmotic stress in terms of root meristem growth. Consistent with this phenotype, whereas the auxin response is down-regulated in wild-type roots under osmotic stress, the inhibition of auxin response by osmotic stress was alleviated in hat2 roots. Conversely, transgenic lines overexpressing HAT2 (Pro35S::HAT2) had shorter roots and reduced auxin accumulation compared with wild-type plants. PIN3 expression was significantly reduced in the Pro35S::HAT2 lines. We determined that osmotic stress-mediated repression of PIN3 was alleviated in the hat2 mutant because HAT2 normally binds to the promoter of PIN3 and inhibits its expression. Taken together, our data reveal that osmotic stress inhibits root growth via HAT2, which regulates auxin activity by directly repressing PIN3 transcription.
PMID: 34420215
Cold Spring Harb Perspect Biol , IF:10.005 , 2021 Aug doi: 10.1101/cshperspect.a039859
Fourteen Stations of Auxin.
Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
Auxin has always been at the forefront of research in plant physiology and development. Since the earliest contemplations by Julius von Sachs and Charles Darwin, more than a century-long struggle has been waged to understand its function. This largely reflects the failures, successes, and inevitable progress in the entire field of plant signaling and development. Here I present 14 stations on our long and sometimes mystical journey to understand auxin. These highlights were selected to give a flavor of the field and to show the scope and limits of our current knowledge. A special focus is put on features that make auxin unique among phytohormones, such as its dynamic, directional transport network, which integrates external and internal signals, including self-organizing feedback. Accented are persistent mysteries and controversies. The unexpected discoveries related to rapid auxin responses and growth regulation recently disturbed our contentment regarding understanding of the auxin signaling mechanism. These new revelations, along with advances in technology, usher us into a new, exciting era in auxin research.
PMID: 34400554
Cold Spring Harb Perspect Biol , IF:10.005 , 2021 Aug , V13 (8) doi: 10.1101/cshperspect.a039891
No Time for Transcription-Rapid Auxin Responses in Plants.
Department of Experimental Plant Biology, Charles University, 128 00 Prague, Czech Republic.
Auxin regulates the transcription of auxin-responsive genes by the TIR1/AFBs-Aux/IAA-ARF signaling pathway, and in this way facilitates plant growth and development. However, rapid, nontranscriptional responses to auxin that cannot be explained by this pathway have been reported. In this review, we focus on several examples of rapid auxin responses: (1) the triggering of changes in plasma membrane potential in various plant species and tissues, (2) inhibition of root growth, which also correlates with membrane potential changes, cytosolic Ca(2+) spikes, and a rise of apoplastic pH, (3) the influence on endomembrane trafficking of PIN proteins and other membrane cargoes, and (4) activation of ROPs (Rho of plants) and their downstream effectors such as the cytoskeleton or vesicle trafficking. In most cases, the signaling pathway triggering the response is poorly understood. A role for the TIR1/AFBs in rapid root growth regulation is emerging, as well as the involvement of transmembrane kinases (TMKs) in the activation of ROPs. We discuss similarities and differences among these rapid responses and focus on their physiological significance, which remains an enigma in most cases.
PMID: 33648988
EMBO Rep , IF:8.807 , 2021 Aug : Pe51813 doi: 10.15252/embr.202051813
Nitrate triggered phosphoproteome changes and a PIN2 phosphosite modulating root system architecture.
Departamento de Genetica Molecular y Microbiologia, Pontificia Universidad Catolica de Chile, Santiago, Chile.; FONDAP Center for Genome Regulation, ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile.; Departamento de Fruticultura y Enologia, Pontificia Universidad Catolica de Chile, Santiago, Chile.; Cell and Developmental Biology, University of California San Diego. San Diego, CA, USA.; Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.; Bioresources Unit, Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria.
Nitrate commands genome-wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild-type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post-translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate.
PMID: 34357701
Sci Total Environ , IF:7.963 , 2021 Aug , V801 : P149732 doi: 10.1016/j.scitotenv.2021.149732
Damage and recovery from drift of synthetic-auxin herbicide dicamba depends on concentration and varies among floral, vegetative, and lifetime traits in rapid cycling Brassica rapa.
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA. Electronic address: s.ramos.castro@gmail.com.; Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
Herbicides can drift from intended plants onto non-target species. It remains unclear how drift impacts plant functional traits that are important for fitness. To address this gap, we conducted an experiment where fast cycling Brassica rapa plants were exposed to one of three drift concentrations (0.5%, 1%, 10%) of synthetic-auxin dicamba. We evaluated damage to and capacity of floral and vegetative traits to recover as well as lifetime fitness by comparing treated plants to controls. Response to dicamba exposure was concentration-dependent across all traits but varied with trait type. At 0.5% dicamba, three out of five floral traits were affected, while at 1% dicamba, four floral traits and one out of two vegetative traits were negatively impacted. At 10% dicamba all floral and vegetative traits were stunted. Overall, floral traits were more responsive to all dicamba drift concentrations than vegetative traits and displayed a wide range of variation ranging from no response (e.g., pistil length) to up to 84% reduction (ovule number). However, despite floral traits were more affected across the dicamba drift concentrations they were also more likely to recover than the vegetative traits. There was also variation among lifetime traits; the onset of flowering was delayed, and reproductive fitness was negatively affected in a concentration-dependent manner, but the final biomass and total flower production were not affected. Altogether, we show substantial variation across plant traits in their response to dicamba and conclude that accounting for this variation is essential to understand the full impact of herbicide drift on plants and the ecological interactions these traits mediate.
PMID: 34438156
ACS Sens , IF:7.711 , 2021 Aug , V6 (8) : P3032-3046 doi: 10.1021/acssensors.1c01022
Nanosensor Detection of Synthetic Auxins In Planta using Corona Phase Molecular Recognition.
Disruptive & Sustainable Technologies for Agricultural Precision IRG, Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, #03-06/07/08 Research Wing, Singapore 138602, Singapore.; Temasek Life Sciences Laboratory Limited, 1 Research Link National University of Singapore, Singapore 117604, Singapore.; Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.; Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore.; Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore.; School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore.
Synthetic auxins such as 1-naphthalene acetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) have been extensively used in plant tissue cultures and as herbicides because they are chemically more stable and potent than most endogenous auxins. A tool for rapid in planta detection of these compounds will enhance our knowledge about hormone distribution and signaling and facilitate more efficient usage of synthetic auxins in agriculture. In this work, we show the development of real-time and nondestructive in planta NAA and 2,4-D nanosensors based on the concept of corona phase molecular recognition (CoPhMoRe), to replace the current state-of-the-art sensing methods that are destructive and laborious. By designing a library of cationic polymers wrapped around single-walled carbon nanotubes with general affinity for chemical moieties displayed on auxins and its derivatives, we developed selective sensors for these synthetic auxins, with a particularly large quenching response to NAA (46%) and a turn-on response to 2,4-D (51%). The NAA and 2,4-D nanosensors are demonstrated in planta across several plant species including spinach, Arabidopsis thaliana (A. thaliana), Brassica rapa subsp. chinensis (pak choi), and Oryza sativa (rice) grown in various media, including soil, hydroponic, and plant tissue culture media. After 5 h of 2,4-D supplementation to the hydroponic medium, 2,4-D is seen to accumulate in susceptible dicotyledon pak choi leaves, while no uptake is observed in tolerant monocotyledon rice leaves. As such, the 2,4-D nanosensor had demonstrated its capability for rapid testing of herbicide susceptibility and could help elucidate the mechanisms of 2,4-D transport and the basis for herbicide resistance in crops. The success of the CoPhMoRe technique for measuring these challenging plant hormones holds tremendous potential to advance the plant biology study.
PMID: 34375072
J Integr Plant Biol , IF:7.061 , 2021 Aug , V63 (8) : P1521-1537 doi: 10.1111/jipb.13140
Rice SPL10 positively regulates trichome development through expression of HL6 and auxin-related genes.
State Key Laboratory of Agrobiotechnology/Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.; College of Plant Protection, China Agricultural University, Beijing, 100193, China.
Trichomes function in plant defenses against biotic and abiotic stresses; examination of glabrous lines, which lack trichomes, has revealed key aspects of trichome development and function. Tests of allelism in 51 glabrous rice (Oryza sativa) accessions collected worldwide identified OsSPL10 and OsWOX3B as regulators of trichome development in rice. Here, we report that OsSPL10 acts as a transcriptional regulator controlling trichome development. Haplotype and transient expression analyses revealed that variation in the approximately 700-bp OsSPL10 promoter region is the primary cause of the glabrous phenotype in the indica cultivar WD-17993. Disruption of OsSPL10 by genome editing decreased leaf trichome density and length in the NIL-HL6 background. Plants with genotype OsSPL10(WD-17993) /HL6 generated by crossing WD-17993 with NIL-HL6 also had fewer trichomes in the glumes. HAIRY LEAF6 (HL6) encodes another transcription factor that regulates trichome initiation and elongation, and OsSPL10 directly binds to the HL6 promoter to regulate its expression. Moreover, the transcript levels of auxin-related genes, such as OsYUCCA5 and OsPIN-FORMED1b, were altered in OsSPL10 overexpression and RNAi transgenic lines. Feeding tests using locusts (Locusta migratoria) demonstrated that non-glandular trichomes affect feeding by this herbivore. Our findings provide a molecular framework for trichome development and an ecological perspective on trichome functions.
PMID: 34038040
Int J Biol Macromol , IF:6.953 , 2021 Aug , V185 : P277-286 doi: 10.1016/j.ijbiomac.2021.06.097
Auxin transport mechanism of membrane transporter encoded by AEC gene of Bacillus licheniformis isolated from metagenome of Tapta Kund Hotspring of Uttrakhand, India.
Department of Biotechnology, School of Life Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India.; Department of Biotechnology, School of Life Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India. Electronic address: monashimla@gmail.com.; Department of Biotechnology, School of Life Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India. Electronic address: yusuf@daad-alumni.de.
Members of group Bacillus are most widely occurring microbes in agricultural soil and they affect crop health in various ways. They directly stimulate plant growth either by augmenting nutrients availability, invigorating plants' defence mechanisms; repressing soil-borne phytopathogens or by producing growth-regulating hormones like auxins and cytokinins. It is a well known fact that indole-3- acetic acid (a type of auxin) is a vital biologically active phytohormone excreted by certain Bacillus species, but its molecular mechanism has not yet been described. In this study, the auxin efflux carrier gene is isolated from the metagenome of the Tapta Kund hot spring, Uttrakhand, India. In addition, auxin efflux carrier (AEC) transporter protein of Bacillus licheniformis is modeled and the 318 amino acid residues long protein was found homologous to the apical sodium-dependent bile acid transporter (ASBT) of Yersinia frederiksnii, with 10 transmembrane segments (TM1-10) split into different domains: a panel domain defined by TM1, 2, 6 and 7; and a core domain defined by TM3-5 and 8-10. Finally, the predicted Bacillus licheniformis AEC protein has also been phylogenetically evaluated and its detailed molecular transport mechanism was worked out using molecular dynamics simulation analysis. Conclusively, this study demonstrates the efflux mechanism of the substrate, Indole 3- acetic acid by AEC transporter protein.
PMID: 34147526
Plant J , IF:6.417 , 2021 Aug doi: 10.1111/tpj.15450
SNARE proteins VAMP721 and VAMP722 mediate the post-Golgi trafficking required for auxin-mediated development in Arabidopsis.
College of Life Science, Henan Normal University, Xinxiang, 453007, China.; Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.; Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, 457001, China.; State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China.; College of Biological Sciences & Biotechnology, Beijing Forestry University, Beijing, 100083, China.
The plant hormone auxin controls many aspects of plant development. Membrane trafficking processes such as secretion, endocytosis, and recycling regulate the polar localization of auxin transporters to establish an auxin concentration gradient. Here, we investigate the function of the Arabidopsis thaliana R-SNAREs VESICLE-ASSOCIATED MEMBRANE PROTEIN 721 (VAMP721) and VAMP722 in the post-Golgi trafficking required for proper auxin distribution and seedling growth. We show that multiple growth phenotypes, such as cotyledon development, vein patterning, and lateral root growth, were defective in the double homozygous vamp721vamp722 mutant. Abnormal auxin distribution and root patterning were also observed in the mutant seedlings. Fluorescence imaging revealed that three auxin transporters, PIN-FORMED 1 (PIN1), PIN2, and AUXIN RESISTANT 1 (AUX1), aberrantly accumulate within the cytoplasm of the double mutant, impairing the polar localization at the plasma membrane (PM). The analysis of intracellular trafficking demonstrated the involvement of VAMP721 and VAMP722 in endocytosis of FM4-64 and the secretion and recycling of the PIN2 transporter protein to the PM, but not its trafficking to the vacuole. Furthermore, vamp721vamp722 mutant roots display enlarged trans-Golgi network (TGN) structures, as indicated by the subcellular localization of a variety of marker proteins and the ultrastructure observed using transmission electron microscopy. Thus, our results suggest that the R-SNAREs VAMP721 and VAMP722 mediate the post-Golgi trafficking of auxin transporters to the plasma membrane from the TGN subdomains, substantially contributing to plant growth.
PMID: 34343378
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22169018
A Gain-of-Function Mutant of IAA7 Inhibits Stem Elongation by Transcriptional Repression of EXPA5 Genes in Brassica napus.
Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu 610065, China.
Plant height is one of the most important agronomic traits of rapeseeds. In this study, we characterized a dwarf Brassica napus mutant, named ndf-2, obtained from fast neutrons and DES mutagenesis. Based on BSA-Seq and genetic properties, we identified causal mutations with a time-saving approach. The ndf-2 mutation was identified on chromosome A03 and can result in an amino acid substitution in the conserved degron motif (GWPPV to EWPPV) of the Auxin/indole-3-acetic acid protein 7 (BnaA03.IAA7) encoded by the causative gene. Aux/IAA protein is one of the core components of the auxin signaling pathway, which regulates many growth and development processes. However, the molecular mechanism of auxin signal regulating plant height is still not well understood. In the following work, we identified that BnaARF6 and BnaARF8 as interactors of BnaA03.IAA7 and BnaEXPA5 as a target of BnaARF6 and BnaARF8. The three genes BnaA03.IAA7, BnaARF6/8 and BnaEXPA5 were highly expressed in stem, suggesting that these genes were involved in stem development. The overexpression of BnaEXPA5 results in larger rosettes leaves and longer inflorescence stems in Arabidopsis thaliana. Our results indicate that BnaA03.IAA7- and BnaARF6/8-dependent auxin signal control stem elongation and plant height by regulating the transcription of BnaEXPA5 gene, which is one of the targets of this signal.
PMID: 34445724
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168568
Function and Mechanism of Jasmonic Acid in Plant Responses to Abiotic and Biotic Stresses.
College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
As sessile organisms, plants must tolerate various environmental stresses. Plant hormones play vital roles in plant responses to biotic and abiotic stresses. Among these hormones, jasmonic acid (JA) and its precursors and derivatives (jasmonates, JAs) play important roles in the mediation of plant responses and defenses to biotic and abiotic stresses and have received extensive research attention. Although some reviews of JAs are available, this review focuses on JAs in the regulation of plant stress responses, as well as JA synthesis, metabolism, and signaling pathways. We summarize recent progress in clarifying the functions and mechanisms of JAs in plant responses to abiotic stresses (drought, cold, salt, heat, and heavy metal toxicity) and biotic stresses (pathogen, insect, and herbivore). Meanwhile, the crosstalk of JA with various other plant hormones regulates the balance between plant growth and defense. Therefore, we review the crosstalk of JAs with other phytohormones, including auxin, gibberellic acid, salicylic acid, brassinosteroid, ethylene, and abscisic acid. Finally, we discuss current issues and future opportunities in research into JAs in plant stress responses.
PMID: 34445272
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168554
Integrating the Roles for Cytokinin and Auxin in De Novo Shoot Organogenesis: From Hormone Uptake to Signaling Outputs.
Department of Plant Physiology, Institute for Biological Research "Sinisa Stankovic"-National Institute of Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia.; Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojova 263, 16502 Prague 6, Czech Republic.; School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
De novo shoot organogenesis (DNSO) is a procedure commonly used for the in vitro regeneration of shoots from a variety of plant tissues. Shoot regeneration occurs on nutrient media supplemented with the plant hormones cytokinin (CK) and auxin, which play essential roles in this process, and genes involved in their signaling cascades act as master regulators of the different phases of shoot regeneration. In the last 20 years, the genetic regulation of DNSO has been characterized in detail. However, as of today, the CK and auxin signaling events associated with shoot regeneration are often interpreted as a consequence of these hormones simply being present in the regeneration media, whereas the roles for their prior uptake and transport into the cultivated plant tissues are generally overlooked. Additionally, sucrose, commonly added to the regeneration media as a carbon source, plays a signaling role and has been recently shown to interact with CK and auxin and to affect the efficiency of shoot regeneration. In this review, we provide an integrative interpretation of the roles for CK and auxin in the process of DNSO, adding emphasis on their uptake from the regeneration media and their interaction with sucrose present in the media to their complex signaling outputs that mediate shoot regeneration.
PMID: 34445260
Int J Mol Sci , IF:5.923 , 2021 Aug , V22 (16) doi: 10.3390/ijms22168495
The Lotus japonicus AFB6 Gene Is Involved in the Auxin Dependent Root Developmental Program.
Institute of Biosciences and Bioresources (IBBR), CNR, 80131 Napoli, Italy.; Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark.
Auxin is essential for root development, and its regulatory action is exerted at different steps from perception of the hormone up to transcriptional regulation of target genes. In legume plants there is an overlap between the developmental programs governing lateral root and N2-fixing nodule organogenesis, the latter induced as the result of the symbiotic interaction with rhizobia. Here we report the characterization of a member of the L. japonicus TIR1/AFB auxin receptor family, LjAFB6. A preferential expression of the LjAFB6 gene in the aerial portion of L. japonicus plants was observed. Significant regulation of the expression was not observed during the symbiotic interaction with Mesorhizobium loti and the nodule organogenesis process. In roots, the LjAFB6 expression was induced in response to nitrate supply and was mainly localized in the meristematic regions of both primary and lateral roots. The phenotypic analyses conducted on two independent null mutants indicated a specialized role in the control of primary and lateral root elongation processes in response to auxin, whereas no involvement in the nodulation process was found. We also report the involvement of LjAFB6 in the hypocotyl elongation process and in the control of the expression profile of an auxin-responsive gene.
PMID: 34445201
PLoS Genet , IF:5.917 , 2021 Aug , V17 (8) : Pe1009674 doi: 10.1371/journal.pgen.1009674
An auxin signaling network translates low-sugar-state input into compensated cell enlargement in the fugu5 cotyledon.
Department of Biology, Tokyo Gakugei University, Koganei-shi, Tokyo, Japan.; RIKEN Center for Sustainable Resource Science, Yokohama, Japan.; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, Japan.; Laboratoire de Reproduction et Developpement des Plantes, Universite de Lyon, UCB Lyon 1, ENS de Lyon, INRA, CNRS, Lyon, France.; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
In plants, the effective mobilization of seed nutrient reserves is crucial during germination and for seedling establishment. The Arabidopsis H+-PPase-loss-of-function fugu5 mutants exhibit a reduced number of cells in the cotyledons. This leads to enhanced post-mitotic cell expansion, also known as compensated cell enlargement (CCE). While decreased cell numbers have been ascribed to reduced gluconeogenesis from triacylglycerol, the molecular mechanisms underlying CCE remain ill-known. Given the role of indole 3-butyric acid (IBA) in cotyledon development, and because CCE in fugu5 is specifically and completely cancelled by ech2, which shows defective IBA-to-indoleacetic acid (IAA) conversion, IBA has emerged as a potential regulator of CCE. Here, to further illuminate the regulatory role of IBA in CCE, we used a series of high-order mutants that harbored a specific defect in IBA-to-IAA conversion, IBA efflux, IAA signaling, or vacuolar type H+-ATPase (V-ATPase) activity and analyzed the genetic interaction with fugu5-1. We found that while CCE in fugu5 was promoted by IBA, defects in IBA-to-IAA conversion, IAA response, or the V-ATPase activity alone cancelled CCE. Consistently, endogenous IAA in fugu5 reached a level 2.2-fold higher than the WT in 1-week-old seedlings. Finally, the above findings were validated in icl-2, mls-2, pck1-2 and ibr10 mutants, in which CCE was triggered by low sugar contents. This provides a scenario in which following seed germination, the low-sugar-state triggers IAA synthesis, leading to CCE through the activation of the V-ATPase. These findings illustrate how fine-tuning cell and organ size regulation depend on interplays between metabolism and IAA levels in plants.
PMID: 34351899
J Fungi (Basel) , IF:5.816 , 2021 Aug , V7 (8) doi: 10.3390/jof7080640
Transcriptome Analysis Revealed Plant Hormone Biosynthesis and Response Pathway Modification by Epichloegansuensis in Achnatheruminebrians under Different Soil Moisture Availability.
State Key Laboratory of Grassland Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China.; Grasslands Research Centre, Private Bag 11-008, Palmerston North 4442, New Zealand.
The present study was designed to explore the effects of the endophyte Epichloe gansuensis on gene expression related to plant hormone biosynthesis and response pathways and the content of salicylic acid (SA) and jasmonic acid (JA) hormones of Achnatherum inebrians, under different moisture conditions. Through a pot experiment and transcriptome analysis, we found a total of 51 differentially expressed genes (DEGs) related to hormone biosynthesis and response pathways, including 12 auxin related genes, 8 cytokinin (CTK) related genes, 3 gibberellin (GA) related genes, 7 abscisic acid (ABA) related genes, 7 ethylene (ET) related genes, 12 JA related genes and 4 SA related genes. Furthermore, key genes of JA and SA biosynthesis and response pathways, such as LOX2S, AOS, OPR, ACX, JMT, JAZ, PAL, NPR1, TGA and PR-1, showed different degrees of upregulation or downregulation. Under 60% soil moisture content, the JA content of endophyte-free (EF) A. inebrians was significantly (p < 0.05) higher than that of endophyte-infected (EI) A. inebrians. Under 30% and 60% soil moisture content, the SA content of EF A. inebrians was significantly (p < 0.05) higher than that of EI A. inebrians. SA content of EI A. inebrians under 30% and 60% soil moisture content was significantly (p < 0.05) higher than that under 15% soil moisture content. With both EI and EF plants, the SA and JA levels, respectively, are very similar at 15% soil moisture content. This study has revealed that E. gansuensis differentially activated plant hormone synthesis and signal transduction pathways of A. inebrians plants under different soil moisture availability.
PMID: 34436179
Front Plant Sci , IF:5.753 , 2021 , V12 : P717649 doi: 10.3389/fpls.2021.717649
LFR Physically and Genetically Interacts With SWI/SNF Component SWI3B to Regulate Leaf Blade Development in Arabidopsis.
Hebei Key Laboratory of Molecular and Cellular Biology, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, College of Life Sciences, Hebei Normal University, Shijiazhuang, China.; School of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China.
Leaves start to develop at the peripheral zone of the shoot apical meristem. Thereafter, symmetric and flattened leaf laminae are formed. These events are simultaneously regulated by auxin, transcription factors, and epigenetic regulatory factors. However, the relationships among these factors are not well known. In this study, we conducted protein-protein interaction assays to show that our previously reported Leaf and Flower Related (LFR) physically interacted with SWI3B, a component of the ATP-dependent chromatin remodeling SWI/SNF complex in Arabidopsis. The results of truncated analysis and transgenic complementation showed that the N-terminal domain (25-60 amino acids) of LFR was necessary for its interaction with SWI3B and was crucial for LFR functions in Arabidopsis leaf development. Genetic results showed that the artificial microRNA knockdown lines of SWI3B (SWI3B-amic) had a similar upward-curling leaf phenotype with that of LFR loss-of-function mutants. ChIP-qPCR assay was conducted to show that LFR and SWI3B co-targeted the promoters of YABBY1/FILAMENTOUS FLOWER (YAB1/FIL) and IAA carboxyl methyltransferase 1 (IAMT1), which were misexpressed in lfr and SWI3B-amic mutants. In addition, the association between LFR and the FIL and IAMT1 loci was partly hampered by the knockdown of SWI3B. These data suggest that LFR interacts with the chromatin-remodeling complex component, SWI3B, and influences the transcriptional expression of the important transcription factor, FIL, and the auxin metabolism enzyme, IAMT1, in flattened leaf lamina development.
PMID: 34456957
Front Plant Sci , IF:5.753 , 2021 , V12 : P641087 doi: 10.3389/fpls.2021.641087
Association Analysis Revealed That TaPYL4 Genes Are Linked to Plant Growth Related Traits in Multiple Environment.
College of Agronomy, Shanxi Agricultural University, Jinzhong, China.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Abscisic acid (ABA), one of phytohormones, plays an important regulatory role in plant growth and development. ABA receptor PYL4 (pyrabactin resistance 1-like 4) was previously detected to be involved in plant response to a variety of stresses. TaPYL4 overexpression could enhance wheat (Triticum aestivum) drought resistance. In order to further investigate TaPYL4's role in regulating development of other major agronomic traits in wheat, genes of TaPYL4-2A, TaPYL4-2B, and TaPYL4-2D were cloned from wheat, respectively. Polymorphism analysis on TaPYL4 sequences revealed that encoding regions of the three genes were highly conserved, without any SNP (single nucleotide polymorphism) presence. However, nine SNPs and four SNPs were identified in the promoter regions of TaPYL4-2A and TaPYL4-2B, respectively. Functional molecular markers were developed based on these polymorphisms, which were then used to scan a natural population of 323 common wheat accessions for correlation analysis between genotype and the target phenotypic traits. Both TaPYL4-2A and TaPYL4-2B markers were significantly correlated with plant growth-related traits under multiple environments (well-watered, drought and heat stress treatments). The additive effects of TaPYL4-2A and TaPYL4-2B were verified by the combinational haplotype (Hap-AB1 approximately Hap-AB4) effects determined from field data. Cis-acting elements were analyzed in the promoters of TaPYL4-2A and TaPYL4-2B, showing that a TGA-element bound by ARFs (auxin response factors) existed only in Hap-2A-1 of TaPYL4-2A. Gene expression assays indicated that TaPYL4-2A was constitutively expressed in various tissues, with higher expression in Hap-2A-1 genotypes than in Hap-2A-2 materials. Notably, TaARF4 could act as TaPYL4-2A transcription activator in Hap-2A-1 materials, but not in Hap-2A-2 genotypes. Analysis of geographic distribution and temporal frequency of haplotypes indicated that Hap-AB1 was positively selected in wheat breeding in China. Therefore, TaPYL4-2A and TaPYL4-2B could be a valuable target gene in wheat genetic improvement to develop the ideal plant architecture.
PMID: 34456932
Front Plant Sci , IF:5.753 , 2021 , V12 : P715820 doi: 10.3389/fpls.2021.715820
Genome-Wide Identification of the ARF Gene Family and ARF3 Target Genes Regulating Ovary Initiation in Hazel via ChIP Sequencing.
Jilin Provincial Key Laboratory of Plant Resource Science and Green Production, Jilin Normal University, Siping, China.
Hazel (Corylus spp.) is an economically important nut species with a unique biological characteristic of ovary differentiation and development initiating from the ovary primordium after pollination. Auxin participates in ovary initiation and has an essential impact on hazel fruit yield and quality. The regulation of auxin in ovary development is thought to be related to auxin response factors (ARFs); however, its detailed regulatory mechanism remains unclear. The spatiotemporal expression pattern of C. heterophylla ARF3 (ChARF3) was accessed via ARF gene family member identification and expression abundance analysis as well as immunohistochemistry. ChARF3 target genes were identified via chromatin immunoprecipitation followed by next-generation sequencing (ChIP-Seq). In total, 14 ChARF members containing at least B3 and Auxin_resp domains were found to be distributed on 9 of 11 chromosomes, and the protein molecular weights were predicted to range from 70.93-139.22 kD. Among eight differentially expressed ChARFs, ChARF3 showed the most significant differences over four ovary developmental stages. Immunohistochemical analysis revealed that ChARF3 was expressed in the ovary primordium and funiculus, integument, endosperm, radicle, and cotyledon indicating its potential regulatory roles in ovary differentiation and development. In total, 3,167 ChARF3 target genes were identified through ChIP-Seq in four ovary developmental stages and were significantly enriched in the biosynthesis of secondary metabolites (ko01110), phenylpropanoid biosynthesis (ko00940), and phytohormone signal transduction (ko04075). ChARF3 was hypothesized to be involved in the regulation of auxin-induced genes and the transcription factors MADS, AP2/ERF, TCP, FT, and LFY. These results suggest that ChARF3 may regulate ovary initiation and ovule development by mediating genes related to auxin biosynthesis and transport, cell division and proliferation, and flower and fruit development. This study provides new insights into the molecular mechanism of hazel yield formation.
PMID: 34447403
Front Plant Sci , IF:5.753 , 2021 , V12 : P650252 doi: 10.3389/fpls.2021.650252
Transcriptome and Coexpression Network Analyses Reveal Hub Genes in Chinese Cabbage (Brassica rapa L. ssp. pekinensis) During Different Stages of Plasmodiophora brassicae Infection.
Institute of Horticulture, Henan Academy of Agricultural Sciences, Graduate T&R Base of Zhengzhou University, Zhengzhou, China.; School of Life Sciences, Zhengzhou University, Zhengzhou, China.
Clubroot, caused by the soil-borne protist Plasmodiophora brassicae, is one of the most destructive diseases of Chinese cabbage worldwide. However, the clubroot resistance mechanisms remain unclear. In this study, in both clubroot-resistant (DH40R) and clubroot-susceptible (DH199S) Chinese cabbage lines, the primary (root hair infection) and secondary (cortical infection) infection stages started 2 and 5 days after inoculation (dai), respectively. With the extension of the infection time, cortical infection was blocked and complete P. brassica resistance was observed in DH40R, while disease scales of 1, 2, and 3 were observed at 8, 13, and 22 dai in DH199S. Transcriptome analysis at 0, 2, 5, 8, 13, and 22 dai identified 5,750 relative DEGs (rDEGs) between DH40R and DH199S. The results indicated that genes associated with auxin, PR, disease resistance proteins, oxidative stress, and WRKY and MYB transcription factors were involved in clubroot resistance regulation. In addition, weighted gene coexpression network analysis (WGCNA) identified three of the modules whose functions were highly associated with clubroot-resistant, including ten hub genes related to clubroot resistance (ARF2, EDR1, LOX4, NHL3, NHL13, NAC29, two AOP1, EARLI 1, and POD56). These results provide valuable information for better understanding the molecular regulatory mechanism of Chinese cabbage clubroot resistance.
PMID: 34447397
Front Plant Sci , IF:5.753 , 2021 , V12 : P710826 doi: 10.3389/fpls.2021.710826
Auxin-Responsive R2R3-MYB Transcription Factors HcMYB1 and HcMYB2 Activate Volatile Biosynthesis in Hedychium coronarium Flowers.
The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China.; College of Economics and Management, Kunming University, Kunming, China.; College of Life Sciences, South China Agricultural University, Guangzhou, China.; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, South China Agricultural University, Guangzhou, China.
Auxin, an important plant hormone, induces the biosynthesis of various secondary metabolites by modulating the expression of auxin-responsive genes. In the ornamental plant Hedychium coronarium, linalool and methyl benzoate are biosynthesized by the terpene synthase (TPS) HcTPS5 and the benzoic/salicylic acid methyltransferase (BSMT) HcBSMT2, respectively. However, the transcriptional regulation of this process remains unclear. Here, we identified and functionally characterized the R2R3-MYB transcription factors HcMYB1 and HcMYB2 in regulating the biosynthesis of these floral aroma compounds. HcMYB1 and HcMYB2 are specifically expressed in flowers, their expression is correlated with the emission of volatile compounds in flowers, and is induced by auxin. Moreover, HcMYB1 and HcMYB2 interact with the HcBSMT2 promoter region. HcMYB2 activates the expression of the linalool synthase gene HcTPS5. In flowers with HcMYB1 or HcMYB2 silenced, the levels of floral scent compounds were significantly reduced, and HcBSMT2 and HcTPS5 were downregulated compared with the wild type. Moreover, HcMYB1 form protein-protein interaction with key scent-related HcIAA4 protein to regulate floral aroma production. Taken together, these results indicate that HcMYB1 and HcMYB2 play crucial roles in regulating the formation of scent compounds in Hedychium coronarium (H. coronarium) flowers in response to auxin signaling.
PMID: 34413870
Front Plant Sci , IF:5.753 , 2021 , V12 : P671713 doi: 10.3389/fpls.2021.671713
Auxin Metabolism Is Involved in Fruit Set and Early Fruit Development in the Parthenocarpic Tomato "R35-P".
Key Laboratory of Molecular Module-Based Breeding of High Yield and Abiotic Resistant Plants in Universities of Shandong (Ludong University), College of Agriculture, Ludong University, Yantai, China.; Institute of Vegetable, Gansu Academy of Agricultural Science, Lanzhou, China.; College of Horticulture, China Agricultural University, Beijing, China.; Agricultural and Rural Bureau of Shouguang, Shouguang, China.
Parthenocarpic tomato can set fruit and develop without pollination and exogenous hormone treatments under unfavorable environmental conditions, which is beneficial to tomato production from late fall to early spring in greenhouses. In this study, the endogenous hormones in the ovaries of the parthenocarpic tomato line "R35-P" (stigma removed or self-pollination) and the non-parthenocarpic tomato line "R35-N" (self-pollination) at four stages between preanthesis and postanthesis investigated, using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A nearly twofold IAA (indoleacetic acid) content was found in "R35-P" rather than in "R35-N" at -2 and 0 days after anthesis (DAA). Except at -2 DAA, a lower ABA (abscisic acid) content was observed in Pe (stigma removed in "R35-P") compared to that in Ps (self-pollination in "R35-P") or CK (self-pollination in "R35-N"). After pollination, although the content of GA1 (gibberellins acid 1) in CK increased, the levels of GAs (gibberellins acids) were notably low. At all four stages, a lower SA (salicylic acid) content was found in Ps and CK than in Pe, while the content and the change trend were similar in Ps and CK. The variation tendencies of JA (jasmonic acid) varied among Pe, Ps, and CK at the studied periods. Furthermore, KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses of transcriptomic data identified 175 differentially expressed genes (DEGs) related to plant hormone signal transduction, including 63 auxin-related genes, 27 abscisic acid-related genes, 22 ethylene-related genes, 16 cytokinin-related genes, 16 salicylic acid-related genes, 14 brassinosteroid-related genes, 13 jasmonic acid-related genes, and 4 gibberellin-related genes at -2 DAA and 0 DAA. Our results suggest that the fate of a fruit set or degeneration occurred before anthesis in tomato. Auxins, whose levels were independent of pollination and fertilization, play prominent roles in controlling a fruit set in "R35-P," and other hormones are integrated in a synergistic or antagonistic way.
PMID: 34408758
Genomics , IF:5.736 , 2021 Aug doi: 10.1016/j.ygeno.2021.08.022
Comparative transcriptome analysis of a fan-shaped inflorescence in pineapple using RNA-seq.
Department of Horticulture, Foshan University, Foshan 528231, China; Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.; Department of Horticulture, Foshan University, Foshan 528231, China.; Tropical Crops Genetic Resources Institute of Chinese Academy of Tropical Agricultural Science, Haikou 571101, China.; Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.; Department of Horticulture, Foshan University, Foshan 528231, China. Electronic address: zhiquan.cai@126.com.; Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in South China, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China. Electronic address: heyehua@hotmail.com.
Pineapple plant usually has a capitulum. However, a fan-shaped inflorescence was exceptionally evolved in pineapple, having multiple crown buds. In order to reveal the molecular mechanisms of the formation of the fan-shaped inflorescence, fruit traits and the transcriptional differences between the fan-shaped inflorescence and the wild-shaped inflorescence pineapples were analyzed in three tissues, i.e., the flower stem apex, the base of the inflorescence, and the inflorescence axis. The weight (i.e., individual yield) of fan-shaped fruit is 4.5 times that of wild-shaped fruitand non-significant difference in soluble solids, soluble sugar, titratable acid, and Vitamin C was found. Between the fan-shaped inflorescence and wild-shaped inflorescence, a total of 5370 differentially expressed genes were identified across the three tissues. Of these genes, there were 489 overlapping differentially expressed genes in all three tissue comparisons. Between the two pineapples, functional analysis indicated that 444 transcription factors and 206 inflorescence development-related genes were differentially expressed in at least one tissue comparison, while 45 transcription factors and 21 inflorescence development-related genes were overlapped across three tissues. Among the 489 overlapping differentially expressed genes in the three tissue comparisons, excluding the inflorescence development-related genes and transcription factors, 80 of them revealed a higher percentage of involvement in the biological processes relating to response to auxin, and reproductive processes. RNA-seq value and real-time quantitative PCR analysis exhibited the similar gene expression patterns in the three tissues. Our result provided novel cues for understanding the molecular mechanisms of the formation of the fan-shaped inflorescence in pineapple, making a valuable resource for the study of plant breeding and the speciation of pineapple.
PMID: 34455035
Mol Plant Pathol , IF:5.663 , 2021 Aug doi: 10.1111/mpp.13122
Manipulation of auxin signalling by plant viruses.
Department of Phytopathology, Institute of Sugar Beet Research, Gottingen, Germany.; Department of Plant Biology, Uppsala BioCenter SLU, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden.
Compatible plant-virus interactions result in dramatic changes of the plant transcriptome and morphogenesis, and are often associated with rapid alterations in plant hormone homeostasis and signalling. Auxin controls many aspects of plant organogenesis, development, and growth; therefore, plants can rapidly perceive and respond to changes in the cellular auxin levels. Auxin signalling is a tightly controlled process and, hence, is highly vulnerable to changes in the mRNA and protein levels of its components. There are several core nuclear components of auxin signalling. In the nucleus, the interaction of auxin response factors (ARFs) and auxin/indole acetic acid (Aux/IAA) proteins is essential for the control of auxin-regulated pathways. Aux/IAA proteins are negative regulators, whereas ARFs are positive regulators of the auxin response. The interplay between both is essential for the transcriptional regulation of auxin-responsive genes, which primarily regulate developmental processes but also modulate the plant immune system. Recent studies suggest that plant viruses belonging to different families have developed various strategies to disrupt auxin signalling, namely by (a) changing the subcellular localization of Aux/IAAs, (b) preventing degradation of Aux/IAAs by stabilization, or (c) inhibiting the transcriptional activity of ARFs. These interactions perturb auxin signalling and experimental evidence from various studies highlights their importance for virus replication, systemic movement, interaction with vectors for efficient transmission, and symptom development. In this microreview, we summarize and discuss the current knowledge on the interaction of plant viruses with auxin signalling components of their hosts.
PMID: 34420252
Biomolecules , IF:4.879 , 2021 Aug , V11 (8) doi: 10.3390/biom11081207
Beyond the Usual Suspects: Physiological Roles of the Arabidopsis Amidase Signature (AS) Superfamily Members in Plant Growth Processes and Stress Responses.
Centro de Biotecnologia y Genomica de Plantas, Universidad Politecnica de Madrid (UPM)-Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentacion (INIA), Campus de Montegancedo, Pozuelo de Alarcon, 28233 Madrid, Spain.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umea, Sweden.; Departamento de Biotecnologia-Biologia Vegetal, Escuela Tecnica Superior de Ingenieria Agronomica, Alimentaria y de Biosistemas, Universidad Politecnica de Madrid (UPM), 28040 Madrid, Spain.
The diversification of land plants largely relies on their ability to cope with constant environmental fluctuations, which negatively impact their reproductive fitness and trigger adaptive responses to biotic and abiotic stresses. In this limiting landscape, cumulative research attention has centred on deepening the roles of major phytohormones, mostly auxins, together with brassinosteroids, jasmonates, and abscisic acid, despite the signaling networks orchestrating the crosstalk among them are so far only poorly understood. Accordingly, this review focuses on the Arabidopsis Amidase Signature (AS) superfamily members, with the aim of highlighting the hitherto relatively underappreciated functions of AMIDASE1 (AMI1) and FATTY ACID AMIDE HYDROLASE (FAAH), as comparable coordinators of the growth-defense trade-off, by balancing auxin and ABA homeostasis through the conversion of their likely bioactive substrates, indole-3-acetamide and N-acylethanolamine.
PMID: 34439873
Biomolecules , IF:4.879 , 2021 Aug , V11 (8) doi: 10.3390/biom11081153
Two Auxinic Herbicides Affect Brassica napus Plant Hormone Levels and Induce Molecular Changes in Transcription.
Institut fur Botanik, Technische Universitat Dresden, 01062 Dresden, Germany.; Corteva Agriscience Germany GmbH, Riedenburger Str. 7, 81677 Munchen, Germany.
With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2-168 h after treatment). At 15 degrees C growth temperature, the effect was more pronounced than at 9 degrees C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.
PMID: 34439819
DNA Res , IF:4.458 , 2021 Aug doi: 10.1093/dnares/dsab014
Transcriptomes and DNA methylomes in apomictic cells delineate nucellar embryogenesis initiation in citrus.
Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Citrus nucellar poly-embryony (NPE) is a mode of sporophytic apomixis (SA) that asexual embryos formed in the seed through adventitious embryogenesis from the somatic nucellar cells. NPE allows clonal propagation of rootstocks, but it impedes citrus cross breeding. To understand the cellular processes involved in NPE initiation, we profiled the transcriptomes and DNA methylomes in laser microdissection (LMD) captured citrus apomictic cells. In apomictic cells, ribosome biogenesis and protein degradation were activated, whereas auxin polar transport was repressed. Reactive oxygen species (ROS) accumulated in the poly-embryonic ovules, and response to oxidative stress was provoked. The global DNA methylation level, especially that of CHH context, was decreased, whereas the methylation level of the NPE-controlling key gene CitRWP was increased. A C2H2 domain-containing transcription factor (TF) gene and CitRWP co-expressed specifically in apomictic cells may coordinate to initiate NPE. The activated embryogenic development and callose deposition processes indicated embryogenic fate of nucellar embryo initial (NEI) cells. In our working model for citrus NPE initiation, DNA hyper-methylation may activate transcription of CitRWP, which increases C2H2 expression and ROS accumulation, triggers epigenetic regulation, and regulates cell fate transition and NEI cell identity in the apomictic cells.
PMID: 34424285
BMC Plant Biol , IF:4.215 , 2021 Aug , V21 (1) : P375 doi: 10.1186/s12870-021-03066-7
RNA-Seq analysis reveals potential regulators of programmed cell death and leaf remodelling in lace plant (Aponogeton madagascariensis).
Department of Biology, Dalhousie University, Halifax, NS, Canada.; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS, Canada.; Department of Biology, University of Prince Edward Island, Charlottetown, PEI, Canada.; Department of Biology, Dalhousie University, Halifax, NS, Canada. Arunika.gunawardena@dal.ca.
BACKGROUND: The lace plant (Aponogeton madagascariensis) is an aquatic monocot that develops leaves with uniquely formed perforations through the use of a developmentally regulated process called programmed cell death (PCD). The process of perforation formation in lace plant leaves is subdivided into several developmental stages: pre-perforation, window, perforation formation, perforation expansion and mature. The first three emerging "imperforate leaves" do not form perforations, while all subsequent leaves form perforations via developmentally regulated PCD. PCD is active in cells called "PCD cells" that do not retain the antioxidant anthocyanin in spaces called areoles framed by the leaf veins of window stage leaves. Cells near the veins called "NPCD cells" retain a red pigmentation from anthocyanin and do not undergo PCD. While the cellular changes that occur during PCD are well studied, the gene expression patterns underlying these changes and driving PCD during leaf morphogenesis are mostly unknown. We sought to characterize differentially expressed genes (DEGs) that mediate lace plant leaf remodelling and PCD. This was achieved performing gene expression analysis using transcriptomics and comparing DEGs among different stages of leaf development, and between NPCD and PCD cells isolated by laser capture microdissection. RESULTS: Transcriptomes were sequenced from imperforate, pre-perforation, window, and mature leaf stages, as well as PCD and NPCD cells isolated from window stage leaves. Differential expression analysis of the data revealed distinct gene expression profiles: pre-perforation and window stage leaves were characterized by higher expression of genes involved in anthocyanin biosynthesis, plant proteases, expansins, and autophagy-related genes. Mature and imperforate leaves upregulated genes associated with chlorophyll development, photosynthesis, and negative regulators of PCD. PCD cells were found to have a higher expression of genes involved with ethylene biosynthesis, brassinosteroid biosynthesis, and hydrolase activity whereas NPCD cells possessed higher expression of auxin transport, auxin signalling, aspartyl proteases, cysteine protease, Bag5, and anthocyanin biosynthesis enzymes. CONCLUSIONS: RNA sequencing was used to generate a de novo transcriptome for A. madagascariensis leaves and revealed numerous DEGs potentially involved in PCD and leaf remodelling. The data generated from this investigation will be useful for future experiments on lace plant leaf development and PCD in planta.
PMID: 34388962
Microorganisms , IF:4.128 , 2021 Aug , V9 (8) doi: 10.3390/microorganisms9081703
A Plant Endophytic Bacterium, Burkholderia seminalis Strain 869T2, Promotes Plant Growth in Arabidopsis, Pak Choi, Chinese Amaranth, Lettuces, and Other Vegetables.
Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.; Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan.; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan.; Department of Plant Pathology, National Chung Hsing University, Taichung 402, Taiwan.; Department of Food Science and Biotechnology, National Chung Hsing University, Taichung 402, Taiwan.
Plant endophytic bacteria live inside host plants, can be isolated from surface-sterilized plant tissues, and are non-pathogenic. These bacteria can assist host plants in obtaining more nutrients and can improve plant growth via multiple mechanisms. Certain Gram-negative Burkholderia species, including rhizobacteria, bioremediators, and biocontrol strains, have been recognized for their plant-growth-promoting abilities, while other isolates have been identified as opportunistic plant or human pathogens. In this study, we observed the auxin production, siderophore synthesis, and phosphate solubilization abilities of B. seminalis strain 869T2. Our results demonstrated that strain 869T2 promoted growth in Arabidopsis, ching chiang pak choi, pak choi, loose-leaf lettuce, romaine lettuce, red leaf lettuce, and Chinese amaranth. Leafy vegetables inoculated with strain 869T2 were larger, heavier, and had more and larger leaves and longer and heavier roots than mock-inoculated plants. Furthermore, inoculations of strain 869T2 into hot pepper caused increased flower and fruit production, and a higher percentage of fruits turned red. Inoculation of strain 869T2 into okra plants resulted in earlier flowering and increased fruit weight. In conclusion, the plant endophytic bacterium Burkholderia seminalis 869T2 exerted positive effects on growth and production in several plant species.
PMID: 34442782
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081732
Auxin and Cytokinin Interplay during Leaf Morphogenesis and Phyllotaxy.
The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.; State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China.; Soil and Water Testing Laboratory, Marketing Division, Pak Arab Fertilizer Limited, Multan 66000, Pakistan.; MS Swaminathan School of Agriculture, Centurion University of Technology and Management, Odisha 761200, India.; Department of Agronomy, Ghazi University, Dera Ghazi Khan 32200, Pakistan.
Auxins (IAA) and cytokinins (CKs) are the most influential phytohormones, having multifaceted roles in plants. They are key regulators of plant growth and developmental processes. Additionally, their interplay exerts tight control on plant development and differentiation. Although several reviews have been published detailing the auxin-cytokinin interplay in controlling root growth and differentiation, their roles in the shoot, particularly in leaf morphogenesis are largely unexplored. Recent reports have provided new insights on the roles of these two hormones and their interplay on leaf growth and development. In this review, we focus on the effect of auxins, CKs, and their interactions in regulating leaf morphogenesis. Additionally, the regulatory effects of the auxins and CKs interplay on the phyllotaxy of plants are discussed.
PMID: 34451776
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081709
Novel Sources of Pre-Harvest Sprouting Resistance for Japonica Rice Improvement.
International Rice Research Institute, Los Banos 4031, Philippines.; National Institute of Crop Science, Rural Development Administration, Wanju 55365, Korea.; Department of Crop Science and Biotechnology, Jeonbuk National University, Jeonju 54896, Korea.
Pre-harvest sprouting (PHS), induced by unexpected weather events, such as typhoons, at the late seed maturity stage, is becoming a serious threat to rice production, especially in the state of California, USA, Japan, and the Republic of Korea, where japonica varieties (mostly susceptible to PHS) are mainly cultivated. A projected economic loss by severe PHS in these three countries could range between 8-10 billion USD per year during the next 10 years. Here, we present promising rice germplasm with strong resistance to PHS that were selected from a diverse rice panel of accessions held in the International Rice Genebank (IRG) at the International Rice Research Institute (IRRI). To induce PHS, three panicle samples per accession were harvested at 20 and 30 days after flowering (DAF), respectively, and incubated at 100% relative humidity (RH), 30 degrees C in a growth chamber for 15 days. A genome-wide association (GWA) analysis using a 4.8 million single nucleotide polymorphisms (SNP) marker set was performed to identify loci and candidate genes conferring PHS resistance. Interestingly, two tropical japonica and four temperate japonica accessions showed outstanding PHS resistance as compared to tolerant indica accessions. Two major loci on chromosomes 1 and 4 were associated with PHS resistance. A priori candidate genes interactions with rice gene networks, which are based on the gene ontology (GO), co-expression, and other evidence, suggested that a key resistance mechanism is related to abscisic acid (ABA), gibberellic acid (GA), and auxin mediated signaling pathways.
PMID: 34451754
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081612
Potential Markers for Selecting Self-Eliminating Apple Genotypes.
Lithuanian Research Centre for Agriculture and Forestry, Department of Orchard Plant Genetics and Biotechnology, Institute of Horticulture, Babtai, LT-54333 Kaunas, Lithuania.
The heavy blooming of apple trees results in the inefficient usage of energy and nutritional material, and additional expenditure on fruitlet thinning is required to maintain fruit quality. A possible solution for controlling the fruit load on trees is the development of new cultivars that self-eliminate excess fruitlets, thus controlling yield. The aim of our study was to identify biological differences in apple cultivars in terms of blooming intensity and fruitlet load self-regulation. In total, 19 apple cultivars were studied in the years 2015-2017. The dynamics of fruitlet self-elimination, seed development in fruitlets and fruits, photosynthetic parameters, carbohydrates, and plant hormones were evaluated. We established that apple cultivars self-eliminating a small number of fruitlets need a lower number of well-developed seeds in fruit, and their number of leaves and area per fruit on a bearing branch are larger, compared to cultivars, self-eliminating large numbers of fruitlets. A higher carbohydrate amount in the leaves may be related to smaller fruitlet self-elimination. The amount of auxin and a high indole-3-acetic acid/zeatin ratio between leaves of cultivar groups with heavy blooming were higher than in cultivars with moderate blooming. A lower amount of abscisic acid was found in heavy-blooming cultivars during drought stress. All these parameters may be used as markers for the selection of different apple genotypes that self-eliminate fruitlets.
PMID: 34451657
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081606
Regulation of Glycosylphosphatidylinositol-Anchored Protein (GPI-AP) Expression by F-Box/LRR-Repeat (FBXL) Protein in Wheat (Triticum aestivum L.).
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 29 Geumgu, Jeongeup 56212, Korea.; Division of Biotechnology, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul 02841, Korea.; Institute of Animal Molecular Biotechnology, Korea University, 145 Anam-Ro, Seongbuk-Gu, Seoul 02841, Korea.
F-box proteins are substrate recognition components of the Skp1-Cullin-F-box (SCF) complex, which performs many important biological functions including the degradation of numerous proteins via the ubiquitin-26S proteasome system. In this study, we isolated the gene encoding the F-box/LRR-repeat (FBXL) protein from wheat (Triticum aestivum L.) seedlings and validated that the TaFBXL protein is a component of the SCF complex. Yeast two-hybrid assays revealed that TaFBXL interacts with the wheat glycosylphosphatidylinositol-anchored protein (TaGPI-AP). The green fluorescent protein (GFP) fusion protein of TaFBXL was detected in the nucleus and plasma membrane, whereas that of TaGPI-AP was observed in the cytosol and probably also plasma membrane. yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays revealed that TaFBXL specifically interacts with TaGPI-AP in the nucleus and plasma membrane, and TaGPI-AP is targeted by TaFBXL for degradation via the 26S proteasome system. In addition, TaFBXL and TaGPI-AP showed antagonistic expression patterns upon treatment with indole-3-acetic acid (IAA), and the level of TaGPI-AP was higher in tobacco leaves treated with both MG132 (proteasome inhibitor) and IAA than in leaves treated with either MG132 or IAA. Taken together, our data suggest that TaFBXL regulates the TaGPI-AP protein level in response to exogenous auxin application.
PMID: 34451651
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081600
The Steroid Saponin Protodioscin Modulates Arabidopsis thaliana Root Morphology Altering Auxin Homeostasis, Transport and Distribution.
Laboratory of Biological Oxidations, Department of Biochemistry, State University of Maringa, Maringa 87020900, Brazil.; Department of Agricultural and Environmental Sciences (DISAA), University of Milan, Via Celoria, 20133 Milano, Italy.; Department of Biology, Ecology and Soil Science, University of Calabria, Arcavacata di Rende (CS), 87036 Arcavacata di Rende, Italy.; Department of Agriculture, University of Reggio di Calabria, 89124 Reggio Calabria, Italy.
To date, synthetic herbicides are the main tools used for weed control, with consequent damage to both the environment and human health. In this respect, searching for new natural molecules and understanding their mode of action could represent an alternative strategy or support to traditional management methods for sustainable agriculture. Protodioscin is a natural molecule belonging to the class of steroid saponins, mainly produced by monocotyledons. In the present paper, protodioscin's phytotoxic potential was assessed to identify its target and the potential mode of action in the model plant Arabidopsis thaliana. The results highlighted that the root system was the main target of protodioscin, which caused a high inhibitory effect on the primary root length (ED50 50 muM) with morphological alteration, accompanied by a significant increase in the lateral root number and root hair density. Through a pharmacological and microscopic approach, it was underlined that this saponin modified both auxin distribution and transport, causing an auxin accumulation in the region of root maturation and an alteration of proteins responsible for the auxin efflux (PIN2). In conclusion, the saponin protodioscin can modulate the root system of A. thaliana by interfering with the auxin transport (PAT).
PMID: 34451648
Plants (Basel) , IF:3.935 , 2021 Aug , V10 (8) doi: 10.3390/plants10081593
Molecular Genetic Characteristics of Different Scenarios of Xylogenesis on the Example of Two Forms of Silver Birch Differing in the Ratio of Structural Elements in the Xylem.
Forest Research Institute, Karelian Research Centre of the Russian Academy of Sciences, 11 Pushkinskaya St., Petrozavodsk 185910, Russia.
Silver birch (Betula pendula Roth) is an economically important species in Northern Europe. The current research focused on the molecular background of different xylogenesis scenarios in the birch trunks. The study objects were two forms of silver birch, silver birch trees, and Karelian birch trees; the latter form is characterized by the formation of two types of wood, non-figured (straight-grained) and figured, respectively, while it is currently not clear which factors cause this difference. We identified VND/NST/SND genes that regulate secondary cell wall biosynthesis in the birch genome and revealed differences in their expression in association with the formation of xylem with different ratios of structural elements. High expression levels of BpVND7 accompanied differentiation of the type of xylem which is characteristic of the species. At the same time, the appearance of figured wood was accompanied by the low expression levels of the VND genes and increased levels of expression of NST and SND genes. We identified BpARF5 as a crucial regulator of auxin-dependent vascular patterning and its direct target-BpHB8. A decrease in the BpARF5 level expression in differentiating xylem was a specific characteristic of both Karelian birch with figured and non-figured wood. Decreased BpARF5 level expression in non-figured trees accompanied by decreased BpHB8 and VND/NST/SND expression levels compared to figured Karelian birch trees. According to the results obtained, we suggested silver birch forms differing in wood anatomy as valuable objects in studying the regulation of xylogenesis.
PMID: 34451638
Biosci Rep , IF:3.84 , 2021 Aug , V41 (8) doi: 10.1042/BSR20210598
Double agent indole-3-acetic acid: mechanistic analysis of indole-3-acetaldehyde dehydrogenase AldA that synthesizes IAA, an auxin that aids bacterial virulence.
Department of Chemistry, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.; Department of Biology, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
The large diversity of organisms inhabiting various environmental niches on our planet are engaged in a lively exchange of biomolecules, including nutrients, hormones, and vitamins. In a quest to survive, organisms that we define as pathogens employ innovative methods to extract valuable resources from their host leading to an infection. One such instance is where plant-associated bacterial pathogens synthesize and deploy hormones or their molecular mimics to manipulate the physiology of the host plant. This commentary describes one such specific example-the mechanism of the enzyme AldA, an aldehyde dehydrogenase (ALDH) from the bacterial plant pathogen Pseudomonas syringae which produces the plant auxin hormone indole-3-acetic acid (IAA) by oxidizing the substrate indole-3-acetaldehyde (IAAld) using the cofactor nicotinamide adenine dinucleotide (NAD+) (Bioscience Reports (2020) 40(12), https://doi.org/10.1042/BSR20202959). Using mutagenesis, enzyme kinetics, and structural analysis, Zhang et al. established that the progress of the reaction hinges on the formation of two distinct conformations of NAD(H) during the reaction course. Additionally, a key mutation in the AldA active site 'aromatic box' changes the enzyme's preference for an aromatic substrate to an aliphatic one. Our commentary concludes that such molecular level investigations help to establish the nature of the dynamics of NAD(H) in ALDH-catalyzed reactions, and further show that the key active site residues control substrate specificity. We also contemplate that insights from the present study can be used to engineer novel ALDH enzymes for environmental, health, and industrial applications.
PMID: 34369556
Gene , IF:3.688 , 2021 Aug , V804 : P145905 doi: 10.1016/j.gene.2021.145905
Auxin drives tomato spotted wilt virus (TSWV) resistance through epigenetic regulation of auxin response factor ARF8 expression in tomato.
Laboratory of Molecular Genetics, Immunology and Biotechnology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 2092, Tunisia.; Institute of Molecular and Cellular Biology of Plants (UPV-CSIC), Valencia 46022, Spain; Dept of Biotechnology, ETSIAMN, Universidad Politecnica de Valencia, 46002, Spain.; Laboratory of Molecular Genetics, Immunology and Biotechnology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 2092, Tunisia; Faculty of Sciences of Bizerte, Zarzouna 702, University of Carthage, Tunisia.; Laboratory of Molecular Genetics, Immunology and Biotechnology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis 2092, Tunisia; Faculty of Sciences of Bizerte, Zarzouna 702, University of Carthage, Tunisia. Electronic address: faten.gorsane@fsb.u-carthage.tn.
Tomato spotted wilt virus (TSWV) causes severe losses of tomato crops worldwide. To cope dynamically with such a threat, plants deploy strategies acting at the molecular and the epigenetic levels. We found that tomato symptoms progress in a specific-genotype-manner upon TSWV infection. Susceptible genotypes showed within the Auxin Response Factor (ARF8) promoter coupled to enhanced expression of miRNA167a, reduced ARF8 gene and decreased levels of the hormone auxin. This constitutes a deliberate attempt of TSWV to disrupt plant growth to promote spread in sensitive cultivars. Epigenetic regulation through the level of cytosine methylation and the miR167a-ARF8 module are part of a complex network modulating auxin-triggered synthesis and shaping tomato responses to TSWV. Furthermore, modulation of miR167a-ARF8 regulatory module could be applied in tomato-resistance breeding programs.
PMID: 34411646
Gene , IF:3.688 , 2021 Aug , V795 : P145782 doi: 10.1016/j.gene.2021.145782
Genome-wide identification of AUX/IAA in radish and functional characterization of RsIAA33 gene during taproot thickening.
National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOA, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China; Hebei Key Laboratory of Horticultural Germplasm Excavation and Innovative Utilization, College of Horticulture Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.; National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOA, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China.; National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOA, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China. Electronic address: nauxuliang@njau.edu.cn.; Hebei Key Laboratory of Horticultural Germplasm Excavation and Innovative Utilization, College of Horticulture Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China.; National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (East China) of MOA, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, People's Republic of China. Electronic address: nauliulw@njau.edu.cn.
Auxin/indole-3-acetic acid (Aux/IAA) genes encode short lived nuclear proteins that cooperated with auxin or auxin response factor (ARF), which are involved in plant growth and developmental processes. However, it's still ambiguous how the Aux/IAA genes regulate the process governing taproot thickening in radish. Herein, 65 Aux/IAA genes were identified from the radish genome. Gene duplication analysis showed that two pairs of tandem duplication and 17 (27%) segmental duplication events were identified among Aux/IAA family genes in radish. Transcriptomic analysis revealed that most of Aux/IAA genes (52/65) exhibited differential expression pattern in different root tissues, and six root-specific genes were highly expressed in root cortex, cambium, xylem, and root tip in radish. RT-qPCR analysis showed that the expression level of RsIAA33 was the highest at cortex splitting stage (CSS), and early expanding stage (ES). Furthermore, amiRNA-mediated gene silencing of RsIAA33 indicated that it could inhibit the reproductive growth, thus promoting taproot thickening and development. These results would provide valuable information for elucidating the molecular function of Aux/IAA genes involved in taproot thickening in radish.
PMID: 34146634
Pathogens , IF:3.492 , 2021 Aug , V10 (8) doi: 10.3390/pathogens10080991
Phytohormone Production Profiles in Trichoderma Species and Their Relationship to Wheat Plant Responses to Water Stress.
Institute for Agribiotechnology Research (CIALE), Department of Microbiology and Genetics, University of Salamanca, Campus de Villamayor, C/Duero, 12, 37185 Salamanca, Spain.
The production of eight phytohormones by Trichoderma species is described, as well as the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) activity, which diverts the ethylene biosynthetic pathway in plants. The use of the Trichoderma strains T. virens T49, T. longibrachiatum T68, T. spirale T75 and T. harzianum T115 served to demonstrate the diverse production of the phytohormones gibberellins (GA) GA1 and GA4, abscisic acid (ABA), salicylic acid (SA), auxin (indole-3-acetic acid: IAA) and the cytokinins (CK) dihydrozeatin (DHZ), isopenteniladenine (iP) and trans-zeatin (tZ) in this genus. Such production is dependent on strain and/or culture medium. These four strains showed different degrees of wheat root colonization. Fresh and dry weights, conductance, H2O2 content and antioxidant activities such as superoxide dismutase, peroxidase and catalase were analyzed, under optimal irrigation and water stress conditions, on 30-days-old wheat plants treated with four-day-old Trichoderma cultures, obtained from potato dextrose broth (PDB) and PDB-tryptophan (Trp). The application of Trichoderma PDB cultures to wheat plants could be linked to the plants' ability to adapt the antioxidant machinery and to tolerate water stress. Plants treated with PDB cultures of T49 and T115 had the significantly highest weights under water stress. Compared to controls, treatments with strains T68 and T75, with constrained GA1 and GA4 production, resulted in smaller plants regardless of fungal growth medium and irrigation regime.
PMID: 34451455
Yi Chuan , IF:3.271 , 2021 Aug , V43 (8) : P723-736 doi: 10.16288/j.yczz.21-105
[The molecular mechanism of apical hook development in dicot plant].
Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China.; FAFU-UCR Joint Center, Horticulture Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
After the seeds of the dicot model plant Arabidopsis germinate in the soil, the tip of the hypocotyl will form a specialized structure called apical hooks to protect the cotyledons and shoot apical meristems from the mechanical damage during the soil emerging process. The development process of the apical hook is divided into three stages: the apical hook formation, maintenance, and opening. In recent decades, studies have shown that different kinds of plant hormones and environmental signals play a vital role in the development of the apical hook. As the downstream of a variety of signals, the asymmetric distribution of auxin and the signal transduction pathways play a decisive role in the development of the apical hook. However, the detailed mechanism of the asymmetric signal transduction pathway of the cells on both sides of the apical hook is still unclear. In this review, we summarize the molecular mechanisms of the development of apical hook and further refine the role of auxin in the development of apical hook, and prospect for future research directions in this field.
PMID: 34413013
Plant Biol (Stuttg) , IF:3.081 , 2021 Aug doi: 10.1111/plb.13299
Function analysis of a cotton R2R3 MYB transcription factor GhMYB3 in regulating plant trichome development.
Cotton Research Institute, Shanxi Agricultural University, Yuncheng, China.; National Key Laboratory of Plant Molecular genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.; Nanjing Agricultural University, Nanjing, China.
Cotton is an important fibre-producing crop. Cotton fibres consist of highly elongated trichomes derived from the ovule. To improve the quality of cotton, it is necessary to identify the genes regulating fibre development. GhMYB3 was identified through bioinfomatic analysis and introduced to Arabidopsis and cotton to observe the phenotype. Protein inteaction and promoter bingding assays were conducted to explore the role of GhMYB3 in trichome fibre growth. Cotton fibre development might share a similar regulatory mechanism to Arabidopsis leaf trichomes, which is determined by the essential regulatory complex, MYB-bHLH-WD40. The GL1-like R2R3 MYB transcription factor GhMYB3 interacts with the AtGL3 protein involved in Arabidopsis trichome development. Ectopic expression of GhMYB3 could rescue the glabrous phenotype of the Arabidopsis gl1 mutant and produced more ectopic trichomes on inflorescence stems and floral organs, confirming its orthologous function in plant trichome development. The expression of GhMYB3 increased in response to exogenous gibberellin (GA3 ), auxin (IAA) and methyl jasmonate (MeJA). Overexpression of this gene in cotton leads to a slight increase in fibre length and lint percentage, possibly by activating the transcription of its downstream gene GhRDL1 or other fibre-related genes. The results increase our understanding of the key role of GhMYB3 in positively controlling plant trichome development, and this gene could be a potential target for molecular breeding in cotton.
PMID: 34396658
Plant Biol (Stuttg) , IF:3.081 , 2021 Aug doi: 10.1111/plb.13303
Auxin and its role in plant development: structure, signalling, regulation and response mechanisms.
Programa de Pos-Graduacao em Bioquimica, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, Natal, Brazil.; Laboratorio de Transformacao de Plantas e Analises em Microscopia, Departamento de Biologia Celular e Genetica, Universidade Federal do Rio Grande do Norte, Natal, Brazil.
Auxins are plant hormones that play a central role in controlling plant growth and development across different environmental conditions. Even at low concentrations, auxins can regulate gene expression through specific transcription factors and proteins that are modulated to environmental responses in the signalling cascade. Auxins are synthesized in tissues with high cell division activity and distributed by specific transmembrane proteins that regulate efflux and influx. This review presents recent advances in understanding the biosynthetic pathways, both dependent and independent of tryptophan, highlighting the intermediate indole compounds (indole-3-acetamide, indole-3-acetaldoxime, indole-3-pyruvic acid and tryptamine) and the key enzymes for auxin biosynthesis, such as YUCs and TAAs. In relation to the signalling cascade, it has been shown that auxins influence gene expression regulation by the connection between synthesis and distribution. Moreover, the molecular action of the auxin response factors and auxin/indole-3-acetic acid transcription factors with the F-box TIR1/AFB auxin receptors regulates gene expression. In addition, the importance of microRNAs in the auxin signalling pathway and their influence on plant plasticity to environmental fluctuations is also demonstrated. Finally, this review describes the chemical and biological processes involving auxins in plants.
PMID: 34396657
Lett Appl Microbiol , IF:2.858 , 2021 Aug doi: 10.1111/lam.13556
Elucidating key plant growth promoting (PGPR) traits in Burkholderia sp. Nafp2/4-1b (=SARCC-3049) using gnotobiotic assays and whole genome sequence analysis.
Agricultural Research Council, Plant Health and Protection, Private Bag X134, Queenswood, Pretoria, 0121, South Africa.; School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, 2000, South Africa.; Agricultural Research Council, Biotechnology Platform, Private Bag X051, Onderstepoort, South Africa.; ARC-Biometry, Central Office, PO Box 8783, Pretoria, 0001, South Africa.
Burkholderia sp. Nafp2/4-1b (= SARCC-3049) is a plant growth promoting rhizobacteria (PGPR) initially isolated from the rhizosphere of pristine grassland in South Africa and its ability to enhance growth was previously evaluated on maize (Zea mays L.). Here, the bacterium was tested with the aim of investigating its role in improving the nodulation and growth of the forage legume lucerne (Medicago sativa L.) when it is co-inoculated with the rhizobial symbionts of this legume in the glasshouse. When the co-inoculation resulted in a statistically significant (p= 0.05) increase in the number of nodules and improved plant biomass as compared to single inoculation, we sequenced and analysed its genome to gain a better understanding of the genetic determinants responsible for the observed PGPR traits. The Illumina HiSeq 2500-sequenced genome resulted in 92 scaffolds, with a N50 of 322,407 bp, a total draft genome size of 7,788,045 bp and GC content of 66.2 %. Analysis of the genome sequence confirmed the presence of a number of essential genes that code for various PGPR traits. The main plant beneficial genes associated with PGPR traits in Burkholderia sp. Nafp2/4-1b include pyoverdine siderophores biosynthesis gene (PvdF); acdS that codes for 1-aminocyclopropane -1-carboxylate (ACC) deaminase; the tryptophan synthase genes involved in auxin biosynthesis (TSA1, TSB1) and the pqqABCDE operon related to phosphate solubilization. This study generated valuable information on the potential of the PGPR Burkholderia sp. strain Nafp2/4-1b as an effective commercial inoculant, which warrants further formulation and field application studies before developing it into a low cost, environmentally safe and effective biofertilizer.
PMID: 34426983
Insects , IF:2.769 , 2021 Aug , V12 (8) doi: 10.3390/insects12080746
Genome-Wide Analysis of the Amino Acid Auxin Permease (AAAP) Gene Family and Identification of an AAAP Gene Associated with the Growth and Reproduction of the Brown Planthopper, Nilaparvata lugens (Stal).
Innovative Institute for Plant Health, College of Agriculture & Biology, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.; Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.; Caofeidian Customs House, Tangshan 063200, China.
Amino acids play a vital role in several biological processes in organisms and are mainly acquired through diet by most insects. The amino acid auxin permease (AAAP) transporter family is an important amino acid transporter gene family in insects for the transportation of amino acids into and out of cells across the plasma membrane. Here, we identified 21 putative AAAP family members in the genome of the brown planthopper (BPH), Nilaparvata lugens, a devastating pest that feeds only on the phloem sap of rice plants. Molecular characteristic analysis indicated large variations in protein features and amino acid sequences among the predicted AAAP family members in BPH. Phylogenetic analysis clustered these AAAP transporters into three subgroups, with the members in the same group sharing a similar pattern of conserved motif distribution. Through ortholog gene recognition and spatiotemporal gene expression analysis, the AAAP gene NlAAAP07, which was predicted to regulate BPH larval growth and female fecundity, was identified. RNA interference (RNAi)-mediated suppression of NlAAAP07 significantly postponed the duration of 3rd instar nymphs developing into adults from 7.4 days to 9.0 days, and decreased the oviposition amount and egg hatching rate of females by 30.7% and 11.0%, respectively. Our results provide a foundation for further functional analysis of AAAP transporters in BPH.
PMID: 34442311
Int J Genomics , IF:2.326 , 2021 , V2021 : P2590665 doi: 10.1155/2021/2590665
Whole-Genome Duplication and Purifying Selection Contributes to the Functional Redundancy of Auxin Response Factor (ARF) Genes in Foxtail Millet (Setaria italica L.).
National Engineering Laboratory of Crop Stress Resistance Breeding, School of Life Sciences, Anhui Agricultural University, Hefei 230036, China.; Precision Medicine Research Laboratory of Anhui Province, Hefei, Anhui 230088, China.
Auxin response factors (ARFs) play crucial roles in auxin-mediated response, whereas molecular genetics of ARF genes was seldom investigated in Setaria italica, an important crop and C4 model plant. In the present study, genome-wide evolutionary analysis of ARFs was performed in S. italica. Twenty-four SiARF genes were identified and unevenly distributed on eight of the nine chromosomes in S. italica. Duplication mode exploration implied that 13 SiARF proteins were originated from whole-genome duplication and suffered purifying selection. Phylogeny reconstruction of SiARFs by maximum likelihood and neighbor-joining trees revealed SiARFs could be divided into four clades. SiARFs clustered within the same clade shared similar gene structure and protein domain composition, implying functional redundancy. Moreover, amino acid composition of the middle regions was conserved in SiARFs belonged to the same clade. SiARFs were categorized into either activators or repressors according to the enrichment of specific amino acids. Intrinsic disorder was featured in the middle regions of ARF activators. Finally, expression profiles of SiARFs under hormone and abiotic stress treatment not only revealed their potential function in stress response but also indicate their functional redundancy. Overall, our results provide insights into evolutionary aspects of SiARFs and benefit for further functional characterization.
PMID: 34414231
Mol Biol Rep , IF:2.316 , 2021 Aug doi: 10.1007/s11033-021-06620-6
Genome-wide identification of serine acetyltransferase (SAT) gene family in rice (Oryza sativa) and their expressions under salt stress.
Department of Plant Production and Technologies, Faculty of Applied Sciences, Mus Alparslan University, Mus, Turkey.; Department of Crop and Animal Production, Cilimli Vocational School, Duzce University, Cilimli, Duzce, Turkey. ertugrulfiliz@gmail.com.; Department of Agricultural Biotechnology, Faculty of Agriculture, Igdir University, Igdir, Turkey.
BACKGROUND: Assimilation of sulfur to cysteine (Cys) occurs in presence of serine acetyltransferase (SAT). Drought and salt stresses are known to be regulated by abscisic acid, whose biosynthesis is limited by Cys. Cys is formed by cysteine synthase complex depending on SAT and OASTL enzymes. Functions of some SAT genes were identified in Arabidopsis; however, it is not known how SAT genes are regulated in rice (Oryza sativa) under salt stress. METHODS AND RESULTS: Sequence, protein domain, gene structure, nucleotide, phylogenetic, selection, gene duplication, motif, synteny, digital expression and co-expression, secondary and tertiary protein structures, and binding site analyses were conducted. The wet-lab expressions of OsSAT genes were also tested under salt stress. OsSATs have underwent purifying selection. Segmental and tandem duplications may be driving force of structural and functional divergences of OsSATs. The digital expression analyses of OsSATs showed that jasmonic acid (JA) was the only hormone inducing the expressions of OsSAT1;1, OsSAT2;1, and OsSAT2;2 whereas auxin and ABA only triggered OsSAT1;1 expression. Leaf blade is the only plant organ where all OsSATs but OsSAT1;1 were expressed. Wet-lab expressions of OsSATs indicated that OsSAT1;1, OsSAT1;2 and OsSAT1;3 genes were upregulated at different exposure times of salt stress. CONCLUSIONS: OsSAT1;1, expressed highly in rice roots, may be a hub gene regulated by cross-talk of JA, ABA and auxin hormones. The cross-talk of the mentioned hormones and the structural variations of OsSAT proteins may also explain the different responses of OsSATs to salt stress.
PMID: 34389920
Plant Signal Behav , IF:2.247 , 2021 Aug , V16 (8) : P1920191 doi: 10.1080/15592324.2021.1920191
The lncRNA APOLO and the transcription factor WRKY42 target common cell wall EXTENSIN encoding genes to trigger root hair cell elongation.
Fundacion Instituto Leloir and IIBBA-CONICET, Buenos Aires, CP, Argentina.; Instituto de Agrobiotecnologia del Litoral, Universidad Nacional del Litoral, CONICET, FBCB/FHUC, Centro Cientifico Tecnologico CONICET Santa Fe, Paraje El Pozo, Santa Fe, Argentina.; Centro de Biotecnologia Vegetal (CBV), Facultad de Ciencias de la Vida (Fcsv), Universidad Andres Bello and Millennium Institute for Integrative Biology (Ibio), Santiago, Chile.
Plant long noncoding RNAs (lncRNAs) are key chromatin dynamics regulators, directing the transcriptional programs driving a wide variety of developmental outputs. Recently, we uncovered how the lncRNA AUXIN REGULATED PROMOTER LOOP (APOLO) directly recognizes the locus encoding the root hair (RH) master regulator ROOT HAIR DEFECTIVE 6 (RHD6) modulating its transcriptional activation and leading to low temperature-induced RH elongation. We further demonstrated that APOLO interacts with the transcription factor WRKY42 in a novel ribonucleoprotein complex shaping RHD6 epigenetic environment and integrating signals governing RH growth and development. In this work, we expand this model showing that APOLO is able to bind and positively control the expression of several cell wall EXTENSIN (EXT) encoding genes, including EXT3, a key regulator for RH growth. Interestingly, EXT3 emerged as a novel common target of APOLO and WRKY42. Furthermore, we showed that the ROS homeostasis-related gene NADPH OXIDASE C (NOXC) is deregulated upon APOLO overexpression, likely through the RHD6-RSL4 pathway, and that NOXC is required for low temperature-dependent enhancement of RH growth. Collectively, our results uncover an intricate regulatory network involving the APOLO/WRKY42 hub in the control of master and effector genes during RH development.
PMID: 33944666
Plant Signal Behav , IF:2.247 , 2021 Aug , V16 (8) : P1922796 doi: 10.1080/15592324.2021.1922796
Vacuolar occupancy is crucial for cell elongation and growth regardless of the underlying mechanism.
Plant Pathology, University of Kaiserslautern, Kaiserslautern, Germany.
In the physiological range, the phytohormone auxin inhibits the growth of underground tissues. In the roots of Arabidopsis thaliana, cell size inhibition has been shown to be accompanied by auxin-mediated reduction of vacuole size. A tonoplast-localized protein family (Networked 4) with actin-binding capacity was demonstrated to modulate the compactness of the vacuole. Overexpression of NET4A led to smaller, more spherical and compact vacuoles, which occupied less cellular space compared to wild type. This reduction of vacuolar occupancy is similar to the observed auxin-induced decrease in occupancy, albeit there are enormous morphological differences. Here, we show that a net4a net4b double mutant and a NET4A overexpressor line are still sensitive to auxin-induced vacuolar constrictions. However, the overexpressor showed a partial auxin resistance accompanied by more compact vacuoles, thereby indicating an additional regulatory mechanism. Furthermore, we show that other NET superfamily members do not compensate for the loss of NET4A and NET4B expression on the transcriptional level. This leads us to hypothesize that regulation of vacuole size is a general mechanism to regulate cell expansion and that other players besides NET4 must participate in regulating the vacuole-cytoskeleton interface.
PMID: 33938395
J Environ Sci Health B , IF:1.99 , 2021 Aug : P1-8 doi: 10.1080/03601234.2021.1966280
Application of 2,4-D hormetic dose associated with the supply of nitrogen and nickel on cotton plants.
Universidade Estadual Paulista (UNESP), Ilha Solteira, SP, Brazil.; Universidade do Oeste Paulista (UNOESTE), Presidente Prudente, SP, Brazil.
Growth traits, yield, N content, photosynthetic pigments, ammonia and amino acids were measured to verify the effect of the interaction between N, Ni, and 2,4-D applied in the cotton crop. The objective was to study the hormonal effect of 2,4-D associated with the application of N and Ni in coverage to improve yield. The N (0, 40, 80, and 120 kg ha(-1)) and Ni(0, 300, 450, and 600 g ha(-1)) were applied to the soil in the square phenological growth stage. The commercial 2,4-D DMA(R) BR (0 and 1.8 g a.e ha(-1)) was applied to the leaves at the same growth stage. The supply of N in cover fertilization up to 120 kg ha(-1) was beneficial for cotton, providing greater yield and content of photosynthetic pigments. The application of 2,4-D in a hormetic dose, as a synthetic auxin during the beginning of flowering, proved to be a promising technique to improve cotton yield. This end-of-cycle response is related to the requirement for auxins during the cotton fruiting process.
PMID: 34405759