Nature , IF:49.962 , 2021 Oct doi: 10.1038/s41586-021-03976-4
TMK-based cell-surface auxin signalling activates cell-wall acidification.
FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China.; Institute of Integrative Genome Biology and Department of Botany and Plant Science, University of California, Riverside, CA, USA.; Graduate School of Science, Nagoya University, Nagoya, Japan.; Institute of Transformative Bio-Molecules, Nagoya University, Nagoya, Japan.; Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA.; Biological Mass Spectrometry Facility, Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey, Piscataway, NJ, USA.; FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China. yang@ucr.edu.; Institute of Integrative Genome Biology and Department of Botany and Plant Science, University of California, Riverside, CA, USA. yang@ucr.edu.
The phytohormone auxin controls many processes in plants, at least in part through its regulation of cell expansion(1). The acid growth hypothesis has been proposed to explain auxin-stimulated cell expansion for five decades, but the mechanism that underlies auxin-induced cell-wall acidification is poorly characterized. Auxin induces the phosphorylation and activation of the plasma membrane H(+)-ATPase that pumps protons into the apoplast(2), yet how auxin activates its phosphorylation remains unclear. Here we show that the transmembrane kinase (TMK) auxin-signalling proteins interact with plasma membrane H(+)-ATPases, inducing their phosphorylation, and thereby promoting cell-wall acidification and hypocotyl cell elongation in Arabidopsis. Auxin induced interactions between TMKs and H(+)-ATPases in the plasma membrane within seconds, as well as TMK-dependent phosphorylation of the penultimate threonine residue on the H+-ATPases. Our genetic, biochemical and molecular evidence demonstrates that TMKs directly phosphorylate plasma membrane H(+)-ATPase and are required for auxin-induced H(+)-ATPase activation, apoplastic acidification and cell expansion. Thus, our findings reveal a crucial connection between auxin and plasma membrane H(+)-ATPase activation in regulating apoplastic pH changes and cell expansion through TMK-based cell surface auxin signalling.
PMID: 34707287
Nature , IF:49.962 , 2021 Oct doi: 10.1038/s41586-021-04037-6
Cell surface and intracellular auxin signalling for H(+) fluxes in root growth.
Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.; Laboratory of Biochemistry, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, the Netherlands.; Institute of Transformative Bio-Molecules, Division of Biological Science, Nagoya University Chikusa, Nagoya, Japan.; Graduate School of Science, Nagoya University Chikusa, Nagoya, Japan.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; VIB Center for Plant Systems Biology, Ghent, Belgium.; Tasmanian Institute of Agriculture, College of Science and Engineering, University of Tasmania, Hobart, Tasmania, Australia.; Department of Plant & Microbial Biology, University of Minnesota, St. Paul, MN, USA.; Laboratory of Plant Growth Analysis, Ghent University Global Campus, Incheon, Republic of Korea.; Department of Plants and Crops, HortiCell, Ghent University, Ghent, Belgium.; International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China.; Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria. jiri.friml@ist.ac.at.
Growth regulation tailors development in plants to their environment. A prominent example of this is the response to gravity, in which shoots bend up and roots bend down(1). This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots while inhibiting it in roots via a yet unknown cellular mechanism(2). Here, by combining microfluidics, live imaging, genetic engineering and phosphoproteomics in Arabidopsis thaliana, we advance understanding of how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on rapid regulation of apoplastic pH, a causative determinant of growth. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H(+)-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H(+) influx, causing apoplast alkalinization. Simultaneous activation of these two counteracting mechanisms poises roots for rapid, fine-tuned growth modulation in navigating complex soil environments.
PMID: 34707283
Cell Host Microbe , IF:21.023 , 2021 Oct , V29 (10) : P1471-1473 doi: 10.1016/j.chom.2021.09.014
Stuck on you: Bacterial-auxin-mediated bacterial colonization of plant roots.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Excellence in Biotic Interactions, College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China; CAS-JIC Centre of Excellence for Plant and Microbial Science, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Excellence in Biotic Interactions, College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China; CAS-JIC Centre of Excellence for Plant and Microbial Science, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101 Beijing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China. Electronic address: ybai@genetics.ac.cn.
Auxin secreted by root-associated bacteria promotes plant growth, yet benefits to bacteria themselves are ill-defined. In this issue of Cell Host & Microbe, Tzipilevich et al. (2021) demonstrate that auxin and plant EFR-triggered response are essential for root colonization of B. velezensis, indicating potential co-evolution of plants and root commensal bacteria.
PMID: 34648737
Cell Host Microbe , IF:21.023 , 2021 Oct , V29 (10) : P1507-1520.e4 doi: 10.1016/j.chom.2021.09.005
Plant immune system activation is necessary for efficient root colonization by auxin-secreting beneficial bacteria.
Department of Biology, Duke University, Durham, NC 27708, USA; Howard Hughes Medical Institute Duke University, Durham, NC 27708, USA.; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Howard Hughes Medical Institute. University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.; Department of Biology, Duke University, Durham, NC 27708, USA; Howard Hughes Medical Institute Duke University, Durham, NC 27708, USA. Electronic address: philip.benfey@duke.edu.
Although plant roots encounter a plethora of microorganisms in the surrounding soil, at the rhizosphere, plants exert selective forces on their bacterial colonizers. Unlike immune recognition of pathogenic bacteria, the mechanisms by which beneficial bacteria are selected and how they interact with the plant immune system are not well understood. To better understand this process, we studied the interaction of auxin-producing Bacillus velezensis FZB42 with Arabidopsis roots and found that activation of the plant immune system is necessary for efficient bacterial colonization and auxin secretion. A feedback loop is established in which bacterial colonization triggers an immune reaction and production of reactive oxygen species, which, in turn, stimulate auxin production by the bacteria. Auxin promotes bacterial survival and efficient root colonization, allowing the bacteria to inhibit fungal infection and promote plant health. Thus, a feedback loop between bacteria and the plant immune system promotes the fitness of both partners.
PMID: 34610294
Nat Commun , IF:14.919 , 2021 Oct , V12 (1) : P6128 doi: 10.1038/s41467-021-26332-6
Light-triggered and phosphorylation-dependent 14-3-3 association with NON-PHOTOTROPIC HYPOCOTYL 3 is required for hypocotyl phototropism.
Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tubingen, Tubingen, Germany.; Proteome Center Tubingen, University of Tubingen, Tubingen, Germany.; Center for Plant Molecular Biology (ZMBP), Plant Physiology, University of Tubingen, Tubingen, Germany. claudia.oecking@zmbp.uni-tuebingen.de.
NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) is a key component of the auxin-dependent plant phototropic growth response. We report that NPH3 directly binds polyacidic phospholipids, required for plasma membrane association in darkness. We further demonstrate that blue light induces an immediate phosphorylation of a C-terminal 14-3-3 binding motif in NPH3. Subsequent association of 14-3-3 proteins is causal for the light-induced release of NPH3 from the membrane and accompanied by NPH3 dephosphorylation. In the cytosol, NPH3 dynamically transitions into membraneless condensate-like structures. The dephosphorylated state of the 14-3-3 binding site and NPH3 membrane recruitment are recoverable in darkness. NPH3 variants that constitutively localize either to the membrane or to condensates are non-functional, revealing a fundamental role of the 14-3-3 mediated dynamic change in NPH3 localization for auxin-dependent phototropism. This regulatory mechanism might be of general nature, given that several members of the NPH3-like family interact with 14-3-3 via a C-terminal motif.
PMID: 34675219
Mol Plant , IF:13.164 , 2021 Oct , V14 (10) : P1683-1698 doi: 10.1016/j.molp.2021.06.023
A novel miR167a-OsARF6-OsAUX3 module regulates grain length and weight in rice.
Key Laboratory of Herbage & Endemic Crop Biology of Ministry of Education, Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, School of Life Sciences, Inner Mongolia University, Hohhot 010000, China; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.; State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China.; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.; Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China.; Key Laboratory of Herbage & Endemic Crop Biology of Ministry of Education, Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, School of Life Sciences, Inner Mongolia University, Hohhot 010000, China.; State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, University of Chinese Academy of Sciences, 100049, China.; Department of Biology, University of Fribourg, Rue Albert-Gockel 3, CH-1700 Fribourg, Switzerland.; Key Laboratory of Herbage & Endemic Crop Biology of Ministry of Education, Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, School of Life Sciences, Inner Mongolia University, Hohhot 010000, China; State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: qyhjp@zju.edu.cn.; State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China. Electronic address: gaozhenyu@caas.cn.; State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China; Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China. Electronic address: qianqian188@hotmail.com.
Grain size is one of the most important factors that control rice yield, as it is associated with grain weight (GW). To date, dozens of rice genes that regulate grain size have been isolated; however, the regulatory mechanism underlying GW control is not fully understood. Here, the quantitative trait locus qGL5 for grain length (GL) and GW was identified in recombinant inbred lines of 9311 and Nipponbare (NPB) and fine mapped to a candidate gene, OsAUX3. Sequence variations between 9311 and NPB in the OsAUX3 promoter and loss of function of OsAUX3 led to higher GL and GW. RNA sequencing, gene expression quantification, dual-luciferase reporter assays, chromatin immunoprecipitation-quantitative PCR, and yeast one-hybrid assays demonstrated that OsARF6 is an upstream transcription factor regulating the expression of OsAUX3. OsARF6 binds directly to the auxin response elements of the OsAUX3 promoter, covering a single-nucleotide polymorphism site between 9311 and NPB/Dongjin/Hwayoung, and thereby controls GL by altering longitudinal expansion and auxin distribution/content in glume cells. Furthermore, we showed that miR167a positively regulate GL and GW by directing OsARF6 mRNA silencing. Taken together, our study reveals that a novel miR167a-OsARF6-OsAUX3 module regulates GL and GW in rice, providing a potential target for the improvement of rice yield.
PMID: 34186219
Curr Biol , IF:10.834 , 2021 Oct , V31 (20) : PR1392-R1395 doi: 10.1016/j.cub.2021.09.007
Plant signaling: Interplay of brassinosteroids and auxin in root meristems.
MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing 210095, China; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: wexua@njau.edu.cn.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, B-9052 Ghent, Belgium; VIB-UGent Center for Plant Systems Biology, Technologiepark 71, B-9052 Ghent, Belgium. Electronic address: Tom.Beeckman@psb.vib-ugent.be.
The plant hormones brassinosteroids (BRs) and auxin interact to regulate root meristem size. A new study reveals dual and opposing roles for BRs in auxin biosynthesis and signaling output in the Arabidopsis root epidermis, demonstrating that epidermis-derived BR signaling is required for root meristem maintenance through its effect on auxin signaling.
PMID: 34699805
Curr Biol , IF:10.834 , 2021 Oct , V31 (20) : P4462-4472.e6 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
J Hazard Mater , IF:10.588 , 2021 Oct , V419 : P126419 doi: 10.1016/j.jhazmat.2021.126419
Transcriptomic evaluation on methyl bromide-induced phytotoxicity in Arabidopsis thaliana and its mode of phytotoxic action via the occurrence of reactive oxygen species and uneven distribution of auxin hormones.
Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea.; Department of Integrative Biology, Kyungpook National University, Daegu 41566, Republic of Korea.; Plant Quarantine Technology Center, Animal and Plant Quarantine Agency, Gimcheon 39660, Republic of Korea.; Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea; Department of Integrative Biology, Kyungpook National University, Daegu 41566, Republic of Korea. Electronic address: selpest@knu.ac.kr.
The increase in worldwide trade has caused the quality maintenance of commercialized agriproducts to be crucial in keeping its economic value. In recent years, methyl bromide (MB) has been used dominantly during quarantine and pre-shipment, despite it being an environmental hazard with global repercussions. Through this study, it was shown that Arabidopsis thaliana's 2 h exposure to the MB treatment displayed no signs of phytotoxicity, whereas its 4 h exposure significantly interfered with growth. The transcriptomic analysis found the molecular modifications in A. thaliana after the MB fumigation with the up-regulation of genes specifically relative to the abiotic and oxidative stress, and the down-regulation of auxin transporter genes. Some important gene expressions were verified by RT-qPCR and their expression patterns were similar. Oxidative stresses via the reactive oxygen species (ROS) in relation to MB phytotoxicity were confirmed with the increased malondialdehyde in MB-4h-treated A. thaliana. Uneven distribution of auxins via lower expression of auxin transporter genes was also determined using UPLC-ESI-QqQ MS. Application of two ROS scavengers such as N-acetyl-cysteine and L-glutathione minimized MB phytotoxic effect in A. thaliana. Therefore, MB caused severe oxidative stress, and alternatives regarding the use of MB should be considered.
PMID: 34171674
ISME J , IF:10.302 , 2021 Oct doi: 10.1038/s41396-021-01133-3
Coordination of root auxin with the fungus Piriformospora indica and bacterium Bacillus cereus enhances rice rhizosheath formation under soil drying.
Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Engineering Research Center of Soil Remediation of Fujian Province University, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.; Department of Biology, Hong Kong Baptist University, Hong Kong, China.; Institute of Plant Biology, College of Life Science, National Taiwan University, Taipei, Taiwan.; Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. wfxu@fafu.edu.cn.
Moderate soil drying (MSD) is a promising agricultural technique that can reduce water consumption and enhance rhizosheath formation promoting drought resistance in plants. The endophytic fungus Piriformospora indica (P. indica) with high auxin production may be beneficial for rhizosheath formation. However, the integrated role of P. indica with native soil microbiome in rhizosheath formation is unclear. Here, we investigated the roles of P. indica and native bacteria on rice rhizosheath formation under MSD using high-throughput sequencing and rice mutants. Under MSD, rice rhizosheath formation was significantly increased by around 30% with P. indica inoculation. Auxins in rice roots and P. indica were responsible for the rhizosheath formation under MSD. Next, the abundance of the genus Bacillus, known as plant growth-promoting rhizobacteria, was enriched in the rice rhizosheath and root endosphere with P. indica inoculation under MSD. Moreover, the abundance of Bacillus cereus (B. cereus) with high auxin production was further increased by P. indica inoculation. After inoculation with both P. indica and B. cereus, rhizosheath formation in wild-type or auxin efflux carrier OsPIN2 complemented line rice was higher than that of the ospin2 mutant. Together, our results suggest that the interaction of the endophytic fungus P. indica with the native soil bacterium B. cereus favors rice rhizosheath formation by auxins modulation in rice and microbes under MSD. This finding reveals a cooperative contribution of P. indica and native microbiota in rice rhizosheath formation under moderate soil drying, which is important for improving water use in agriculture.
PMID: 34621017
New Phytol , IF:10.151 , 2021 Oct doi: 10.1111/nph.17792
Mutually opposing activity of PIN7 splicing isoforms is required for auxin-mediated tropic responses in Arabidopsis thaliana.
Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, 16502, Prague, Czech Republic.; Functional Genomics and Proteomics of Plants, Central European Institute of Technology and National Centre for Biomolecular Research, Masaryk University, 62500, Brno, Czech Republic.; Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, 166 10, Prague, Czech Republic.; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052, Ghent, Belgium.; VIB Center for Plant Systems Biology, 9052, Ghent, Belgium.; Institute of Biotechnology, University of Helsinki, 00014, University of Helsinki, Finland.; Institute of Science and Technology (IST Austria), 3400, Klosterneuburg, Austria.
Advanced transcriptome sequencing has uncovered that the majority of eukaryotic genes undergo alternative splicing (AS). Nonetheless, little effort has been dedicated to investigating the functional relevance of particular splicing events, even those in the key developmental and hormonal regulators. Combining approaches of genetics, biochemistry and advanced confocal microscopy, we describe the impact of alternative splicing on the PIN7 gene in the plant model Arabidopsis thaliana. PIN7 encodes a polarly localized transporter for the phytohormone auxin and produces two evolutionary-conserved transcripts PIN7a and PIN7b. PIN7a and PIN7b, differing in a 4-amino acid motif, exhibit almost identical expression pattern and subcellular localization. We reveal that they closely associate and mutually influence their mobility within the plasma membrane. Phenotypic complementation tests indicate that the functional contribution of PIN7b per se is minor, but it markedly reduces the prominent PIN7a activity, which is required for correct seedling apical hook formation and auxin-mediated tropic responses. Our results establish alternative splicing of the PIN family as a conserved, functionally relevant mechanism, unveiling an additional regulatory level of auxin-mediated plant development.
PMID: 34637542
New Phytol , IF:10.151 , 2021 Oct doi: 10.1111/nph.17783
Abscisic acid employs NRP-dependent PIN2 vacuolar degradation to suppress auxin-mediated primary root elongation in Arabidopsis.
State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, 300071, China.; State Key Laboratory of Microbial Metabolism & Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
How plants balance growth and stress adaptation is a long-standing topic in plant biology. Abscisic acid (ABA) induces the expression of the stress-responsive Asparagine Rich Protein (NRP), which promotes the vacuolar degradation of PP6 phosphatase FyPP3, releasing ABI5 transcription factor to initiate transcription. Whether NRP is required for growth remains unknown. We generated an nrp1 nrp2 double mutant, which had a dwarf phenotype that can be rescued by inhibiting auxin transport. Insufficient auxin in the transition zone and over-accumulation of auxin at the root tip was responsible for the short elongation zone and short-root phenotype of nrp1 nrp2. The auxin efflux carrier PIN2 over-accumulated in nrp1 nrp2 and became de-polarized at the plasma membrane, leading to slower root basipetal auxin transport. Knock-out of PIN2 suppressed the dwarf phenotype of nrp1 nrp2. Furthermore, ABA can induce NRP-dependent vacuolar degradation of PIN2 to inhibit primary root elongation. FyPP3 also is required for NRP-mediated PIN2 turnover. In summary, in growth condition, NRP promotes PIN2 vacuolar degradation to help maintain PIN2 protein concentration and polarity, facilitating the establishment of the elongation zone and primary root elongation. When stressed, ABA employs this pathway to inhibit root elongation for stress adaptation.
PMID: 34618941
Plant Biotechnol J , IF:9.803 , 2021 Oct doi: 10.1111/pbi.13734
ZmTE1 promotes plant height by regulating intercalary meristem formation and internode cell elongation in maize.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, College of Life Sciences, Shandong University, 266237, Shandong, China.; School of Life Science, Anhui Agricultural University, Hefei, Anhui, 230036, China.; Maize Research Institute, Shandong Academy of Agricultural Sciences/National Engineering, Laboratory of Wheat and Maize/Key Laboratory of Biology and Genetic Improvement of Maize in Northern Yellow-huai River Plain, Ministry of Agriculture, Jinan, China.; College of Agronomy, Qingdao Agricultural University, Qingdao, 266109, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
Maize height is determined by the number of nodes and the length of internodes. Node number is driven by intercalary meristem formation and internode length by intercalary cell elongation respectively. However, mechanisms regulating establishment of nodes and internode growth is unclear. We screened EMS-induced maize mutants and identified a dwarf mutant zm66, linked to a single base change in TERMINAL EAR 1 (ZmTE1). Detailed phenotypic analysis revealed that zm66 (zmte1-2) has shorter internodes and increased node numbers, caused by decreased cell elongation and disordered intercalary meristem formation, respectively. Transcriptome analysis showed that auxin signaling genes are also dysregulated in zmte1-2, as are cell elongation and cell cycle-related genes. This argues that ZmTE1 regulates auxin signaling, cell division and cell elongation. We found that the ZmWEE1 kinase phosphorylates ZmTE1, thus confining it to the nucleus and probably reducing cell division. In contrast, the ZmPP2Ac-2 phosphatase promotes dephosphorylation and cytoplasmic localization of ZmTE1, as well as cell division. Taken together, ZmTE1, a key regulator of plant height, is responsible for maintaining organized formation of internode meristems and rapid cell elongation. ZmWEE1 and ZmPP2Ac-2 might balance ZmTE1 activity, controlling cell division and elongation to maintain normal maize growth.
PMID: 34687251
Plant Biotechnol J , IF:9.803 , 2021 Oct doi: 10.1111/pbi.13723
Strong and tunable anti-CRISPR/Cas activities in plants.
Instituto de Biologia Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Cientificas (CSIC), Universitat Politecnica de Valencia, Camino de Vera s/n, 46022, Valencia, Spain.
CRISPR/Cas has revolutionized genome engineering in plants. However, the use of anti-CRISPR proteins as tools to prevent CRISPR/Cas-mediated gene editing and gene activation in plants has not been explored yet. This study describes the characterization of two anti-CRISPR proteins, AcrIIA4 and AcrVA1, in Nicotiana benthamiana. Our results demonstrate that AcrIIA4 prevents site-directed mutagenesis in leaves when transiently co-expressed with CRISPR/Cas9. In a similar way, AcrVA1 is able to prevent CRISPR/Cas12a mediated gene editing. Moreover, using a N. benthamiana line constitutively expressing Cas9 we show that the viral delivery of AcrIIA4 using Tobacco etch virus (TEV) is able to completely abolish the high editing levels obtained when the guide RNA is delivered with a virus, in this case Potato virus X (PVX). We also show that AcrIIA4 and AcrVA1 repress CRISPR/dCas-based transcriptional activation (CRISPRa) of reporter genes. In the case of AcrIIA4, this repression occurs in a highly efficient, dose-dependent manner. Furthermore, the fusion of an auxin degron to AcrIIA4 results in auxin-regulated activation of a downstream reporter gene. The strong anti-Cas activity of AcrIIA4 and AcrVA1 reported here opens new possibilities for customized control of gene editing and gene expression in plants.
PMID: 34632687
Plant Physiol , IF:8.34 , 2021 Oct doi: 10.1093/plphys/kiab486
Origin and adaptive evolution of UV RESISTANCE LOCUS 8-mediated signaling during plant terrestrialization.
College of Life Sciences, Nanjing Normal University, 210023 Nanjing, China.; National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, 200032 Shanghai, China.
UV RESISTANCE LOCUS 8 (UVR8) mediates photomorphogenic responses and acclimation to UV-B radiation by regulating the transcription of a series of transcription factors. However, the origin and evolution of UVR8-mediated signaling pathways remain largely unknown. In this study, we investigated the origin and evolution of the major components of the UVR8-mediated signaling pathway (UVR8, REPRESSOR OF UV-B PHOTOMORPHOGENESIS (RUP), BRI1-EMS-SUPPRESSOR1 (BES1), BES1-INTERACTING MYC-LIKE 1 (BIM1), WRKY DNA-BINDING PROTEIN 36 (WRKY36), MYB DOMAIN PROTEIN 73/77/13 (MYB73/MYB77/MYB13), and PHYTOCHROME INTERACTING FACTOR 4/5 (PIF4 and PIF5)) using comparative genomics and phylogenetic approaches. We showed that the central regulator UVR8 presented a conservative evolutionary route during plant evolution, and the evolutionary history of downstream negative regulators and transcription factors was different from that of green plant phylogeny. The canonical UVR8-COP1/SPA-HY5-RUP signaling pathway originated in chlorophytes and conferred green algae the additional ability to cope with UV-B radiation. Moreover, the emergence of multiple UVR8-mediated signaling pathways in charophytes laid the foundations for the cross-talk between UV-B signals and endogenous hormone responses. Importantly, we observed signatures that reflect plant adaptations to high UV-B irradiance in subaerial/terrestrial environments, including positive selection in UVR8 and RUPs and increased copy number of some vital transcription factors. These results revealed that green plants not only experienced adaptive modifications in the canonical UVR8-COP1/SPA-HY5-RUP signaling pathway, but also diversified their UV-B signal transduction mechanisms through increasing cross-talk with other pathways, such as those associated with brassinosteroids and auxin. This study greatly expands our understanding of molecular evolution and adaptive mechanisms underlying plant UV-B acclimation.
PMID: 34662425
Plant Physiol , IF:8.34 , 2021 Oct doi: 10.1093/plphys/kiab472
Potassium transporter TRH1/KUP4 contributes to distinct auxin-mediated root system architecture responses.
Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.; Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 61 Uppsala, Sweden.; Umea Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden.; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, GR 70 013 Heraklion, Crete, Greece.; Department of Biology, University of Crete, GR 71 500 Heraklion, Crete, Greece.
In plants, auxin transport and development are tightly coupled, just as hormone and growth responses are intimately linked in multicellular systems. Here we provide insights into uncoupling this tight control by specifically targeting the expression of TINY ROOT HAIR 1 (TRH1), a member of plant HAK/KUP/KT transporters that facilitate potassium uptake by co-transporting protons, in Arabidopsis root cell files. Use of this system pinpointed specific root developmental responses to acropetal versus basipetal auxin transport. Loss of TRH1 function shows tiny root hairs and defective root gravitropism, associated with auxin imbalance in the root apex. Cell file-specific expression of TRH1 in the central cylinder rescued trh1 root agravitropism, whereas positional TRH1 expression in peripheral cell layers, including epidermis and cortex, restored trh1 root hair defects. Applying a systems-level approach, the role of RAP2.11 and RSL5 transcription factors in root hair development was verified. Furthermore, ERF53 and WRKY51 transcription factors were overrepresented upon restoration of root gravitropism supporting involvement in gravitropic control. Auxin has a central role in shaping root system architecture by regulating multiple developmental processes. We reveal that TRH1 jointly modulates intracellular ionic gradients and cell-to-cell polar auxin transport to drive root epidermal cell differentiation and gravitropic response. Our results indicate the developmental importance of HAK/KUP/KT proton-coupled K+ transporters.
PMID: 34633458
Plant Physiol , IF:8.34 , 2021 Oct doi: 10.1093/plphys/kiab455
HYPONASTIC LEAVES 1 is required for proper establishment of auxin gradient in apical hooks.
Instituto de Biologia Molecular y Celular de Rosario, CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Argentina.
PMID: 34601613
Curr Opin Plant Biol , IF:7.834 , 2021 Oct , V65 : P102117 doi: 10.1016/j.pbi.2021.102117
Integration of nutrient and water availabilities via auxin into the root developmental program.
Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany.; Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466, Stadt Seeland, OT Gatersleben, Germany. Electronic address: vonwiren@ipk-gatersleben.de.
In most soils, the spatial distribution of nutrients and water in the rooting zone of plants is heterogeneous and changes over time. To access localized resources more efficiently, plants induce foraging responses by modulating individual morphological root traits, such as the length of the primary root or the number and length of lateral roots. These adaptive responses require the integration of exogenous and endogenous nutrient- or water-related signals into the root developmental program. Recent studies corroborated a central role of auxin in shaping root architectural traits in response to fluctuating nutrient and water availabilities. In this review, we highlight current knowledge on nutrient- and water-related developmental processes that impact root foraging and involve auxin as a central player. A deeper understanding and exploitation of these auxin-related processes and mechanisms promises advances in crop breeding for higher resource efficiency.
PMID: 34624806
Plant Cell Environ , IF:7.228 , 2021 Oct doi: 10.1111/pce.14210
Auxin-mediated regulation of arbuscular mycorrhizal symbiosis: A role of SlGH3.4 in tomato.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China.; Guangdong Key Laboratory for New Technology Research of Vegetables, Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, China.; Zhejiang Institute of Subtropical Crops, Zhejiang Academy of Agricultural Sciences, Wenzhou, Zhejiang, China.; Key Laboratory of Tobacco Genetic Improvement and Biotechnology, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266100, China.; Nanjing Institute of Vegetable Science, Nanjing, China.; Suzhou Polytechnic Institute of Agriculture, Suzhou, 215008, China.
Most land plants can establish symbiosis with arbuscular mycorrhizal (AM) fungi to increase fitness to environmental challenges. Development of AM symbiosis is controlled by intricate procedures involving all phytohormones. However, the mechanisms underlying the auxin-mediated regulation of AM symbiosis remains largely unknown. Here, we report that AM colonization promotes auxin response and IAA accumulation, but down-regulates IAA biosynthesis genes in tomato (Solanum lycopersicum). External IAA application modulates the AM symbiosis by promoting arbuscule formation at low concentrations but repressing it at high concentrations. An AM-induced GH3 gene, SlGH3.4, encoding a putative IAA-amido synthetase, negatively regulates mycorrhization via maintaining cellular auxin homeostasis. Loss of SlGH3.4 function increased free IAA content and arbuscule incidence, while constitutively overexpressing SlGH3.4 in either tomato or rice resulted in decreased IAA content, total colonization level and arbuscule abundance in mycorrhizal roots. Several auxin-inducible expansin genes involved in AM formation or resistance to pathogen infection were upregulated in slgh3.4 mycorrhizal roots, but downregulated in the SlGH3.4-overexpressing plants. Taken together, our results highlight a positive correlation between the endogenous IAA content and mycorrhization level, particularly arbuscule incidence, and suggest that the SlGH3.4-mediated auxin homeostasis and regulation of expansin genes is involved in finely tuning the AM development. This article is protected by copyright. All rights reserved.
PMID: 34713922
J Exp Bot , IF:6.992 , 2021 Oct doi: 10.1093/jxb/erab455
Laying it on thick: A study in secondary growth.
Department of Biosciences, Durham University, South Road, Durham.; The Sainsbury Laboratory, Norwich Research Park, Norwich.
The development of secondary vascular tissue enhances the transport capacity and mechanical strength of plant bodies, while contributing a huge proportion of the world's biomass in the form of wood. Cell divisions in the cambium, which constitutes the vascular meristem, provide progenitors from which conductive xylem and phloem are derived. The cambium is a somewhat unusual stem cell population in two respects, making it an interesting subject for developmental research. Firstly, it arises post-germination, and thus represents a model for understanding stem cell initiation beyond embryogenesis. Secondly, xylem and phloem differentiate on opposing sides of cambial stem cells, making them bifacial in nature. Recent discoveries in Arabidopsis thaliana have provided insight into the molecular mechanisms that regulate the initiation, patterning, and maintenance of the cambium. In this review, the roles of intercellular signalling via mobile transcription factors, peptide-receptor modules and phytohormones are described. Cross-talk between these regulatory pathways is becoming increasingly apparent, yet the underlying mechanisms are not fully understood. Future study of the interaction between multiple independently identified regulators, as well as the functions of their orthologs in trees, is needed to deepen our understanding of radial growth in plants.
PMID: 34655214
J Exp Bot , IF:6.992 , 2021 Oct , V72 (20) : P6977-6989 doi: 10.1093/jxb/erab357
The wheat SHORT ROOT LENGTH 1 gene TaSRL1 controls root length in an auxin-dependent pathway.
College of Agronomy, Henan Agricultural University, Zhengzhou, China.; National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
The root is the main organ for water and nutrient uptake and sensing environmental stimuli in the soil. The optimization of root system architecture contributes to stress tolerance and yield improvement. ERF (ETHYLENE RESPONSIVE FACTOR) is one of the plant-specific transcription factor families associated with various developmental processes and stress tolerance. We cloned a novel ERF transcription factor gene TaSRL1 (SHORT ROOT LENGTH 1) from wheat (Triticum aestivum) which is mainly expressed in root. Ectopic expression of TaSRL1 in rice resulted in short root length and plant height. TaSRL1 regulated expression of genes related to auxin synthesis, transport, and signaling. Further studies revealed that TaSRL1 induced expression of the auxin transport gene TaPIN2 by directly binding to its promoter, while the interaction of TaSRL1 and TaTIFY9 repressed TaPIN2 expression. Sequence polymorphisms and association analysis showed that TaSRL1-4A was associated with root depth and angle, plant height, and 1000-grain weight of wheat. The haplotype Hap-4A-2 with shallow roots, short plant height, and high 1000-grain weight has been positively selected in the Chinese wheat breeding process. We demonstrated that TaSRL1 functions as a direct regulator of TaPIN2 in the auxin-dependent pathway, and integrates auxin and jasmonate signaling by interacting with TaTIFY9 to repress root growth. Furthermore, the molecular marker of TaSRL1-4A is valuable for the improvement of the root system, plant architecture, and yield in the wheat breeding process.
PMID: 34328188
J Exp Bot , IF:6.992 , 2021 Oct , V72 (19) : P6739-6745 doi: 10.1093/jxb/erab319
The quiescent center and root regeneration.
The Institute of Plant Sciences, Faculty of Agriculture, The Hebrew University, Rehovot, Israel.
Since its discovery by F.A.L Clowes, extensive research has been dedicated to identifying the functions of the quiescent center (QC). One of the earliest hypotheses was that it serves a key role in regeneration of the root meristem. Recent works provided support for this hypothesis and began to elucidate the molecular mechanisms underlying this phenomenon. There are two scenarios to consider when assessing the role of the QC in regeneration: one, when the damage leaves the QC intact; and the other, when the QC itself is destroyed. In the first scenario, multiple factors are recruited to activate QC cell division in order to replace damaged cells, but whether the QC has a role in the second scenario is less clear. Both using gene expression studies and following the cell division pattern have shown that the QC is assembled gradually, only to appear as a coherent identity late in regeneration. Similar late emergence of the QC was observed during the de novo formation of the lateral root meristem. These observations can lead to the conclusion that the QC has no role in regeneration. However, activities normally occurring in QC cells, such as local auxin biosynthesis, are still found during regeneration but occur in different cells in the regenerating meristem. Thus, we explore an alternative hypothesis, that following destruction of the QC, QC-related gene activity is temporarily distributed to other cells in the regenerating meristem, and only coalesce into a distinct cell identity when regeneration is complete.
PMID: 34324634
J Exp Bot , IF:6.992 , 2021 Oct , V72 (20) : P7092-7106 doi: 10.1093/jxb/erab351
The transcription factor PagLBD3 contributes to the regulation of secondary growth in Populus.
College of Forestry, State Forestry and Grassland Administration Key Laboratory of Silviculture in downstream areas of the Yellow River, Shandong Agriculture University, Taian, Shandong 271018, China.; College of Life Science, State Key Laboratory of Crop Biology, Shandong Agriculture University, Taian, Shandong 271018, China.; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
LATERAL ORGAN BOUNDARIES DOMAIN (LBD) genes encode plant-specific transcription factors that participate in regulating various developmental processes. In this study, we genetically characterized PagLBD3 encoding an important regulator of secondary growth in poplar (Populus alba x Populus glandulosa). Overexpression of PagLBD3 increased stem secondary growth in Populus with a significantly higher rate of cambial cell differentiation into phloem, while dominant repression of PagLBD3 significantly decreased the rate of cambial cell differentiation into phloem. Furthermore, we identified 1756 PagLBD3 genome-wide putative direct target genes (DTGs) through RNA sequencing (RNA-seq)-coupled DNA affinity purification followed by sequencing (DAP-seq) assays. Gene Ontology analysis revealed that genes regulated by PagLBD3 were enriched in biological pathways regulating meristem development, xylem development, and auxin transport. Several central regulator genes for vascular development, including PHLOEM INTERCALATED WITH XYLEM (PXY), WUSCHEL RELATED HOMEOBOX4 (WOX4), Secondary Wall-Associated NAC Domain 1s (SND1-B2), and Vascular-Related NAC-Domain 6s (VND6-B1), were identified as PagLBD3 DTGs. Together, our results indicate that PagLBD3 and its DTGs form a complex transcriptional network to modulate cambium activity and phloem/xylem differentiation.
PMID: 34313722
J Exp Bot , IF:6.992 , 2021 Oct , V72 (20) : P7002-7019 doi: 10.1093/jxb/erab311
Two citrus KNAT-like genes, CsKN1 and CsKN2, are involved in the regulation of spring shoot development in sweet orange.
Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, China.; College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.; Institute of Pomology and Tea, Hubei Academy of Agricultural Sciences, Wuhan, China.
Shoot-tip abortion is a very common phenomenon in some perennial woody plants and it affects the height, architecture, and branch orientation of trees; however, little is currently known about the underlying mechanisms. In this study, we identified a gene in sweet orange (Citrus sinensis) encoding a KNAT-like protein (CsKN1) and found high expression in the shoot apical meristem (SAM). Overexpression of CsKN1 in transgenic plants prolonged the vegetative growth of SAMs, whilst silencing resulted in either the loss or inhibition of SAMs. Yeast two-hybrid analysis revealed that CsKN1 interacted with another citrus KNAT-like protein (CsKN2), and overexpression of CsKN2 in lemon and tobacco caused an extreme multiple-meristem phenotype. Overexpression of CsKN1 and CsKN2 in transgenic plants resulted in the differential expression of numerous genes related to hormone biosynthesis and signaling. Yeast one-hybrid analysis revealed that the CsKN1-CsKN2 complex can bind to the promoter of citrus floral meristem gene LEAFY (CsLFY) and inhibit its expression. These results indicated that CsKN1 might prolong the vegetative growth period of SAMs by delaying flowering. In addition, an ethylene-responsive factor (CsERF) was found to bind to the CsKN1 promoter and suppresses its transcription. Overexpression of CsERF in Arabidopsis increased the contents of ethylene and reactive oxygen species, which might induce the occurrence of shoot-tip abscission. On the basis of our results, we conclude that CsKN1 and CsKN2 might work cooperatively to regulate the shoot-tip abscission process in spring shoots of sweet orange.
PMID: 34185082
J Exp Bot , IF:6.992 , 2021 Oct , V72 (19) : P6727-6738 doi: 10.1093/jxb/erab272
Root stem cell niche networks: it's complexed! Insights from Arabidopsis.
Wageningen University & Research, Plant Sciences department, Plant Developmental Biology group, Droevendaalsesteeg 1, 6708PB Wageningen, Netherlands.
The presence of two meristematic cell populations in the root and shoot apex allows plants to grow indefinitely. Due to its simple and predictable tissue organization, the Arabidopsis root apical meristem remains an ideal model to study mechanisms such as stem cell specification, asymmetric cell division, and differentiation in plants. The root stem cell niche consists of a quiescent organizing centre surrounded by mitotically active stem cells, which originate all root tissues. The transcription factors PLETHORA, SCARECROW, and WOX5 form signalling hubs that integrate multiple inputs from an increasing number of proteins implicated in the regulation of stem cell niche function. Recently, locally produced auxin was added to the list of important mobile factors in the stem cell niche. In addition, protein-protein interaction data elegantly demonstrate how parallel pathways can meet in a common objective. Here we discuss how multiple networks converge to specify and maintain the root stem cell niche.
PMID: 34173817
J Exp Bot , IF:6.992 , 2021 Oct , V72 (19) : P6746-6754 doi: 10.1093/jxb/erab274
Mechanisms of stress response in the root stem cell niche.
Institute of Cytology and Genetics, Novosibirsk, Russia.; Novosibirsk State University, Novosibirsk, Russia.; Department of Plant Systems Physiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
As plants are sessile organisms unable to escape from environmental hazards, they need to adapt for survival. The stem cell niche in the root apical meristem is particularly sensitive to DNA damage induced by environmental stresses such as chilling, flooding, wounding, UV, and irradiation. DNA damage has been proven to cause stem cell death, with stele stem cells being the most vulnerable. Stress also induces the division of quiescent center cells. Both reactions disturb the structure and activity of the root stem cell niche temporarily; however, this preserves root meristem integrity and function in the long term. Plants have evolved many mechanisms that ensure stem cell niche maintenance, recovery, and acclimation, allowing them to survive in a changing environment. Here, we provide an overview of the cellular and molecular aspects of stress responses in the root stem cell niche.
PMID: 34111279
Plant J , IF:6.417 , 2021 Oct doi: 10.1111/tpj.15541
TaIAA21 represses TaARF25-mediated expression of TaERFs required for grain size and weight development in wheat.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Auxin signaling is essential for the development of grain size and grain weight, two important components for crop yield. However, no AUX/IAA has been functionally characterized to be involved in the development of wheat grains to date. Here, we identified a wheat AUX/IAA gene, TaIAA21, and studied its regulatory pathway. We found that TaIAA21 mutation significantly increased grain length, grain width, and grain weight. Cross-section of mutant grains observed elongated outer pericarp cells than those of the wild type where the expression of TaIAA21 was detected by in situ hybridization. Screening of auxin response factor (ARF) genes highly expressed in early developing grains identified TaARF25 that interacted with TaIAA21. In contrast, mutation of the tetraploid wheat (Triticum turgidum) ARF25 gene significantly reduced grain size and weight. RNA-seq analysis revealed up-regulation of several ethylene response factor genes (ERFs) in taiaa21 mutants which carried AuxRE cis-elements in their promoter. One of them, ERF3, was up-regulated in the taiaa21 mutant and down-regulated in ttarf25 mutant. Transactivation assays showed that ARF25 promoted ERF3 transcription, while mutation of TtERF3 resulted in reduced grain size and weight. Analysis of natural variations identified three TaIAA21-A haplotypes with increased allele frequency in cultivars relative to landraces, a signature of breeding selection. Our work demonstrated that TaIAA21 worked as a negative regulator in grain size and weight development via the ARF25-ERFs module and is useful for yield improvement in wheat.
PMID: 34643010
Plant J , IF:6.417 , 2021 Oct doi: 10.1111/tpj.15527
SDG128 is involved in maize leaf inclination.
National Engineering Laboratory of Crop Stress Resistance/Key Laboratory of Crop Biology of Anhui Province, School of Life Sciences, Anhui Agricultural University, Hefei, 230036, China.; Hefei National Laboratory for Physical Sciences at the Microscale, Division of Molecular Cell Biophysics, Chinese Academy of Sciences (CAS) Center for Excellence in Molecular Plant Sciences, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Anhui, 230027, China.; Anhui Forestry High-Tech Development Center, Hefei, Anhui, 230041, China.
Maize leaf angle (LA) is a complex quantitative trait that is controlled by developmental signals, hormones, and environmental factors. However, the connection between histone methylation and LAs in maize remains unclear. Here, we reported that SET domain protein 128 (SDG128) is involved in leaf inclination in maize. Knockdown of SDG128 using an RNA interference approach resulted in an expanded architecture, less large vascular bundles, more small vascular bundles, and larger spacing of large vascular bundles in the auricles. SDG128 interacts with ZmGID2 both in vitro and in vivo. Knockdown of ZmGID2 also showed a larger LA with less large vascular bundles and larger spacing of vascular bundles. In addition, the transcription level of cell wall expansion family genes ZmEXPA1, ZmEXPB2, and GRMZM2G005887; transcriptional factor genes Lg1, ZmTAC1, and ZmCLA4; and auxin pathway genes ZmYUCCA7, ZmYUCCA8, and ZmARF22 was reduced in SDG128 and ZmGID2 knockdown plants. SDG128 directly targets ZmEXPA1, ZmEXPB2, LG1, and ZmTAC1 and is required for H3K4me3 deposition at these genes. Together, the results of the present study suggest that SDG128 and ZmGID2 are involved in the maize leaf inclination.
PMID: 34612535
Int J Mol Sci , IF:5.923 , 2021 Oct , V22 (20) doi: 10.3390/ijms222011296
Biological Control of Leaf Blight Disease Caused by Pestalotiopsis maculans and Growth Promotion of Quercus acutissima Carruth Container Seedlings Using Bacillus velezensis CE 100.
Department of Forest Resources, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea.; Division of Agricultural and Biological Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea.; Forest Technology and Management Research Center, National Institute of Forest Science, Pocheon-si 11186, Korea.
Leaf blight disease caused by Pestalotiopsismaculans lead to deleterious losses in the quality of forest container seedlings. The use of plant growth-promoting bacteria provides a promising strategy to simultaneously control diseases and enhance forest seedling production. This study investigated the biocontrol of leaf blight disease and growth promotion potential of Bacillus velezensis CE 100 in Quercus acutissima Carruth seedlings. B. velezensis CE 100 produced cell wall degrading enzymes, such as chitinase, beta-l,3-glucanase, and protease, which caused cell wall lysis and hyphae deformation of P. maculans, leading to mycelial growth inhibition by 54.94%. Inoculation of B. velezensis CE 100 suppressed P. maculans infection and increased seedling survival rate by 1.6-fold and 1.3-fold compared to chemical fertilizer and control, respectively. In addition, B. velezensis CE 100 produced indole-3-acetic acid, which improved root development and nutrient uptake compared to chemical fertilizer and control. Especially, inoculation with B. velezensis CE 100 increased the total nitrogen content of Q. acutissima seedlings, improved the chlorophyll index in the leaves, and increased seedling biomass by 1.3-fold and 2.2-fold compared to chemical fertilizer and control, respectively. Thus, B. velezensis CE 100 could be applied in the eco-friendly production of high-quality forest seedlings.
PMID: 34681955
Int J Mol Sci , IF:5.923 , 2021 Oct , V22 (20) doi: 10.3390/ijms222011132
BolTLP1, a Thaumatin-like Protein Gene, Confers Tolerance to Salt and Drought Stresses in Broccoli (Brassica oleracea L. var. Italica).
Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.; College of Horticulture and Landscape, Tianjin Agricultural University, Tianjin 300384, China.; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.; State Key Laboratory of Vegetable Germplasm Innovation, Tianjin Academy of Agricultural Sciences, Tianjin 300381, China.
Plant thaumatin-like proteins (TLPs) play pleiotropic roles in defending against biotic and abiotic stresses. However, the functions of TLPs in broccoli, which is one of the major vegetables among the B. oleracea varieties, remain largely unknown. In the present study, bolTLP1 was identified in broccoli, and displayed remarkably inducible expression patterns by abiotic stress. The ectopic overexpression of bolTLP1 conferred increased tolerance to high salt and drought conditions in Arabidopsis. Similarly, bolTLP1-overexpressing broccoli transgenic lines significantly improved tolerance to salt and drought stresses. These results demonstrated that bolTLP1 positively regulates drought and salt tolerance. Transcriptome data displayed that bolTLP1 may function by regulating phytohormone (ABA, ethylene and auxin)-mediated signaling pathways, hydrolase and oxidoreductase activity, sulfur compound synthesis, and the differential expression of histone variants. Further studies confirmed that RESPONSE TO DESICCATION 2 (RD2), RESPONSIVE TO DEHYDRATION 22 (RD22), VASCULAR PLANT ONE-ZINC FINGER 2 (VOZ2), SM-LIKE 1B (LSM1B) and MALATE DEHYDROGENASE (MDH) physically interacted with bolTLP1, which implied that bolTLP1 could directly interact with these proteins to confer abiotic stress tolerance in broccoli. These findings provide new insights into the function and regulation of bolTLP1, and suggest potential applications for bolTLP1 in breeding broccoli and other crops with increased tolerance to salt and drought stresses.
PMID: 34681789
Int J Mol Sci , IF:5.923 , 2021 Oct , V22 (20) doi: 10.3390/ijms222010935
Stage Specificity, the Dynamic Regulators and the Unique Orchid Arundina graminifolia.
Guangdong Key Laboratory of Ornamental Plant Germplasm Innovation and Utilization, Environmental Horticulture Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China.
Orchids take years to reach flowering, but the unique bamboo orchid (Arundina graminifolia) achieves reproductive maturity in six months and then keeps on year round flowering. Therefore, studying different aspects of its growth, development and flowering is key to boost breeding programs for orchids. This study uses transcriptome tools to discuss genetic regulation in five stages of flower development and four tissue types. Stage specificity was focused to distinguish genes specifically expressed in different stages of flower development and tissue types. The top 10 highly expressed genes suggested unique regulatory patterns for each stage or tissue. The A. graminifolia sequences were blasted in Arabidopsis genome to validate stage specific genes and to predict important hormonal and cell regulators. Moreover, weighted gene co-expression network analysis (WGCNA) modules were ascertained to suggest highly influential hubs for early and late stages of flower development, leaf and root. Hormonal regulators were abundant in all data sets, such as auxin (LAX2, GH3.1 and SAUR41), cytokinin (LOG1), gibberellin (GASA3 and YAB4), abscisic acid (DPBF3) and sucrose (SWEET4 and SWEET13). Findings of this study, thus, give a fine sketch of genetic variability in Orchidaceae and broaden our understanding of orchid flower development and the involvement of multiple pathways.
PMID: 34681593
Int J Mol Sci , IF:5.923 , 2021 Oct , V22 (19) doi: 10.3390/ijms221910760
Auxin Treatment Enhances Anthocyanin Production in the Non-Climacteric Sweet Cherry (Prunus avium L.).
Adelaide Glycomics, Waite Campus, School of Agriculture, Food and Wine, University of Adelaide, Adelaide, SA 5064, Australia.; Commonwealth Scientific and Industrial Research Organisation (CSIRO), Waite Campus, Glen Osmond, SA 5064, Australia.; Agilent Technologies Australia Pty Ltd., Mulgrave, Melbourne, VIC 3170, Australia.; Department of Chemistry, Division of Glycoscience, Royal Institute of Technology (KTH), School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Centre, 10691 Stockholm, Sweden.
Abscisic acid (ABA) is a key signaling molecule promoting ripening of non-climacteric fruits such as sweet cherry (Prunus avium L.). To shed light on the role of other hormones on fruit development, ripening and anthocyanin production, the synthetic auxin 1-naphthaleneacetic acid (NAA) was applied to sweet cherry trees during the straw-color stage of fruit development. NAA-treated fruits exhibited higher concentrations of 1-aminocyclopropane-1-carboxylic acid (ACC) and ABA-glucose ester (ABA-GE), which are a precursor of ethylene and a primary storage form of ABA, respectively. Consistent with these observations, transcript levels of genes encoding ACC synthase and ACC oxidase, both involved in ethylene biosynthesis, were increased after 6 days of NAA treatment, and both ABA concentration and expression of the regulator gene of ABA biosynthesis (NCED1 encoding 9-cis-epoxycarotenoid dioxygenase) were highest during early fruit ripening. In addition, transcript levels of key anthocyanin regulatory, biosynthetic and transport genes were significantly upregulated upon fruit exposure to NAA. This was accompanied by an increased anthocyanin concentration and fruit weight whilst fruit firmness and cracking index decreased. Altogether our data suggest that NAA treatment alters ethylene production, which in turn induces ripening in sweet cherry and enhanced anthocyanin production, possibly through ABA metabolism. The results from our study highlight the potential to use a single NAA treatment for manipulation of cherry ripening.
PMID: 34639100
Front Plant Sci , IF:5.753 , 2021 , V12 : P701633 doi: 10.3389/fpls.2021.701633
Transcriptome Analysis Reveals the Senescence Process Controlling the Flower Opening and Closure Rhythm in the Waterlilies (Nymphaea L.).
Key Laboratory of Ministry of Education for Genetics and Germplasm Innovation of Tropical Special Trees and Ornamental Plants, Key Laboratory of Germplasm Resources Biology of Tropical Special Ornamental Plants of Hainan Province, College of Forestry, Hainan University, Haikou, China.; Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China.; Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Plant Science Research Centre, Chinese Academy of Sciences, Shanghai Chenshan Botanical Garden, Shanghai, China.
Most waterlily flowers open at dawn and close after noon usually for three to four days, and thereafter wilt. The short lifespan of flowers restricts the development of the flower postharvest industry. The termination of flower movements is a key event during flower aging process. However, it is still unclear when the senescence process initiates and how it terminates the movement rhythm. In this study, we observed that the opening diameter of flowers was the smallest on the fourth (last) flowering day. Subsequent transcriptome profiles generated from petals at different flowering stages showed that the multiple signaling pathways were activated at the last closure stage (Time 3, T3) of the flowers, including Ca(2+), reactive oxygen species and far red light signaling pathways, as well as auxin, ethylene and jasmonic acid signaling pathways. Moreover, In terms of cell metabolism regulation, the genes related to hydrolase (protease, phospholipase, nuclease) were upregulated at T3 stage, indicating that petals entered the senescence stage at that time; and the genes related to water transport and cell wall modification were also differentially regulated at T3 stage, which would affect the ability of cell expand and contract, and eventually lead to petal not open after the fourth day. Collectively, our data provided a new insight into the termination of flower opening in the waterlilies, and a global understanding of the senescence process of those opening-closure rhythm flowers.
PMID: 34671367
Theor Appl Genet , IF:5.699 , 2021 Oct doi: 10.1007/s00122-021-03960-6
SbbHLH85, a bHLH member, modulates resilience to salt stress by regulating root hair growth in sorghum.
Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, 250014, China.; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.; Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, 271018, China.; Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, 250014, China. suina@sdnu.edu.cn.
bHLH family proteins play an important role in plant stress response. However, the molecular mechanism regulating the salt response of bHLH is largely unknown. This study aimed to investigate the function and regulating mechanism of the sweet sorghum SbbHLH85 during salt stress. The results showed that SbbHLH85 was different from its homologs in other species. Also, it was a new atypical bHLH transcription factor and a key gene for root development in sweet sorghum. The overexpression of SbbHLH85 resulted in significantly increased number and length of root hairs via ABA and auxin signaling pathways, increasing the absorption of Na(+). Thus, SbbHLH85 plays a negative regulatory role in the salt tolerance of sorghum. We identified a potential interaction partner of SbbHLH85, which was phosphate transporter chaperone PHF1 and modulated the distribution of phosphate, through screening a yeast two-hybrid library. Both yeast two-hybrid and BiFC experiments confirmed the interaction between SbbHLH85 and PHF1. The overexpression of SbbHLH85 led to a decrease in the expression of PHF1 as well as the content of Pi. Based on these results, we suggested that the increase in the Na(+) content and the decrease in the Pi content resulted in the salt sensitivity of transgenic sorghum.
PMID: 34633473
Theor Appl Genet , IF:5.699 , 2021 Oct doi: 10.1007/s00122-021-03953-5
Pinpointing genomic regions associated with root system architecture in rice through an integrative meta-analysis approach.
Department of Agronomy & Plant Breeding, University of Mohaghegh Ardabili, Ardabil, Iran.; Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), 31535-1897, Karaj, Iran.; Department of Molecular Physiology, Agricultural Biotechnology Research Institute of Iran, Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.; Department of Agronomy & Plant Breeding, University of Mohaghegh Ardabili, Ardabil, Iran. sdezhsetan@uma.ac.ir.; Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia.; Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), 31535-1897, Karaj, Iran. shobbar@abrii.ac.ir.
KEY MESSAGE: Applying an integrated meta-analysis approach led to identification of meta-QTLs/ candidate genes associated with rice root system architecture, which can be used in MQTL-assisted breeding/ genetic engineering of root traits. Root system architecture (RSA) is an important factor for facilitating water and nutrient uptake from deep soils and adaptation to drought stress conditions. In the present research, an integrated meta-analysis approach was employed to find candidate genes and genomic regions involved in rice RSA traits. A whole-genome meta-analysis was performed for 425 initial QTLs reported in 34 independent experiments controlling RSA traits under control and drought stress conditions in the previous twenty years. Sixty-four consensus meta-QTLs (MQTLs) were detected, unevenly distributed on twelve rice chromosomes. The confidence interval (CI) of the identified MQTLs was obtained as 0.11-14.23 cM with an average of 3.79 cM, which was 3.88 times narrower than the mean CI of the original QTLs. Interestingly, 52 MQTLs were co-located with SNP peak positions reported in rice genome-wide association studies (GWAS) for root morphological traits. The genes located in these RSA-related MQTLs were detected and explored to find the drought-responsive genes in the rice root based on the RNA-seq and microarray data. Multiple RSA and drought tolerance-associated genes were found in the MQTLs including the genes involved in auxin biosynthesis or signaling (e.g. YUCCA, WOX, AUX/IAA, ARF), root angle (DRO1-related genes), lateral root development (e.g. DSR, WRKY), root diameter (e.g. OsNAC5), plant cell wall (e.g. EXPA), and lignification (e.g. C4H, PAL, PRX and CAD). The genes located within both the SNP peak positions and the QTL-overview peaks for RSA are suggested as novel candidate genes for further functional analysis. The promising candidate genes and MQTLs can be used as basis for genetic engineering and MQTL-assisted breeding of root phenotypes to improve yield potential, stability and performance in a water-stressed environment.
PMID: 34623472
Plant Cell Physiol , IF:4.927 , 2021 Oct doi: 10.1093/pcp/pcab155
Auxin-Responsive (phospho)proteome Analysis Reveals Key Biological Processes and Signaling Associated with Shoot-Borne Crown Root Development in Rice.
Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, Uttarakhand, India.; Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium.; VIB Center for Plant Systems Biology, 9052 Ghent, Belgium.
The rice root system is primarily composed of shoot-borne adventitious/crown roots (AR/CR) that develop from the coleoptile base, therefore is an excellent model system for studying shoot-to-root trans-differentiation process. We reveal global changes in protein and metabolite abundance, and protein phosphorylation in response to an auxin stimulus during CR development. The LC-MS/MS and GC-MS analyses of developing crown root primordia (CRP) and emerged CRs identified 334 proteins and 12 amino acids, respectively, that were differentially regulated upon auxin treatment. Gene ontology (GO) enrichment analysis of global proteome data uncovered the biological processes associated with chromatin conformational change, gene expression, and cell cycle that were regulated by auxin signaling. Spatial gene expression pattern analysis of differentially abundant proteins disclosed their stage-specific dynamic expression pattern during CRP development. Further, our tempo-spatial gene expression and functional analyses revealed that auxin creates a regulatory module during CRP development and activates ethylene biosynthesis exclusively during CRP initiation. Further, the phosphoproteome analysis identified 8,220 phosphosites, which could be mapped to 1,594 phosphoproteins and of which 66 phosphosites were differentially phosphorylated upon auxin treatment. Importantly, we observed differential phosphorylation of the Cyclin-dependent kinase G-2 (OsCDKG;2), and cell wall proteins, in response to auxin signaling, suggesting that auxin-dependent phosphorylation may be required for cell cycle activation, and cell wall synthesis during root organogenesis. Thus, our study provides evidence for the translational and post-translational regulation during CR development downstream of the auxin signaling pathway.
PMID: 34679169
Biomolecules , IF:4.879 , 2021 Oct , V11 (10) doi: 10.3390/biom11101513
Cytokinin-Based Tissue Cultures for Stable Medicinal Plant Production: Regeneration and Phytochemical Profiling of Salvia bulleyana Shoots.
Department of Biology and Pharmaceutical Botany, Medical University of Lodz, 90-151 Lodz, Poland.; Department of Molecular Biotechnology and Genetics, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland.; Department of Pharmacognosy, Medical University of Lodz, 90-151 Lodz, Poland.
Salvia bulleyana is a rare Chinese medicinal plant that due to the presence of polyphenols lowers the risk of some chronic diseases especially those related to the cardiovascular system. The present study examines the organogenic competence of various combinations and concentrations of plant growth regulators to develop an efficient protocol for in vitro regeneration of S. bulleyana via leaf explants, maintaining the high production of active constituents. The purpose of the study was also to assess the possibilities of using a cytokinin-based regeneration to effectively produce therapeutic compounds. The adventitious shoot formation was observed through direct organogenesis on media with purine derivatives (meta-topolin, mT and benzylaminopurine, BAP), and through indirect organogenesis on media with urea derivatives (tidiazuron, TDZ and forchlorfenuron, CPPU). The highest regeneration frequency (95%) with 5.2 shoots per explant was obtained on leaves cultured on Murashige and Skoog (MS) medium containing 0.1 mg/L naphthalene-1-acetic acid (NAA) and 2 mg/L BAP. Following inter simple sequence repeat (ISSR) marker-based profiling, the obtained organogenic shoot lines revealed a similar banding pattern to the mother line, with total variability of 4.2-13.7%, indicating high level of genetic stability. The similar genetic profile of the studied lines translated into similar growth parameters. Moreover, HPLC analysis revealed no qualitative differences in the profile of bioactive metabolites; also, the total polyphenol content was similar for different lines, with the exception of the shoots obtained in the presence of CPPU that produced higher level of bioactive compounds. This is the first report of an effective and rapid in vitro organogenesis protocol for S. bulleyana, which can be efficiently employed for obtaining stable cultures rich in bioactive metabolites.
PMID: 34680145
Plant Cell Rep , IF:4.57 , 2021 Oct doi: 10.1007/s00299-021-02807-0
Molecular mechanisms of maize endosperm transfer cell development.
School of Life Sciences, Anqing Normal University, Anqing, 246133, Anhui, China. zhengyankun1985@163.com.
Endosperm transfer cells function as the nutrient transporter, antimicrobic barrier, and signal mediator between filial and maternal tissues. Sugar supply of maternal tissues, sugar demand of filial tissues, and requirement for defence against pathogens are three elemental factors inducing differentiation of endosperm transfer cells. Epigenetic factors, especially MEG1, moderate the key genetic factor ZmMRP-1 to activate endosperm transfer cell-specific genes that control the flange wall ingrowth formation and defensin-like protein secretion in maize. Auxin and cytokinin are primary hormones involved in development of maize endosperm transfer cells. Crosstalk between glucose and hormone signaling regulates endosperm transfer cell development via modifying ZmMRP-1 expression. This review summarizes the current knowledge on maize endosperm transfer cell development, and discusses its potential molecular mechanisms. It is expected to strengthen the theoretical basis for structural and functional optimization of endosperm transfer cells, and yield improvement of kernels in maize.
PMID: 34689216
Microb Ecol , IF:4.552 , 2021 Oct doi: 10.1007/s00248-021-01849-x
Himalayan Microbiomes for Agro-environmental Sustainability: Current Perspectives and Future Challenges.
Department of Microbiology, Akal College of Basic Sciences, Eternal University, Sirmaur, Himachal Pradesh, India.; Uttarakhand Pollution Control Board, Regional Office, Kashipur, Uttarakhand, India.; Division of Crop Research, Research Complex for Eastern Region, Patna, Bihar, India.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, 510642, China.; Forest Research Institute, Dehradun, 2480 06, India.; Rain Forest Research Institute, Jorhat, 785 010, India.; Department of Biotechnology, Invertis Institute of Engineering and Technology (IIET), Invertis University, Bareilly, 243123, Uttar Pradesh, India.; Department of Agricultural Microbiology, College of Agriculture, Indira Gandhi Krishi Vishwa Vidyalaya, Raipur, Chhattisgarh, India.; Department of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India.; Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India.; Microbial Biotechnology Laboratory, Department of Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, Himachal Pradesh, India.; Microbial Biotechnology Laboratory, Department of Biotechnology, Dr. Khem Singh Gill Akal College of Agriculture, Eternal University, Baru Sahib, Sirmour, Himachal Pradesh, India. ajar@eternaluniversity.edu.in.
The Himalayas are one of the most mystical, yet least studied terrains of the world. One of Earth's greatest multifaceted and diverse montane ecosystems is also one of the thirty-four global biodiversity hotspots of the world. These are supposed to have been uplifted about 60-70 million years ago and support, distinct environments, physiography, a variety of orogeny, and great biological diversity (plants, animals, and microbes). Microbes are the pioneer colonizer of the Himalayas that are involved in various bio-geological cycles and play various significant roles. The applications of Himalayan microbiomes inhabiting in lesser to greater Himalayas have been recognized. The researchers explored the applications of indigenous microbiomes in both agricultural and environmental sectors. In agriculture, microbiomes from Himalayan regions have been suggested as better biofertilizers and biopesticides for the crops growing at low temperature and mountainous areas as they help in the alleviation of cold stress and other biotic stresses. Along with alleviation of low temperature, Himalayan microbes also have the capability to enhance plant growth by availing the soluble form of nutrients like nitrogen, phosphorus, potassium, zinc, and iron. These microbes have been recognized for producing plant growth regulators (abscisic acid, auxin, cytokinin, ethylene, and gibberellins). These microbes have been reported for bioremediating the diverse pollutants (pesticides, heavy metals, and xenobiotics) for environmental sustainability. In the current perspectives, present review provides a detailed discussion on the ecology, biodiversity, and adaptive features of the native Himalayan microbiomes in view to achieve agro-environmental sustainability.
PMID: 34647148
Sci Rep , IF:4.379 , 2021 Oct , V11 (1) : P20922 doi: 10.1038/s41598-021-00370-y
Manganese toxicity disrupts indole acetic acid homeostasis and suppresses the CO2 assimilation reaction in rice leaves.
Faculty of Agriculture, Setsunan University, Hirakata, Osaka, 573-0101, Japan. daisuke.takagi@setsunan.ac.jp.; Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-8572, Japan. daisuke.takagi@setsunan.ac.jp.; Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-8572, Japan.; Faculty of Food and Agricultural Sciences, Fukushima University, Kanayagawa, Fukushima, 960-1296, Japan.; Faculty of Agriculture, Setsunan University, Hirakata, Osaka, 573-0101, Japan.; Faculty of Agro-Food Science, Niigata Agro-Food University, Tainai, Niigata, 959-2702, Japan.; Department of Applied Life Science, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392, Japan.
Despite the essentiality of Mn in terrestrial plants, its excessive accumulation in plant tissues can cause growth defects, known as Mn toxicity. Mn toxicity can be classified into apoplastic and symplastic types depending on its onset. Symplastic Mn toxicity is hypothesised to be more critical for growth defects. However, details of the relationship between growth defects and symplastic Mn toxicity remain elusive. In this study, we aimed to elucidate the molecular mechanisms underlying symplastic Mn toxicity in rice plants. We found that under excess Mn conditions, CO2 assimilation was inhibited by stomatal closure, and both carbon anabolic and catabolic activities were decreased. In addition to stomatal dysfunction, stomatal and leaf anatomical development were also altered by excess Mn accumulation. Furthermore, indole acetic acid (IAA) concentration was decreased, and auxin-responsive gene expression analyses showed IAA-deficient symptoms in leaves due to excess Mn accumulation. These results suggest that excessive Mn accumulation causes IAA deficiency, and low IAA concentrations suppress plant growth by suppressing stomatal opening and leaf anatomical development for efficient CO2 assimilation in leaves.
PMID: 34686733
Ann Bot , IF:4.357 , 2021 Oct doi: 10.1093/aob/mcab131
Flavonoids are involved in phosphorus-deficiency-induced cluster-root formation in white lupin.
Department of Plant Nutrition, College of Resources and Environmental Sciences, Academy of National Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China.; School of Biological Sciences and UWA Institute of Agriculture, University of Western Australia, Perth, WA 6009, Australia.; Department of Agronomy and Plant Genetics, University of Minnesota; and United States Department of Agriculture Agricultural Research Service, St. Paul, Minnesota 55108, USA.
BACKGROUND AND AIMS: Initiation of cluster roots in white lupin (Lupinus albus L.) under phosphorus (P) deficiency requires auxin signaling, whereas flavonoids inhibit auxin transport. However, little information is available about the interactions between P deficiency and flavonoids in terms of cluster-root formation in white lupin. METHODS: Hydroponic and aeroponic systems were used to investigate the role of flavonoids in cluster-root formation, with or without 75 microM P supply. KEY RESULTS: Phosphorus-deficiency-induced flavonoid accumulation in cluster roots depended on developmental stage, based on in situ determination of fluorescence of flavonoids and flavonoid concentration. LaCHS8, which codes for a chalcone synthase isoform, was highly expressed in cluster roots, and silencing LaCHS8 reduced flavonoid production and rootlet density. Exogenous flavonoids suppressed cluster-root formation. Tissue-specific distribution of flavonoids in roots was altered by P deficiency, suggesting that P deficiency induced flavonoid accumulation, thus fine-tuning the effect of flavonoids on cluster-root formation. Furthermore, naringenin inhibited expression of an auxin-responsive DR5:GUS marker, suggesting an interaction of flavonoids and auxin in regulating cluster-root formation. CONCLUSIONS: Phosphorus deficiency triggered cluster-root formation through the regulation of flavonoid distribution, which fine-tuned an auxin response in the early stages of cluster-root development. These findings provide valuable insights into the mechanisms of cluster-root formation under P deficiency.
PMID: 34668958
BMC Plant Biol , IF:4.215 , 2021 Oct , V21 (1) : P464 doi: 10.1186/s12870-021-03239-4
Small RNA profiling for identification of microRNAs involved in regulation of seed development and lipid biosynthesis in yellowhorn.
Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Institute of Plant Resources, Dalian Minzu University, Dalian, 116600, China.; Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, College of Marine Life Science, Ocean University of China, Qingdao, 266100, China.; Key Laboratory of Biotechnology and Bioresources Utilization, Ministry of Education, Institute of Plant Resources, Dalian Minzu University, Dalian, 116600, China. ruan@dlnu.edu.cn.; Institute of Economic Forest, Tongliao Academy of Forestry Science and Technology, Tongliao, 028000, China.
BACKGROUND: Yellowhorn (Xanthoceras sorbifolium), an endemic woody oil-bearing tree, has become economically important and is widely cultivated in northern China for bioactive oil production. However, the regulatory mechanisms of seed development and lipid biosynthesis affecting oil production in yellowhorn are still elusive. MicroRNAs (miRNAs) play crucial roles in diverse aspects of biological and metabolic processes in seeds, especially in seed development and lipid metabolism. It is still unknown how the miRNAs regulate the seed development and lipid biosynthesis in yellowhorn. RESULTS: Here, based on investigations of differences in the seed growth tendency and embryo oil content between high-oil-content and low-oil-content lines, we constructed small RNA libraries from yellowhorn embryos at four seed development stages of the two lines and then profiled small RNA expression using high-throughput sequencing. A total of 249 known miRNAs from 46 families and 88 novel miRNAs were identified. Furthermore, by pairwise comparisons among the four seed development stages in each line, we found that 64 miRNAs (53 known and 11 novel miRNAs) were differentially expressed in the two lines. Across the two lines, 15, 11, 10, and 7 differentially expressed miRNAs were detected at 40, 54, 68, and 81 days after anthesis, respectively. Bioinformatic analysis was used to predict a total of 2654 target genes for 141 differentially expressed miRNAs (120 known and 21 novel miRNAs). Most of these genes were involved in the fatty acid biosynthetic process, regulation of transcription, nucleus, and response to auxin. Using quantitative real-time PCR and an integrated analysis of miRNA and mRNA expression, miRNA-target regulatory modules that may be involved in yellowhorn seed size, weight, and lipid biosynthesis were identified, such as miR172b-ARF2 (auxin response factor 2), miR7760-p3_1-AGL61 (AGAMOUS-LIKE 61), miR319p_1-FAD2-2 (omega-6 fatty acid desaturase 2-2), miR5647-p3_1-DGAT1 (diacylglycerol acyltransferase 1), and miR7760-p5_1-MED15A (Mediator subunit 15a). CONCLUSIONS: This study provides new insights into the important regulatory roles of miRNAs in the seed development and lipid biosynthesis in yellowhorn. Our results will be valuable for dissecting the post-transcriptional and transcriptional regulation of seed development and lipid biosynthesis, as well as improving yellowhorn in northern China.
PMID: 34641783
Tree Physiol , IF:4.196 , 2021 Oct , V41 (10) : P1938-1952 doi: 10.1093/treephys/tpab038
Rejuvenation remodels transcriptional network to improve rhizogenesis in mature Juglans tree.
State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Institute of Forestry, the Chinese Academy of Forestry, 1958 Box, Beijing 100091, China.; Institute of Computing Technology, Chinese Academy of Sciences, No.6 Kexueyuan South Road Zhongguancun, Haidian District, Beijing 100190, China.; Forestry Bureau of Luoning County, Luoning County, Luoyang City, Henan Province 471700, China.
Adventitious rooting of walnut species (Juglans L.) is known to be rather difficult, especially for mature trees. The adventitious root formation (ARF) capacities of mature trees can be significantly improved by rejuvenation. However, the underlying gene regulatory networks (GRNs) of rejuvenation remain largely unknown. To characterize such regulatory networks, we carried out the transcriptomic study using RNA samples of the cambia and peripheral tissues on the bottom of rejuvenated and mature walnut (Juglans hindsii x J. regia) cuttings during the ARF. The RNA sequencing data suggested that zeatin biosynthesis, energy metabolism and substance metabolism were activated by rejuvenation, whereas photosynthesis, fatty acid biosynthesis and the synthesis pathways for secondary metabolites were inhibited. The inter- and intra-module GRNs were constructed using differentially expressed genes. We identified 35 hub genes involved in five modules associated with ARF. Among these hub genes, particularly, beta-glucosidase-like (BGLs) family members involved in auxin metabolism were overexpressed at the early stage of the ARF. Furthermore, BGL12 from the cuttings of Juglans was overexpressed in Populus alba x P. glandulosa. Accelerated ARF and increased number of ARs were observed in the transgenic poplars. These results provide a high-resolution atlas of gene activity during ARF and help to uncover the regulatory modules associated with the ARF promoted by rejuvenation.
PMID: 34014320
Plant Mol Biol , IF:4.076 , 2021 Oct doi: 10.1007/s11103-021-01199-9
Different regulatory mechanisms of plant hormones in the ripening of climacteric and non-climacteric fruits: a review.
School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China.; College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China.; School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. zhhxue@tju.edu.cn.
KEY MESSAGE: This review contains the regulatory mechanisms of plant hormones in the ripening process of climacteric and non-climacteric fruits, interactions between plant hormones and future research directions. The fruit ripening process involves physiological and biochemical changes such as pigment accumulation, softening, aroma and flavor formation. There is a great difference in the ripening process between climacteric fruits and non-climacteric fruits. The ripening of these two types of fruits is affected by endogenous signals and exogenous environments. Endogenous signaling plant hormones play an important regulatory role in fruit ripening. This paper systematically reviews recent progress in the regulation of plant hormones in fruit ripening, including ethylene, abscisic acid, auxin, jasmonic acid (JA), gibberellin, brassinosteroid (BR), salicylic acid (SA) and melatonin. The role of plant hormones in both climacteric and non-climacteric fruits is discussed, with emphasis on the interaction between ethylene and other adjustment factors. Specifically, the research progress and future research directions of JA, SA and BR in fruit ripening are discussed, and the regulatory network between JA and other signaling molecules remains to be further revealed. This study is meant to expand the understanding of the importance of plant hormones, clarify the hormonal regulation network and provide a basis for targeted manipulation of fruit ripening.
PMID: 34633626
Phytopathology , IF:4.025 , 2021 Oct doi: 10.1094/PHYTO-05-21-0189-R
The role of the wheat Reduced height (Rht)-DELLA mutants and associated hormones in infection by Claviceps purpurea, the causal agent of ergot.
National Institute of Agricultural Botany, 2148, Cambridge, Cambridgeshire, United Kingdom of Great Britain and Northern Ireland; eleni.tente@niab.com.; Instituto de Biologia Molecular y Celular de Plantas, 54403, Valencia, Valenciana, Spain; ecarrera@ibmcp.upv.es.; National Institute of Agricultural Botany, 2148, Cambridge, Cambridgeshire, United Kingdom of Great Britain and Northern Ireland; anna.gordon@niab.com.; National Institute of Agricultural Botany, 2148, Department of Crop Sience, Cambridge, Cambridgeshire, United Kingdom of Great Britain and Northern Ireland; lesley.boyd@niab.com.
Partial resistance to the biotrophic fungal pathogen Claviceps purpurea, causal agent of ergot, has been found that co-locates with mutant alleles of the wheat Reduced height (Rht) loci on chromosomes 4B and 4D. These Rht loci represent the wheat orthologues of the Arabidopsis Della genes. To investigate the role of the Rht mutant DELLA proteins in ergot resistance we assessed C. purpurea infection in wheat near-isogenic lines (NILs) carrying the gibberellic acid (GA)-insensitive semi-dwarf alleles Rht-B1b and Rht-D1b and the severe dwarf alleles Rht-B1c and Rht-D1c. NILs of the GA-sensitive alleles Rht8 (chromosome 2D) and Rht12 (chromosome 5A) were also included. A general trend towards increased resistance to C. purpurea, with smaller and lighter sclerotia, was observed on the NILs Rht-B1b, Rht-D1b, Rht-B1c and Rht-D1c, but also on Rht8. Levels of the bioactive GA4 and the auxin indole-3-acetic acid (IAA) increased following inoculation with C. purpurea, following similar patterns and implicating a potential auxin-mediated induction of GA biosynthesis. In contrast, jasmonic acid (JA) levels fell in the parental lines Mercia and Maris Huntsman following inoculation with C. purpurea, but increased in all the Rht-mutant NILs. Inoculation with C. purpurea did not show any informative changes in the levels of salicylic acid. Our results suggest that GA-mediated degradation of the DELLA proteins and down-regulation of JA-signalling pathways supports infection of wheat by C. purpurea. As these responses are generally associated with necrotrophic fungal pathogens, we propose that the biotroph C. purpurea may have a necrotrophic growth stage.
PMID: 34698539
BMC Genomics , IF:3.969 , 2021 Oct , V22 (1) : P760 doi: 10.1186/s12864-021-08076-1
Comparative phenotypic and transcriptomic analyses unravel conserved and distinct mechanisms underlying shade avoidance syndrome in Brassicaceae vegetables.
Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore.; Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.; Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore. jangi@tll.org.sg.; Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore. jangi@tll.org.sg.
BACKGROUND: Plants grown under shade are exposed to low red/far-red ratio, thereby triggering an array of altered phenotypes called shade avoidance syndrome (SAS). Shade negatively influences plant growth, leading to a reduction in agricultural productivity. Understanding of SAS is crucial for sustainable agricultural practices, especially for high-density indoor farming. Brassicaceae vegetables are widely consumed around the world and are commonly cultivated in indoor farms. However, our understanding of SAS in Brassicaceae vegetables and their genome-wide transcriptional regulatory networks are still largely unexplored. RESULTS: Shade induced common signs of SAS, including hypocotyl elongation and reduced carotenoids/anthocyanins biosynthesis, in two different Brassicaceae species: Brassica rapa (Choy Sum and Pak Choy) and Brassica oleracea (Kai Lan). Phenotype-assisted transcriptome analysis identified a set of genes induced by shade in these species, many of which were related to auxin biosynthesis and signaling [e.g. YUCCA8 (YUC8), YUC9, and INDOLE-3-ACETIC ACID INDUCIBLE (IAAs)] and other phytohormones signaling pathways including brassinosteroids and ethylene. The genes functioning in plant defense (e.g. MYB29 and JASMONATE-ZIM-DOMAIN PROTEIN 9) as well as in biosynthesis of anthocyanins and glucosinolates were repressed upon shade. Besides, each species also exhibited distinct SAS phenotypes. Shade strongly reduced primary roots and elongated petioles of B. oleracea, Kai Lan. However, these SAS phenotypes were not clearly recognized in B. rapa, Choy Sum and Pak Choy. Some auxin signaling genes (e.g. AUXIN RESPONSE FACTOR 19, IAA10, and IAA20) were specifically induced in B. oleracea, while homologs in B. rapa were not up-regulated under shade. Contrastingly, shade-exposed B. rapa vegetables triggered the ethylene signaling pathway earlier than B. oleracea, Kai Lan. Interestingly, shade induced the transcript levels of LONG HYPOCOTYL IN FAR-RED 1 (HFR1) homolog in only Pak Choy as B. rapa. As HFR1 is a key negative regulator of SAS in Arabidopsis, our finding suggests that Pak Choy HFR1 homolog may also function in conferring higher shade tolerance in this variety. CONCLUSIONS: Our study shows that two Brassicaceae species not only share a conserved SAS mechanism but also exhibit distinct responses to shade, which will provide comprehensive information to develop new shade-tolerant cultivars that are suitable for high-density indoor farms.
PMID: 34696740
BMC Genomics , IF:3.969 , 2021 Oct , V22 (1) : P743 doi: 10.1186/s12864-021-08022-1
Comprehensive genome-wide analysis of calmodulin-binding transcription activator (CAMTA) in Durio zibethinus and identification of fruit ripening-associated DzCAMTAs.
Molecular Crop Research Unit, Department of Biochemistry, Chulalongkorn University, Bangkok, Thailand.; Amity Institute of Biotechnology, Amity University, Lucknow Campus, Lucknow, Uttar Pradesh, India.; Omics Sciences and Bioinformatics Center, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.; Molecular Crop Research Unit, Department of Biochemistry, Chulalongkorn University, Bangkok, Thailand. teerapong.b@chula.ac.th.; Omics Sciences and Bioinformatics Center, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. teerapong.b@chula.ac.th.
BACKGROUND: Fruit ripening is an intricate developmental process driven by a highly coordinated action of complex hormonal networks. Ethylene is considered as the main phytohormone that regulates the ripening of climacteric fruits. Concomitantly, several ethylene-responsive transcription factors (TFs) are pivotal components of the regulatory network underlying fruit ripening. Calmodulin-binding transcription activator (CAMTA) is one such ethylene-induced TF implicated in various stress and plant developmental processes. RESULTS: Our comprehensive analysis of the CAMTA gene family in Durio zibethinus (durian, Dz) identified 10 CAMTAs with conserved domains. Phylogenetic analysis of DzCAMTAs, positioned DzCAMTA3 with its tomato ortholog that has already been validated for its role in the fruit ripening process through ethylene-mediated signaling. Furthermore, the transcriptome-wide analysis revealed DzCAMTA3 and DzCAMTA8 as the highest expressing durian CAMTA genes. These two DzCAMTAs possessed a distinct ripening-associated expression pattern during post-harvest ripening in Monthong, a durian cultivar native to Thailand. The expression profiling of DzCAMTA3 and DzCAMTA8 under natural ripening conditions and ethylene-induced/delayed ripening conditions substantiated their roles as ethylene-induced transcriptional activators of ripening. Similarly, auxin-suppressed expression of DzCAMTA3 and DzCAMTA8 confirmed their responsiveness to exogenous auxin treatment in a time-dependent manner. Accordingly, we propose that DzCAMTA3 and DzCAMTA8 synergistically crosstalk with ethylene during durian fruit ripening. In contrast, DzCAMTA3 and DzCAMTA8 antagonistically with auxin could affect the post-harvest ripening process in durian. Furthermore, DzCAMTA3 and DzCAMTA8 interacting genes contain significant CAMTA recognition motifs and regulated several pivotal fruit-ripening-associated pathways. CONCLUSION: Taken together, the present study contributes to an in-depth understanding of the structure and probable function of CAMTA genes in the post-harvest ripening of durian.
PMID: 34649525
Plants (Basel) , IF:3.935 , 2021 Oct , V10 (10) doi: 10.3390/plants10102141
The Efficient and Easy Micropropagation Protocol of Phyllanthus niruri.
Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.; Laboratory of Sustainable Resources Management, Institute of Tropical Forestry and Forest Products, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Phyllanthus niruri (P. niruri) or Dukung Anak is a herbal plant in the Phyllanthaceae family that has been used traditionally to treat various ailments such as diabetes, jaundice, flu and cough. P. niruri contains numerous medicinal benefits such as anti-tumor and anti-carcinogenic properties and a remedy for hepatitis B viral infection. Due to its beneficial properties, P. niruri is overharvested and wild plants become scarce. This study was conducted to develop an appropriate in vitro culture protocol for the mass production of P. niruri. An aseptic culture of P. niruri was established followed by multiplication of explants using different types of basal medium and its strength and plant growth regulators manipulation. This study also established the induction of in vitro rooting utilizing various types and concentrations of auxin. Treatment of Clorox((R)) with 30% concentration showed the lowest percentage (%) of contamination, 4.44% in P. niruri culture. Nodal segments of P. niruri were successfully induced in full-strength of Murashige and Skoog (MS) basal media with 2.33 number of shoots, 3.11 cm length of shoot and 27.91 number of leaves. In addition, explants in full-strength MS media without any additional cytokinin were recorded as the optimum results for all parameters including the number of shoots (5.0 shoots), the length of shoots (3.68 cm) and the number of leaves (27.33 leaves). Treatment of 2.5 microM indole-3-butyric acid (IBA) showed the highest number of roots (17.92 roots) and root length (1.29 cm). Rooted explants were transferred for acclimatization, and the plantlet showed over 80% of survival rate. In conclusion, plantlets of P. niruri were successfully induced and multiplied via in vitro culture, which could be a step closer to its commercialization.
PMID: 34685949
J Appl Microbiol , IF:3.772 , 2021 Oct doi: 10.1111/jam.15317
Rhizospheric and endophytic Pseudomonas aeruginosa in edible vegetable plants share molecular and metabolic traits with clinical isolates.
Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.; Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Florida, United States of America.; Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.
AIM: Pseudomonas aeruginosa, a leading opportunistic pathogen causing hospital-acquired infections, is predominantly present in agricultural settings. However, there are minimal attempts to examine the molecular and functional attributes shared by agricultural and clinical strains of P. aeruginosa. This study investigates the presence of P. aeruginosa in edible vegetable plants (including salad vegetables) and analyzes the evolutionary and metabolic relatedness of the agricultural and clinical strains. METHODS AND RESULTS: Eighteen rhizospheric and endophytic P. aeruginosa strains were isolated from cucumber, tomato, eggplant, and chili directly from the farms. The identity of these strains was confirmed using biochemical and molecular assays. The genetic and metabolic traits of these plant-associated P. aeruginosa isolates were compared with clinical strains. DNA fingerprinting and 16S rDNA-based phylogenetic analyses revealed that the plant- and human-associated strains are evolutionarily related. Both agricultural and clinical isolates possessed plant-beneficial properties, including mineral solubilization to release essential nutrients (phosphorous, potassium, and zinc), ammonification, and the ability to release extracellular pyocyanin, siderophore, and indole-3 acetic acid. CONCLUSION: These findings suggest that rhizospheric and endophytic P. aeruginosa strains are genetically and functionally analogous to the clinical isolates. In addition, the genotypic and phenotypic traits do not correlate with plant sources or ecosystems. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reconfirms that edible plants are the potential source for human and animal transmission of P. aeruginosa.
PMID: 34608722
Gene , IF:3.688 , 2021 Oct , V809 : P146030 doi: 10.1016/j.gene.2021.146030
Time-course transcriptome profiling revealed the specific expression patterns of MADS-box genes associated with the distinct developmental processes between winter and spring wheat.
College of Agriculture, Northeast Agricultural University, Harbin 150031, PR China.; College of Agriculture, Northeast Agricultural University, Harbin 150031, PR China; National Key Facility for Crop Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 10081, PR China.; College of Agriculture, Northeast Agricultural University, Harbin 150031, PR China. Electronic address: xnwang1982@neau.edu.cn.
The shoot apex is a region where new cells are produced and elongate. The developmental state of the wheat shoot apex under low temperature affects its cold resistance. In this study, the morphology of shoot apex before overwintering was characterized for 24 wheat line with different winter and spring characteristics. Our research showed that the shoot apex of autumn-sown spring wheat lines reached the temperature sensitive double-ridge stage before overwintering, whereas shoot apex of winter wheat lines are found in temperature-insensitive vegetative or elongation stages. In order to explore how gene expression is associated with shoot apex differentiation in winter and spring wheat, we used strand-specific RNA sequencing to profile the gene expression patterns at four time-points between 14 after germination and 45 days after germination in the winter wheat cultivar Dongnongdongmai No. 1 (DM1) and in the spring wheat cultivar China Spring (CS). We identified 11,848 differentially expressed genes between the two cultivars. Most up-regulated genes in CS were involved in energy metabolism and transport during the seedling stage, whereas up-regulated genes in DM1 were involved in protein and DNA synthesis. MADS-box genes affect plant growth and development. In this study, MADS-boxes with differential expression between CS and DM1 were screened and evolutionary tree analysis was conducted. During all sampling periods, CS highly expressed MADS-box genes that induce flowering promotion genes such as VRN1, VRT and AG, while lowly expressed MADS-box genes that induce flowering-inhibiting homologous genes such as SVP. TaVRN1 composition in DM1 and CS was vrn-A1, vrn-B1, and Vrn-D1b. Analysis of the sequence of TaVRN1 (TraesCS5A01G391700) from DM1 and CS revealed 5 SNP differences in the promoter regions and 3 SNP deletions in the intron regions. The expression levels of cold resistant genes in DM1 were significantly higher than those in CS at seedling stage (neither DM1 nor CS experienced cold in this study), including CBF, cold induced protein,acid desaturase and proline rich proteins. Additionally, the expression levels of auxin-related genes were significantly higher in CS than those in DM1 at 45 days after germination. Our study identified candidate genes associated with the process of differentiation of the shoot apex in winter and spring wheat at the seedling stage and also raised an internal stress tolerance model for winter wheat to endogenously anticipate the coming stressful conditions in winter.
PMID: 34673213
BMC Microbiol , IF:3.605 , 2021 Oct , V21 (1) : P295 doi: 10.1186/s12866-021-02358-0
Complete genomic sequence and phylogenomics analysis of Agrobacterium strain AB2/73: a new Rhizobium species with a unique mega-Ti plasmid.
Institute of Biology, Leiden University, Leiden, The Netherlands.; Institute of Biology, Leiden University, Leiden, The Netherlands. p.j.j.hooykaas@biology.leidenuniv.nl.
BACKGROUND: The Agrobacterium strain AB2/73 has a unique host range for the induction of crown gall tumors, and contains an exceptionally large, over 500 kbp mega Ti plasmid. We used whole genome sequencing to fully characterize and comparatively analyze the complex genome of strain AB2/73, including its Ti plasmid and virulence factors. RESULTS: We obtained a high-quality, full genomic sequence of AB2/73 by a combination of short-read Illumina sequencing and long-read Nanopore sequencing. The AB2/73 genome has a total size of 7,266,754 bp with 59.5% GC for which 7012 genes (6948 protein coding sequences) are predicted. Phylogenetic and comparative genomics analysis revealed that strain AB2/73 does not belong to the genus Agrobacterium, but to a new species in the genus Rhizobium, which is most related to Rhizobium tropici. In addition to the chromosome, the genome consists of 6 plasmids of which the largest two, of more than 1 Mbp, have chromid-like properties. The mega Ti plasmid is 605 kbp in size and contains two, one of which is incomplete, repABC replication units and thus appears to be a cointegrate consisting of about 175 kbp derived from an unknown Ti plasmid linked to 430 kbp from another large plasmid. In pTiAB2/73 we identified a complete set of virulence genes and two T-DNAs. Besides the previously described T-DNA we found a larger, second T-DNA containing a 6b-like onc gene and the acs gene for agrocinopine synthase. Also we identified two clusters of genes responsible for opine catabolism, including an acc-operon for agrocinopine degradation, and genes putatively involved in rideopine catabolism. The plasmid also harbours tzs, iaaM and iaaH genes for the biosynthesis of the plant growth regulators cytokinin and auxin. CONCLUSIONS: The comparative genomics analysis of the high quality genome of strain AB2/73 provided insight into the unusual phylogeny and genetic composition of the limited host range Agrobacterium strain AB2/73. The description of its unique genomic composition and of all the virulence determinants in pTiAB2/73 will be an invaluable tool for further studies into the special host range properties of this bacterium.
PMID: 34711172
J Plant Physiol , IF:3.549 , 2021 Nov , V266 : P153539 doi: 10.1016/j.jplph.2021.153539
Arabidopsis antiporter CHX23 and auxin transporter PIN8 coordinately regulate pollen growth.
MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.; Qinghai Provincial Key Laboratory of Medicinal Plant and Animal Resources of Qinghai-Tibet Plateau, School of Life Sciences, Qinghai Normal University, Xining, 810008, China.; MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China. Electronic address: qiuqsh@lzu.edu.cn.
Both the antiporter CHX23 (Cation/Proton Exchangers 23) and auxin transporter PIN8 (PIN-FORMED 8) are localized in the ER and regulate pollen growth in Arabidopsis. But how these two proteins regulate pollen growth remains to be studied. Here, we report that CHX23 and PIN8 act coordinately in regulating pollen growth. The chx23 mutant was reduced in pollen growth and normally shaped pollen grains, and complementation with CHX23 restored both pollen growth and normal pollen morphology. NAA treatments showed that CHX23 was crucial for pollen auxin homeostasis. The pin8 chx23 double mutant was decreased in pollen growth and normal pollen grains, indicating the joint effort of CHX23 and PIN8 in pollen growth. In vivo germination assay showed that CHX23 and PIN8 were involved in the early stage of pollen growth. CHX23 and PIN8 also function collaboratively in maintaining pollen auxin homeostasis. PIN8 depends on CHX23 in regulating pollen morphology and response to NAA treatments. CHX23 co-localized with PIN8, but there was no physical interaction. KCl and NaCl treatments showed that pollen growth of chx23 was reduced less than Col-0; pin8 chx23 was reduced less than chx23 and pin8. Together, CHX23 may regulate PIN8 function and hence pollen growth through controlling K(+) and Na(+) homeostasis mediated by its transport activity.
PMID: 34628190
J Bacteriol , IF:3.49 , 2021 Oct : PJB0038021 doi: 10.1128/JB.00380-21
Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000.
Department of Biology, Washington University in St. Louis, St. Louis, MO 63130 USA.; School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, USA 14853.; Emerging Pests and Pathogens Research Unit, Robert W. Holley Center for Agriculture and Health, Agricultural Research Service, United States Department of Agriculture, Ithaca, New York, USA 14853.
The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.
PMID: 34662236
J Biotechnol , IF:3.307 , 2021 Oct doi: 10.1016/j.jbiotec.2021.10.002
Green revolution to grain revolution: Florigen in the frontiers.
ICAR- National Institute for Plant Biotechnology, PUSA, New Delhi-110012, India. Electronic address: prasanta01@yahoo.com.; ICAR- National Institute for Plant Biotechnology, PUSA, New Delhi-110012, India.
Burgeoning human population dents, globally, the brimming buffer stock as well as gain in food grain production. An imminent global starvation was averted through precise scientific intervention and pragmatic policy changes in the 1960s and was eulogized as the "Green Revolution". Miracle rice and wheat obtained through morphometric changes in the ideotype of these two crops yielded bumper harvest that nucleated in Asia and translated into Latin America. The altered agronomic traits in these two crops were the result of the tinkering of the phyto-hormone "Gibberellin'. Recently, another plant hormone 'Cytokinin' has gained prominence for its involvement in the grain revolution in rice and other field crops. Suo moto homeostasis of CK by the cytokinin oxidase enzyme governs the cardinal shoot apical meristem that produces new flowering primordia thereby enhances grain number. Similarly, the flowering hormone 'Florigen' impacts sympodia formation, flowering, and fruit production in tomato. The role of heterozygosity induced heterosis by florigen in revolutionizing tomato production and cellular homeostasis of CK by CK oxidising enzyme (CKX) in enhancing rice production has been path-breaking. This review highlights role of phytohormones in grain revolution and crop specific fine-tuning of gibberellins, cytokinins and florigen to accomplish maximum yield potential in field crops.
PMID: 34673121
J Biotechnol , IF:3.307 , 2021 Oct , V342 : P36-44 doi: 10.1016/j.jbiotec.2021.09.013
Detoxification of phenanthrene in Arabidopsis thaliana involves a Dioxygenase For Auxin Oxidation 1 (AtDAO1).
Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA.; Department of Biology, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA. Electronic address: adan.colon-carmona@umb.edu.
Polycyclic aromatic hydrocarbon (PAH) contamination has a negative impact on ecosystems. PAHs are a large group of toxins with two or more benzene rings that are persistent in the environment. Some PAHs can be cytotoxic, teratogenic, and/or carcinogenic. In the bacterium Pseudomonas, PAHs can be modified by dioxygenases, which increase the reactivity of PAHs. We hypothesize that some plant dioxygenases are capable of PAH biodegradation. Herein, we investigate the involvement of Arabidopsis thaliana At1g14130 in the degradation of phenanthrene, our model PAH. The At1g14130 gene encodes Dioxygenase For Auxin Oxidation 1 (AtDAO1), an enzyme involved in the oxidative inactivation of the hormone auxin. Expression analysis using a beta-glucuronidase (GUS) reporter revealed that At1g14130 is prominently expressed in new leaves of plants exposed to media with phenanthrene. Analysis of the oxidative state of gain-of-function mutants showed elevated levels of H2O2 after phenanthrene treatments, probably due to an increase in the oxidation of phenanthrene by AtDAO1. Biochemical assays with purified AtDAO1 and phenanthrene suggest an enzymatic activity towards the PAH. Thus, data presented in this study support the hypothesis that an auxin dioxygenase, AtDAO1, from Arabidopsis thaliana contributes to the degradation of phenanthrene and that there is possible toxic metabolite accumulation after PAH exposure.
PMID: 34610365
Virus Res , IF:3.303 , 2021 Oct , V303 : P198400 doi: 10.1016/j.virusres.2021.198400
Differential miRNA profiles in South African cassava mosaic virus-infected cassava landraces reveal clues to susceptibility and tolerance to cassava mosaic disease.
School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa.; School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa. Electronic address: Chrissie.Rey@wits.ac.za.
Specific miRNA families are involved in susceptibility or antiviral immunity in plants. Manihot esculenta Crantz (cassava) is a perennial plant that is an important food security crop in sub-Saharan Africa. Cassava is susceptible to several begomoviruses that cause cassava mosaic disease (CMD). In this study, we investigated the leaf miRNAome response in a tolerant (TME3) and susceptible (T200) cassava landrace challenged with South African cassava mosaic virus. RNAseq was performed on leaf samples at 12, 32 and 67 days post infection (dpi), representing early, symptomatic and late persistent stages of CMD infection. Significantly, distinct profiles of conserved miRNA family expression between the T200 and TME3 landraces at the three infection stages were observed. Notably at 12 days post SACMV infection, TME3 exhibited significant downregulation (log2fold<2.0) of 42 %, compared to 9% in T200, of the conserved miRNA families. This demonstrates an overall early response to SACMV in TME3 prior to symptom appearance not observed in T200, and expression of a large cohort of miRNA-regulated genes. Notably, at early infection, downregulation of mes-miR162 and 168 that target antiviral posttransriptional gene silencing (PTGS) regulators DCL1 and AGO1, respectively, was observed in TME3, and AGO1 and DCL1 expression was higher compared to T200 post infection. Early rapid responses prior to symptom development, including RNA silencing, may be key to establishing the tolerance/recovery phenotype exhibited by TME3 landrace later on at 67 dpi. At recovery, TME3 was hallmarked by a highly significant down-regulation of mes-miR167. MiR167 targets an auxin responsive factor which plays a role in auxin signaling and adaptive responses to stress, suggesting the importance of the auxin signaling in recovery of SACMV-induced symptoms. The gene targets of these miRNAs and their associated networks may provide clues to the molecular basis of CMD tolerance in perennial hosts such as cassava.
PMID: 33753179
J Plant Res , IF:2.629 , 2021 Oct doi: 10.1007/s10265-021-01349-6
Arabidopsis ASYMMETRIC LEAVES2 (AS2): roles in plant morphogenesis, cell division, and pathogenesis.
Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, 464-8602, Japan. yas@bio.nagoya-u.ac.jp.; Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, 464-8602, Japan.; Central Research Institute, Ishihara Sangyo Kaisha, Ltd., 2-3-1 Nishi-Shibukawa, Kusatsu, Shiga, 525-0025, Japan.; Department of Biology, Faculty of Agriculture and Life Science, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561, Japan.; Graduate School of Bioscience and Biotechnology, Chubu University, Kasugai, Aichi, 487-8501, Japan.
The ASYMMETRIC LEAVES2 (AS2) gene in Arabidopsis thaliana is responsible for the development of flat, symmetric, and extended leaf laminae and their vein systems. AS2 protein is a member of the plant-specific AS2/LOB protein family, which includes 42 members comprising the conserved amino-terminal domain referred to as the AS2/LOB domain, and the variable carboxyl-terminal region. Among the members, AS2 has been most intensively investigated on both genetic and molecular levels. AS2 forms a complex with the myb protein AS1, and is involved in epigenetic repression of the abaxial genes ETTIN/AUXIN RESPONSE FACTOR3 (ETT/ARF3), ARF4, and class 1 KNOX homeobox genes. The repressed expression of these genes by AS2 is markedly enhanced by the cooperative action of various modifier genes, some of which encode nucleolar proteins. Further downstream, progression of the cell division cycle in the developing organs is stimulated; meristematic states are suppressed in determinate leaf primordia; and the extension of leaf primordia is induced. AS2 binds the specific sequence in exon 1 of ETT/ARF3 and maintains methylated CpGs in several exons of ETT/ARF3. AS2 forms bodies (designated as AS2 bodies) at nucleolar peripheries. AS2 bodies partially overlap chromocenters, including inactive 45S ribosomal DNA repeats, suggesting the presence of molecular and functional links among AS2, the 45S rDNAs, and the nucleolus to exert the repressive regulation of ETT/ARF3. The AS2/LOB domain is characterized by three subdomains, the zinc finger (ZF) motif, the internally conserved-glycine containing (ICG) region, and the leucine-zipper-like (LZL) region. Each of these subdomains is essential for the formation of AS2 bodies. ICG to LZL are required for nuclear localization, but ZF is not. LZL intrinsically has the potential to be exported to the cytoplasm. In addition to its nuclear function, it has been reported that AS2 plays a positive role in geminivirus infection: its protein BV1 stimulates the expression of AS2 and recruits AS2 to the cytoplasm, which enhances virus infectivity by suppression of cytoplasmic post transcriptional gene silencing.
PMID: 34668105
Mol Biol Rep , IF:2.316 , 2021 Oct doi: 10.1007/s11033-021-06729-8
Comparison of the transcriptomic responses of two Chrysanthemum morifolium cultivars to low light.
Henan Provincial Key University Laboratory of Plant-Microbe Interactions, College of Biology and Food, Shangqiu Normal University, Shangqiu, 476000, China.; Henan Provincial Key University Laboratory of Plant-Microbe Interactions, College of Biology and Food, Shangqiu Normal University, Shangqiu, 476000, China. peidongli@126.com.
BACKGROUND: Low light is a primary regulator of chrysanthemum growth. Our aim was to analyse the different transcriptomic responses of two Chrysanthemum morifolium cultivars to low light. METHODS AND RESULTS: We conducted a transcriptomic analysis of leaf samples from the 'Nannonggongfen' and 'Nannongxuefeng' chrysanthemum cultivars following a 5-day exposure to optimal light (70%, control [CK]) or low-light (20%, LL) conditions. Gene Ontology (GO) classification of upregulated genes revealed these genes to be associated with 11 cellular components, 9 molecular functions, and 15 biological processes, with the majority being localized to the chloroplast, highlighting the role of chloroplast proteins as regulators of shading tolerance. Downregulated genes were associated with 11 cellular components, 8 molecular functions, and 16 biological processes. Heat map analyses suggested that basic helix-loop-helix domain genes and elongation factors were markedly downregulated in 'Nannongxuefeng' leaves, consistent with the maintenance of normal stem length, whereas no comparable changes were observed in 'Nanonggongfen' leaves. Subsequent qPCR analyses revealed that phytochrome-interacting factors and dormancy-associated genes were significantly upregulated under LL conditions relative to CK conditions, while succinate dehydrogenase 1, elongated hypocotyls 5, and auxin-responsive gene of were significantly downregulated under LL conditions. CONCLUSIONS: These findings suggest that LL plants were significantly lower than those of the CK plants. Low-light tolerant chrysanthemum cultivars may maintain reduced indole-3-acetic acid (IAA) and elongation factor expression as a means of preventing the onset of shade-avoidance symptoms.
PMID: 34689280
Plant Signal Behav , IF:2.247 , 2021 Oct : P1989216 doi: 10.1080/15592324.2021.1989216
Spatiotemporal relationship between auxin dynamics and hydathode development in Arabidopsis leaf teeth.
Graduate School of Science, Kyoto University, Kyoto, Japan.; Department of Environmental and Life Sciences, University of Shizuoka, Shizuoka, Japan.
Hydathode is a plant tissue of vascular plants involved in water release called guttation. Arabidopsis hydathodes are found at the tips of leaf teeth and contain three major components: water pores, xylem ends, and small cells. Leaf teeth are known as the main parts for auxin biosynthesis and accumulation during leaf development. However, the detailed spatiotemporal relationship between auxin dynamics and hydathode development is unknown. In this study, we show that auxin biosynthesis and accumulation precede hydathode development. A triple marker line (called YDE line) containing three leaf tooth markers: YUC4:nls-3xGFP (auxin biosynthesis), DR5rev:erRFP (auxin accumulation or maxima), and E325-GFP (hydathode development), was generated, and spatiotemporal confocal microscopic analysis was carried out. The expression area of these markers became larger during leaf development, implying that the hydathode size enlarges as the leaf tooth grows. Detailed observation revealed that the auxin-related markers YUC4:nls-GFP and DR5rev:erRFP were first expressed in the early stage of leaf tooth growth. Then, E325-GFP was expressed partly overlapping with the auxin markers at a later stage. These findings provide new insights into the spatiotemporal relationship between auxin dynamics and hydathode development in Arabidopsis.
PMID: 34696695
Plant Signal Behav , IF:2.247 , 2021 Oct : P1970447 doi: 10.1080/15592324.2021.1970447
Phytomelatonin inhibits seed germination by regulating germination-related hormone signaling in Arabidopsis.
State Key Laboratory for Conservation and Utilization of Bio-resources in Yunnan, Yunnan University, Kunming, China.
Seed germination is a vital initial stage in the life cycle of a plant, which determines subsequent vegetative growth and reproduction. Melatonin acts as a plant's master regulator and is also involved in the process of seed germination. In a recent study, we show that the high concentration melatonin inhibited seed germination in Arabidopsis. Transcriptome and phenotype analysis implied that melatonin-mediated seed germination interacted with phytohormones abscisic acid (ABA), gibberellin (GA), and auxin. In this short communication, we discuss the mechanism of phytomelatonin that inhibits seed germination through ABA, GA, and IAA in Arabidopsis.
PMID: 34633895
Plant Signal Behav , IF:2.247 , 2021 Oct , V16 (10) : P1930442 doi: 10.1080/15592324.2021.1930442
Molecular cloning and expression analysis of a WRKY transcription factor gene, GbWRKY20, from Ginkgo biloba.
Co-Innovation Center for Sustainable Forestry in Southern China; College of Forestry, Nanjing Forestry University, Nanjing, China.
WRKY transcription factors are important regulators of diverse plant life processes. Our aim was to clone and characterize GbWRKY20, a WRKY gene of group IIc, derived from Ginkgo biloba. The cDNA sequence of GbWRKY20 was 818 bp long, encoding a 271-amino acid proteins and containing two introns and three exons. The proteinic molecular weight was 30.99 kDa, with a relevant theoretical isoelectric point of 8.15. Subcellular localization analysis confirmed that the GbWRKY20 protein localized to the nucleus. In total, 75 cis-regulatory elements of 19 different types were identified in the GbWRKY20 promoter sequence, including some elements involved in light responsiveness, anaerobic induction and circadian control, low-temperature responsiveness, as well as salicylic acid (SA) and auxin responsiveness. Expression pattern analysis of plant samples from different developmental stages and tissue types, revealed differential GbWRKY20 expression. The GbWRKY20 transcript was downregulated 12 h after heat treatment and at 4-12 h after drought treatment, but was upregulated 12 h after NaCl, cold and methyl jasmonate treatments. For abscisic acid and SA treatments, the GbWRKY20 transcript was upregulated at 24 h. In summary, GbWRKY20 encoded a newly cloned WRKY transcription factor of G. biloba that might be involved in plant growth and plant responses to abiotic stresses and hormones treatments.
PMID: 34024256
J Environ Sci Health B , IF:1.99 , 2021 Oct : P1-9 doi: 10.1080/03601234.2021.1997282
Hormesis of 2,4-D choline salt in productive aspects of cotton.
Departamento de Producao Vegetal (Matologia), FCAV-Faculdade de Ciencias Agrarias e Veterinarias, UNESP, Jaboticabal, Brazil.; Departamento de Producao Vegetal, Universidade Federal de Goias - UFG, Jatai, Brazil.; Departamento de Matologia, Universidade Federal de Mato Grosso - UFMT, Barra do Garcas, Brazil.
The stimulating effect of a low dose of a substance considered to be toxic is known as hormesis. The aim of this work was to use dose-response curves to evaluate the hormesis effect provided by sub-doses of the herbicide 2,4-D choline salt on the productivity of cotton at different phenological stages. The experimental design was based on randomized blocks, with four repetitions and the treatments were distributed in a 9x3 factorial design, with nine fractions of the mean label dose of the herbicide 2,4-D choline salt formulation (0 (control); 0.4275; 0.855; 1.71; 3.42; 8.55; 17.1; 34.2 and 68.4 g a.e. ha(-1)) associated with three different phenological stage of cotton, namely: V4, B4 and C4. The plants were evaluated as to the main productive parameters of the cotton plant. When applied at the V4 stage, sub-doses of the herbicide 2,4-D choline salt negatively affect the cotton crop. Sub-doses between 0.82 and 2.23 g a.e. ha(-1) of the herbicide 2,4-D choline salt applied at the B4 stage of cotton can increase all the productive variables of the crop. The productive aspects of cotton plants in the C4 stage were not influenced by the application of sub-doses of 2,4-D choline salt.
PMID: 34709963