Plant Cell , IF:9.618 , 2020 Apr doi: 10.1105/tpc.19.00578
STRESS INDUCED FACTOR 2 Regulates Arabidopsis Stomatal Immunity Through Phosphorylation of the Anion Channel SLAC1.
National Taiwan University CITY: Taipei STATE: TAIWAN, PROVINCE OF CHINA Taiwan.; Okayama University CITY: Okayama Japan [JP].; University of Tartu CITY: Tartu Estonia [EE].; National Taiwan University CITY: Taipei STATE: TAIWAN, Republic of China (ROC) Taiwan.; National Taiwan University CITY: Taipei Taiwan.; Agricultural Biotechnology Research Center, Academia Sinica CITY: Taipei Taiwan.; National Taiwan University Taipei CITY: Taipei POSTAL_CODE: 10617 Taiwan.; Academia Sinica CITY: Taipei POSTAL_CODE: 115 Taiwan.; Okayama University CITY: Okayama POSTAL_CODE: 700-8530 Japan [JP].; University of Tartu Nooruse 1 CITY: Tartu POSTAL_CODE: 50411 Estonia [EE].; National Taiwan University CITY: Taipei STATE: TAIWAN, PROVINCE OF CHINA POSTAL_CODE: 106 Taiwan lozim4@gmail.com.
Upon recognition of microbes, pattern-recognition receptors (PRRs) activate pattern-triggered immunity (PTI). FLAGELLIN SENSING2 (FLS2) and BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) form a typical PRR complex that senses bacteria. Here we report that the kinase activity of the malectin-like receptor-like kinase STRESS INDUCED FACTOR 2 (SIF2) is critical for Arabidopsis thaliana resistance to bacteria by regulating stomatal immunity. SIF2 physically associates with the FLS2-BAK1 PRR complex and interacts with and phosphorylates the guard cell SLOW ANION CHANNEL1 (SLAC1), which is necessary for abscisic acid (ABA)-mediated stomatal closure. SIF2 is also required for the activation of ABA-induced S-type anion currents in Arabidopsis protoplasts and SIF2 is sufficient to activate SLAC1 anion channels in Xenopus oocytes. SIF2-mediated activation of SLAC1 depends on specific phosphorylation of Serine 65. This work reveals that SIF2 functions between the FLS2-BAK1 initial immunity receptor complex and the final actuator SLAC1 in stomatal immunity.
PMID: 32327536
Plant Cell , IF:9.618 , 2020 Apr , V32 (4) : P923-934 doi: 10.1105/tpc.19.00580
A Single Amino Acid Substitution in STKc_GSK3 Kinase Conferring Semispherical Grains and Its Implications for the Origin of Triticum sphaerococcum.
State Key Laboratory for Agrobiotechnology/Key Laboratory of Crop Heterosis and Utilization, the Ministry of Education/Key Laboratory of Crop Genetic Improvement, National Plant Gene Research Centre, Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing, People's Republic of China.; State Key Laboratory for Agrobiotechnology/Key Laboratory of Crop Heterosis and Utilization, the Ministry of Education/Key Laboratory of Crop Genetic Improvement, National Plant Gene Research Centre, Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing, People's Republic of China qxsun@cau.edu.cn nizf@cau.edu.cn.
Six subspecies of hexaploid wheat (Triticum aestivum) have been identified, but the origin of Indian dwarf wheat (Triticum sphaerococcum), the only subspecies with round grains, is currently unknown. Here, we isolated the grain-shape gene Tasg-D1 in T sphaerococcum via positional cloning. Tasg-D1 encodes a Ser/Thr protein kinase glycogen synthase kinase3 (STKc_GSK3) that negatively regulates brassinosteroid signaling. Expression of TaSG-D1 and the mutant form Tasg-D1 in Arabidopsis (Arabidopsis thaliana) suggested that a single amino acid substitution in the Thr-283-Arg-284-Glu-285-Glu-286 domain of TaSG-D1 enhances protein stability in response to brassinosteroids, likely leading to formation of round grains in wheat. This gain-of-function mutation has pleiotropic effects on plant architecture and exhibits incomplete dominance. Haplotype analysis of 898 wheat accessions indicated that the origin of T sphaerococcum in ancient India involved at least two independent mutations of TaSG-D1 Our results demonstrate that modest genetic changes in a single gene can induce dramatic phenotypic changes.
PMID: 32060175
Plant Cell , IF:9.618 , 2020 Apr , V32 (4) : P984-999 doi: 10.1105/tpc.19.00587
Brassinosteroid and Hydrogen Peroxide Interdependently Induce Stomatal Opening by Promoting Guard Cell Starch Degradation.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, 266237, Qingdao, China.; The Key Laboratory of Molecular and Cellular Biology, Ministry of Education, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Normal University, 050024, Shijiazhuang, China.; Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024, Shijiazhuang, China.; The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University, 266237, Qingdao, China baimingyi@sdu.edu.cn.
Starch is the major storage carbohydrate in plants and functions in buffering carbon and energy availability for plant fitness with challenging environmental conditions. The timing and extent of starch degradation appear to be determined by diverse hormonal and environmental signals; however, our understanding of the regulation of starch metabolism is fragmentary. Here, we demonstrate that the phytohormone brassinosteroid (BR) and redox signal hydrogen peroxide (H2O2) induce the breakdown of starch in guard cells, which promotes stomatal opening. The BR-insensitive mutant bri1-116 accumulated high levels of starch in guard cells, impairing stomatal opening in response to light. The gain-of-function mutant bzr1-1D suppressed the starch excess phenotype of bri1-116, thereby promoting stomatal opening. BRASSINAZOLE-RESISTANT1 (BZR1) interacts with the basic leucine zipper transcription factor G-BOX BINDING FACTOR2 (GBF2) to promote the expression of beta-AMYLASE1 (BAM1), which is responsible for starch degradation in guard cells. H2O2 induces BZR1 oxidation, enhancing the interaction between BZR1 and GBF2 to increase BAM1 transcription. Mutations in BAM1 lead to starch accumulation and reduce the effects of BR and H2O2 on stomatal opening. Overall, this study uncovers the critical roles of BR and H2O2 in regulating guard cell starch metabolism and stomatal opening.
PMID: 32051210
Curr Biol , IF:9.601 , 2020 Apr , V30 (7) : PR294-R298 doi: 10.1016/j.cub.2020.02.011
Brassinosteroid signalling.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. Center for Plant Systems Biology, VIB, Ghent, Belgium. Electronic address: eukim@psb.vib-ugent.be.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. Center for Plant Systems Biology, VIB, Ghent, Belgium. Electronic address: eurus@psb.vib-ugent.be.
In this Primer, Kim and Russinova provide an overview of brassinosteroid signalling in plants.
PMID: 32259497
Curr Biol , IF:9.601 , 2020 Apr , V30 (8) : P1410-1423.e3 doi: 10.1016/j.cub.2020.01.089
SUMO Conjugation to BZR1 Enables Brassinosteroid Signaling to Integrate Environmental Cues to Shape Plant Growth.
Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK.; Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK. Electronic address: ari.sadanandom@durham.ac.uk.
Brassinosteroids (BRs) play crucial roles in plant development, but little is known of mechanisms that integrate environmental cues into BR signaling. Conjugation to the small ubiquitin-like modifier (SUMO) is emerging as an important mechanism to transduce environmental cues into cellular signaling. In this study, we show that SUMOylation of BZR1, a key transcription factor of BR signaling, provides a conduit for environmental influence to modulate growth during stress. SUMOylation stabilizes BZR1 in the nucleus by inhibiting its interaction with BIN2 kinase. During salt stress, Arabidopsis plants arrest growth through deSUMOylation of BZR1 in the cytoplasm by promoting the accumulation of the BZR1 targeting SUMO protease, ULP1a. ULP1a mutants are salt tolerant and insensitive to the BR inhibitor, brassinazole. BR treatment stimulates ULP1a degradation, allowing SUMOylated BZR1 to accumulate and promote growth. This study uncovers a mechanism for integrating environmental cues into BR signaling to shape growth.
PMID: 32109396
Plant Physiol , IF:6.902 , 2020 Apr , V182 (4) : P1762-1775 doi: 10.1104/pp.19.01172
EPSIN1 Modulates the Plasma Membrane Abundance of FLAGELLIN SENSING2 for Effective Immune Responses.
University of Missouri, Division of Biochemistry, Interdisciplinary Plant Group, Columbia, Missouri 65211.; University of Missouri, Division of Biochemistry, Interdisciplinary Plant Group, Christopher S. Bond Life Sciences Center, Columbia, Missouri 65211.; University of Missouri, Division of Biochemistry, Interdisciplinary Plant Group, Columbia, Missouri 65211 heesea@missouri.edu.
The plasma membrane (PM) provides a critical interface between plant cells and their environment to control cellular responses. To perceive the bacterial flagellin peptide flg22 for effective defense signaling, the immune receptor FLAGELLIN SENSING2 (FLS2) needs to be at its site of function, the PM, in the correct abundance. However, the intracellular machinery that controls PM accumulation of FLS2 remains largely undefined. The Arabidopsis (Arabidopsis thaliana) clathrin adaptor EPSIN1 (EPS1) is implicated in clathrin-coated vesicle formation at the trans-Golgi network (TGN), likely aiding the transport of cargo proteins from the TGN for proper location; but EPS1's impact on physiological responses remains elusive. Here, we identify EPS1 as a positive regulator of flg22 signaling and pattern-triggered immunity against Pseudomonas syringae pv tomato DC3000. We provide evidence that EPS1 contributes to modulating the PM abundance of defense proteins for effective immune signaling because in eps1, impaired flg22 signaling correlated with reduced PM accumulation of FLS2 and its coreceptor BRASSINOSTEROID INSENSITIVE1-ASSOCIATED RECEPTOR KINASE1 (BAK1). The eps1 mutant also exhibited reduced responses to the pathogen/damage-associated molecular patterns elf26 and AtPep1, which are perceived by the coreceptor BAK1 and cognate PM receptors. Furthermore, quantitative proteomics of enriched PM fractions revealed that EPS1 was required for proper PM abundance of a discrete subset of proteins with different cellular functions. In conclusion, our study expands the limited understanding of the physiological roles of EPSIN family members in plants and provides novel insight into the TGN-associated clathrin-coated vesicle trafficking machinery that impacts plant PM-derived defense processes.
PMID: 32094305
J Integr Plant Biol , IF:4.885 , 2020 Apr , V62 (4) : P456-469 doi: 10.1111/jipb.12803
Specifying the role of BAK1-interacting receptor-like kinase 3 in brassinosteroid signaling.
Centre for Organismal Studies/ BioQuant, Heidelberg University, 69120, Heidelberg, Germany.; Center for Plant Molecular Biology (ZMBP), University Tubingen, 72076, Tubingen, Germany.
Brassinosteroids (BR) are involved in the control of several developmental processes ranging from root elongation to senescence and adaptation to environmental cues. Thus, BR perception and signaling have to be precisely regulated. One regulator is BRI1-associated kinase 1 (BAK1)-interacting receptor-like kinase 3 (BIR3). In the absence of BR, BIR3 forms complexes with BR insensitive 1 (BRI1) and BAK1. However, the biophysical and energetic requirements for complex formation in the absence of the ligand have yet to be determined. Using computational modeling, we simulated the potential complexes between the cytoplasmic domains of BAK1, BRI1 and BIR3. Our calculations and experimental data confirm the interaction of BIR3 with BAK1 and BRI1, with the BAK1 BIR3 interaction clearly favored. Furthermore, we demonstrate that BIR3 and BRI1 share the same interaction site with BAK1. This suggests a competition between BIR3 and BRI1 for binding to BAK1, which results in preferential binding of BIR3 to BAK1 in the absence of the ligand thereby preventing the active participation of BAK1 in BR signaling. Our model also suggests that BAK1 and BRI1 can interact even while BAK1 is in complex with BIR3 at an additional binding site of BAK1 that does not allow active BR signaling.
PMID: 30912278
J Integr Plant Biol , IF:4.885 , 2020 Apr , V62 (4) : P509-526 doi: 10.1111/jipb.12796
Elicitor hydrophobin Hyd1 interacts with Ubiquilin1-like to induce maize systemic resistance.
Key Laboratory of Urban Agriculture (South) Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.; State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China.; School of Life Science, Fuyang Normal University, Fuyang, 236037, China.
Trichoderma harzianum is a plant-beneficial fungus that secretes small cysteine-rich proteins that induce plant defense responses; however, the molecular mechanism involved in this induction is largely unknown. Here, we report that the class II hydrophobin ThHyd1 acts as an elicitor of induced systemic resistance (ISR) in plants. Immunogold labeling and immunofluorescence revealed ThHyd1 localized on maize (Zea mays) root cell plasma membranes. To identify host plant protein interactors of Hyd1, we screened a maize B73 root cDNA library. ThHyd1 interacted directly with ubiquilin 1-like (UBL). Furthermore, the N-terminal fragment of UBL was primarily responsible for binding with Hyd1 and the eight-cysteine amino acid of Hyd1 participated in the protein-protein interactions. Hyd1 from T. harzianum (Thhyd1) and ubl from maize were co-expressed in Arabidopsis thaliana, they synergistically promoted plant resistance against Botrytis cinerea. RNA-sequencing analysis of global gene expression in maize leaves 24 h after spraying with Curvularia lunata spore suspension showed that Thhyd1-induced systemic resistance was primarily associated with brassinosteroid signaling, likely mediated through BAK1. Jasmonate/ethylene (JA/ET) signaling was also involved to some extent in this response. Our results suggest that the Hyd1-UBL axis might play a key role in inducing systemic resistance as a result of Trichoderma-plant interactions.
PMID: 30803127
Int J Mol Sci , IF:4.556 , 2020 Apr , V21 (8) doi: 10.3390/ijms21082737
Molecular Mechanisms of Brassinosteroid-Mediated Responses to Changing Environments in Arabidopsis.
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu, China.
Plant adaptations to changing environments rely on integrating external stimuli into internal responses. Brassinosteroids (BRs), a group of growth-promoting phytohormones, have been reported to act as signal molecules mediating these processes. BRs are perceived by cell surface receptor complex including receptor BRI1 and coreceptor BAK1, which subsequently triggers a signaling cascade that leads to inhibition of BIN2 and activation of BES1/BZR1 transcription factors. BES1/BZR1 can directly regulate the expression of thousands of downstream responsive genes. Recent studies in the model plant Arabidopsis demonstrated that BR biosynthesis and signal transduction, especially the regulatory components BIN2 and BES1/BZR1, are finely tuned by various environmental cues. Here, we summarize these research updates and give a comprehensive review of how BR biosynthesis and signaling are modulated by changing environments and how these changes regulate plant adaptive growth or stress tolerance.
PMID: 32326491
Int J Mol Sci , IF:4.556 , 2020 Apr , V21 (7) doi: 10.3390/ijms21072540
Prospects of Gene Knockouts in the Functional Study of MAMP-Triggered Immunity: A Review.
Department of Biochemistry, University of Johannesburg, Auckland Park 2006, South Africa.
Plants depend on both preformed and inducible defence responses to defend themselves against biotic stresses stemming from pathogen attacks. In this regard, plants perceive pathogenic threats from the environment through pattern recognition receptors (PRRs) that recognise microbe-associated molecular patterns (MAMPs), and so induce plant defence responses against invading pathogens. Close to thirty PRR proteins have been identified in plants, however, the molecular mechanisms underlying MAMP perception by these receptors/receptor complexes are not fully understood. As such, knockout (KO) of genes that code for PRRs and co-receptors/defence-associated proteins is a valuable tool to study plant immunity. The loss of gene activity often causes changes in the phenotype of the model plant, allowing in vivo studies of gene function and associated biological mechanisms. Here, we review the functions of selected PRRs, brassinosteroid insensitive 1 (BRI1) associated receptor kinase 1 (BAK1) and other associated defence proteins that have been identified in plants, and also outline KO lines generated by T-DNA insertional mutagenesis as well as the effect on MAMP perception-and triggered immunity (MTI). In addition, we further review the role of membrane raft domains in flg22-induced MTI in Arabidopsis, due to the vital role in the activation of several proteins that are part of the membrane raft domain theory in this regard.
PMID: 32268496
Plant Cell Physiol , IF:4.062 , 2020 Apr doi: 10.1093/pcp/pcaa053
Light Activates Brassinosteroid Biosynthesis to Promote Hook Opening and Petiole Development in Arabidopsis thaliana.
Yokohama City University Kihara Institute for Biological Research, Totsuka, Yokohama, Kanagawa, Japan.; RIKEN Plant Science Center, Suehirocho 1-7-22, Tsurumi, Yokohama, Japan.; RIKEN Advanced Science Institute, Wako, Saitama, Japan.; Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan.; Department of Chemistry, Joetsu University of Education, Joetsu, Niigata, Japan.; RIKEN Center for Sustainable Resource Science, Suehirocho 1-7-22, Tsurumi, Yokohama, Japan.
Although brassinosteroids (BRs) have been proposed to be negative regulators of photomorphogenesis, their physiological role therein has remained elusive. We studied light-induced photomorphogenic development in the presence of the BR-biosynthesis inhibitor, brassinazole (Brz). Hook opening was inhibited in the presence of Brz; this inhibition was reversed in the presence of brassinolide. Hook opening was accompanied by cell expansion on the inner (concave) side of the hook. This cell expansion was inhibited in the presence of Brz, but was restored upon addition of brassinolide. We then evaluated light-induced organ-specific expression of three BR biosynthesis genes, DWF4, BR6ox1, BR6ox2, and a BR-responsive gene, SAUR-AC1, during photomorphogenesis of Arabidopsis. Expression of these genes was induced, particularly in the hook region, in response to illumination. The induction peaked after 3 h light exposure and preceded hook opening. Phytochrome-deficient mutants, hy1, hy2, and phyAphyB, and a light-signaling mutant, hy5, were defective in light-induced expression of BR6ox1, BR6ox2 and SAUR-AC1. Light induced both expression of BR6ox genes and petiole development. Petiole development was inhibited in the presence of Brz. Our results largely contradict the early view that BRs are negative regulators of photomorphogenesis. Our data collectively suggest that light activates expression of BR biosynthesis genes in the hook region via a phytochrome-signaling pathway and HY5, and that BR biosynthesis is essential for hook opening and petiole development during photomorphogenesis.
PMID: 32333772
Ann Bot , IF:4.005 , 2020 Apr doi: 10.1093/aob/mcaa077
Processes controlling programmed cell death of root velamen radicum in an epiphytic orchid.
CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China.; Center of Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, Yunnan, China.; Key Laboratory for Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China.; Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China.; Global Ecology, College of Science and Engineering, Flinders University, , Adelaide, South Australia, Australia.
BACKGROUND AND AIMS: Development of the velamen radicum on the outer surface of the root epidermis is an important characteristic for water uptake and retention in some plant families, particularly in epiphytic orchids, for survival under water-limited environments. Velamen radicum cells derive from the primary root meristem, however, following this development, velamen radicum cells die by incompletely understood processes of programmed cell death (PCD). METHODS: We combined the use of transmission electron microscopy, x-ray microtomography, and transcriptome methods to characterize the major anatomical and molecular changes that occur during the development and death of velamen radicum cells of Cymbidium tracyanum, a typical epiphytic orchid, to determine how PCD occurs. KEY RESULTS: Typical changes of PCD in anatomy and gene expression were observed in the development of velamen radicum cells. During the initiation of PCD, we found that both cell and vacuole size increased, and several genes involved in brassinosteroid and ethylene pathways were up-regulated. In the stage of secondary cell wall formation, significant anatomical changes included DNA degradation, cytoplasm thinning, organelle decrease, vacuole rupture and cell wall thickening. Changes were found in the expression of genes related to the biosynthesis of cellulose and lignin, which are instrumental in the formation of secondary cell walls, and are regulated by cytoskeleton-related factors and phenylalanine ammonia-lyase. In the final stage of PCD, cell autolysis was terminated from the outside to the inside of the velamen radicum. The regulation of genes related to autophagy, vacuolar processing enzyme, cysteine proteases and metacaspase were involved in the final execution of cell death and autolysis. CONCLUSIONS: Our results found that the development of the root velamen radicum in an epiphytic orchid was controlled by the process of PCD, which included initiation of PCD, followed by formation of the secondary cell wall, and execution of autolysis following cell death.
PMID: 32318689
Mol Plant Microbe Interact , IF:3.696 , 2020 Apr , V33 (4) : P600-611 doi: 10.1094/MPMI-09-19-0250-R
Benzothiadiazole Conditions the Bean Proteome for Immunity to Bean Rust.
Soybean Genomics and Improvement Laboratory, USDA-ARS, Beltsville, MD, U.S.A.; Animal Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, MD, U.S.A.
The common bean rust fungus reduces harvests of the dry, edible common bean. Natural resistance genes in the plant can provide protection until a fungal strain that breaks resistance emerges. In this study, we demonstrate that benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH) sprayed on susceptible beans induces resistance to common bean rust. Protection occurred as soon as 72 h after treatment and resulted in no signs of disease 10 days after inoculation with rust spores. By contrast, the susceptible control plants sustained heavy infections and died. To understand the effect BTH has on the bean proteome, we measured the changes of accumulation for 3,973 proteins using mass spectrometry. The set of 409 proteins with significantly increased accumulation in BTH-treated leaves included receptor-like kinases SOBIR1, CERK1, and LYK5, which perceive pathogens, and EDS1, a regulator of the salicylic acid defense pathway. Other proteins that likely contributed to resistance included pathogenesis-related proteins, a full complement of enzymes that catalyze phenylpropanoid biosynthesis, and protein receptors, transporters, and enzymes that modulate other defense responses controlled by jasmonic acid, ethylene, brassinosteroid, abscisic acid, and auxin. Increases in the accumulation of proteins required for vesicle-mediated protein secretion and RNA splicing occurred as well. By contrast, more than half of the 168 decreases belonged to chloroplast proteins and proteins involved in cell expansion. These results reveal a set of proteins needed for rust resistance and reaffirm the utility of BTH to control disease by amplifying the natural immune system of the bean plant.
PMID: 31999214
Plant Sci , IF:3.591 , 2020 Apr , V293 : P110435 doi: 10.1016/j.plantsci.2020.110435
Gibberellin recovers seed germination in rice with impaired brassinosteroid signalling.
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China. Electronic address: qfli@yzu.edu.cn.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.; Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China. Electronic address: qqliu@yzu.edu.cn.
Seed germination is essential for ensuring grain yield and quality. Germination rate, uniformity, and post-germination growth all contribute to cultivation. Although the phytohormones gibberellin (GA) and brassinosteroid (BR) are known to regulate germination, the underlying mechanism of their crosstalk in co-regulating rice seed germination remains unclear. In this study, the isobaric tags for relative and absolute quantitation (iTRAQ) proteomic approach was employed to identify target proteins responsive to GA during recovery of germination in BR-deficient and BR-insensitive rice. A total of 42 differentially abundant proteins were identified in both BR-deficient and BR-insensitive plants, and most were altered consistently in the two groups. Gene Ontology (GO) analysis revealed enrichment in proteins with binding and catalytic activity. A potential protein-protein interaction network was constructed using STRING analysis, and five Late Embryogenesis Abundant (LEA) family members were markedly down-regulated at both mRNA transcript and protein levels. These LEA genes were specifically expressed in rice seeds, especially during the latter stages of seed development. Mutation of LEA33 affected rice grain size and seed germination, possibly by reducing BR accumulation and enhancing GA biosynthesis. The findings improve our knowledge of the mechanisms by which GA and BR coordinate seed germination.
PMID: 32081273
Plant Mol Biol , IF:3.302 , 2020 Apr , V102 (6) : P589-602 doi: 10.1007/s11103-020-00965-5
The basic helix-loop-helix transcription factor OsBLR1 regulates leaf angle in rice via brassinosteroid signalling.
College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, Henan, China.; College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, Henan, China.; College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, Henan, China. qzzhaoh@126.com.; College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, Henan, China. zhaowenli19900218@163.com.
Leaf angle is a key factor in plant architecture and crop yield. Brassinosteroids (BRs) regulate many developmental processes, especially the leaf angle in monocots. However, the BR signalling pathway is complex and includes many unknown members. Here, we propose that Oryza sativa BRASSINOSTEROID-RESPONSIVE LEAF ANGLE REGULATOR 1 (OsBLR1) encodes a bHLH transcription factor, and positively regulates BR signalling to increase the leaf angle and grain length in rice (Oryza sativa L.). Lines overexpressing OsBLR1 (blr1-D and BLR1-OE-1/2/3) had similar traits, with increased leaf angle and grain length. Conversely, OsBLR1-knockout mutants (blr1-1/2/3) had erect leaves and shorter grains. Lamina joint inclination, coleoptile elongation, and root elongation assay results indicated that these overexpression lines were more sensitive to BR, while the knockout mutants were less sensitive. There was no significant difference in the endogenous BR contents of blr1-1/2 and wild-type plants. These results suggest that OsBLR1 is involved in BR signal transduction. The blr1-D mutant, with increased cell growth in the lamina joint and smaller leaf midrib, showed significant changes in gene expression related to the cell wall and leaf development compared with wild-type plants; furthermore, the cellulose and protopectin contents in blr1-D were reduced, which resulted in the increased leaf angle and bent leaves. As the potential downstream target gene of OsBLR1, the REGULATOR OF LEAF INCLINATION1 (OsRLI1) gene expression was up-regulated in OsBLR1-overexpression lines and down-regulated in OsBLR1-knockout mutants. Moreover, we screened OsRACK1A as an interaction protein of OsBLR1 using a yeast two-hybrid assay and glutathione-S-transferase pull-down.
PMID: 32026326
Plant Direct , IF:1.725 , 2020 Apr , V4 (4) : Pe00212 doi: 10.1002/pld3.212
Exogenous sodium diethyldithiocarbamate, a Jasmonic acid biosynthesis inhibitor, induced resistance to powdery mildew in wheat.
Key Laboratory of Crop Heterosis and Utilization (MOE) and State Key Laboratory for Agrobiotechnology Beijing Key Laboratory of Crop Genetic Improvement China Agricultural University Beijing China.; Institute of Evolution University of Haifa, Mt. Carmel Haifa Israel.
Jasmonic acid (JA) is an important plant hormone associated with plant-pathogen defense. To study the role of JA in plant-fungal interactions, we applied a JA biosynthesis inhibitor, sodium diethyldithiocarbamate (DIECA), on wheat leaves. Our results showed that application of 10 mM DIECA 0-2 days before inoculation effectively induced resistance to powdery mildew (Bgt) in wheat. Transcriptome analysis identified 364 up-regulated and 68 down-regulated differentially expressed genes (DEGs) in DIECA-treated leaves compared with water-treated leaves. Gene ontology (GO) enrichment analysis of the DEGs revealed important GO terms and pathways, in particular, response to growth hormones, activity of glutathione metabolism (e.g., glutathione transferase activity), oxalate oxidase, and chitinase activity. Gene annotaion revealed that some pathogenesis-related (PR) genes, such as PR1.1, PR1, PR10, PR4a, Chitinase 8, beta-1,3-glucanase, RPM1, RGA2, and HSP70, were induced by DIECA treatment. DIECA reduced JA and auxin (IAA) levels, while increased brassinosteroid, glutathione, and ROS lesions in wheat leaves, which corroborated with the transcriptional changes. Our results suggest that DIECA can be applied to increase plant immunity and reduce the severity of Bgt disease in wheat fields.
PMID: 32285024