Mol Plant , IF:13.164 , 2022 May doi: 10.1016/j.molp.2022.05.002
Brassinosteroids enhance salicylic acid-mediated immune responses by inhibiting BIN2 phosphorylation of clade I TGA transcription factors in Arabidopsis.
Department of Life Science, Hanyang University, Seoul 04763, Republic of Korea.; Department of Life Science, Chung-Ang University, Seoul 06973, Republic of Korea.; Department of Life Science, Chung-Ang University, Seoul 06973, Republic of Korea. Electronic address: skkimbio@cau.ac.kr.; Department of Life Science, Hanyang University, Seoul 04763, Republic of Korea; Research Institute for Convergence of Basic Science, Hanyang University, Seoul 04763, Republic of Korea; Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul 04763, Republic of Korea. Electronic address: twgibio@hanyang.ac.kr.
Salicylic acid (SA) plays an important role in plant immune response, including resistance to pathogens and systemic acquired resistance. Two major components, NONEXPRESSOR OF PATHOGENESIS-RELATED GENES (NPRs) and TGACG motif-binding transcription factors (TGAs), are known to mediate SA signaling, which might also be orchestrated by other hormonal and environmental changes. Nevertheless, the molecular and functional interactions between SA signaling components and other cellular signaling pathways remain poorly understood. Here we showed that the steroid plant hormone brassinosteroid (BR) promotes SA responses by inactivating BR-INSENSITIVE 2 (BIN2), which inhibits the redox-sensitive clade I TGAs in Arabidopsis. We found that both BR and the BIN2 inhibitor bikinin synergistically increase SA-mediated physiological responses, such as resistance to Pst DC3000. Our genetic and biochemical analyses indicated that BIN2 functionally interacts with TGA1 and TGA4, but not with other TGAs. We further demonstrated that BIN2 phosphorylates Ser-202 of TGA4, resulting in the suppression of the redox-dependent interaction between TGA4 and NPR1 as well as destabilization of TGA4. Consistently, transgenic Arabidopsis overexpressing TGA4-YFP with a S202A mutation displayed enhanced SA responses compared to the wild-type TGA4-YFP plants. Taken together, these results suggest a novel crosstalk mechanism by which BR signaling coordinates the SA responses mediated by redox-sensitive clade I TGAs.
PMID: 35524409
Plant Cell , IF:11.277 , 2022 May , V34 (6) : P2266-2285 doi: 10.1093/plcell/koac092
The photomorphogenic repressors BBX28 and BBX29 integrate light and brassinosteroid signaling to inhibit seedling development in Arabidopsis.
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.; Department of Biology, Institute of Plant and Food Sciences, Southern University of Science and Technology, Shenzhen 518055, China.; State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing 100871, China.; National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.; State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361102, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, College of Agriculture, Nanjing Agricultural University, Nanjing 210095, China.; School of Life Sciences, Guangzhou University, Guangzhou 510006, China.
B-box containing proteins (BBXs) integrate light and various hormonal signals to regulate plant growth and development. Here, we demonstrate that the photomorphogenic repressors BBX28 and BBX29 positively regulate brassinosteroid (BR) signaling in Arabidopsis thaliana seedlings. Treatment with the BR brassinolide stabilized BBX28 and BBX29, which partially depended on BR INSENSITIVE1 (BRI1) and BIN2. bbx28 bbx29 seedlings exhibited larger cotyledon aperture than the wild-type when treated with brassinazole in the dark, which partially suppressed the closed cotyledons of brassinazole resistant 1-1D (bzr1-1D). Consistently, overexpressing BBX28 and BBX29 partially rescued the short hypocotyls of bri1-5 and bin2-1 in both the dark and light, while the loss-of-function of BBX28 and BBX29 partially suppressed the long hypocotyls of bzr1-1D in the light. BBX28 and BBX29 physically interacted with BR-ENHANCED EXPRESSION1 (BEE1), BEE2, and BEE3 and enhanced their binding to and activation of their target genes. Moreover, BBX28 and BBX29 as well as BEE1, BEE2, and BEE3 increased BZR1 accumulation to promote the BR signaling pathway. Therefore, both BBX28 and BBX29 interact with BEE1, BEE2, and BEE3 to orchestrate light and BR signaling by facilitating the transcriptional activity of BEE target genes. Our study provides insights into the pivotal roles of BBX28 and BBX29 as signal integrators in ensuring normal seedling development.
PMID: 35294019
Plant Cell , IF:11.277 , 2022 Apr , V34 (5) : P1768-1783 doi: 10.1093/plcell/koac027
BRASSINOSTEROID-SIGNALING KINASE1 modulates MAP KINASE15 phosphorylation to confer powdery mildew resistance in Arabidopsis.
State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; Fujian Provincial Key Laboratory of Crop Breeding by Design, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Perception of pathogen-associated molecular patterns (PAMPs) by plant cell surface-localized pattern-recognition receptors (PRRs) triggers the first line of plant innate immunity. In Arabidopsis thaliana, the receptor-like cytoplasmic kinase BRASSINOSTEROID-SIGNALING KINASE1 (BSK1) physically associates with PRR FLAGELLIN SENSING2 and plays an important role in defense against multiple pathogens. However, how BSK1 transduces signals to activate downstream immune responses remains elusive. Previously, through whole-genome phosphorylation analysis using mass spectrometry, we showed that phosphorylation of the mitogen-activated protein kinase (MAPK) MPK15 was affected in the bsk1 mutant compared with the wild-type plants. Here, we demonstrated that MPK15 is important for powdery mildew fungal resistance. PAMPs and fungal pathogens significantly induced the phosphorylation of MPK15 Ser-511, a key phosphorylation site critical for the functions of MPK15 in powdery mildew resistance. BSK1 physically associates with MPK15 and is required for basal and pathogen-induced MPK15 Ser-511 phosphorylation, which contributes to BSK1-mediated fungal resistance. Taken together, our data identified MPK15 as a player in plant defense against powdery mildew fungi and showed that BSK1 promotes fungal resistance in part by enhancing MPK15 Ser-511 phosphorylation. These results uncovered a mechanism of BSK1-mediated disease resistance and provided new insight into the role of MAPK phosphorylation in plant immunity.
PMID: 35099562
Curr Biol , IF:10.834 , 2022 Apr doi: 10.1016/j.cub.2022.04.028
The receptor kinase OsWAK11 monitors cell wall pectin changes to fine-tune brassinosteroid signaling and regulate cell elongation in rice.
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024 Shijiazhuang, China; Institute of Cash Crops, Hebei Academy of Agriculture & Forestry Sciences, Shijiazhuang 050051, China.; Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024 Shijiazhuang, China.; State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.; Institute of Cash Crops, Hebei Academy of Agriculture & Forestry Sciences, Shijiazhuang 050051, China.; Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA.; Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024 Shijiazhuang, China. Electronic address: swzhang@hebtu.edu.cn.
Rates of plant cell elongation change with day-night alternation, reflecting differences in metabolism related to cell wall remodeling. Information from cell wall surveillance pathways must be integrated with growth regulation pathways to provide feedback regulation of cell wall modification; such feedback regulation is important to ensure sufficient strength and prevent rupture of the cell wall during growth. Several lines of evidence suggest that cell wall perturbations often influence phytohormone signaling, but the identity of the nexus between these two processes remained elusive. Here, we show that wall-associated kinase11 (OsWAK11) acts as a linker connecting cell wall pectin methyl-esterification changes and brassinosteroid (BR) signaling in rice. Our data show that OsWAK11 controls several important agronomical traits by regulating cell elongation in rice. OsWAK11 directly binds and phosphorylates the BR receptor OsBRI1 at residue Thr752, within a motif conserved across most monocot graminaceous crops, thus hindering OsBRI1 interaction with its co-receptor OsSERK1/OsBAK1 and inhibiting BR signaling. The extracellular domain of OsWAK11 shows a much stronger interaction toward methyl-esterified pectin as compared with de-methyl-esterified pectin. OsWAK11 is stabilized in light but is degraded in darkness, in a process triggered by changes in the ratio of methyl-esterified to de-methyl-esterified pectin, creating fluctuations in plant BR signaling in response to day and night alternation. We conclude that OsWAK11 is a cell wall monitor that regulates cell elongation rates to adapt to the environment from the outside in, which complements the well-established inside-out signaling pathway affecting cell elongation in plants.
PMID: 35512695
New Phytol , IF:10.151 , 2022 May doi: 10.1111/nph.18228
Pan-brassinosteroid signaling revealed by functional analysis of NILR1 in land plants.
College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China.
Brassinosteroid (BR) signaling has been identified from the ligand BRs sensed by the receptor BRI1 to the final activation of BZR1/BES1 through a series of transduction events. Extensive studies have been conducted to characterize the role of BR signaling in various biological processes. Our previous study has shown that EMS1 and BRI1 control different aspects of plant growth and development via the conserved intracellular signaling. Here, we reveal that another receptor NILR1 can complement the bri1 mutant in absence of BRs, indicating a pathway that resembles BR signaling activated by NILR1. Genetic analysis shows the intracellular domains of NILR1, BRI1 and EMS1 have a common signal output. Furthermore, we demonstrate that NILR1 and BRI1 share the co-receptor BAK1 and substrate BSKs. Notably, the NILR1-mediated downstream pathway is conserved across land plants. In summary, we provide evidence for the signaling cascade of NILR1, suggesting pan-brassinosteroid signaling initiated by a group of distant receptor-ligand pairs in land plants.
PMID: 35570834
EMBO Rep , IF:8.807 , 2022 Apr , V23 (4) : Pe53354 doi: 10.15252/embr.202153354
Deubiquitinating enzymes UBP12 and UBP13 stabilize the brassinosteroid receptor BRI1.
Graduate School of Life Science, Hokkaido University, Sapporo, Japan.; Faculty of Science, Hokkaido University, Sapporo, Japan.; Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.; Center for Plant Systems Biology, VIB, Ghent, Belgium.; Department of Plant Pathology & Microbiology, Texas A&M University, College Station, TX, USA.; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX, USA.
Protein ubiquitination is a dynamic and reversible post-translational modification that controls diverse cellular processes in eukaryotes. Ubiquitin-dependent internalization, recycling, and degradation are important mechanisms that regulate the activity and the abundance of plasma membrane (PM)-localized proteins. In plants, although several ubiquitin ligases are implicated in these processes, no deubiquitinating enzymes (DUBs), have been identified that directly remove ubiquitin from membrane proteins and limit their vacuolar degradation. Here, we discover two DUB proteins, UBP12 and UBP13, that directly target the PM-localized brassinosteroid (BR) receptor BR INSENSITIVE1 (BRI1) in Arabidopsis. BRI1 protein abundance is decreased in the ubp12i/ubp13 double mutant that displayed severe growth defects and reduced sensitivity to BRs. UBP13 directly interacts with and effectively removes K63-linked polyubiquitin chains from BRI1, thereby negatively modulating its vacuolar targeting and degradation. Our study reveals that UBP12 and UBP13 play crucial roles in governing BRI1 abundance and BR signaling activity to regulate plant growth.
PMID: 35166439
Plant Physiol , IF:8.34 , 2022 May doi: 10.1093/plphys/kiac237
Receptor-like protein kinase BAK1 promotes K+ uptake by regulating H+-ATPase AHA2 under low potassium stress.
State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing 100193, China.; School of Life Science, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei, 071002, China.
Potassium (K+) is one of the essential macronutrients for plant growth and development. However, the available K+ concentration in soil is relatively low. Plant roots can perceive low K+ (LK) stress, then enhance high-affinity K+ uptake by activating H+-ATPases in root cells, but the mechanisms are still unclear. Here, we identified the receptor-like protein kinase BAK1 (Brassinosteroid Insensitive 1-Associated Receptor Kinase 1) that is involved in LK response by regulating the Arabidopsis (Arabidopsis thaliana) PM (plasma membrane) H+-ATPase isoform 2 (AHA2). The bak1 mutant showed leaf chlorosis phenotype and reduced K+ content under LK conditions, which was due to the decline of K+ uptake capacity. BAK1 could directly interact with the AHA2 C terminus and phosphorylate T858 and T881, by which the H+ pump activity of AHA2 was enhanced. The bak1 aha2 double mutant also displayed a leaf chlorosis phenotype that was similar to their single mutants. The constitutively activated form AHA2Delta98 and phosphorylation-mimic form AHA2T858D or AHA2T881D could complement the LK sensitive phenotypes of both aha2 and bak1 mutants. Together, our data demonstrate that BAK1 phosphorylates AHA2 and enhances its activity, which subsequently promotes K+ uptake under LK conditions.
PMID: 35604103
Plant Physiol , IF:8.34 , 2022 May doi: 10.1093/plphys/kiac194
SAUR15 interaction with BRI1 activates plasma membrane H+-ATPase to promote organ development of Arabidopsis.
State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, People's Republic of China.; Department of Biology, Institute of Biochemistry, Carleton University, Ottawa, Ontario, K1S 5B6, Canada.; Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, People's Republic of China.; School of Life Sciences, Guangzhou University, Guangzhou 510006, People's Republic of China.
Brassinosteroids (BRs) are an important group of plant steroid hormones that regulate growth and development. Several members of the SMALL AUXIN UP RNA (SAUR) family have roles in BR-regulated hypocotyl elongation and root growth. However, the mechanisms are unclear. Here, we show in Arabidopsis (Arabidopsis thaliana) that SAUR15 interacts with cell surface receptor-like kinase BRASSINOSTEROID-INSENSITIVE 1 (BRI1) in BR-treated plants, resulting in enhanced BRI1 phosphorylation status and recruitment of the co-receptor BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1). Genetic and phenotypic assays indicated that the SAUR15 effect on BRI1 can be uncoupled from BRASSINOSTEROID INSENSITIVE 2 (BIN2) activity. Instead, we show that SAUR15 promotes BRI1 direct activation of plasma membrane H+-ATPase (PM H+-ATPase) via phosphorylation. Consequently, SAUR15-BRI1-PM H+-ATPase acts as a direct, PM-based mode of BR signaling that drives cell expansion to promote the growth and development of various organs. These data define an alternate mode of BR signaling in plants.
PMID: 35511168
Plant Physiol , IF:8.34 , 2022 Apr doi: 10.1093/plphys/kiac185
Transcription factor OsNAC016: a convergent point of brassinosteroid and abscisic acid signaling in rice.
International Genome Center, Jiangsu University, Zhenjiang 212013, China.
PMID: 35460247
Plant Physiol , IF:8.34 , 2022 Apr doi: 10.1093/plphys/kiac157
The interplay of auxin and brassinosteroid signaling tunes root growth under low and different nitrogen forms.
National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India, 110067.
The coordinated signaling activity of auxin and brassinosteroids (BRs) is critical for optimal plant growth and development. Nutrient-derived signals regulate root growth by modulating the levels and spatial distribution of growth hormones to optimize nutrient uptake and assimilation. However, the effect of the interaction of these two hormones and their signaling on root plasticity during low and differential availability of nitrogen (N) forms (NH4+/NO3-) remains elusive. We demonstrate that root elongation under low nitrogen (LN) is an outcome of the interdependent activity of auxin and BR signaling pathways in Arabidopsis (Arabidopsis thaliana). LN promotes root elongation by increasing BR-induced auxin transport activity in the roots. Increased nuclear auxin signaling and its transport efficiency have a distinct impact on root elongation under LN conditions. High auxin levels reversibly inhibit BR signaling via BRI1 KINASE INHIBITOR1 (BKI1). Using the tissue-specific approach, we show that BR signaling from root vasculature (stele) tissues is sufficient to promote cell elongation and, hence, root growth under LN condition. Further, we show that N form-defined root growth attenuation or enhancement depends on the fine balance of BR and auxin signaling activity. NH4+ as a sole N source represses BR signaling and response, which in turn inhibits auxin response and transport, whereas NO3- promotes root elongation in a BR signaling-dependent manner. In this study, we demonstrate the interplay of auxin and BR-derived signals, which are critical for root growth in a heterogeneous N environment and appear essential for root N foraging response and adaptation.
PMID: 35377445
Plant Physiol , IF:8.34 , 2022 May , V189 (1) : P402-418 doi: 10.1093/plphys/kiac043
Brassinosteroids regulate rice seed germination through the BZR1-RAmy3D transcriptional module.
Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Jiangsu Key Laboratory of Crop Genetics and Physiology/Sate Key Laboratory of Hybrid Rice, College of Agriculture, Yangzhou University, Yangzhou 225009, Jiangsu, China.; Co-Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province/Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou 225009, Jiangsu, China.
Seed dormancy and germination, two physiological processes unique to seed-bearing plants, are critical for plant growth and crop production. The phytohormone brassinosteroid (BR) regulates many aspects of plant growth and development, including seed germination. The molecular mechanisms underlying BR control of rice (Oryza sativa) seed germination are mostly unknown. We investigated the molecular regulatory cascade of BR in promoting rice seed germination and post-germination growth. Physiological assays indicated that blocking BR signaling, including introducing defects into the BR-insensitive 1 (BRI1) receptor or overexpressing the glycogen synthase kinase 2 (GSK2) kinase delayed seed germination and suppressed embryo growth. Our results also indicated that brassinazole-resistant 1 (BZR1) is the key downstream transcription factor that mediates BR regulation of seed germination by binding to the alpha-Amylase 3D (RAmy3D) promoter, which affects alpha-amylase expression and activity and the degradation of starch in the endosperm. The BZR1-RAmy3D module functions independently from the established Gibberellin MYB-alpha-amylase 1A (RAmy1A) module of the gibberellin (GA) pathway. We demonstrate that the BZR1-RAmy3D module also functions in embryo-related tissues. Moreover, RNA-sequencing (RNA-seq) analysis identified more potential BZR1-responsive genes, including those involved in starch and sucrose metabolism. Our study successfully identified the role of the BZR1-RAmy3D transcriptional module in regulating rice seed germination.
PMID: 35139229
Plant Physiol , IF:8.34 , 2022 May , V189 (1) : P285-300 doi: 10.1093/plphys/kiac046
The CCCH zinc finger protein C3H15 negatively regulates cell elongation by inhibiting brassinosteroid signaling.
College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, China.; Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.; Academy of Dongying Efficient Agricultural Technology and Industry on Saline and Alkaline Land in Collaboration with Qingdao Agricultural University, Dongying 257000, China.; State Key Laboratory of Wheat and Maize Crop Science and College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.; College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China.; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.; Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Sciences, Shandong University, Jinan 250100, China.; College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China.
Plant CCCH proteins participate in the control of multiple developmental and adaptive processes, but the regulatory mechanisms underlying these processes are not well known. In this study, we showed that the Arabidopsis (Arabidopsis thaliana) CCCH protein C3H15 negatively regulates cell elongation by inhibiting brassinosteroid (BR) signaling. Genetic and biochemical evidence showed that C3H15 functions downstream of the receptor BR INSENSITIVE 1 (BRI1) as a negative regulator in the BR pathway. C3H15 is phosphorylated by the GLYCOGEN SYNTHASE KINASE 3 -like kinase BR-INSENSITIVE 2 (BIN2) at Ser111 in the cytoplasm in the absence of BRs. Upon BR perception, C3H15 transcription is enhanced, and the phosphorylation of C3H15 by BIN2 is reduced. The dephosphorylated C3H15 protein accumulates in the nucleus, where C3H15 regulates transcription via G-rich elements (typically GGGAGA). C3H15 and BRASSINAZOLE RESISTANT 1 (BZR1)/BRI1-EMS-SUPPRESSOR 1 (BES1), two central transcriptional regulators of BR signaling, directly suppress each other and share a number of BR-responsive target genes. Moreover, C3H15 antagonizes BZR1 and BES1 to regulate the expression of their shared cell elongation-associated target gene, SMALL AUXIN-UP RNA 15 (SAUR15). This study demonstrates that C3H15-mediated BR signaling may be parallel to, or even attenuate, the dominant BZR1 and BES1 signaling pathways to control cell elongation. This finding expands our understanding of the regulatory mechanisms underlying BR-induced cell elongation in plants.
PMID: 35139225
Elife , IF:8.14 , 2022 May , V11 doi: 10.7554/eLife.74687
Perception of a conserved family of plant signalling peptides by the receptor kinase HSL3.
The Sainsbury Laboratory, Norwich, United Kingdom.; Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.; Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.; The Sainsbury Laboratory,, Norwich, United Kingdom.; MWSchmid GmbH, Glarus, Switzerland.; Department of Plant Molecular Biology, University of Zurich, Zurich, Switzerland.
Plant genomes encode hundreds of secreted peptides; however, relatively few have been characterised. We report here an uncharacterised, stress-induced family of plant signalling peptides, which we call CTNIPs. Based on the role of the common co-receptor BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1) in CTNIP-induced responses, we identified in Arabidopsis thaliana the orphan receptor kinase HAESA-LIKE 3 (HSL3) as the CTNIP receptor via a proteomics approach. CTNIP binding, ligand-triggered complex formation with BAK1, and induced downstream responses all involve HSL3. Notably, the HSL3-CTNIP signalling module is evolutionarily conserved amongst most extant angiosperms. The identification of this novel signalling module will further shed light on the diverse functions played by plant signalling peptides and will provide insights into receptor-ligand co-evolution.
PMID: 35617122
J Exp Bot , IF:6.992 , 2022 Apr , V73 (7) : P2125-2141 doi: 10.1093/jxb/erab530
Fungal oxysterol-binding protein-related proteins promote pathogen virulence and activate plant immunity.
Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.; State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China.
Oxysterol-binding protein-related proteins (ORPs) are a conserved class of lipid transfer proteins that are closely involved in multiple cellular processes in eukaryotes, but their roles in plant-pathogen interactions are mostly unknown. We show that transient expression of ORPs of Magnaporthe oryzae (MoORPs) in Nicotiana benthamina plants triggered oxidative bursts and cell death; treatment of tobacco Bright Yellow-2 suspension cells with recombinant MoORPs elicited the production of reactive oxygen species. Despite ORPs being normally described as intracellular proteins, we detected MoORPs in fungal culture filtrates and intercellular fluids from barley plants infected with the fungus. More importantly, infiltration of Arabidopsis plants with recombinant Arabidopsis or fungal ORPs activated oxidative bursts, callose deposition, and PR1 gene expression, and enhanced plant disease resistance, implying that ORPs may function as endogenous and exogenous danger signals triggering plant innate immunity. Extracellular application of fungal ORPs exerted an opposite impact on salicylic acid and jasmonic acid/ethylene signaling pathways. Brassinosteroid Insensitive 1-associated Kinase 1 was dispensable for the ORP-activated defense. Besides, simultaneous knockout of MoORP1 and MoORP3 abolished fungal colony radial growth and conidiation, whereas double knockout of MoORP1 and MoORP2 compromised fungal virulence on barley and rice plants. These observations collectively highlight the multifaceted role of MoORPs in the modulation of plant innate immunity and promotion of fungal development and virulence in M. oryzae.
PMID: 34864987
Plant J , IF:6.417 , 2022 Apr doi: 10.1111/tpj.15786
A lineage-specific arginine in POS1 is required for fruit size control in Physaleae (Solanaceae) via gene co-option.
State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, 100093, Beijing, China.; University of Chinese Academy of Sciences, Yuquan Road 19, 100049, Beijing, China.; The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China.
Solanaceae have important economic value mainly due to their edible fruits. Physalis organ size 1/cytokinin response factor 3 (POS1/CRF3), a unique gene in Solanaceae, is involved in fruit size variation in Physalis but not in Solanum. However, the underlying mechanisms remain elusive. Here, we found that POS1/CRF3 was likely created via the fusion of CRF7 and CRF8 duplicates. Multiple genetic manipulations revealed that only POS1 and Capsicum POS1 (CaPOS1) functioned in fruit size control via the positive regulation of cell expansion. Comparative studies in a phylogenetic framework showed the directional enhancement of POS1-like expression in the flowers and fruits of Physaleae and the specific gain of certain interacting proteins associated with cell expansion by POS1 and CaPOS1. A lineage-specific single nucleotide polymorphism (SNP) caused the 68th amino acid histidine in the POS1 orthologs of non-Physaleae (Nicotiana and Solanum) to change to arginine in Physaleae (Physalis and Capsicum). Substituting the arginine in Physaleae POS1-like by histidine completely abolished their function in the fruits and the protein-protein interaction (PPI) with calreticulin-3. Transcriptomic comparison revealed the potential downstream pathways of POS1, including the brassinosteroid biosynthesis pathway. However, POS1-like may have functioned ancestrally in abiotic stress within Solanaceae. Our work demonstrated that heterometric expression and a SNP caused a single amino acid change to establish new PPIs, which contributed to the co-option of POS1 in multiple regulatory pathways to regulate cell expansion and thus fruit size in Physaleae. These results provide new insights into fruit morphological evolution and fruit yield control.
PMID: 35481627
Plant J , IF:6.417 , 2022 May , V110 (4) : P1111-1127 doi: 10.1111/tpj.15727
OsSLA1 functions in leaf angle regulation by enhancing the interaction between OsBRI1 and OsBAK1 in rice.
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, Hebei, China.
Leaf angle is an important trait in plants. Here, we demonstrate that the leucine-rich repeat receptor-like kinase OsSLA1 plays an important role in leaf angle regulation in rice (Oryza sativa). OsSLA1 mutant plants exhibited a small leaf angle phenotype due to changes of adaxial cells in the lamina joint. GUS staining revealed that OsSLA1 was highly expressed in adaxial cells of the lamina joint. The OsSLA1 mutant plants were insensitive to exogenous epibrassinolide (eBL) and showed upregulated expression of DWARF and CPD, but downregulated expression of BU1, BUL1, and ILI1, indicating that brassinosteroid (BR) signal transduction was blocked. Fluorescence microscopy showed that OsSLA1 was localized to the plasma membrane and nearby periplasmic vesicles. Further study showed that OsSLA1 interacts with OsBRI1 and OsBAK1 via its intracellular domain and promotes the interaction between OsBRI1 and OsBAK1. In addition, phosphorylation experiments revealed that OsSLA1 does not possess kinase activity, but that it can be phosphorylated by OsBRI1 in vitro. Knockout of OsSLA1 in the context of d61 caused exacerbation of the mutant phenotype. These results demonstrate that OsSLA1 regulates leaf angle formation via positive regulation of BR signaling by enhancing the interaction of OsBRI1 with OsBAK1.
PMID: 35275421
Antioxidants (Basel) , IF:6.312 , 2022 May , V11 (5) doi: 10.3390/antiox11050918
Molecular Regulation of Antioxidant Melatonin Biosynthesis by Brassinosteroid Acting as an Endogenous Elicitor of Melatonin Induction in Rice Seedlings.
Department of Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea.
Gibberellic acid (GA) was recently shown to induce melatonin synthesis in rice. Here, we examined whether brassinosteroids (BRs) also induce melatonin synthesis because BRs and GA show redundancy in many functions. Among several plant hormones, exogenous BR treatment induced melatonin synthesis by twofold compared to control treatment, whereas ethylene, 6-benzylaminopurine (BA), and indole-3-acetic acid (IAA) showed negligible effects on melatonin synthesis. Correspondingly, BR treatment also induced a number of melatonin biosynthetic genes in conjunction with the suppression of melatonin catabolic gene expression. Several transgenic rice plants with downregulated BR biosynthesis-related genes, such as DWARF4, DWARF11, and RAV-Like1 (RAVL1), were generated and exhibited decreased melatonin synthesis, indicating that BRs act as endogenous elicitors of melatonin synthesis. Notably, treatment with either GA or BR fully restored melatonin synthesis in the presence of paclobutrazol, a GA biosynthesis inhibitor. Moreover, exogenous BR treatment partially restored melatonin synthesis in both RAVL1 and Galpha RNAi transgenic rice plants, whereas GA treatment fully restored melatonin synthesis comparable to wild type in RAVL1 RNAi plants. Taken together, our results highlight a role of BR as an endogenous elicitor of melatonin synthesis in a GA-independent manner in rice plants.
PMID: 35624782
Int J Mol Sci , IF:5.923 , 2022 May , V23 (10) doi: 10.3390/ijms23105811
The Role of SBI2/ALG12/EBS4 in the Regulation of Endoplasmic Reticulum-Associated Degradation (ERAD) Studied by a Null Allele.
College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China.
Redundancy and lethality is a long-standing problem in genetics but generating minimal and lethal phenotypes in the knockouts of the same gene by different approaches drives this problem to a new high. In Asn (N)-linked glycosylation, a complex and ubiquitous cotranslational and post-translational protein modification required for the transfer of correctly folded proteins and endoplasmic reticulum-associated degradation (ERAD) of misfolded proteins, ALG12 (EBS4) is an alpha 1, 6-mannosyltransferase catalyzing a mannose into Glc3Man9GlcNAc2. In Arabidopsis, T-DNA knockout alg12-T is lethal while likely ebs4 null mutants isolated by forward genetics are most healthy as weak alleles, perplexing researchers and demanding further investigations. Here, we isolated a true null allele, sbi2, with the W258Stop mutation in ALG12/EBS4. sbi2 restored the sensitivity of brassinosteroid receptor mutants bri1-5, bri1-9, and bri1-235 with ER-trapped BRI1 to brassinosteroids. Furthermore, sbi2 maturated earlier than the wild-type. Moreover, concomitant with impaired and misfolded proteins accumulated in the ER, sbi2 had higher sensitivity to tunicamycin and salt than the wild-type. Our findings thus clarify the role of SBI2/ALG12/EBS4 in the regulation of the ERAD of misfolded glycoproteins, and plant growth and stress response. Further, our study advocates the necessity and importance of using multiple approaches to validate genetics study.
PMID: 35628619
Int J Mol Sci , IF:5.923 , 2022 May , V23 (10) doi: 10.3390/ijms23105551
Genome-Wide Identification of Gramineae Brassinosteroid-Related Genes and Their Roles in Plant Architecture and Salt Stress Adaptation.
School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, China.
Brassinosteroid-related genes are involved in regulating plant growth and stress responses. However, systematic analysis is limited to Gramineae species, and their roles in plant architecture and salt stress remain unclear. In this study, we identified brassinosteroid-related genes in wheat, barley, maize, and sorghum and investigated their evolutionary relationships, conserved domains, transmembrane topologies, promoter sequences, syntenic relationships, and gene/protein structures. Gene and genome duplications led to considerable differences in gene numbers. Specific domains were revealed in several genes (i.e., HvSPY, HvSMOS1, and ZmLIC), indicating diverse functions. Protein-protein interactions suggested their synergistic functions. Their expression profiles were investigated in wheat and maize, which indicated involvement in adaptation to stress and regulation of plant architecture. Several candidate genes for plant architecture (ZmBZR1 and TaGSK1/2/3/4-3D) and salinity resistance (TaMADS22/47/55-4B, TaGRAS19-4B, and TaBRD1-2A.1) were identified. This study is the first to comprehensively investigate brassinosteroid-related plant architecture genes in four Gramineae species and should help elucidate the biological roles of brassinosteroid-related genes in crops.
PMID: 35628372
Int J Mol Sci , IF:5.923 , 2022 May , V23 (9) doi: 10.3390/ijms23095224
Deacclimation-Induced Changes of Photosynthetic Efficiency, Brassinosteroid Homeostasis and BRI1 Expression in Winter Oilseed Rape (Brassica napus L.)-Relation to Frost Tolerance.
The Franciszek Gorski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Krakow, Poland.; Department of Plant Physiology, Faculty of Agriculture and Economics, University of Agriculture in Krakow, Podluzna 3, 30-239 Krakow, Poland.; Institute of Technology and Life Sciences-National Research Institute, Falenty, Al. Hrabska 3, 05-090 Raszyn, Poland.; Department of Plant Physiology, Institute of Biology, Warsaw University of Life Sciences-SGGW, 02-766 Warsaw, Poland.; Institute of Environmental Engineering, Warsaw University of Life Sciences-SGGW, 02-766 Warsaw, Poland.; Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacky University, Slechtitelu 27, CZ-78371 Olomouc, Czech Republic.
The objective of this study was to answer the question of how the deacclimation process affects frost tolerance, photosynthetic efficiency, brassinosteroid (BR) homeostasis and BRI1 expression of winter oilseed rape. A comparative study was conducted on cultivars with different agronomic and physiological traits. The deacclimation process can occur when there are periods of higher temperatures, particularly in the late autumn or winter. This interrupts the process of the acclimation (hardening) of winter crops to low temperatures, thus reducing their frost tolerance and becoming a serious problem for agriculture. The experimental model included plants that were non-acclimated, cold acclimated (at 4 degrees C) and deacclimated (at 16 degrees C/9 degrees C, one week). We found that deacclimation tolerance (maintaining a high frost tolerance despite warm deacclimating periods) was a cultivar-dependent trait. Some of the cultivars developed a high frost tolerance after cold acclimation and maintained it after deacclimation. However, there were also cultivars that had a high frost tolerance after cold acclimation but lost some of it after deacclimation (the cultivars that were more susceptible to deacclimation). Deacclimation reversed the changes in the photosystem efficiency that had been induced by cold acclimation, and therefore, measuring the different signals associated with photosynthetic efficiency (based on prompt and delayed chlorophyll fluorescence) of plants could be a sensitive tool for monitoring the deacclimation process (and possible changes in frost tolerance) in oilseed rape. Higher levels of BR were characteristic of the better frost-tolerant cultivars in both the cold-acclimated and deacclimated plants. The relative expression of the BRI1 transcript (encoding the BR-receptor protein) was lower after cold acclimation and remained low in the more frost-tolerant cultivars after deacclimation. The role of brassinosteroids in oilseed rape acclimation/deacclimation is briefly discussed.
PMID: 35563614
Int J Mol Sci , IF:5.923 , 2022 Apr , V23 (8) doi: 10.3390/ijms23084223
The Combination of Conventional QTL Analysis, Bulked-Segregant Analysis, and RNA-Sequencing Provide New Genetic Insights into Maize Mesocotyl Elongation under Multiple Deep-Seeding Environments.
State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China.
Mesocotyl length (MES) is an important trait that affects the emergence of maize seedlings after deep-seeding and is closely associated with abiotic stress. The elucidation of constitutive-QTLs (cQTLs) and candidate genes for MES and tightly molecular markers are thus of great importance in marker-assisted selection (MAS) breeding. Therefore, the objective of this study was to perform detailed genetic analysis of maize MES across 346 F2:3 families, 30/30 extreme bulks of an F2 population, and two parents by conventional QTL analysis, bulked-segregation analysis (BSA), and RNA-sequencing when maize was sown at the depths of 3, 15, and 20 cm, respectively. QTL analysis identified four major QTLs in Bin 1.09, Bin 3.04, Bin 4.06-4.07, and Bin 6.01 under two or more environments, which explained 2.89-13.97% of the phenotypic variance within a single environment. BSA results revealed the presence of seven significantly linked SNP/InDel regions on chromosomes 1 and 4, and six SNP/InDel regions and the major QTL of qMES4-1 overlapped and formed a cQTL, cQMES4, within the 160.98-176.22 Mb region. In total, 18,001 differentially expressed genes (DEGs) were identified across two parents by RNA-sequencing, and 24 of these genes were conserved core DEGs. Finally, we validated 15 candidate genes in cQMES4 to involve in cell wall structure, lignin biosyntheis, phytohormones (auxin, abscisic acid, brassinosteroid) signal transduction, circadian clock, and plant organ formation and development. Our findings provide a basis for MAS breeding and enhance our understanding of the deep-seeding tolerance of maize.
PMID: 35457037
Front Plant Sci , IF:5.753 , 2022 , V13 : P830349 doi: 10.3389/fpls.2022.830349
MdJa2 Participates in the Brassinosteroid Signaling Pathway to Regulate the Synthesis of Anthocyanin and Proanthocyanidin in Red-Fleshed Apple.
State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China.; Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production in Shandong, Tai'an, China.; College of Continuing Education, Shandong Agricultural University, Tai'an, China.
Anthocyanin and proanthocyanidin play important roles in plant secondary metabolism. Although previous studies identified many transcription factors involved in anthocyanin and proanthocyanidin synthesis, the effects of MADS-box transcription factors are unclear in apple. Brassinosteroids (BRs) are steroid hormones that affect plant flavonoid biosynthesis, but the underlying regulatory mechanism is not yet well established. In this study, we identified a MADS-box transcription factor, MdJa2, which contained a highly conserved MADS-box domain and belonged to the STMADS11 subfamily. Additionally, MdJa2 was responsive to BR signal, and the overexpression of MdJa2 inhibited the synthesis of anthocyanin and proanthocyanidin. The silencing of MdJa2 in "Orin" calli promoted anthocyanin and proanthocyanidin accumulations. Moreover, MdJa2 interacted with MdBZR1. MdJa2 was revealed to independently regulate anthocyanin and proanthocyanidin synthesis pathways. The MdJa2-MdBZR1 complex enhanced the binding of MdJa2 to the promoters of downstream target genes. Our research provides new insights into how MADS-box transcription factors in the BR signaling pathway control the accumulations of anthocyanin and proanthocyanidin in red-fleshed apple.
PMID: 35615132
Front Plant Sci , IF:5.753 , 2022 , V13 : P894710 doi: 10.3389/fpls.2022.894710
Overexpression of a Zea mays Brassinosteroid-Signaling Kinase Gene ZmBSK1 Confers Salt Stress Tolerance in Maize.
Provincial Key Laboratory of Agrobiology, Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing, China.; College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
Salinity has become a crucial environmental factor seriously restricting maize (Zea mays L.) growth, development and productivity. However, how plants respond to salt stress is still poorly understood. In this study, we report that a maize brassinosteroid-signaling kinase gene ZmBSK1 plays a significant role in salt stress response. Expression pattern analysis revealed that the transcript level of ZmBSK1 was upregulated by NaCl treatment both in maize leaves, roots, and stems. Phenotypic and physiological analysis showed that overexpression of ZmBSK1 in maize improved salt tolerance by reducing the malondialdehyde (MDA) content, the percentage of electrolyte leakage, O2 (-) and H2O2 accumulation under salt stress, relying on the increases of antioxidant defense enzyme activities and proline content. qRT-PCR analysis showed that overexpression of ZmBSK1 also positively modulated the expression levels of reactive oxygen species (ROS)-scavenging and proline biosynthesis-related genes under salt stress. Moreover, immunoprecipitation-mass spectrometry (IP-MS) assay and firefly luciferase complementation imaging (LCI) assay showed that ZmBSK1 could associate with heat shock protein ZmHSP8 and 14-3-3-like protein ZmGF14-6, and their gene expression levels could be significantly induced by NaCl treatment in different maize tissues. Our findings unravel the new function of ZmBSK1 in salt stress response, which provides the theoretical bases for the improvement of maize salt resistance.
PMID: 35599886
Front Plant Sci , IF:5.753 , 2022 , V13 : P883363 doi: 10.3389/fpls.2022.883363
Cytoplasmic Linker Protein-Associating Protein at the Nexus of Hormone Signaling, Microtubule Organization, and the Transition From Division to Differentiation in Primary Roots.
Department of Botany, University of British Columbia, Vancouver, BC, Canada.
The transition from cell division to differentiation in primary roots is dependent on precise gradients of phytohormones, including auxin, cytokinins and brassinosteroids. The reorganization of microtubules also plays a key role in determining whether a cell will enter another round of mitosis or begin to rapidly elongate as the first step in terminal differentiation. In the last few years, progress has been made to establish connections between signaling pathways at distinct locations within the root. This review focuses on the different factors that influence whether a root cell remains in the division zone or transitions to elongation and differentiation using Arabidopsis thaliana as a model system. We highlight the role of the microtubule-associated protein CLASP as an intermediary between sustaining hormone signaling and controlling microtubule organization. We discuss new, innovative tools and methods, such as hormone sensors and computer modeling, that are allowing researchers to more accurately visualize the belowground growth dynamics of plants.
PMID: 35574108
Front Plant Sci , IF:5.753 , 2022 , V13 : P849467 doi: 10.3389/fpls.2022.849467
Brassinosteroid-Insensitive 1-Associated Receptor Kinase 1 Modulates Abscisic Acid Signaling by Inducing PYR1 Monomerization and Association With ABI1 in Arabidopsis.
Department of Biological Sciences, Sookmyung Women's University, Seoul, South Korea.; Research Institute of Women's Health, Sookmyung Women's University, Seoul, South Korea.; Department of Systems Biology, Yonsei University, Seoul, South Korea.
Brassinosteroid-Insensitive 1-Associated Receptor Kinase 1 (BAK1) is a versatile kinase involved in many different plant developmental responses. Previously, we showed that BAK1 interacts with open stomata 1 (OST1), a cytoplasmic kinase, to promote abscisic acid (ABA)-induced stomatal closure. ABA is a plant hormone that primarily regulates stress responses and is recognized by the PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENT OF ABA RECEPTORS (RCAR), which activates ABA signaling. Here, we demonstrated that BAK1 interacts with PYR1 and phosphorylates PYR1 in response to ABA in plants. We identified T137 and S142 of PYR1 as the phosphosites targeted by BAK1. Using phosphomimetic (PYR1DD) and phospho-dead (PYR1AA) PYR1 compared with wild-type PYR1, we showed that transgenic plants overexpressing a phosphomimetic PYR1 exhibited hypersensitivity to the inhibition of ABA-induced root growth and seed germination and increased ABA-induced stomatal closure and ABA-inducible gene expression. As underlying reasons for these phenomena, we further demonstrated that phosphorylated PYR1 existed in a monomeric form, in which ABA binding was increased, and the degree of complex formation with ABI1 was also increased. These results suggest that BAK1 positively modulates ABA signaling through interaction with PYR1, in addition to OST1.
PMID: 35548282
Front Plant Sci , IF:5.753 , 2022 , V13 : P873688 doi: 10.3389/fpls.2022.873688
A Non-redundant Function of MNS5: A Class I alpha-1, 2 Mannosidase, in the Regulation of Endoplasmic Reticulum-Associated Degradation of Misfolded Glycoproteins.
College of Life Sciences, Shaanxi Normal University, Xi'an, China.
Endoplasmic Reticulum-Associated Degradation (ERAD) is one of the major processes in maintaining protein homeostasis. Class I alpha-mannosidases MNS4 and MNS5 are involved in the degradation of misfolded variants of the heavily glycosylated proteins, playing an important role for glycan-dependent ERAD in planta. MNS4 and MNS5 reportedly have functional redundancy, meaning that only the loss of both MNS4 and MNS5 shows phenotypes. However, MNS4 is a membrane-associated protein while MNS5 is a soluble protein, and both can localize to the endoplasmic reticulum (ER). Furthermore, MNS4 and MNS5 differentially demannosylate the glycoprotein substrates. Importantly, we found that their gene expression patterns are complemented rather than overlapped. This raises the question of whether they indeed work redundantly, warranting a further investigation. Here, we conducted an exhaustive genetic screen for a suppressor of the bri1-5, a brassinosteroid (BR) receptor mutant with its receptor downregulated by ERAD, and isolated sbi3, a suppressor of bri1-5 mutant named after sbi1 (suppressor of bri1). After genetic mapping together with whole-genome re-sequencing, we identified a point mutation G343E in AT1G27520 (MNS5) in sbi3. Genetic complementation experiments confirmed that sbi3 was a loss-of-function allele of MNS5. In addition, sbi3 suppressed the dwarf phenotype of bri1-235 in the proteasome-independent ERAD pathway and bri1-9 in the proteasome-dependent ERAD pathway. Importantly, sbi3 could only affect BRI1/bri1 with kinase activities such that it restored BR-sensitivities of bri1-5, bri1-9, and bri1-235 but not null bri1. Furthermore, sbi3 was less tolerant to tunicamycin and salt than the wild-type plants. Thus, our study uncovers a non-redundant function of MNS5 in the regulation of ERAD as well as plant growth and ER stress response, highlighting a need of the traditional forward genetic approach to complement the T-DNA or CRISPR-Cas9 systems on gene functional study.
PMID: 35519817
Front Plant Sci , IF:5.753 , 2022 , V13 : P873993 doi: 10.3389/fpls.2022.873993
OsDDM1b Controls Grain Size by Influencing Cell Cycling and Regulating Homeostasis and Signaling of Brassinosteroid in Rice.
State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China.; College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.; College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning, China.; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.; Biotechnology Research Institute, Fujian Provincial Key Laboratory of Genetic Engineering for Agriculture, Fujian Academy of Agricultural Sciences, Fuzhou, China.; Center for Crop Biotechnology, College of Agriculture, Anhui Science and Technology University, Fengyang, China.
Snf2 family proteins are the crucial subunits of chromatin-remodeling complexes (CRCs), which contributes to the biological processes of transcription, replication, and DNA repair using ATP as energy. Some CRC subunits have been confirmed to be the critical regulators in various aspects of plant growth and development and in epigenetic mechanisms such as histone modification, DNA methylation, and histone variants. However, the functions of Snf2 family genes in rice were poorly investigated. In this study, the relative expression profile of 40 members of Snf2 family in rice was studied at certain developmental stages of seed. Our results revealed that OsCHR741/OsDDM1b (Decrease in DNA methylation 1) was accumulated highly in the early developmental stage of seeds. We further analyzed the OsDDM1b T-DNA insertion loss-of-function of mutant, which exhibited dwarfism, smaller organ size, and shorter and wider grain size than the wild type (Hwayoung, HY), yet no difference in 1,000-grain weight. Consistent with the grain size, the outer parenchyma cell layers of lemma in osddm1b developed more cells with decreased size. OsDDM1b encoded a nucleus, membrane-localized protein and was distributed predominately in young spikelets and seeds, asserting its role in grain size. Meanwhile, the osddm1b was less sensitive to brassinosteroids (BRs) while the endogenous BR levels increased. We detected changes in the expression levels of the BR signaling pathway and feedback-inhibited genes with and without exogenous BR application, and the alterations of expression were also observed in grain size-related genes in the osddm1b. Altogether, our results suggest that OsDDM1b plays a crucial role in grain size via influencing cell proliferation and regulating BR signaling and homeostasis.
PMID: 35463416
Theor Appl Genet , IF:5.699 , 2022 May , V135 (5) : P1751-1766 doi: 10.1007/s00122-022-04067-2
The kinesin-13 protein BR HYPERSENSITIVE 1 is a negative brassinosteroid signaling component regulating rice growth and development.
College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China.; Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China.; State Key Laboratory for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.; Plant Phenomics Research Center, Nanjing Agricultural University, Nanjing, 210095, China.; College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China. ycyu@hznu.edu.cn.; College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China. lmwu2006@aliyun.com.; Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, Hangzhou, 310036, China. lmwu2006@aliyun.com.
Phytohormones performed critical roles in regulating plant architecture and thus determine grain yield in rice. However, the roles of brassinosteroids (BRs) compared to other phytohormones in shaping rice architecture are less studied. In this study, we report that BR hypersensitive1 (BHS1) plays a negative role in BR signaling and regulate rice architecture. BHS1 encodes the kinesin-13a protein and regulates grain length. We found that bhs1 was hypersensitive to BR, while BHS1-overexpression was less sensitive to BR compare to WT. BHS1 was down-regulated at RNA and protein level upon exogenous BR treatment, and proteasome inhibitor MG132 delayed the BHS1 degradation, indicating that both the transcriptional and posttranscriptional regulation machineries are involved in BHS1-mediated regulation of plant growth and development. Furthermore, we found that the BR-induced degradation of BHS1 was attenuated in Osbri1 and Osbak1 mutants, but not in Osbzr1 and Oslic mutants. Together, these results suggest that BHS1 is a novel component which is involved in negative regulation of the BR signaling downstream player of BRI1.
PMID: 35258682
J Agric Food Chem , IF:5.279 , 2022 Apr , V70 (14) : P4303-4315 doi: 10.1021/acs.jafc.2c00541
Novel Dioxolane Ring Compounds for the Management of Phytopathogen Diseases as Ergosterol Biosynthesis Inhibitors: Synthesis, Biological Activities, and Molecular Docking.
College of Life Science, Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, Huzhou University, Huzhou 313000, Zhejiang, China.; College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.; Natural Products Utilization Research Unit, USDA ARS, University, Mississippi 38677, United States.; College of Biology and Environmental Engineering, Zhejiang Shuren University, Hangzhou 310015, Zhejiang, China.; National Center for Natural Product Research, School of Pharmacy, University of Mississippi, P.O. Box 1848, University, Mississippi 38677, United States.
Thirty novel dioxolane ring compounds were designed and synthesized. Their chemical structures were confirmed by (1)H NMR, HRMS, and single crystal X-ray diffraction analysis. Bioassays indicated that these dioxolane ring derivatives exhibited excellent fungicidal activity against Rhizoctonia solani, Pyricularia oryae, Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum, Physalospora piricola, Cercospora arachidicola and herbicidal activity against lettuce (Lactuca sativa), bentgrass (Agrostis stolonifera), and duckweed (Lemna pausicostata). Among these compounds, 1-((2-(4-chlorophenyl)-5-methyl-1,3-dioxan-2-yl)methyl)-1H-1,2,4-triazole (D17), 1-(((4R)-2-(4-chlorophenyl)-4-methyl-1,3-dioxolan-2-yl)methyl)-1H-1,2,4-triazole (D20), 1-((5-methyl-2-(4-(trifluoromethyl)phenyl)-1,3-dioxan-2-yl)methyl)-1H-1,2,4-triaz ole (D22), and 1-((2-(4-fluorophenyl)-1,3-dioxolan-2-yl)methyl)-1H-1,2,4-triazole (D26) had broad spectrum fungicidal and herbicidal activity. The IC50 values against duckweed were 20.5 +/- 9.0, 14.2 +/- 6.7, 24.0 +/- 11.0, 8.7 +/- 3.5, and 8.0 +/- 3.1 muM for D17, D20, D22, and D26 and the positive control difenoconazole, respectively. The EC50 values were 7.31 +/- 0.67, 9.74 +/- 0.83, 17.32 +/- 1.23, 11.96 +/- 0.98, and 8.93 +/- 0.91 mg/L for D17, D20, D22, and D26 and the positive control difenoconazole against the plant pathogen R. solani, respectively. Germination experiments with Arabidopsis seeds indicated that the target of these dioxolane ring compounds in plants is brassinosteroid biosynthesis. Molecular simulation docking results of compound D26 and difenoconazole with fungal CYP51 P450 confirmed that they both inhibit this enzyme involved in ergosterol biosynthesis. The structure-activity relationships (SAR) are discussed by substituent effect, molecular docking, and density functional theory analysis, which provided useful information for designing more active compounds.
PMID: 35357135
Metabolites , IF:4.932 , 2022 Apr , V12 (5) doi: 10.3390/metabo12050379
Untargeted Metabolomics Profiling of Arabidopsis WT, lbr-2-2 and bak1-4 Mutants Following Treatment with Two LPS Chemotypes.
Department of Biochemistry, University of Johannesburg, Auckland Park, Johannesburg 2006, South Africa.
Plants perceive pathogenic threats from the environment that have evaded preformed barriers through pattern recognition receptors (PRRs) that recognise microbe-associated molecular patterns (MAMPs). The perception of and triggered defence to lipopolysaccharides (LPSs) as a MAMP is well-studied in mammals, but little is known in plants, including the PRR(s). Understanding LPS-induced secondary metabolites and perturbed metabolic pathways in Arabidopsis will be key to generating disease-resistant plants and improving global plant crop yield. Recently, Arabidopsis LPS-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI)-related proteins (LBP/BPI related-1) and (LBP/BPI related-2) were shown to perceive LPS from Pseudomonas aeruginosa and trigger defence responses. In turn, brassinosteroid insensitive 1 (BRI1)-associated receptor kinase 1 (BAK1) is a well-established co-receptor for several defence-related PRRs in plants. Due to the lack of knowledge pertaining to LPS perception in plants and given the involvement of the afore-mentioned proteins in MAMPs recognition, in this study, Arabidopsis wild type (WT) and mutant (lbr2-2 and bak1-4) plants were pressure-infiltrated with LPSs purified from Pseudomonas syringae pv. tomato DC3000 (Pst) and Xanthomonas campestris pv. campestris 8004 (Xcc). Metabolites were extracted from the leaves at four time points over a 24 h period and analysed by UHPLC-MS, generating distinct metabolite profiles. Data analysed using unsupervised and supervised multivariate data analysis (MVDA) tools generated results that reflected time- and treatment-related variations after both LPS chemotypes treatments. Forty-five significant metabolites were putatively annotated and belong to the following groups: glucosinolates, hydroxycinnamic acid derivatives, flavonoids, lignans, lipids, oxylipins, arabidopsides and phytohormones, while metabolic pathway analysis (MetPA) showed enrichment of flavone and flavanol biosynthesis, phenylpropanoid biosynthesis, alpha-linolenic acid metabolism and glucosinolate biosynthesis. Distinct metabolite accumulations depended on the LPS chemotype and the genetic background of the lbr2-2 and bak1-4 mutants. This study highlights the role of LPSs in the reprogramming Arabidopsis metabolism into a defensive state, and the possible role of LBR and BAK1 proteins in LPSs perception and thus plant defence against pathogenic bacteria.
PMID: 35629883
BMC Plant Biol , IF:4.215 , 2022 May , V22 (1) : P246 doi: 10.1186/s12870-022-03619-4
Brassinosteroid-lipid membrane interaction under low and high temperature stress in model systems.
Institute of Biology, Pedagogical University, Podchorazych 2, 30-084, Krakow, Poland. elzbieta.rudolphi-szydlo@up.krakow.pl.; Institute of Biology, Pedagogical University, Podchorazych 2, 30-084, Krakow, Poland.; Polish Academy of Sciences, The Franciszek Gorski Institute of Plant Physiology, 30-239, Krakow, Poland.; Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
BACKGROUND: In earlier studies [1], we indicated that applying brassinosteroids (BRs) to lipids that had been isolated from plants altered the physicochemical properties of the monolayers. A continuation of these dependencies using the defined model lipid systems is presented in this paper. The influence of homocastasterone (HCS) and castasterone (CS) (BRs for which the increase in concentration were characteristic of plants grown at low temperatures) on the membrane properties of their polar and the hydrophobic parts were studied. RESULTS: Changes in the electrokinetic potential indicate that both BRs decreased the negative charge of the surface, which is an important factor in modifying the contacts with the polar substances. This property of BRs has not yet been described. The studies of the interactions that occur in the hydrophobic part of the membrane were investigated using the EPR methods and Langmuir techniques. The physicochemical parameters of the lipid structure were determined, and the excess of Gibbs free energy was calculated. CONCLUSION: We conclude that examined BRs modify both the hydrophilic and hydrophobic properties of the membranes, but to a greater extent HCS. The consequence of these changes may be the attempt to maintain the stability of the membranes in stressful temperature conditions and / or to the possibility of adsorption of other substances on membranes surfaces. The change of plant metabolism towards increasing the amount of BR, mainly HCS (under cooling) may by an important factor for maintaining optimal structural properties of membranes and their functionality despite temperature changes.
PMID: 35585507
FEBS Lett , IF:4.124 , 2022 Apr doi: 10.1002/1873-3468.14355
Interactions between autophagy and phytohormone signaling pathways in plants.
Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA.
Autophagy is a conserved recycling process with important functions in plant growth, development, and stress responses. Phytohormones also play key roles in the regulation of some of the same processes. Increasing evidence indicates that a close relationship exists between autophagy and phytohormone signaling pathways, and the mechanisms of interaction between these pathways have begun to be revealed. Here, we review recent advances in our understanding of how autophagy regulates hormone signaling and, conversely, how hormones regulate the activity of autophagy, both in plant growth and development and in environmental stress responses. We highlight in particular recent mechanistic insights into the coordination between autophagy and signaling events controlled by the stress hormone abscisic acid and by the growth hormones brassinosteroid and cytokinin and briefly discuss potential connections between autophagy and other phytohormones.
PMID: 35460261
Planta , IF:4.116 , 2022 Apr , V255 (6) : P111 doi: 10.1007/s00425-022-03886-3
An ortholog of the MADS-box gene SEPALLATA3 regulates stamen development in the woody plant Jatropha curcas.
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China.; CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China. chenms@xtbg.org.cn.; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China. chenms@xtbg.org.cn.; CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Mengla, 666303, Yunnan, China. zfxu@gxu.edu.cn.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Forestry, Guangxi University, Nanning, 530004, Guangxi, China. zfxu@gxu.edu.cn.
MAIN CONCLUSION: Overexpression of JcSEP3 causes defective stamen development in Jatropha curcas, in which brassinosteroid and gibberellin signaling pathways may be involved. SEPALLATAs (SEPs), the class E genes of the ABCE model, are required for floral organ determination. In this study, we investigated the role of the JcSEP3 gene in floral organ development in the woody plant Jatropha curcas. Transgenic Jatropha plants overexpressing JcSEP3 displayed abnormal phenotypes such as deficient anthers and pollen, as well as free stamen filaments, whereas JcSEP3-RNA interference (RNAi) transgenic plants had no obvious phenotypic changes, suggesting that JcSEP3 is redundant with other JcSEP genes in Jatropha. Moreover, we compared the transcriptomes of wild-type plants, JcSEP3-overexpressing, and JcSEP3-RNAi transgenic plants. In the JcSEP3-overexpressing transgenic plants, we discovered 25 upregulated genes involved in anther and pollen development, as well as 12 induced genes in brassinosteroid (BR) and gibberellin (GA) signaling pathways. These results suggest that JcSEP3 directly or indirectly regulates stamen development, concomitant with the regulation of BR and GA signaling pathways. Our findings help to understand the roles of SEP genes in stamen development in perennial woody plants.
PMID: 35478059
Plant Mol Biol , IF:4.076 , 2022 May , V109 (1-2) : P1-12 doi: 10.1007/s11103-022-01258-9
TOPLESS in the regulation of plant immunity.
415, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.; 415, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India. ashis_nandi@mail.jnu.ac.in.
KEY MESSAGE: This review presents the multiple ways how topless and topless-related proteins regulate defense activation in plants and help in optimizing the defense-growth tradeoff. Eukaryotic gene expression is tightly regulated at various levels by hormones, transcription regulators, post-translational modifications, and transcriptional coregulators. TOPLESS (TPL)/TOPLESS-related (TPR) corepressors regulate gene expression by interacting with other transcription factors. TPRs regulate auxin, gibberellins, jasmonic acid, strigolactone, and brassinosteroid signaling in plants. In general, except for GA, TPLs suppress these signaling pathways to prevent unwanted activation of hormone signaling. The association of TPL/TPRs in these hormonal signaling reflects a wide role of this class of corepressors in plants' normal and stress physiology. The involvement of TPL in immune responses was first demonstrated a decade ago as a repressor of DND1 and DND2 that are negative regulators of plant immune response. Over the last decade, several research groups have established a larger role of TPL/TPRs in plant immunity during both pattern- and effector-triggered immunity. Very recent research unraveled the significant involvement of TPRs in balancing the growth and defense trade-off. TPRs, along with proteasomal degradation complex, miRNA, and phasiRNA, suppress the activation of autoimmunity in plants under normal conditions and promote defense under pathogen attack.
PMID: 35347548
Gene , IF:3.688 , 2022 Apr , V818 : P146214 doi: 10.1016/j.gene.2022.146214
Whole genome re-sequencing and transcriptome reveal an alteration in hormone signal transduction in a more-branching mutant of apple.
Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: ghj042@163.com.; College of Horticulture, Hebei Agricultural University, Baoding, Hebei 071001, China. Electronic address: liguofang@hebau.edu.cn.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: qdsnky@163.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: 774572825@qq.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: huangyuehy@126.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: 1196328026@qq.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: zhangruifen316@qq.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: songerg9@126.com.; Academy of Agricultural Sciences of Qingdao, Qingdao, Shandong 266100, China. Electronic address: guanglisha@126.com.
Branch number is an important trait in grafted apple breeding and cultivation. To provide new information on molecular mechanisms of apple branching, whole reduced-representation genomes and transcriptome of a wild-type (WT) apple (Malus spectabilis) and its more-branching (MB) mutant at the branching stage were examined in this study. Comparison of WT and MB genomes against the Malus domestica reference genome identified 14,908,939 single nucleotide polymorphisms (SNPs) and 173,315 insertions and deletions (InDels) in WT and 1,483,221 SNPs and 1,725,977 InDels in MB. Analysis of the genetic variation between MB and WT revealed 1,048,575 SNPs and 37,327 InDels. Among them, 24,303 SNPs and 891 InDels mapped to coding regions of 5,072 and 596 genes, respectively. GO and KEGG functional annotation of 3,846 and 944 genes, respectively, identified 32 variant genes related to plant hormone signal transduction that were involved in auxin, cytokinin, gibberellin, abscisic acid, ethylene, and brassinosteroid pathways. The transcriptome pathways of plant hormone signal transduction and zeatin biosynthesis were also significantly enriched during MB branching. Furthermore, transcriptome data suggested the regulatory roles of auxin signaling, increase of cytokinin and genes of cytokinin synthesis and signaling, and the suppressed abscisic acid signaling. Our findings suggest that branching development in apple is regulated by plant hormone signal transduction.
PMID: 35066064
Biosci Biotechnol Biochem , IF:2.043 , 2022 May doi: 10.1093/bbb/zbac071
BRZ-INSENSITIVE-PALE GREEN 1 is encoded by chlorophyll biosynthesis enzyme gene that functions in the downstream of brassinosteroid signaling.
Graduate School of Biostudies, Kyoto University, KItashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Japan.; Department of Biology, Ochanomizu University, Bunkyo-ku, Tokyo, Japan.; RIKEN, CSRS, Tsurumi-ku, Yokohama, Japan.; The Institute of Oncology, Riga Stradins University, 16 Dzirciema Street, Riga, LV-1007, Latvia.; Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University, Tama-ku, Kawasaki, Japan.; Institute of Low Temperature Science, Hokkaido University, Kita-ku, Sapporo, Japan.; Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Brassinosteroids (BRs), a kind of phytohormone, have various biological activities such as promoting of plant growth, increasing of stress resistance, and chloroplast development. Though BRs have been known to have physiological effects on chloroplast, the detailed mechanism of chloroplast development and chlorophyll biosynthesis in BR signaling remains unknown. Here we identified a recessive pale green Arabidopsis mutant, Brz-insensitive-pale green1 (bpg1), which was insensitive to promoting of greening by BR biosynthesis-specific inhibitor Brz in the light. BPG1 gene encoded chlorophyll biosynthesis enzyme, 3, 8-divinyl protochlorophyllide a 8-vinyl reductase (DVR), and bpg1 accumulated divinyl chlorophylls. Chloroplast development was suppressed in bpg1. Brz dramatically increased the expression of chlorophyll biosynthesis enzyme genes, including BPG1. These results suggest that chlorophyll biosynthesis enzymes are regulated by BR signaling in the aspect of gene expression and BPG1 plays an important role in regulating of chloroplast development.
PMID: 35583242
Genes Genomics , IF:1.839 , 2022 May doi: 10.1007/s13258-022-01266-5
Role of tyrosine autophosphorylation and methionine residues in BRI1 function in Arabidopsis thaliana.
Department of Biological Sciences, Chungnam National University, Daejeon, 34134, Korea.; Department of Environmental Horticulture, Dankook University, Cheonan, 31116, Korea.; Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, USA.; Department of Biological Sciences, Chungnam National University, Daejeon, 34134, Korea. manhooh@cnu.ac.kr.
BACKGROUND: Brassinosteroids (BRs), a group of plant growth hormones, control biomass accumulation and biotic and abiotic stress tolerance, and therefore are highly relevant to agriculture. BRs bind to the BR receptor protein, brassinosteroid insensitive 1 (BRI1), which is classified as a serine/threonine (Ser/Thr) protein kinase. Recently, we reported that BRI1 acts as a dual-specificity kinase both in vitro and in vivo by undergoing autophosphorylation at tyrosine (Tyr) residues. OBJECTIVE: In this study, we characterized the increased leaf growth and early flowering phenotypes of transgenic lines expressing the mutated recombinant protein, BRI1(Y831F)-Flag, compared with those expressing BRI1-Flag. BRI1(Y831F)-Flag transgenic plants showed a reduction in hypocotyl and petiole length compared with BRI1-Flag seedlings. Transcriptome analysis revealed differential expression of flowering time-associated genes (AP1, AP2, AG, FLC, and SMZ) between BRI1(Y831F)-Flag and BRI1-Flag transgenic seedlings. We also performed site-directed mutagenesis of the BRI1 gene, and investigated the effect of methionine (Met) substitution in the extracellular domain (ECD) of BRI1 on plant growth and BR sensitivity by evaluating hypocotyl elongation and root growth inhibition. METHODS: The pBIB-Hyg(+)-pBR-BRI1-Flag construct(Li et al. 2002) was used as the template for SDM with QuickChange XL Site Directed Mutagenesis Kit (Stratagene, La Jolla, CA, USA) to make the SDM mutants. After PCR with SDM kit, add 1 mul of Dpn1 to PCR reaction. Incubate at 37 degrees C for 2 h to digest parental DNA and then transformed into XL10-gold competent cells. Transcriptome analysis was carried out at the University of Illinois (Urbana-Champaign, Illinois, USA). RNA was prepared and hybridized to the Affymetrix GeneChip Arabidopsis ATH1 Genome Array using the Gene Chip Express Kit (Ambion, Austin, TX, USA). RESULTS: Tyrosine 831 autophosphorylation of BRI1 regulates Arabidopsis flowering time, and mutation of methionine residues in the extracellular domain of BRI1 affects hypocotyl and root length. BRI1(M656Q)-Flag, BRI1(M657Q)-Flag, and BRI1(M661Q)-Flag seedlings were insensitive to the BL treatment and showed no inhibition of root elongation. However, BRI1(M665Q)-Flag and BRI1(M671Q)-Flag seedlings were sensitive to the BL treatment, and exhibited root elongation inhibition. the early flowering phenotype of BRI1(Y831F)-Flag transgenic plants is consistent with the expression levels of key flowering-related genes, including those promoting flowering (AP1, AP2, and AG) and repressing flowering (FLC and SMZ).
PMID: 35598220