Mol Plant , IF:13.164 , 2021 Sep doi: 10.1016/j.molp.2021.09.010
A Cryptic Inhibitor of Cytokinin Phosphorelay Controls Rice Grain Size.
National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; Biogle Genome Editing Center, Changzhou, Jiangsu Province 213125, China.; Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, the Innovative Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: tonghongning@caas.cn.; National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China. Electronic address: tonghongning@caas.cn.
Plant hormone cytokinin signals through histidine-aspartic acid (H-D) phosphorelay to regulate plant growth and development. Whilst it's well-known that the phosphorelay involves histidine kinases, histidine phosphotransfer proteins (HPs) and responsive regulators (RRs), how this process is regulated by external components remains unknown. Here we demonstrate that PPKL1 (Protein Phosphatase with Kelch-Like domains), known as a signaling component of steroid hormone brassinosteroid, is actually a cryptic inhibitor of cytokinin phosphorelay in rice (Oryza sativa L.). Mutation at a specific amino acid D364 of PPKL1 activates cytokinin response, thus enlarges grain size in a semi-dominant mutant named s48. Overexpression of PPKL1 containing D364, either with the deletion of the phosphatase domain or not, rescues the s48 mutant phenotype. PPKL1 interacts with OsAHP2, one of authentic HPs, and D364 resides in a region resembling the receiver domain of RRs. Accordingly, PPKL1 can utilize D364 to suppress OsAHP2-to-RR phosphorelay, whereas mutation of D364 abolishes the effect. This function is independent of the phosphatase domain that should be required for brassinosteroid signaling. Importantly, editing of the D364-residential region produces a diversity of semi-dominant mutations associated with variously increased grain sizes. Screening of them enables the identification of two genotypes conferring significantly improved grain yield. We therefore uncover a noncanonical cytokinin signaling suppressor and a robust tool for seed rational design.
PMID: 34562665
Plant Cell , IF:11.277 , 2021 Sep doi: 10.1093/plcell/koab208
Erratum to: Arabidopsis NF-YCs play dual roles in repressing brassinosteroid biosynthesis and signaling during light-regulated hypocotyl elongation.
Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Guangzhou, China.; University of the Chinese Academy of Sciences, Beijing, China.; School of Life Sciences, Guangzhou University, Guangzhou, China.
PMID: 34529795
Plant Cell , IF:11.277 , 2021 Sep , V33 (9) : P3004-3021 doi: 10.1093/plcell/koab165
HBI transcription factor-mediated ROS homeostasis regulates nitrate signal transduction.
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China.; College of Agriculture, Shanxi Agricultural University, Taigu 030801, China.; Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan 250100, China.; State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China.; School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.; School of Life Sciences and Division of Molecular & Cell Biophysics, Hefei National Science Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230027, China.
Nitrate is both an important nutrient and a critical signaling molecule that regulates plant metabolism, growth, and development. Although several components of the nitrate signaling pathway have been identified, the molecular mechanism of nitrate signaling remains unclear. Here, we showed that the growth-related transcription factors HOMOLOG OF BRASSINOSTEROID ENHANCED EXPRESSION2 INTERACTING WITH IBH1 (HBI1) and its three closest homologs (HBIs) positively regulate nitrate signaling in Arabidopsis thaliana. HBI1 is rapidly induced by nitrate through NLP6 and NLP7, which are master regulators of nitrate signaling. Mutations in HBIs result in the reduced effects of nitrate on plant growth and approximately 22% nitrate-responsive genes no longer to be regulated by nitrate. HBIs increase the expression levels of a set of antioxidant genes to reduce the accumulation of reactive oxygen species (ROS) in plants. Nitrate treatment induces the nuclear localization of NLP7, whereas such promoting effects of nitrate are significantly impaired in the hbi-q and cat2 cat3 mutants, which accumulate high levels of H2O2. These results demonstrate that HBI-mediated ROS homeostasis regulates nitrate signal transduction through modulating the nucleocytoplasmic shuttling of NLP7. Overall, our findings reveal that nitrate treatment reduces the accumulation of H2O2, and H2O2 inhibits nitrate signaling, thereby forming a feedback regulatory loop to regulate plant growth and development.
PMID: 34129038
Proc Natl Acad Sci U S A , IF:11.205 , 2021 Sep , V118 (38) doi: 10.1073/pnas.2108242118
Activation loop phosphorylaton of a non-RD receptor kinase initiates plant innate immune signaling.
Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland.; The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom.; Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland; cyril.zipfel@botinst.uzh.ch.
Receptor kinases (RKs) are fundamental for extracellular sensing and regulate development and stress responses across kingdoms. In plants, leucine-rich repeat receptor kinases (LRR-RKs) are primarily peptide receptors that regulate responses to myriad internal and external stimuli. Phosphorylation of LRR-RK cytoplasmic domains is among the earliest responses following ligand perception, and reciprocal transphosphorylation between a receptor and its coreceptor is thought to activate the receptor complex. Originally proposed based on characterization of the brassinosteroid receptor, the prevalence of complex activation via reciprocal transphosphorylation across the plant RK family has not been tested. Using the LRR-RK ELONGATION FACTOR TU RECEPTOR (EFR) as a model, we set out to understand the steps critical for activating RK complexes. While the EFR cytoplasmic domain is an active protein kinase in vitro and is phosphorylated in a ligand-dependent manner in vivo, catalytically deficient EFR variants are functional in antibacterial immunity. These results reveal a noncatalytic role for EFR in triggering immune signaling and indicate that reciprocal transphoshorylation is not a ubiquitous requirement for LRR-RK complex activation. Rather, our analysis of EFR along with a detailed survey of the literature suggests a distinction between LRR-RKs with RD- versus non-RD protein kinase domains. Based on newly identified phosphorylation sites that regulate the activation state of the EFR complex in vivo, we propose that LRR-RK complexes containing a non-RD protein kinase may be regulated by phosphorylation-dependent conformational changes of the ligand-binding receptor, which could initiate signaling either allosterically or through driving the dissociation of negative regulators of the complex.
PMID: 34531323
J Cell Sci , IF:5.285 , 2021 Sep doi: 10.1242/jcs.259134
Phosphorylation-dependent routing of RLP44 towards brassinosteroid or phytosulfokine signalling.
Centre for Organismal Studies Heidelberg, University of Heidelberg, INF230, 69120 Heidelberg, Germany.; Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 201602, China.; Department of Plant Biochemistry, Centre for Plant Molecular Biology (ZMBP), Eberhard Karls University, D-72076 Tubingen, Germany.
Plants rely on cell surface receptors to integrate developmental and environmental cues into behaviour adapted to the conditions. The largest group of these receptors, leucine-rich repeat receptor-like kinases, form a complex interaction network that is modulated and extended by receptor-like proteins. This raises the question of how specific outputs can be generated when receptor proteins are engaged in a plethora of promiscuous interactions. RECEPTOR-LIKE PROTEIN 44 (RLP44) acts to promote both brassinosteroid and phytosulfokine signalling, which orchestrate diverse cellular responses. However, it's unclear how these activities are coordinated. Here, we show that RLP44 is phosphorylated in its highly conserved cytosolic tail and that this post-translational modification governs its subcellular localization. Whereas phosphorylation is essential for brassinosteroid-associated functions of RLP44, its role in phytosulfokine signalling is not affected by phospho-status. Detailed mutational analysis suggests that phospho-charge, rather than modification of individual amino acids determines routing of RLP44 to its target receptor complexes, providing a framework to understand how a common component of different receptor complexes can get specifically engaged in a particular signalling pathway.
PMID: 34569597
Tree Physiol , IF:4.196 , 2021 Sep , V41 (9) : P1749-1766 doi: 10.1093/treephys/tpab025
Unraveling hydrogen sulfide-promoted lateral root development and growth in mangrove plant Kandelia obovata: insight into regulatory mechanism by TMT-based quantitative proteomic approaches.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361005, P.R. China.
Mangroves are the main intertidal ecosystems with varieties of root types along the tropical and subtropical coastlines around the world. The typical characteristics of mangrove habitats, including the abundant organic matter and nutrients, as well as the strong reductive environment, are favor for the production of hydrogen sulfide (H2S). H2S, as a pivotal signaling molecule, has been evidenced in a wide variety of plant physiological and developmental processes. However, whether H2S functions in the mangrove root system establishment is not clear yet. Here, we reported the possible role of H2S in regulation of Kandelia obovata root development and growth by tandem mass tag (TMT)-based quantitative proteomic approaches coupled with bioinformatic methods. The results showed that H2S could induce the root morphogenesis of K. obovata in a dose-dependent manner. The proteomic results successfully identified 8075 proteins, and 697 were determined as differentially expressed proteins. Based on the functional enrichment analysis, we demonstrated that H2S could promote the lateral root development and growth by predominantly regulating the proteins associated with carbohydrate metabolism, sulfur metabolism, glutathione metabolism and other antioxidant associated proteins. In addition, transcriptional regulation and brassinosteroid signal transduction associated proteins also act as important roles in lateral root development. The protein-protein interaction analysis further unravels a complicated regulation network of carbohydrate metabolism, cellular redox homeostasis, protein metabolism, secondary metabolism, and amino acid metabolism in H2S-promoted root development and growth of K. obovata. Overall, our results revealed that H2S could contribute to the morphogenesis of the unique root system of mangrove plant K. obovata, and play a positive role in the adaption of mangrove plants to intertidal habitats.
PMID: 33580961
Planta , IF:4.116 , 2021 Sep , V254 (4) : P75 doi: 10.1007/s00425-021-03727-9
Identification of BR biosynthesis genes in cotton reveals that GhCPD-3 restores BR biosynthesis and mediates plant growth and development.
Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China.; Xinjiang Production and Construction Group Key Laboratory of Crop Germplasm Enhancement and Gene Resources Utilization, Biotechnology Research Institute of Xinjiang Academy of Agricultural and Reclamation Science, Shihezi, 832000, Xinjiang, China.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, Henan, China.; Development Center for Science and Technology, Ministry of Agriculture and Rural Affairs, Beijing, 100122, China.; Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China. liuzhaocaas@163.com.; Zhengzhou Research Base, State Key Laboratory of Cotton Biology, School of Agricultural Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China. yangzuoren@caas.cn.; State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, Henan, China. yangzuoren@caas.cn.
MAIN CONCLUSION: Brassinosteroid (BR) synthesis genes in different cotton species was comprehensively identified, and the participation of GhCPD-3 in the BR synthesis signaling pathway for regulating plant development was verified. Brassinosteroid is a natural steroidal phytohormone that plays fundamental roles in plant growth and development. In cotton, detailed characterization and functional validation of BR biosynthesis genes remain rare. Here, 16, 8 and 9 BR biosynthesis genes were identified in Gossypium hirsutum, Gossypium raimondii and Gossypium arboreum, respectively, and their phylogenetic relationships, gene structures, conserved motifs of the encoded proteins, chromosomal locations were determined and a synteny analysis was performed. Gossypium hirsutum and Arabidopsis BR biosynthesis genes closely clustered in the phylogenetic tree and fragment duplication was likely the primary cause promoting gene family expansion in G. hirsutum. Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis showed their relevance as BR biosynthesis genes. GhCPD-3 was highly expressed in roots and stems and the loci of single nucleotide polymorphisms (SNPs) were significantly associated with these traits.Ectopic overexpression of GhCPD-3 in the cpd91 Arabidopsis mutant rescued the mutant phenotype by increasing plant height and leaf size in comparison to those of cpd91 and WT plants. Moreover, overexpressed GhCPD-3 in cpd91 mutants showed greater hypocotyl and root lengths than those of cpd91 and WT plants under light and dark conditions, respectively, indicating that BR actively promotes hypocotyl and root growth. Similar to CPD (CONSTITUTIVE PHOTOMORPHOGENIC DWARF), GhCPD-3 restores BR biosynthesis thereby mediating plant growth and development.
PMID: 34533620
Plant Genome , IF:4.089 , 2021 Sep : Pe20140 doi: 10.1002/tpg2.20140
Characterization of evolutionarily distinct rice BAHD-Acyltransferases provides insight into their plausible role in rice susceptibility to Rhizoctonia solani.
Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India.; National Agri-Food Biotechnology Institute, Mohali, Punjab, 140306, India.; Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, 141 004, India.; School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, 141004, India.; Academy of Scientific and Innovative Research, Ghaziabad, Uttar Pradesh, 201002, India.
Plants produce diverse secondary metabolites in response to different environmental cues including pathogens. The modification of secondary metabolites, including acylation, modulates their biological activity, stability, transport, and localization. A plant-specific BAHD-acyltransferase (BAHD-AT) gene family members catalyze the acylation of secondary metabolites. Here we characterized the rice (Oryza sativa L.) BAHD-ATs at the genome-wide level and endeavor to define their plausible role in the tolerance against Rhizoctonia solani AG1-IA. We identified a total of 85 rice OsBAHD-AT genes and classified them into five canonical clades based on their phylogenetic relationship with characterized BAHD-ATs from other plant species. The time-course RNA sequencing (RNA-seq) analysis of OsBAHD-AT genes and qualitative real-time polymerase chain reaction (qRT-PCR) validation showed higher expression in sheath blight susceptible rice genotype. Furthermore, the DNA methylation analysis revealed higher hypomethylation of OsBAHD-AT genes that corresponds to their higher expression in susceptible rice genotype, indicating epigenetic regulation of OsBAHD-AT genes in response to R. solani AG1-IA inoculation. The results shown here indicate that BAHD-ATs may have a negative role in rice tolerance against R. solani AG1-IA possibly mediated through the brassinosteroid (BR) signaling pathway. Altogether, the present analysis suggests the putative functions of several OsBAHD-AT genes, which will provide a blueprint for their functional characterization and to understand the rice-R. solani AG1-IA interaction.
PMID: 34498798
BMC Genomics , IF:3.969 , 2021 Sep , V22 (1) : P682 doi: 10.1186/s12864-021-08002-5
Genome-wide identification and characterization of the BES/BZR gene family in wheat and foxtail millet.
Tianjin Key Laboratory of Crop Genetics and Breeding, Institute of Crop Sciences, Tianjin Academy of Agricultural Sciences, Tianjin, China.; Department of Life Sciences, Tangshan Normal University, Tangshan, China.; Tianjin Key Laboratory of Crop Genetics and Breeding, Institute of Crop Sciences, Tianjin Academy of Agricultural Sciences, Tianjin, China. jianhew@sina.com.; Department of Life Sciences, Tangshan Normal University, Tangshan, China. liuzhengli65@126.com.
BACKGROUND: BES/BZR family genes have vital roles in plant growth, development, and adaptation to environmental stimuli. However, they have not yet been characterized and systematically analyzed in wheat and foxtail millet. RESULTS: In the current study, five common and two unique BES/BZR genes were identified by genome-wide analysis in wheat and foxtail millet, respectively. These genes were unevenly distributed on 14 and five chromosomes of wheat and foxtail millet, respectively, and clustered in two subgroups in a phylogenetic analysis. The BES/BZR gene family members in each subgroup contained similar conserved motifs. Investigation of cis-acting elements and expression profile analysis revealed that the BES/BZR genes were predominantly expressed in leaf tissues of wheat and foxtail millet seedlings and responded to brassinosteroid, abscisic acid, and NaCl treatments. CONCLUSIONS: Our results provide a basis for future studies on the function and molecular mechanisms of the BES/BZR gene family in wheat, foxtail millet, and other plants.
PMID: 34548036
Biochem Biophys Res Commun , IF:3.575 , 2021 Sep , V578 : P129-135 doi: 10.1016/j.bbrc.2021.09.035
A bHLH protein, OsBIM1, positively regulates rice leaf angle by promoting brassinosteroid signaling.
State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China; College of Life and Environmental Science, Hangzhou Normal University, Hangzhou, 311121, China.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.; Excellence and Innovation Center, Jiangsu Academy of Agricultural Science, Nanjing, 210014, China. Electronic address: zhenzhenzhounj@163.com.; State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China. Electronic address: likeshen@njau.edu.cn.
Rice leaf angle is an important agronomic trait determining plant architecture and crop yield. Brassinosteroids (BRs) play crucial roles in controlling rice leaf angle, thus an increasing number of researches were focused on the BR signaling pathway in rice. However, the orthologs of some important components in Arabidopsis BR signaling have not yet been characterized in rice. In this study, we identified a rice bHLH transcription factor named OsBIM1, as the closest rice homolog of AtBIM1 (BES1-Interacting MYC-like Protein1). Overexpression of OsBIM1 significantly increases rice leaf angles, whereas the T-DNA knock-out mutant osbim1 and wide type (WT) showed similar leaf inclination. OsBIM1 overexpression enhances the sensitivity and response to BR treatment in rice. Gene expression analysis showed that the overexpression of OsBIM1 significantly increased the transcripts of INCREASED LEAF INCLINATION1 (OsILI1) that functions as a key transcription factor promoting BR signaling and response. Meanwhile, OsBIM1 inhibited the expression of DWARF2 (OsD2, a key enzyme in BR biosynthesis pathway). OsBIM1 can bind with OsILI1 promoter and enhance OsILI1 expression in response to BR treatment. The promoting effect of OsBIM1 overexpression on leaf angle can still be observed at harvest stage, but overexpression of OsBIM1 resulted in smaller grain size and reduced yield. These results indicate that OsBIM1 functions as a positive regulator in BR signaling, and its overexpression increases rice lamina inclination by promoting BR sensitivity and response.
PMID: 34562652
Plant Signal Behav , IF:2.247 , 2021 Sep : P1976561 doi: 10.1080/15592324.2021.1976561
Kinase activity is required for the receptor kinase DROOPY LEAF1 to control leaf droopiness.
College of Life Sciences, Hebei Normal University, Shijiazhuang, China.; Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.; School of Biological and Food Science, Hebei Normal University for Nationalities, Chengde, China.; Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, China.
Plants have evolved many leucine-rich repeat receptor-like kinases (LRR-RLKs) that control all aspects of plant life in a kinase-dependent or -independent manner. DROOPY LEAF1 (DPY1), which is a subfamily II LRR-RLK authentic kinase, controls leaf droopiness by negatively regulating early brassinosteroid (BR) signaling in foxtail millet. In this study, we proved that overexpressing kinase-inactive DPY1 does not rescue the droopy leaf phenotype of dpy1 plants because the mutated DPY1 cannot repress BR signaling, suggesting that kinase activity is required for DPY1 to control BR signaling. Moreover, seven DPY1 sites potentially transphosphorylated by SiBAK1 were identified as crucial for DPY1 activation. These findings highlight the importance of kinase activity for the functionality of DPY1.
PMID: 34523390
Plant Signal Behav , IF:2.247 , 2021 Sep , V16 (9) : P1926130 doi: 10.1080/15592324.2021.1926130
Endogenous level of abscisic acid down-regulated by brassinosteroids signaling via BZR1 to control the growth of Arabidopsis thaliana.
Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.; Department of Plant Biology, Carnegie Institution for Science, Standford, USA.
The increased level of endogenous abscisic acid (ABA) in brassinosteroid (BR)-deficient mutants, such as det2 and cyp85a1 x cyp85a2, suggests that ABA synthesis is inhibited by endogenous BRs in Arabidopsis thaliana. Expression of the ABA biosynthesis gene ABA-deficient 2 (ABA2) was negatively regulated by exogenously applied BR but up-regulated by the application of brassinazole and in det2 and cyp85a1 x cyp85a2. In addition, ABA2 expression decreased in bzr1-1D, showing that ABA biosynthesis is inhibited by BR signaling via BZR1, intermediated by ABA2, in Arabidopsis. Four cis-element sequences (E-boxes 1-4) in the putative promoter region of ABA2 were identified as BZR1 binding sites. The electrophoretic mobility shift assay and chromatin immune precipitation analysis demonstrated that BZR1 directly binds to overlapped E-boxes (E-box 3/4) in the promoter region of ABA2. The level of endogenous ABA was decreased in bzr1-1D compared to wild-type, indicating that binding of BZR1 to the ABA2 promoter inhibits ABA synthesis in Arabidopsis. Compared to wild-type, aba2-1 exhibited severely reduced growth and development. The abnormalities in aba2-1 were rescued by the application of ABA, suggesting that ABA2 expression and ABA synthesis are necessary for the normal growth and development of A. thaliana. Finally, bzr1-KO x aba2-1 exhibited inhibitory growth of primary roots compared to bzr1-KO, verifying that ABA2 is a downstream target of BZR1 in the plant. Taken together, the level of endogenous ABA is down-regulated by BR signaling via BZR1, controlling the growth of A. thaliana.
PMID: 33980131