Nat Rev Mol Cell Biol , IF:94.444 , 2023 Dec doi: 10.1038/s41580-023-00691-y
Structure and growth of plant cell walls.
Department of Biology, Pennsylvania State University, University Park, Pennsylvania, USA. dcosgrove@psu.edu.
Plant cells build nanofibrillar walls that are central to plant growth, morphogenesis and mechanics. Starting from simple sugars, three groups of polysaccharides, namely, cellulose, hemicelluloses and pectins, with very different physical properties are assembled by the cell to make a strong yet extensible wall. This Review describes the physics of wall growth and its regulation by cellular processes such as cellulose production by cellulose synthase, modulation of wall pH by plasma membrane H(+)-ATPase, wall loosening by expansin and signalling by plant hormones such as auxin and brassinosteroid. In addition, this Review discusses the nuanced roles, properties and interactions of cellulose, matrix polysaccharides and cell wall proteins and describes how wall stress and wall loosening cooperatively result in cell wall growth.
PMID: 38102449
Nat Biotechnol , IF:54.908 , 2023 Dec , V41 (12) : P1758-1764 doi: 10.1038/s41587-023-01707-w
Tuning plant phenotypes by precise, graded downregulation of gene expression.
State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China.; Qi Biodesign, Beijing, China.; State Key Laboratory of Plant Cell and Chromosome Engineering, Center for Genome Editing, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China. cxgao@genetics.ac.cn.; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China. cxgao@genetics.ac.cn.
The ability to control gene expression and generate quantitative phenotypic changes is essential for breeding new and desired traits into crops. Here we report an efficient, facile method for downregulating gene expression to predictable, desired levels by engineering upstream open reading frames (uORFs). We used base editing or prime editing to generate de novo uORFs or to extend existing uORFs by mutating their stop codons. By combining these approaches, we generated a suite of uORFs that incrementally downregulate the translation of primary open reading frames (pORFs) to 2.5-84.9% of the wild-type level. By editing the 5' untranslated region of OsDLT, which encodes a member of the GRAS family and is involved in the brassinosteroid transduction pathway, we obtained, as predicted, a series of rice plants with varied plant heights and tiller numbers. These methods offer an efficient way to obtain genome-edited plants with graded expression of traits.
PMID: 36894598
Trends Plant Sci , IF:18.313 , 2023 Dec , V28 (12) : P1337-1339 doi: 10.1016/j.tplants.2023.08.014
BTL2 phospho-switch surveils plant immunity.
Department of Plant Pathology, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China.; National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450046, China.; National Key Laboratory of Wheat and Maize Crop Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450046, China. Electronic address: wuliuji@henau.edu.cn.; Department of Plant Pathology, Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: ymwang@njau.edu.cn.
BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) is a co-receptor involved in the recognition of pattern-associated molecular patterns (PAMPs) via plasma membrane-localized pattern recognition receptors (PRRs). Absence of BAK1/SERK4 leads to the activation of autoimmunity in plants. Yu et al. recently showed that BAK-TO-LIFE 2 (BTL2) is required for the surveillance of BAK1/SERK4 integrity to maintain immune homeostasis.
PMID: 37690906
Mol Plant , IF:13.164 , 2023 Dec , V16 (12) : P1976-1989 doi: 10.1016/j.molp.2023.10.007
Vacuolar H(+)-ATPase and BZR1 form a feedback loop to regulate the homeostasis of BR signaling in Arabidopsis.
School of Life Sciences and Biotechnology, The Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, Shanghai 200240, China; School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.; School of Life Sciences and Biotechnology, The Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China.; Zhiyuan College, Shanghai Jiao Tong University, Shanghai 200240, China.; Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, Shanghai 200240, China; School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.; School of Life Sciences and Biotechnology, The Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Collaborative Innovation Center of Agri-Seeds, Joint Center for Single Cell Biology, Shanghai 200240, China. Electronic address: whlin@sjtu.edu.cn.
Brassinosteroid (BR) is a vital plant hormone that regulates plant growth and development. BRASSINAZOLE RESISTANT 1 (BZR1) is a key transcription factor in BR signaling, and its nucleocytoplasmic localization is crucial for BR signaling. However, the mechanisms that regulate BZR1 nucleocytoplasmic distribution and thus the homeostasis of BR signaling remain largely unclear. The vacuole is the largest organelle in mature plant cells and plays a key role in maintenance of cellular pH, storage of intracellular substances, and transport of ions. In this study, we uncovered a novel mechanism of BR signaling homeostasis regulated by the vacuolar H(+)-ATPase (V-ATPase) and BZR1 feedback loop. Our results revealed that the vha-a2 vha-a3 mutant (vha2, lacking V-ATPase activity) exhibits enhanced BR signaling with increased total amount of BZR1, nuclear-localized BZR1, and the ratio of BZR1/phosphorylated BZR1 in the nucleus. Further biochemical assays revealed that VHA-a2 and VHA-a3 of V-ATPase interact with the BZR1 protein through a domain that is conserved across multiple species. VHA-a2 and VHA-a3 negatively regulate BR signaling by interacting with BZR1 and promoting its retention in the tonoplast. Interestingly, a series of molecular analyses demonstrated that nuclear-localized BZR1 could bind directly to specific motifs in the promoters of VHA-a2 and VHA-a3 to promote their expression. Taken together, these results suggest that V-ATPase and BZR1 may form a feedback regulatory loop to maintain the homeostasis of BR signaling in Arabidopsis, providing new insights into vacuole-mediated regulation of hormone signaling.
PMID: 37837193
New Phytol , IF:10.151 , 2023 Dec doi: 10.1111/nph.19469
PHB3 interacts with BRI1 and BAK1 to mediate brassinosteroid signal transduction in Arabidopsis and tomato.
Institute of Vegetables, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.; State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China.; Shandong Institute of Innovation and Development, Jinan, 250101, China.; Hybrid Rapeseed Research Center of Shaanxi Province, Yangling, Shaanxi, 712100, China.; Xian Highness Agricultural Science & Technology Co. Ltd, Xian, Shaanxi, 710086, China.; Department of Plant Sciences, University of Idaho, Moscow, ID, 83844, USA.
Brassinosteroids (BRs) are plant hormones that are essential in plant growth and development. BRASSINOSTEROID-INSENSITIVE 1 (BRI1) and BRI1 ASSOCIATED RECEPTOR KINASE 1 (BAK1), which are located on the plasma membrane, function as co-receptors that accept and transmit BR signals. PROHIBITIN 3 (PHB3) was identified in both BRI1 and BAK1 complexes by affinity purification and LC-MS/MS analysis. Biochemical data showed that BRI1/BAK1 interacted with PHB3 in vitro and in vivo. BRI1/BAK1 phosphorylated PHB3 in vitro. When the Thr-80 amino acid in PHB3 was mutated to Ala, the mutant protein was not phosphorylated by BRI1 and the mutant protein interaction with BRI1 was abolished in the yeast two-hybrid assay. BAK1 did not phosphorylate the mutant protein PHB3(T54A) . The loss-of-function phb3 mutant showed a weaker BR signal than the wild-type. Genetic analyses revealed that PHB3 is a BRI1/BAK1 downstream substrate that participates in BR signalling. PHB3 has five homozygous in tomato, and we named the closest to AtPHB3 as SlPHB3.1. Biochemical data showed that SlBRI1/SlSERK3A/SlSERK3B interacted with SlPHB3.1 and SlPHB3.3. The CRISPR-Cas9 method generated slphb3.1 mutant led to a BR signal stunted relatively in tomatoes. PHB3 is a new component of the BR signal pathway in both Arabidopsis and tomato.
PMID: 38130037
Plant Physiol , IF:8.34 , 2023 Dec doi: 10.1093/plphys/kiad638
Oomycete pathogen pectin acetylesterase targets host lipid transfer protein to reduce salicylic acid signaling.
National Key Laboratory of Green Pesticide/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, 510642, China.; State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, 510642 China.
During initial stages of microbial invasion, the extracellular space (apoplast) of plant cells is a vital battleground between plants and pathogens. The oomycete plant pathogens secrete an array of apoplastic carbohydrate active enzymes, which are central molecules for understanding the complex plant-oomycete interactions. Among them, pectin acetylesterase (PAE) plays a critical role in the pathogenesis of plant pathogens including bacteria, fungi and oomycetes. Here, we demonstrated that Peronophythora litchii (syn. Phytophthora litchii) PlPAE5 suppresses litchi (Litchi chinensis) plant immunity by interacting with litchi lipid transfer protein 1 (LcLTP1). The LcLTP1-binding activity and virulence function of PlPAE5 depend on its PAE domain but not on its pectin acetylesterase activity. The high expression of LcLTP1 enhances plant resistance to oomycete and fungal pathogens, and this disease resistance depends on BRASSINOSTEROID INSENSITIVE 1-associated receptor kinase 1 (BAK1) and Suppressor of BIR1 (SOBIR1) in Nicotiana benthamiana. LcLTP1 activates the plant salicylic acid (SA) signaling pathway, while PlPAE5 subverts the LcLTP1-mediated SA signaling pathway by destabilizing LcLTP1. Conclusively, this study reports a virulence mechanism of oomycete pectin acetylesterase suppressing plant LTP-mediated SA immune signaling and will be instrumental for boosting plant resistance breeding.
PMID: 38039157
Plant Physiol , IF:8.34 , 2023 Dec doi: 10.1093/plphys/kiad635
Rice ILI atypical bHLH transcription factors antagonize OsbHLH157/OsbHLH158 during brassinosteroid signaling.
State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China.; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.; College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.; Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China; Hainan Yazhou Bay Seed Laboratory/National Nanfan Research Institute (Sanya), CAAS, Sanya 572024, China.
Brassinosteroids (BRs) are a group of steroid hormones that play crucial roles in plant growth and development. Atypical bHLH transcription factors that lack the basic region for DNA binding have been implicated in BR signaling. However, the underlying mechanisms of atypical bHLHs in regulation of rice (Oryza sativa) BR signaling is still largely unknown. Here, we describe a systematic characterization of INCREASED LEAF INCLINATION (ILI) subfamily atypical bHLH transcription factors in rice. A total of eight members, ILI1 to ILI8, with substantial sequence similarity were retrieved. Knockout and overexpression analyses demonstrated that these ILIs play unequally redundant and indispensable roles in BR-mediated growth and development in rice, with a more prominent role for ILI4 and ILI5. The ili3/4/5/8 quadruple and ili1/3/4/7/8 quintuple mutants displayed tremendous BR-related defects with severe dwarfism, erect leaves, and sterility. Biochemical analysis showed that ILIs interact with OsbHLH157 and OsbHLH158, which are also atypical bHLHs and have no obvious transcriptional activity. Overexpression of OsbHLH157 and OsbHLH158 led to drastic BR-defective growth, whereas the osbhlh157 osbhlh158 double mutant developed a typical BR enhanced phenotype, indicating that OsbHLH157 and OsbHLH158 play a major negative role in rice BR signaling. Further transcriptome analyses revealed opposite effects of ILIs and OsbHLH157/OsbHLH158 in regulation of downstream gene expression, supporting the antagonism of ILIs and OsbHLH157/OsbHLH158 in maintaining the balance of BR signaling. Our results provide insights into the mechanism of brassinosteroid signaling and plant architecture formation in rice.
PMID: 38039100
Plant Physiol , IF:8.34 , 2023 Nov doi: 10.1093/plphys/kiad634
R-SNARE protein YKT61 mediates root apical meristem cell division via BRASSINOSTEROID-INSENSITIVE1 recycling.
College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.; Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China.
Root growth is sustained by cell division and differentiation of the root apical meristem (RAM), in which brassinosteroid (BR) signaling mediated via dynamic targeting of BRASSINOSTEROID-INSENSITIVE1 (BRI1) plays complex roles. BRI1 is constitutively secreted to the plasma membrane (PM), internalized, and recycled or delivered into vacuoles, whose PM abundance is critical for BR signaling. Vesicle-target membrane fusion is regulated by heterotetrameric SNARE complexes. SNARE proteins have been implicated in BRI1 targeting, but how SNAREs affect RAM development is unclear. We report that Arabidopsis (Arabidopsis thaliana) YKT61, an atypical R-SNARE protein, is critical for BR-controlled RAM development through the dynamic targeting of BRI1. Functional loss of YKT61 is lethal for both male and female gametophytes. By using weak mutant alleles of YKT61, ykt61-partially complemented (ykt61-pc), we show that YKT61 knock-down results in a reduction of RAM length due to reduced cell division, similar to that in bri1-116. YKT61 physically interacts with BRI1 and is critical for the dynamic recycling of BRI1 to the PM. We further determine that YKT61 is critical for the dynamic biogenesis of vacuoles, for the maintenance of Golgi morphology, and for endocytosis, which may have a broad effect on development. Endomembrane compartments connected via vesicular machinery, such as SNAREs, influence nuclear-controlled cellular activities such as division and differentiation by affecting dynamic targeting of membrane proteins, supporting a retro-signaling pathway from the endomembrane system to the nucleus.
PMID: 38036295
Plant Physiol , IF:8.34 , 2023 Nov doi: 10.1093/plphys/kiad633
Transcription factors BZR2/MYC2 modulate brassinosteroid and jasmonic acid crosstalk during pear dormancy.
Hainan Institute of Zhejiang University, Sanya, Hainan 572000, China.; College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, PR China.; Zhejiang Provincial Key Laboratory of Integrative Biology of Horticultural Plants, Hangzhou 310058, Zhejiang, PR China.; The Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture of China, Hangzhou 310058, Zhejiang, PR China.; Department of Pomology, Faculty of Agriculture, Alexandria University, Alexandria 21545, Egypt.
Bud dormancy is an important physiological process during winter. Its release requires a certain period of chilling. In pear (Pyrus pyrifolia), the abscisic acid (ABA)-induced expression of DORMANCY-ASSOCIATED MADS-box (DAM) genes represses bud break, whereas exogenous gibberellin (GA) promotes dormancy release. However, with the exception of ABA and GA, the regulatory effects of phytohormones on dormancy remain largely uncharacterized. In this study, we confirmed brassinosteroids (BRs) and jasmonic acid (JA) contribute to pear bud dormancy release. If chilling accumulation is insufficient, both 24-epibrassinolide (EBR) and methyl jasmonic acid (MeJA) can promote pear bud break, implying they positively regulate dormancy release. BRASSINAZOLE RESISTANT 2 (BZR2), which is a BR-responsive transcription factor, inhibited PpyDAM3 expression and accelerated pear bud break. The transient overexpression of PpyBZR2 increased endogenous GA, JA, and JA-Ile levels. In addition, the direct interaction between PpyBZR2 and MYELOCYTOMATOSIS 2 (PpyMYC2) enhanced the PpyMYC2-mediated activation of Gibberellin 20-oxidase genes PpyGA20OX1L1 and PpyGA20OX2L2 transcription, thereby increasing GA3 contents and accelerating pear bud dormancy release. Interestingly, treatment with 5 microM MeJA increased the bud break rate, while also enhancing PpyMYC2-activated PpyGA20OX expression and increasing GA3,4 contents. The 100 muM MeJA treatment decreased the PpyMYC2-mediated activation of the PpyGA20OX1L1 and PpyGA20OX2L2 promoters and suppressed the inhibitory effect of PpyBZR2 on PpyDAM3 transcription, ultimately inhibiting pear bud break. In summary, our data provide insights into the crosstalk between the BR and JA signaling pathways that regulate the BZR2/MYC2-mediated pathway in the pear dormancy release process.
PMID: 38036294
J Exp Bot , IF:6.992 , 2024 Jan , V75 (1) : P13-16 doi: 10.1093/jxb/erad394
How do brassinosteroids fit in bud outgrowth models?
Waite Research Institute, School of Agriculture Food & Wine, The University of Adelaide, Adelaide, SA 5064, Australia.; Australian Research Council Training Centre for Future Crops Development, The University of Adelaide, Adelaide, SA 5064, Australia.; Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland, Brisbane, QLD 4072, Australia.
A network of plant hormonal signals coordinates plant branching. Brassinosteroids are important in this network, acting as repressors of the strigolactone pathway and TEOSINTE BRANCHED1 .
PMID: 37846132
Plant J , IF:6.417 , 2023 Dec , V116 (6) : P1766-1783 doi: 10.1111/tpj.16464
DWARF AND LOW-TILLERING 2 functions in brassinosteroid signaling and controls plant architecture and grain size in rice.
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.; Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.; Technical Center of Chengdu Customs, Chengdu, 610041, Sichuan, China.
Brassinosteroids (BRs) are a class of steroid phytohormones that control various aspects of plant growth and development. Several transcriptional factors (TFs) have been suggested to play roles in BR signaling. However, their possible relationship remains largely unknown. Here, we identified a rice mutant dwarf and low-tillering 2 (dlt2) with altered plant architecture, increased grain width, and reduced BR sensitivity. DLT2 encodes a GIBBERELLIN INSENSITIVE (GAI)-REPRESSOR OF GAI (RGA)-SCARECROW (GRAS) TF that is mainly localized in the nucleus and has weak transcriptional activity. Our further genetic and biochemical analyses indicate that DLT2 interacts with two BR-signaling-related TFs, DLT and BRASSINAZOLE-RESISTANT 1, and probably modulates their transcriptional activity. These findings imply that DLT2 is implicated in a potentially transcriptional complex that mediates BR signaling and rice development and suggests that DLT2 could be a potential target for improving rice architecture and grain morphology. This work also sheds light on the role of rice GRAS members in regulating numerous developmental processes.
PMID: 37699038
Int J Mol Sci , IF:5.923 , 2023 Dec , V24 (24) doi: 10.3390/ijms242417252
Physiological Characteristics and Transcriptome Analysis of Exogenous Brassinosteroid-Treated Kiwifruit.
National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, China.; Zhongyuan Research Center, Chinese Academy of Agricultural Sciences, Xinxiang 453514, China.
Brassinosteroids (BRs) play pivotal roles in improving plant stress tolerance. To investigate the mechanism of BR regulation of salt tolerance in kiwifruit, we used 'Hongyang' kiwifruit as the test material. We exposed the plants to 150 mmol/L NaCl stress and irrigated them with exogenous BR (2,4-epibrassinolide). The phenotypic analysis showed that salt stress significantly inhibited photosynthesis in kiwifruit, leading to a significant increase in the H(2)O(2) content of leaves and roots and a significant increase in Na(+)/K(+), resulting in oxidative damage and an ion imbalance. BR treatment resulted in enhanced photosynthesis, reduced H(2)O(2) content, and reduced Na(+)/K(+) in leaves, alleviating the salt stress injury. Furthermore, transcriptome enrichment analysis showed that the differentially expressed genes (DEGs) related to BR treatment are involved in pathways such as starch and sucrose metabolism, pentose and glucuronate interconversions, and plant hormone signal transduction, among others. Among the DEGs involved in plant hormone signal transduction, those with the highest expression were involved in abscisic acid signal transduction. Moreover, there was a significant increase in the expression of the AcHKT1 gene, which regulates ion transduction, and the antioxidant enzyme AcFSD2 gene, which is a key gene for improving salt tolerance. The data suggest that BRs can improve salt tolerance by regulating ion homeostasis and reducing oxidative stress.
PMID: 38139080
Int J Mol Sci , IF:5.923 , 2023 Dec , V24 (24) doi: 10.3390/ijms242417246
Brassinosteroid Signaling Pathways: Insights into Plant Responses under Abiotic Stress.
Department of Biology, College of Science, United Arab Emirates University, Al Ain 15551, United Arab Emirates.; Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409, USA.
With the growing global population, abiotic factors have emerged as a formidable threat to agricultural food production. If left unaddressed, these stress factors might reduce food yields by up to 25% by 2050. Plants utilize natural mechanisms, such as reactive oxygen species scavenging, to mitigate the adverse impacts of abiotic stressors. Diverse plants exhibit unique adaptations to abiotic stresses, which are regulated by phytohormones at various levels. Brassinosteroids (BRs) play a crucial role in controlling essential physiological processes in plants, including seed germination, xylem differentiation, and reproduction. The BR cascade serves as the mechanism through which plants respond to environmental stimuli, including drought and extreme temperatures. Despite two decades of research, the complex signaling of BRs under different stress conditions is still being elucidated. Manipulating BR signaling, biosynthesis, or perception holds promise for enhancing crop resilience. This review explores the role of BRs in signaling cascades and summarizes their substantial contribution to plants' ability to withstand abiotic stresses.
PMID: 38139074
Front Microbiol , IF:5.64 , 2023 , V14 : P1295107 doi: 10.3389/fmicb.2023.1295107
Biological control of potato common scab and growth promotion of potato by Bacillus velezensis Y6.
College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China.; Guangdong Provincial Key Laboratory of Crop Genetic Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China.; Guangdong Institute Center of Wine and Spirits, Guangdong Institute of Food Inspection, Guangzhou, China.; Department of Pharmaceutical Engineering, School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, China.; Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education Changsha, Hunan Provincial Engineering Research Center for Potatoes, Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, Key Laboratory for Vegetable Biology of Hunan Province, College of Horticulture, Hunan Agricultural University, Changsha, China.; Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
Potato common scab, caused mainly by Streptomyces scabies, causes surface necrosis and reduces the economic value of potato tubers, but effective chemical control is still lacking. In this study, an attempt was made to control potato common scab by inoculating potatoes with Bacillus velezensis (B. velezensis) and to further investigate the mechanism of biological control. The results showed that B. velezensis Y6 could reduce the disease severity of potato common scab from 49.92 +/- 25.74% [inoculated with Streptomyces scabies (S. scabies) only] to 5.56 +/- 1.89% (inoculated with S. scabies and Y6 on the same day) and increase the potato yield by 37.32% compared with the control under pot experiment in this study. Moreover, in the field trial, it was found that Y6 could also significantly reduce disease severity from 13.20 +/- 1.00% to 4.00 +/- 0.70% and increase the potato yield from 2.07 +/- 0.10 ton/mu to 2.87 +/- 0.28 ton/mu (p < 0.01; Tukey's test). Furthermore, RNA-seq analysis indicated that 256 potato genes were upregulated and 183 potato genes were downregulated in response to B. velezensis Y6 inoculation. In addition, strain Y6 was found to induce the expression of plant growth-related genes in potato, including cell wall organization, biogenesis, brassinosteroid biosynthesis, and plant hormone transduction genes, by 1.01-4.29 times. As well as up-regulate hydroquinone metabolism-related genes and several transcription factors (bHLH, MYB, and NAC) by 1.13-4.21 times. In summary, our study will help to understand the molecular mechanism of biological control of potato common scab and improve potato yield.
PMID: 38149275
J Biol Chem , IF:5.157 , 2023 Dec , V299 (12) : P105456 doi: 10.1016/j.jbc.2023.105456
Resolving binding pathways and solvation thermodynamics of plant hormone receptors.
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. Electronic address: diwakar@illinois.edu.
Plant hormones are small molecules that regulate plant growth, development, and responses to biotic and abiotic stresses. They are specifically recognized by the binding site of their receptors. In this work, we resolved the binding pathways for eight classes of phytohormones (auxin, jasmonate, gibberellin, strigolactone, brassinosteroid, cytokinin, salicylic acid, and abscisic acid) to their canonical receptors using extensive molecular dynamics simulations. Furthermore, we investigated the role of water displacement and reorganization at the binding site of the plant receptors through inhomogeneous solvation theory. Our findings predict that displacement of water molecules by phytohormones contributes to free energy of binding via entropy gain and is associated with significant free energy barriers for most systems analyzed. Also, our results indicate that displacement of unfavorable water molecules in the binding site can be exploited in rational agrochemical design. Overall, this study uncovers the mechanism of ligand binding and the role of water molecules in plant hormone perception, which creates new avenues for agrochemical design to target plant growth and development.
PMID: 37949229
Plant Cell Rep , IF:4.57 , 2023 Dec , V43 (1) : P11 doi: 10.1007/s00299-023-03113-7
Attenuation of brassinosteroid signaling enhances grain yield in semi-dwarf wheat varieties.
College of General Education, Kookmin University, Seoul, 02707, South Korea. ravigupta07@ymail.com.
A recent study identified a natural deletion in the r-e-z haploblock which confers a semi-dwarf trait, higher nitrogen use efficiency, and improved yield in semi-dwarf wheat varieties by attenuating the brassinosteroid signaling.
PMID: 38135808
Plant Physiol Biochem , IF:4.27 , 2023 Dec , V206 : P108254 doi: 10.1016/j.plaphy.2023.108254
Effects of exogenous GA(3) on stem secondary growth of Pinus massoniana seedlings.
Institute for Forest Resources and Environment of Guizhou Province & Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province & College of Forestry, Guizhou University, Guiyang, 550025, China.; Institute for Forest Resources and Environment of Guizhou Province & Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province & College of Forestry, Guizhou University, Guiyang, 550025, China. Electronic address: fhfan1@gzu.edu.cn.; Institute for Forest Resources and Environment of Guizhou Province & Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou Province & College of Forestry, Guizhou University, Guiyang, 550025, China. Electronic address: gjdinggzu@126.com.
Gibberellins (GAs) play a crucial role in regulating secondary growth in angiosperms, but their effects on the secondary growth of gymnosperms are rarely reported. In this study, we administered exogenous GA(3) to two-year-old P. massoniana seedlings, and examined its effects on anatomical structure, physiological and biochemical changes, and gene expression in stems. The results showed that exogenous GA(3) could enhance xylem development in P. massoniana by promoting cell division. The content of endogenous hormone (including auxins, brassinosteroids, and gibberellins) were changed and the genes related to phytohormone biosynthesis and signaling pathway, such as GID1, DELLA, TIR1, ARF, SAUR, CPD, BR6ox1, and CYCD3, were differentially expressed under GA(3) treatment. Furthermore, GA(3) and BR (brassinosteroid) might act synergistically in promoting secondary growth in P. massoniana. Additionally, lignin content was significantly increased after GA(3) treatment accompanied by the express of lignin biosynthesis related genes. PmCAD (TRINITY_DN142116_c0_g1), a crucial gene involved in the lignin biosynthesis, was cloned and overexpressed in Nicotiana benthamiana, significantly promoting the xylem development and enhancing stem lignification. It was regarded as a key candidate gene for improving stem growth of P. massoniana. The findings of this study have demonstrated the impact of GA(3) treatment on secondary growth of stems in P. massoniana, providing a foundation for understanding the molecular regulatory mechanism of stem secondary growth in Pinaceae seedlings and offering theoretical guidance for cultivating new germplasm with enhanced growth and yield.
PMID: 38056037
Planta , IF:4.116 , 2023 Dec , V259 (1) : P11 doi: 10.1007/s00425-023-04288-9
The overexpression of SlBRI1 driven by Atrd29A promoter-transgenic plants improves the chilling stress tolerance of tomato.
Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637002, Sichuan, China.; Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637002, Sichuan, China. nieshuming@cwnu.edu.cn.
Overexpression of SlBRI1 driven by the Atrd29A promoter could increase the cold resistance of tomato plants during chilling stress but did not improve the expression of SlBRI1 and plant growth under normal conditions. Low temperature is the main limiting factor severely affecting tomato plant development, growth, and fruit quality in winter and spring. Brassinosteroids (BRs) and key BR signaling genes positively regulate tomato plant development and response to chilling stress. Brassinosteroid-insensitive 1 (BRI1) is a major BR receptor that initiates BR signaling. Our results showed that overexpression of SlBRI1 driven by the Atrd29A promoter in transgenic plants did not increase the expression of SlBRI1 under normal conditions but rapidly induced the expression of SlBRI1 during chilling stress. The degree of wilting was lower in Atrd29A promoter-transgenic plants than in wild-type (WT) plants after chilling stress. Atrd29A promoter-transgenic plants exhibited low relative electrolyte leakage and reactive oxygen species (ROS) accumulation under chilling stress. Transgenic plants showed higher photosynthetic ability and antioxidant enzyme activity than WT plants under chilling stress. The BR content and expression levels of key genes involved in BR biosynthesis in Atrd29A-promoter transgenic plants were significantly lower than those in WT plants during chilling stress. The abscisic acid (ABA) content and expression levels of key ABA biosynthesis genes in the Atrd29A promoter-transgenic plants were significantly higher than those in the WT plants during chilling stress. In addition, Atrd29A promoter-transgenic plants positively enhanced the expression levels of ICE-CBF-COR cold-responsive pathway genes. Therefore, the overexpression of SlBRI1 driven by the Atrd29A promoter in transgenic plants can be a valuable tool for reducing chilling stress.
PMID: 38047928
Plants (Basel) , IF:3.935 , 2023 Dec , V12 (24) doi: 10.3390/plants12244103
Hydrangea arborescens 'Annabelle' Flower Formation and Flowering in the Current Year.
Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, China National Engineering Research Center for Floriculture, College of Landscape Architecture, Beijing Forestry University, Beijing 100083, China.; Beijing Flower Engineering Technology Research Center, Plant Institute, China National Botanical Garden North Garden, Beijing 100093, China.
The perennial woody plant Hydrangea arborescens 'Annabelle' is of great research value due to its unique mechanism of flower development that occurs in the current year, resulting in decorative flowers that can be enjoyed for a relatively long period of time. However, the mechanisms underlying the regulation of current-year flower development in H. arborescens 'Annabelle' are still not fully understood. In this study, we conducted an associated analysis to explore the core regulating network in H. arborescens 'Annabelle' by combining phenological observations, physiological assays, and transcriptome comparisons across seven flower developmental stages. Through this analysis, we constructed a gene co-expression network (GCN) based on the highest reciprocal rank (HRR), using 509 differentially expressed genes (DEGs) identified from seven flowering-related pathways, as well as the biosynthesis of eight flowering-related phytohormones and signal transduction in the transcriptomic analysis. According to the analysis of the GCN, we identified 14 key genes with the highest functional connectivity that played critical roles in specific development stages. We confirmed that 135 transcription factors (AP2/ERF, bHLH, CO-like, GRAS, MIKC, SBP, WRKY) were highly co-expressed with the 14 key genes, indicating their close associations with the development of current-year flowers. We further proposed a hypothetical model of a gene regulatory network for the development of the whole flower. This model suggested that the photoperiod, aging, and gibberellin pathways, along with the phytohormones abscisic acid (ABA), gibberellin (GA), brassinosteroid (BR), and jasmonic acid (JA), work synergistically to promote the floral transition. Additionally, auxin, GA, JA, ABA, and salicylic acid (SA) regulated the blooming process by involving the circadian clock. Cytokinin (CTK), ethylene (ETH), and SA were key regulators that affected flower senescence. Additionally, several floral integrators (HaLFY, HaSOC1-2, HaAP1, HaFULL, HaAGL24, HaFLC, etc.) were dominant contributors to the development of H. arborescens flowers. Overall, this research provides a comprehensive understanding of the dynamic mechanism underlying the entire process of current-year flower development, thereby offering valuable insights for further studies on the flower development of H. arborescens 'Annabelle'.
PMID: 38140430
J Plant Physiol , IF:3.549 , 2023 Dec , V291 : P154126 doi: 10.1016/j.jplph.2023.154126
Medium-chain-length polyprenol (C45-C55) formation in chloroplasts of Arabidopsis is brassinosteroid-dependent.
Institute of Biology, Warsaw University of Life Sciences, ul. Nowoursynowska 159, bldg. 37, 02-776, Warsaw, Poland. Electronic address: malgorzata_gutkowska-stronkowska@sggw.edu.pl.; Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5a, 02-106, Warsaw, Poland.; Faculty of Biology, University of Warsaw, ul. Miecznikowa 1, 02-096, Warsaw, Poland.
Brassinosteroids are important plant hormones influencing, among other processes, chloroplast development, the electron transport chain during light reactions of photosynthesis, and the Calvin-Benson cycle. Medium-chain-length polyprenols built of 9-11 isoprenoid units (C45-C55 carbons) are a class of isoprenoid compounds present in abundance in thylakoid membranes. They are synthetized in chloroplast by CPT7 gene from Calvin cycle derived precursors on MEP (methylerythritol 4-phosphate) isoprenoid biosynthesis pathway. C45-C55 polyprenols affect thylakoid membrane ultra-structure and hence influence photosynthetic apparatus performance in plants such as Arabidopsis and tomato. So far nothing is known about the hormonal or environmental regulation of CPT7 gene expression. The aim of our study was to find out if medium-chain-length polyprenol biosynthesis in plants may be regulated by hormonal cues.We found that the CPT7 gene in Arabidopsis has a BZR1 binding element (brassinosteroid dependent) in its promoter. Brassinosteroid signaling mutants in Arabidopsis accumulate a lower amount of medium-chain-length C45-C55 polyprenols than control plants. At the same time carotenoid and chlorophyll content is increased, and the amount of PsbD1A protein coming from photosystem II does not undergo a significant change. On contrary, treatment of WT plants with epi-brassinolide increases C45-C55 polyprenols content. We also report decreased transcription of MEP enzymes (besides C45-C55 polyprenols, precursors of numerous isoprenoids, e.g. phytol, carotenoids are derived from this pathway) and genes encoding biosynthesis of medium-chain-length polyprenol enzymes in brassinosteroid perception mutant bri1-116. Taken together, we document that brassinosteroids affect biosynthetic pathway of C45-C55 polyprenols.
PMID: 37948907
Plant Signal Behav , IF:2.247 , 2023 Dec , V18 (1) : P2229957 doi: 10.1080/15592324.2023.2229957
The RGI1-BAK1 module acts as the main receptor-coreceptor pair for regulating primary root gravitropism and meristem activity in response to RGF1 peptide in Arabidopsis.
Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, Korea.; Kumho Life Science Laboratory, Chonnam National University, Gwangju, Korea.; Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, Korea.
ROOT MERISTEM GROWTH FACTOR1 (RGF1) and its receptors RGF1 INSENSITIVEs (RGIs), a group of leucine-rich repeat receptor kinases, promote primary root meristem activity via a mitogen-activated protein kinase (MPK) signaling cascade and control root gravitropism in Arabidopsis. Genetic analyses and in vitro binding assays have indicated that among five RGIs identified in Arabidopsis, RGI1, RGI2, and RGI3 recognize RGF1 peptides. However, it remains unclear whether the RGF1 peptide is redundantly recognized by these RGIs or mainly by a single RGI in the regulation of primary root meristem activity. In the present study, we analyzed root meristem growth of the rgi1, rgi2, and rgi3 single mutants in response to RGF1 treatment and observed a significantly decreased sensitivity in meristem growth of rgi1 and complete insensitivity in rgi1 rgi2 rgi3 triple mutant compared with the wild type but not in the rgi1 and rgi2 single mutants. We also observed that both root gravitropism and meristem growth in the BRASSINOSTEROID INSENSITIVE1-ASSOCIATED RECEPTOR KINASE 1 (bak1) single mutant were insensitive to RGF1 peptide treatment, whereas other serk mutants, such as serk1, serk2, and serk4, were fully sensitive to RGF1 peptide like the wild type. These mutant analyses suggest that RGI1-BAK1 pair acts as the main receptor-coreceptor pair for regulating primary root gravitropism and meristem activity in response to RGF1 peptide in Arabidopsis.
PMID: 37382066
Plant Signal Behav , IF:2.247 , 2023 Dec , V18 (1) : P2186640 doi: 10.1080/15592324.2023.2186640
Exogenous Brassinosteroid Enhances Zinc tolerance by activating the Phenylpropanoid Biosynthesis pathway in Citrullus lanatus L.
College of Resources and Environmental Engineering, Yangzhou Polytechnic College, Yangzhou, China.; Jiangsu Safety & Environment Technology and Equipment for Planting and Breeding Industry Engineering Research Center, Yangzhou, China.
Zinc (Zn) is an important element in plants, but over-accumulation of Zn is harmful. The phytohormone brassinosteroids (BRs) play a key role in regulating plant growth, development, and response to stress. However, the role of BRs in watermelon (Citrullus lanatus L.) under Zn stress, one of the most important horticultural crops, remains largely unknown. In this study, we revealed that 24-epibrassinolide (EBR), a bioactive BR enhanced Zn tolerance in watermelon plants, which was related to the EBR-induced increase in the fresh weight, chlorophyll content, and net photosynthetic rate (Pn) and decrease in the content of hydrogen peroxide (H(2)O(2)), malondialdehyde (MDA), and Zn in watermelon leaves. Through RNA deep sequencing (RNA-seq), 350 different expressed genes (DEG) were found to be involved in the response to Zn stress after EBR treatment, including 175 up-regulated DEGs and 175 down-regulated DEGs. The up-regulated DEGs were significantly enriched in 'phenylpropanoid biosynthesis' pathway (map00940) using KEGG enrichment analysis. The gene expression levels of PAL, 4CL, CCR, and CCoAOMT, key genes involved in phenylpropanoid pathway, were significantly induced after EBR treatment. In addition, compared with Zn stress alone, EBR treatment significantly promoted the activities of PAL, 4CL, and POD by 30.90%, 20.69%, and 47.28%, respectively, and increased the content of total phenolic compounds, total flavonoids, and lignin by 23.02%, 40.37%, and 29.26%, respectively. The present research indicates that EBR plays an active role in strengthening Zn tolerance, thus providing new insights into the mechanism of BRs enhancing heavy metal tolerance.
PMID: 37083111
Plant Signal Behav , IF:2.247 , 2023 Dec , V18 (1) : P2163337 doi: 10.1080/15592324.2022.2163337
Arabidopsis clathrin adaptor EPSIN1 but not MODIFIED TRANSPORT TO THE VACOULE1 contributes to effective plant immunity against pathogenic Pseudomonas bacteria.
University of Missouri-Columbia, Division of Biochemistry, Interdisciplinary Plant Group (IPG), Columbia, MO, USA.; Department of Plant Physiology, University of Potsdam, Potsdam, Germany.
In eukaryotes, EPSINs are Epsin N-terminal Homology (ENTH) domain-containing proteins that serve as monomeric clathrin adaptors at the plasma membrane (PM) or the trans-Golgi Network (TGN)/early endosomes (EE). The model plant Arabidopsis thaliana encodes for seven ENTH proteins, of which so far, only AtEPSIN1 (AtEPS1) and MODIFIED TRANSPORT TO THE VACUOLE1 (AtMTV1) localize to the TGN/EE and contribute to cargo trafficking to both the cell surface and the vacuole. However, relatively little is known about role(s) of any plant EPSIN in governing physiological responses. We have recently shown that AtEPS1 is a positive modulator of plant immune signaling and pattern-triggered immunity against flagellated Pseudomonas syringae pv. tomato (Pto) DC3000 bacteria. In eps1 mutants, impaired immune responses correlate with reduced accumulation of the receptor FLAGELLIN SENSING2 (AtFLS2) and the convergent immune co-receptor BRASSINOSTEROID INSENTIVE1-ASSOCIATED RECEPTOR KINASE1 (AtBAK1) in the PM. Here, we report that in contrast to AtEPS1, the TGN/EE-localized AtMTV1 did not contribute significantly to immunity against pathogenic Pto DC3000 bacteria. We also compared the amino acid sequences, peptide motif structures and in silico tertiary structures of the ENTH domains of AtEPS1 and AtMTV1 in more detail. We conclude that despite sharing the classical tertiary alpha helical ENTH-domain structure and clathrin-binding motifs, the overall low amino acid identity and differences in peptide motifs may explain their role(s) in trafficking of some of the same as well as distinct cargo components to their site of function, with the latter potentially contributing to differences in physiological responses.
PMID: 36603596
Plant Signal Behav , IF:2.247 , 2023 Dec , V18 (1) : P2153209 doi: 10.1080/15592324.2022.2153209
MYB3R-SCL28-SMR module with a role in cell size control negatively regulates G2 progression in Arabidopsis.
School of Biological Science and Technology, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan.; RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Japan.; Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.; Graduate School of Biostudies, Kyoto University, Kyoto, Japan.; Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Japan.; Department of Biological Sciences, Graduate School of Science, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.; School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar, Mongolia.
Cell size control is one of the prerequisites for plant growth and development. Recently, a GRAS family transcription factor, SCARECROW-LIKE28 (SCL28), was identified as a critical regulator for both mitotic and postmitotic cell-size control. Here, we show that SCL28 is specifically expressed in proliferating cells and exerts its function to delay G2 progression during mitotic cell cycle in Arabidopsis thaliana. Overexpression of SCL28 provokes a significant enlargement of cells in various organs and tissues, such as leaves, flowers and seeds, to different extents depending on the type of cells. The increased cell size is most likely due to a delayed G2 progression and accelerated onset of endoreplication, an atypical cell cycle repeating DNA replication without cytokinesis or mitosis. Unlike DWARF AND LOW-TILLERING, a rice ortholog of SCL28, SCL28 may not have a role in brassinosteroid (BR) signaling because sensitivity against brassinazole, a BR biosynthesis inhibitor, was not dramatically altered in scl28 mutant and SCL28-overexpressing plants. Collectively, our findings strengthen a recently proposed model of cell size control by SCL28 and suggest the presence of diversified evolutionary mechanisms for the regulation and action of SCL28.
PMID: 36576149
Biosci Biotechnol Biochem , IF:2.043 , 2023 Dec doi: 10.1093/bbb/zbad180
Genome-wide identification and expression profiles of the Phytophthora infestans responsive CYPome (Cytochrome P450 complement) in Solanum tuberosum.
College of Life Sciences, Sichuan Normal University, Chengdu 610101, China.
Cytochrome P450s represent one of the largest protein families across all domains of life. In plants, biotic stress can regulate the expression of some P450 genes. However, the CYPome (cytochrome P450 complement) in Solanum tuberosum and its response to Phytophthora infestans infection remains unrevealed. In this study, 488 P450 genes were identified from potato genome, which can be divided into 41 families and 57 subfamilies. Responding to the infection of P. infestans, 375 potato P450 genes were expressed in late blight resistant or susceptible cultivars. A total of 14 P450 genes were identified as resistant related candidates, and 81 P450 genes were identified as late blight responsive candidates. Several phytohormone biosynthesis, brassinosteroid biosynthesis, and phenylpropanoid biosynthesis involved P450 genes were differentially expressed during the potato-pathogen interactions. This study firstly reported the CYPome in S. tuberosum, and characterized the expression patterns of these P450 genes during the infection of P. infestans.
PMID: 38115610
J Genet Genomics , 2023 Dec , V50 (12) : P960-970 doi: 10.1016/j.jgg.2023.04.010
Inhibition of the maize salt overly sensitive pathway by ZmSK3 and ZmSK4.
State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing 100193, China.; College of Life Sciences, Qingdao Agricultural University, Qingdao, Shandong 266109, China.; Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100093, China.; State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100093, China; National Maize Improvement Center of China, China Agricultural University, Beijing 100193, China.; State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100093, China.; State Key Laboratory of Plant Environmental Resilience, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100093, China. Electronic address: guoyan@cau.edu.cn.
Soil salinity is a worldwide problem that adversely affects plant growth and crop productivity. The salt overly sensitive (SOS) pathway is evolutionarily conserved and essential for plant salt tolerance. In this study, we reveal how the maize shaggy/glycogen synthase kinase 3-like kinases ZmSK3 and ZmSK4, orthologs of brassinosteroid insensitive 2 in Arabidopsis thaliana, regulate the maize SOS pathway. ZmSK3 and ZmSK4 interact with and phosphorylate ZmSOS2, a core member of the maize SOS pathway. The mutants defective in ZmSK3 or ZmSK4 are hyposensitive to salt stress, with higher salt-induced activity of ZmSOS2 than that in the wild type. Furthermore, the Ca(2+) sensors ZmSOS3 and ZmSOS3-like calcium binding protein 8 (ZmSCaBP8) activate ZmSOS2 to maintain Na(+)/K(+) homeostasis under salt stress and may participate in the regulation of ZmSOS2 by ZmSK3 and ZmSK4. These findings discover the regulation of the maize SOS pathway and provide important gene targets for breeding salt-tolerant maize.
PMID: 37127254