Trends Plant Sci , IF:18.313 , 2024 Nov doi: 10.1016/j.tplants.2024.10.015
The whole and its parts: cell-specific functions of brassinosteroids.
Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.; Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel. Electronic address: sigal@technion.ac.il.
Brassinosteroid (BR) phytohormones operate at both the cellular and organ levels, and impart distinct transcriptional responses in different cell types and developmental zones, with distinct effects on organ size and shape. Here, we review recent advances implementing high-resolution and modeling tools that have provided new insights into the role of BR signaling in growth coordination across cell layers. We discuss recently gained knowledge on BR movement and its relevance for intercellular communication, as well as how local protein environments enable cell- and stage-specific BR regulation. We also explore how tissue-specific alterations in BR signaling enhance crop yield. Together, we offer a comprehensive view of how BR signaling shapes the whole (overall growth dynamics) through its parts (intricate cellular interactions).
PMID: 39562236
Plant Cell , IF:11.277 , 2024 Nov , V36 (11) : P4768-4785 doi: 10.1093/plcell/koae251
The rice R2R3 MYB transcription factor FOUR LIPS connects brassinosteroid signaling to lignin deposition and leaf angle.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.; International College, University of Chinese Academy of Sciences, Beijing 100049, China.; Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.; China National Botanical Garden, Beijing 10093, China.
Leaf angle is an important agronomic trait for crop architecture and yield. In rice (Oryza sativa), the lamina joint is a unique structure connecting the leaf blade and sheath that determines leaf angle. Brassinosteroid (BR) signaling involving GLYCOGEN SYNTHASE KINASE-3 (GSK3)/SHAGGY-like kinases and BRASSINAZOLE-RESISTANT1 (BZR1) has a central role in regulating leaf angle in rice. In this study, we identified the atypical R2R3-MYB transcription factor FOUR LIPS (OsFLP), the rice homolog of Arabidopsis (Arabidopsis thaliana) AtFLP, as a participant in BR-regulated leaf angle formation. The spatiotemporal specificity of OsFLP expression in the lamina joint was closely associated with lignin deposition in vascular bundles and sclerenchyma cells. OsFLP mutation caused loose plant architecture with droopy flag leaves and hypersensitivity to BRs. OsBZR1 directly targeted OsFLP, and OsFLP transduced BR signals to lignin deposition in the lamina joint. Moreover, OsFLP promoted the transcription of the phenylalanine ammonia-lyase family genes OsPAL4 and OsPAL6. Intriguingly, OsFLP feedback regulated OsGSK1 transcription and OsBZR1 phosphorylation status. In addition, an Ala-to-Thr substitution within the OsFLP R3 helix-turn-helix domain, an equivalent mutation to that in Osflp-1, affected the DNA-binding ability and transcriptional activity of OsFLP. Our results reveal that OsFLP functions with OsGSK1 and OsBZR1 in BR signaling to maintain optimal leaf angle by modulating the lignin deposition in mechanical tissues of the lamina joint.
PMID: 39259275
New Phytol , IF:10.151 , 2024 Nov , V244 (3) : P883-899 doi: 10.1111/nph.20055
RACK1 links phyB and BES1 to coordinate brassinosteroid-dependent root meristem development.
Shenzhen Key Laboratory of Plant Genetic Engineering and Molecular Design, Department of Biology, School of Life Sciences, Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, 518055, China.
Light and brassinosteroids (BR) are indispensable for plant growth and control cell division in the apical meristem. However, how external light signals cooperate with internal brassinosteroids to program root meristem development remains elusive. We reveal that the photoreceptor phytochrome B (phyB) guides the scaffold protein RACK1 to coordinate BR signaling for maintaining root meristematic activity. phyB and RACK1 promote early root meristem development. Mechanistically, RACK1 could reinforce the phyB-SPA1 association by interacting with both phyB and SPA1, which indirectly affects COP1-dependent RACK1 degradation, resulting in the accumulation of RACK1 in roots. Subsequently, RACK1 interacts with BES1 to repress its DNA-binding activity toward the target gene CYCD3;1, leading to the release of BES1-mediated inhibition of CYCD3;1 transcription, and hence the promotion of root meristem development. Our study provides mechanistic insights into the regulation of root meristem development by combination of light and phytohormones signals through the photoreceptors and scaffold proteins.
PMID: 39149918
Plant Biotechnol J , IF:9.803 , 2024 Dec , V22 (12) : P3406-3423 doi: 10.1111/pbi.14461
Untargeted mutagenesis of brassinosteroid receptor SbBRI1 confers drought tolerance by altering phenylpropanoid metabolism in Sorghum bicolor.
Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona, Spain.; Institute for Integrative Systems Biology (I2SysBio), Universitat de Valencia-CSIC, Paterna, Valencia, Spain.; Max-Planck-Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.; Center of Plant Systems Biology and Biotechnology, Plovdiv, Bulgaria.; Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
Drought is a critical issue in modern agriculture; therefore, there is a need to create crops with drought resilience. The complexity of plant responses to abiotic stresses, particularly in the field of brassinosteroid (BR) signalling, has been the subject of extensive research. In this study, we unveil compelling insights indicating that the BRASSINOSTEROID-INSENSITIVE 1 (BRI1) receptor in Arabidopsis and Sorghum plays a critical role as a negative regulator of drought responses. Introducing untargeted mutation in the sorghum BRI1 receptor (SbBRI1) effectively enhances the plant's ability to withstand osmotic and drought stress. Through DNA Affinity Purification sequencing (DAP-seq), we show that the sorghum BRI1-EMS-SUPPRESSOR 1 (SbBES1) transcription factor, a downstream player of the BR signalling, binds to a conserved G-box binding motif, and it is responsible for regulating BR homeostasis, as its Arabidopsis ortholog AtBES1. We further characterized the drought tolerance of sorghum bri1 mutants and decipher SbBES1-mediated regulation of phenylpropanoid pathway. Our findings suggest that SbBRI1 signalling serves a dual purpose: under normal conditions, it regulates lignin biosynthesis by SbBES1, but during drought conditions, BES1 becomes less active, allowing the activation of the flavonoid pathway. This adaptive shift improves the photosynthetic rate and photoprotection, reinforcing crop adaptation to drought.
PMID: 39325724
Plant Biotechnol J , IF:9.803 , 2024 Nov , V22 (11) : P3054-3067 doi: 10.1111/pbi.14428
Cotton BOP1 mediates SUMOylation of GhBES1 to regulate fibre development and plant architecture.
State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.; Institute of Cotton Research, Shanxi Agricultural University, Yuncheng, China.
The Arabidopsis BLADE-ON-PETIOLE (BOP) genes are primarily known for their roles in regulating leaf and floral patterning. However, the broader functions of BOPs in regulating plant traits remain largely unexplored. In this study, we investigated the role of the Gossypium hirsutum BOP1 gene in the regulation of fibre length and plant height through the brassinosteroid (BR) signalling pathway. Transgenic cotton plants overexpressing GhBOP1 display shorter fibre lengths and reduced plant height compared to the wild type. Conversely, GhBOP1 knockdown led to increased plant height and longer fibre, indicating a connection with phenotypes influenced by the BR pathway. Our genetic evidence supports the notion that GhBOP1 regulates fibre length and plant height in a GhBES1-dependent manner, with GhBES1 being a major transcription factor in the BR signalling pathway. Yeast two-hybrid, luciferase complementation assay and pull-down assay results demonstrated a direct interaction between GhBOP1 and GhSUMO1, potentially forming protein complexes with GhBES1. In vitro and in vivo SUMOylation analyses revealed that GhBOP1 functions in an E3 ligase-like manner to mediate GhBES1 SUMOylation and subsequent degradation. Therefore, our study not only uncovers a novel mechanism of GhBES1 SUMOylation but also provides significant insights into how GhBOP1 regulates fibre length and plant height by controlling GhBES1 accumulation.
PMID: 39003587
Sci Total Environ , IF:7.963 , 2024 Dec , V954 : P176369 doi: 10.1016/j.scitotenv.2024.176369
Synergistic interaction between brassinosteroid and jasmonate pathways in rice response to cadmium toxicity.
Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China; College of Bee Science and Biomedicine, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China; Key Laboratory of Biological Breeding for Fujian and Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China. Electronic address: lulong_fafu@163.com.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China; Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, National Engineering Research Center for Sugarcane, Fujian Agriculture and Forestry University, Fujian Province, Fuzhou 350002, PR China.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China; Key Laboratory of Biological Breeding for Fujian and Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China. Electronic address: yyuansong@fafu.edu.cn.; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China; Key Laboratory of Biological Breeding for Fujian and Taiwan Crops, Ministry of Agriculture and Rural Affairs, Fujian Agriculture and Forestry University, Fuzhou 350002, PR China. Electronic address: rszeng@fafu.edu.cn.
Brassinosteroids (BRs) and jasmonic acid (JA) are known to be involved in regulating plant responses to cadmium (Cd) stress. However, their specific roles and interaction in this process remain unclear. In this study, we discovered that exogenous BR alleviated Cd-mediated growth inhibition of rice seedlings. Enhanced Cd tolerance was also observed in m107, a BR-overproduction mutant. Phenotypic analysis of genetic materials involved in BR signaling confirmed the positive role of BR in regulating rice response to Cd toxicity. OsDLT, a key component in the BR signaling pathway, was found to be crucial for BR-mediated Cd tolerance. Further analysis demonstrated that activation of the BR pathway reduced the accumulation of Cd and reactive oxygen species (ROS) by modulating the expression of genes associated with Cd transport and ROS scavenging. Interestingly, transcriptome analysis indicated that the JA pathway was enriched in OsDLT-regulated differently expressed genes (DEGs). Gene expression and hormone assays showed that BR promoted the expression of JA pathway genes and JA levels in plants. Moreover, BR-induced tolerance was compromised in the JA signaling-deficient mutant osmyc2, suggesting that BR-mediated Cd resistance depends on the activation of the JA signaling pathway. Overall, our study revealed the synergistic interaction between BR and JA pathways in rice response to Cd stress, providing insights into the complex hormonal interplay in plant tolerance to heavy metals.
PMID: 39299342
Plant Cell Environ , IF:7.228 , 2024 Nov doi: 10.1111/pce.15258
Crucial Roles of Brassinosteroids in Cell Wall Composition and Structure Across Species: New Insights and Biotechnological Applications.
Area de Mejora y Fisiologia de Plantas, Instituto de Hortofruticultura Subtropical y Mediterranea "La Mayora", Universidad de Malaga-Consejo Superior de Investigaciones Cientificas (IHSM-UMA-CSIC), Universidad de Malaga, Malaga, Malaga, Spain.; Departamento de Botanica y Fisiologia Vegetal, Facultad de Ciencias, Universidad de Malaga, Malaga, Malaga, Spain.
Brassinosteroids (BR) are steroidal phytohormones essential for plant growth, development, and stress resistance. They fulfil this role partially by modulating cell wall structure and composition through the control of gene expression involved in primary and secondary cell wall biosynthesis and metabolism. This affects the deposition of cellulose, lignin, and other components, and modifies the inner architecture of the wall, allowing it to adapt to the developmental status and environmental conditions. This review focuses on the effects that BR exerts on the main components of the cell wall, cellulose, hemicellulose, pectin and lignin, in multiple and relevant plant species. We summarize the outcomes that result from modifying cell wall components by altering BR gene expression, applying exogenous BR and utilizing natural variability in BR content and describing new roles of BR in cell wall structure. Additionally, we discuss the potential use of BR to address pressing needs, such as increasing crop yield and quality, enhancing stress resistance and improving wood production through cell wall modulation.
PMID: 39491539
J Integr Plant Biol , IF:7.061 , 2024 Nov doi: 10.1111/jipb.13802
The miR3367-lncRNA67-GhCYP724B module regulates male sterility by modulating brassinosteroid biosynthesis and interacting with Aorf27 in Gossypium hirsutum.
Laboratory of Cotton Genetics, Genomics and Breeding/Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education/Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China.; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Cytoplasmic male sterile (CMS) lines play a crucial role in utilization of heterosis in crop plants. However, the mechanism underlying the manipulation of male sterility in cotton by long non-coding RNA (lncRNA) and brassinosteroids (BRs) remains elusive. Here, using an integrative approach combining lncRNA transcriptomic profiles with virus-induced gene silencing experiments, we identify a flower bud-specific lncRNA in the maintainer line 2074B, lncRNA67, negatively modulating with male sterility in upland cotton (Gossypium hirsutum). lncRNA67 positively regulates cytochrome P274B (GhCYP724B), which acted as an eTM (endogenous target mimic) for miR3367. The suppression of GhCYP724B induced symptoms of BR deficiency and male semi-sterility in upland cotton as well as in tobacco, which resulted from a reduction in the endogenous BR contents. GhCYP724B regulates BRs synthesis by interacting with GhDIM and GhCYP90B, two BRs biosynthesis proteins. Additionally, GhCYP724B suppressed a unique chimeric open reading frame (Aorf27) in 2074A mitochondrial genome. Ectopic expression of Aorf27 in yeast inhibited cellular growth, and over expression of Aorf27 in tobacco showed male sterility. Overall, the results proved that the miR3367-lncRNA67-GhCYP724B module positively regulates male sterility by modulating BRs biosynthesis. The findings uncovered the function of lncRNA67-GhCYP724B in male sterility, providing a new mechanism for understanding male sterility in upland cotton.
PMID: 39526576
J Exp Bot , IF:6.992 , 2024 Nov doi: 10.1093/jxb/erae468
Diverse roles of phytohormonal signaling in modulating plant-virus interaction.
National Institute of Plant Genome Research, New Delhi, India.; Department of Genetics, University of Delhi South Campus, New Delhi, India.
Virus infection brings about changes in the transcriptome, proteome and metabolome status of the infected plant wherein substantial alterations in the abundance of phytohormones and associated components involved in their signaling pathways have been observed. In the recent years, extensive research in the field of plant virology has showcased the undisputable significance of phytohormone signaling during plant-virus interactions. Apart from acting as growth regulators, phytohormones elicit robust immune response, which restricts the viral multiplication within the plant as well as its propagation by vector. Interestingly, these pathways have been shown to not only act as isolated mechanisms but as complex intertwined regulatory cascades where, the cross-talk among different phytohormones and with other antiviral pathways takes place during plant-virus interplay. Viruses cleverly disrupt phytohormone homeostasis via their multifunctional effectors that seems to be smart approach adopted by viruses to circumvent phytohormone-mediated plant immune responses. In this review, we summarize the current understanding of role of phytohormone signaling pathways during plant-virus interaction in activating antiviral immune responses of plant and also, how viruses exploit these signaling pathways favoring their pathogenesis.
PMID: 39548750
Int J Biol Macromol , IF:6.953 , 2024 Nov , V281 (Pt 1) : P136047 doi: 10.1016/j.ijbiomac.2024.136047
The S-nitrosylation of monodehydroascorbate reductase positively regulated the low temperature tolerance of mini Chinese cabbage.
Gansu Agricultural University, Lanzhou, Gansu 730070, China. Electronic address: gaoxq@st.gsau.edu.cn.; Gansu Agricultural University, Lanzhou, Gansu 730070, China.; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China; Gansu Agricultural University, Lanzhou, Gansu 730070, China. Electronic address: hull@gsau.edu.cn.; Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, Gansu 730070, China; Gansu Agricultural University, Lanzhou, Gansu 730070, China. Electronic address: yujihua@gsau.edu.cn.
One of the main environmental stresses that considerably reduced vegetable yields are low temperature stress. Brassinosteroids (BRs) is essential for controlling a number of physiological functions. Protein S-nitrosylation is thought to be a crucial process in plants that use NO to carry out their biological functions. The exact process by which the mini Chinese cabbage responded to low temperature stress through BR-mediated S-nitrosylation modification of the monodehydroascorbate reductase (MDHAR) is still unknown. BR significantly increased the S-nitrosoylation level and antioxidant capacity at low temperature. One noteworthy development was the in vitroS-nitrosylation of the MDHAR protein. The overexpressed lines exhibited considerably high nitric oxide (NO) and S-nitrosothiol (SNO) contents at low temperature compared to the WT lines. Treatment of the WT and OE-BrMDHAR lines with BR at low temperature increased the antioxidant capacity. According to the biotin signaling, BR considerably enhanced the silenced lines total S-nitrosylation level in vivo at low temperature. Furthermore, BrMDHAR, BrAAO, and BrAPX gene transcript levels were dramatically up-regulated by BR, which in turn reduced the H(2)O(2) content in the silenced lines. These findings demonstrated that the S-nitrosylation of MDHAR was essential to the improvement of BR on low-temperature tolerance in the mini Chinese cabbage.
PMID: 39357708
Plant J , IF:6.417 , 2024 Nov doi: 10.1111/tpj.17159
Downy mildew effector HaRxL106 interacts with the transcription factor BIM1 altering plant growth, BR signaling and susceptibility to pathogens.
CIQUIBIC-CONICET, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Cordoba, 5000, Argentina.; Departamento de Quimica Biologica "Ranwel Caputto", Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Cordoba, 5000, Argentina.; Department Biochemistry of Plant Interactions, Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), Germany.; Timing of Environmental Signaling (TimES lab), Molecular Biology Group, Plant Developmental Biology, Plant Sciences, Wageningen University & Research, The Netherlands.
Hyaloperonospora arabidopsidis (Hpa) is an oomycete pathogen that causes downy mildew disease on Arabidopsis. This obligate biotroph manipulates the homeostasis of its host plant by secreting numerous effector proteins, among which are the RxLR effectors. Identifying the host targets of effectors and understanding how their manipulation facilitates colonization of plants are key to improve plant resistance to pathogens. Here we characterize the interaction between the RxLR effector HaRxL106 and BIM1, an Arabidopsis transcription factor (TF) involved in Brassinosteroid (BR) signaling. We report that HaRxL106 interacts with BIM1 in vitro and in planta. BIM1 is required by the effector to increase the host plant susceptibility to (hemi)biotrophic pathogens, and thus can be regarded as a susceptibility factor. Mechanistically, HaRxL106 requires BIM1 to induce the transcriptional activation of BR-responsive genes and cause alterations in plant growth patterns that phenocopy the shade avoidance syndrome. Our results support previous observations of antagonistic interactions between activation of BR signaling and suppression of plant immune responses and reveal that BIM1, a new player in this crosstalk, is manipulated by the pathogenic effector HaRxL106.
PMID: 39570675
Microbiol Res , IF:5.415 , 2024 Dec , V289 : P127924 doi: 10.1016/j.micres.2024.127924
Brassinosteroids mediate arbuscular mycorrhizal symbiosis through multiple potential pathways and partial identification in tomato.
State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China. Electronic address: yingren@stu.scau.edu.cn.; School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Ireland. Electronic address: brian.tobin@ucd.ie.; School of Agriculture & Food Science and UCD Earth Institute, University College Dublin, Ireland. Electronic address: shuyi.yang@ucdconnect.ie.; Boone Pickens School of Geology, Oklahoma State University, Stillwater, OK 74074, United States. Electronic address: tingying.xu@okstate.edu.; State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China. Electronic address: chenhui@scau.edu.cn.; State Key Laboratory of Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China. Electronic address: tangm@nwafu.edu.cn.
Currently, little is known regarding the specific processes through which brassinosteroids (BR) affect arbuscular mycorrhizal (AM) symbiosis. Understanding this relationship is vital for advancing plant physiology and agricultural applications. In this study, we aimed to elucidate the regulatory mechanisms of BR in AM symbiosis. According to the log2 fold change-value and adjP-value, we integrated the common differentially expressed genes (DEGs) in maize (Zea mays L.) treated with BR and AM, Arabidopsis (Arabidopsis thaliana) mutants deficient in BR receptors, and tomato (Solanum lycopersicum) plants inoculated with AM fungi. In addition, we characterized the symbiotic performance of tomato plants with BR receptor defects and overexpression. The results indicated that the common differential genes induced by BR and AM were involved in metabolic processes, such as cell wall modification, cytoskeleton remodeling, auxin and ethylene signaling, photosynthesis, mineral nutrient transport, and stress defense. Specifically, these include the BR1 gene, which modifies the cell wall. However, the fungal colonization rate of BR receptor-deficient tomato plants was significantly reduced, and the total phosphorus concentration was increased. Conversely, the performance of the overexpressing tomato transformation plants demonstrated a significant contrast. Additionally, the mild rescue of mycorrhizal attenuation in mutants treated with exogenous BR suggests the possibility of direct feedback from BR synthesis to AM. Notably, the cell wall modification gene (SlBR1) and calcium spike gene (SlIPD3) were induced by both BR and AM, suggesting that BR may influence cell penetration during the early stages of AM colonization. Synthesis: Our results demonstrated that BR positively regulates AM symbiosis through multiple pathways. These findings pave the way for future research, including isolation of the individual contributions of each pathway to this complex process and exploration of possible agricultural applications.
PMID: 39395377
J Agric Food Chem , IF:5.279 , 2024 Oct , V72 (43) : P23671-23688 doi: 10.1021/acs.jafc.4c05680
Roles of Nitric Oxide and Brassinosteroid in Improving Fruit Quality during Postharvest: Potential Regulators?
Hubei Key Laboratory of Spices & Horticultural Plant Germplasm Innovation & Utilization, College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, China.
Most postharvest fruits are highly perishable, which directly impairs fruit taste and causes an economic loss of fresh products. Thus, it is necessary to find effective techniques to alleviate this issue. Recently, nitric oxide (NO) and brassinosteroid (BR) have been developed as postharvest alternatives to improve fruit quality. This work mainly reviews the recent processes of NO and BR in improving fruit quality during postharvest. Exogenous NO or BR treatments delayed fruit senescence, enhanced disease resistance, and alleviated chilling injury in postharvest fruit, and potential physiological and biochemical mechanisms mainly include (1) enhancing antioxidant and defense ability, (2) affecting ethylene biosynthesis, (3) regulating sugar and energy metabolism, (4) mediating plant hormone signaling, and (5) regulating protein S-nitrosylation and DNA methylation. This review concludes the functions and mechanisms of NO and BR in improving postharvest fruit quality. Additionally, a specific finding is the possible crosstalk of applications of NO and BR during postharvest fruit storage, which provides new insights into the applicability of NO and BR for delaying fruit senescence, enhancing disease resistances of fruit, and alleviating chilling injury in postharvest fruit.
PMID: 39406695
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1544-1551 doi: 10.1093/pcp/pcae066
Post-translational Regulation of BRI1-EMS Suppressor 1 and Brassinazole-Resistant 1.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, 483 Wusan Road, Tianhe District, Guangzhou 510642, China.; Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong.
Brassinosteroid-insensitive 1 (BRI1)-EMS suppressor 1 (BES1) and Brassinazole-resistant 1 (BZR1) are two highly similar master transcription factors of the brassinosteroid (BR) signaling pathway that regulates a variety of plant growth and development processes as well as stress responses. Previous genetic and biochemical analyses have established a complex regulatory network to control the two transcription factors. This network includes coordination with other transcription factors and interactors, multiple post-translational modifications (PTMs) and differential subcellular localizations. In this review, we systematically detail the functions and regulatory mechanisms of various PTMs: phosphorylation/dephosphorylation, ubiquitination/deubiquitination, SUMOylation/deSUMOylation and oxidation/reduction, in regulating the subcellular localization, protein stability and the transcriptional activity of BES1/BZR1. We also discuss the current knowledge about the BES1/BZR1 interactors mediating the dynamic nucleocytoplasmic shuttling of BES1 and BZR1.
PMID: 38896040
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1674-1688 doi: 10.1093/pcp/pcae056
Mechanistic Insights into the Function of 14-3-3 Proteins as Negative Regulators of Brassinosteroid Signaling in Arabidopsis.
Structural Plant Biology Laboratory, Department of Plant Sciences, University of Geneva, 30 Quai E. Ansermet, Geneva 1211, Switzerland.
Brassinosteroids (BRs) are vital plant steroid hormones sensed at the cell surface by a membrane signaling complex comprising the receptor kinase BRI1 and a SERK family co-receptor kinase. Activation of this complex lead to dissociation of the inhibitor protein BKI1 from the receptor and to differential phosphorylation of BZR1/BES1 transcription factors by the glycogen synthase kinase 3 protein BIN2. Many phosphoproteins of the BR signaling pathway, including BRI1, SERKs, BKI1 and BZR1/BES1 can associate with 14-3-3 proteins. In this study, we use quantitative ligand binding assays to define the minimal 14-3-3 binding sites in the N-terminal lobe of the BRI1 kinase domain, in BKI1, and in BZR1 from Arabidopsis thaliana. All three motifs require to be phosphorylated to specifically bind 14-3-3s with mid- to low-micromolar affinity. BR signaling components display minimal isoform preference within the 14-3-3 non-epsilon subgroup. 14-3-3lambda and 14-3-3 omega isoform complex crystal structures reveal that BKI1 and BZR1 bind as canonical type II 14-3-3 linear motifs. Disruption of key amino acids in the phosphopeptide binding site through mutation impairs the interaction of 14-3-3lambda with all three linear motifs. Notably, quadruple loss-of-function mutants from the non-epsilon group exhibit gain-of-function BR signaling phenotypes, suggesting a role for 14-3-3 proteins as overall negative regulators of the BR pathway. Collectively, our work provides further mechanistic and genetic evidence for the regulatory role of 14-3-3 proteins at various stages of the BR signaling cascade.
PMID: 38783418
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1655-1673 doi: 10.1093/pcp/pcae054
Bona Fide Plant Steroid Receptors are Innovated in Seed Plants and Angiosperms through Successive Whole-Genome Duplication Events.
College of Life Science, Shaanxi Normal University, Xi'an, Shaanxi Province 710119, China.
Whole-genome duplication (WGD) events are widespread in plants and animals, thus their long-term evolutionary contribution has long been speculated, yet a specific contribution is difficult to verify. Here, we show that varepsilon-WGD and zeta-WGD contribute to the origin and evolution of bona fide brassinosteroid (BR) signaling through the innovation of active BR biosynthetic enzymes and active BR receptors from their respective ancestors. We found that BR receptors BRI1 (BR INSENSITIVE 1) and BRL1/3 (BRI1-LIKES 1/3) derived by varepsilon-WGD and zeta-WGD, which occurred in the common ancestor of angiosperms and seed plants, respectively, while orphan BR receptor BRL2 first appeared in stomatophytes. Additionally, CYP85A enzymes synthesizing the bioactive BRs derived from a common ancestor of seed plants, while its sister enzymes CYP90 synthesizing BR precursors presented in all land plants, implying possible ligand-receptor coevolution. Consistently, the island domains (IDs) responsible for BR perception in BR receptors were most divergent among different receptor branches, supporting ligand-driven evolution. As a result, BRI1 was the most diversified BR receptor in angiosperms. Importantly, relative to the BR biosynthetic DET2 gene presented in all land plants, BRL2, BRL1/3 and BRI1 had high expression in vascular plants ferns, gymnosperms and angiosperms, respectively. Notably, BRI1 is the most diversified BR receptor with the most abundant expression in angiosperms, suggesting potential positive selection. Therefore, WGDs initiate a neofunctionalization process diverged by ligand-perception and transcriptional expression, which might optimize both BR biosynthetic enzymes and BR receptors, likely contributing to the evolution of land plants, especially seed plants and angiosperms.
PMID: 38757845
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1618-1626 doi: 10.1093/pcp/pcae038
Analytical Methods for Brassinosteroid Analysis: Recent Advances and Applications.
Laboratory of Growth Regulators, Faculty of Science, Palacky University & Institute of Experimental Botany, Czech Academy of Sciences, Slechtitelu 27, Olomouc CZ-78371, Czech Republic.
Brassinosteroids (BRs) are plant steroidal hormones that play crucial roles in plant growth and development. Accurate quantification of BRs in plant tissues is essential for understanding their biological functions. This study presents a comprehensive overview of the latest methods used for the quantification of BRs in plants. We discuss the principles, advantages and limitations of various analytical techniques, including immunoassays, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry that are used for the detection and quantification of BRs from complex plant matrixes. We also explore the use of isotopically labeled internal standards to improve the accuracy and reliability of BR quantification.
PMID: 38619131
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1601-1607 doi: 10.1093/pcp/pcae037
Multiple Roles of Brassinosteroid Signaling in Vascular Development.
College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, 525-8577 Japan.; Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, 560-0043 Japan.; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan.; Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai, Kobe, 657-8501 Japan.
Brassinosteroids (BRs) are plant steroid hormones that control growth and stress responses. In the context of development, BRs play diverse roles in controlling cell differentiation and tissue patterning. The vascular system, which is essential for transporting water and nutrients throughout the plant body, initially establishes a tissue pattern during primary development and then dramatically increases the number of vascular cells during secondary development. This complex developmental process is properly regulated by a network consisting of various hormonal signaling pathways. Genetic studies have revealed that mutants that are defective in BR biosynthesis or the BR signaling cascade exhibit a multifaceted vascular development phenotype. Furthermore, BR crosstalk with other plant hormones, including peptide hormones, coordinately regulates vascular development. Recently, the involvement of BR in vascular development, especially in xylem differentiation, has also been suggested in plant species other than the model plant Arabidopsis thaliana. In this review, we briefly summarize the recent findings on the roles of BR in primary and secondary vascular development in Arabidopsis and other species.
PMID: 38590039
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1608-1617 doi: 10.1093/pcp/pcae040
Shaping Brassinosteroid Signaling through Scaffold Proteins.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Technolgiepark 71, Ghent 9052, Belgium.; Center for Plant Systems Biology, VIB, Technolgiepark 71, Ghent 9052, Belgium.; College of Life Sciences, Wuhan University, 299 Bayi Road, Wuchang District, Wuhan 430072, China.
Cellular responses to internal and external stimuli are orchestrated by intricate intracellular signaling pathways. To ensure an efficient and specific information flow, cells employ scaffold proteins as critical signaling organizers. With the ability to bind multiple signaling molecules, scaffold proteins can sequester signaling components within specific subcellular domains or modulate the efficiency of signal transduction. Scaffolds can also tune the output of signaling pathways by serving as regulatory targets. This review focuses on scaffold proteins associated with the plant GLYCOGEN SYNTHASE KINASE3-like kinase, BRASSINOSTEROID-INSENSITIVE2 (BIN2), that serves as a key negative regulator of brassinosteroid (BR) signaling. Here, we summarize current understanding of how scaffold proteins actively shape BR signaling outputs and cross-talk in plant cells via interactions with BIN2.
PMID: 38590034
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1515-1529 doi: 10.1093/pcp/pcae014
Recent Advances in Understanding the Regulatory Mechanism of Plasma Membrane H+-ATPase through the Brassinosteroid Signaling Pathway.
Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.; School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
The polyhydroxylated steroid phytohormone brassinosteroid (BR) controls many aspects of plant growth, development and responses to environmental changes. Plasma membrane (PM) H+-ATPase, the well-known PM proton pump, is a central regulator in plant physiology, which mediates not only plant growth and development, but also adaptation to stresses. Recent studies highlight that PM H+-ATPase is at least partly regulated via the BR signaling. Firstly, the BR cell surface receptor BRASSINOSTEROID-INSENSITIVE 1 (BRI1) and multiple key components of BR signaling directly or indirectly influence PM H+-ATPase activity. Secondly, the SMALL AUXIN UP RNA (SAUR) gene family physically interacts with BRI1 to enhance organ development of Arabidopsis by activating PM H+-ATPase. Thirdly, RNA-sequencing (RNA-seq) assays showed that the expression of some SAUR genes is upregulated under the light or sucrose conditions, which is related to the phosphorylation state of the penultimate residue of PM H+-ATPase in a time-course manner. In this review, we describe the structural and functional features of PM H+-ATPase and summarize recent progress towards understanding the regulatory mechanism of PM H+-ATPase by BRs, and briefly introduce how PM H+-ATPase activity is modulated by its own biterminal regions and the post-translational modifications.
PMID: 38372617
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1640-1654 doi: 10.1093/pcp/pcae009
BIL9 Promotes Both Plant Growth via BR Signaling and Drought Stress Resistance by Binding with the Transcription Factor HDG11.
Graduate School of Biostudies, Kyoto University, Sakyo-Ku, Kyoto, 606-8501 Japan.; RIKEN Center for Sustainable Resource Science, Wako, Saitama, 351-0198 Japan.; Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566 Japan.; Global Zero Emission Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8566 Japan.; Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, Tsukuba, Ibaraki, 305-0074 Japan.; Department of Biological Sciences, Ochanomizu University, Bunkyo-Ku, Tokyo, 112-8610 Japan.; Graduate School of Agricultural and Life Sciences, Tokyo University, Bunkyo-Ku, Tokyo, 113-8657 Japan.
Drought stress is a major threat leading to global plant and crop losses in the context of the climate change crisis. Brassinosteroids (BRs) are plant steroid hormones, and the BR signaling mechanism in plant development has been well elucidated. Nevertheless, the specific mechanisms of BR signaling in drought stress are still unclear. Here, we identify a novel Arabidopsis gene, BRZ INSENSITIVE LONG HYPOCOTYL 9 (BIL9), which promotes plant growth via BR signaling. Overexpression of BIL9 enhances drought and mannitol stress resistance and increases the expression of drought-responsive genes. BIL9 protein is induced by dehydration and interacts with the HD-Zip IV transcription factor HOMEODOMAIN GLABROUS 11 (HDG11), which is known to promote plant resistance to drought stress, in vitro and in vivo. BIL9 enhanced the transcriptional activity of HDG11 for drought-stress-resistant genes. BIL9 is a novel BR signaling factor that enhances both plant growth and plant drought resistance.
PMID: 38242155
Plant Cell Physiol , IF:4.927 , 2024 Nov , V65 (10) : P1627-1639 doi: 10.1093/pcp/pcad126
BBX21 Integrates Brassinosteroid Biosynthesis and Signaling in the Inhibition of Hypocotyl Growth under Shade.
IFEVA (CONICET-UBA), Facultad de Agronomia, Universidad de Buenos Aires, Av. San Martin 4453, Ciudad Autonoma de Buenos Aires C1417DSE, Argentina.; Laboratory of Growth Regulators, Palacky University & Institute of Experimental Botany, The Czech Academy of Sciences, Slechtitelu 27, Olomouc CZ-78371, Czech Republic.; Fundacion Instituto Leloir, IIBBA-CONICET, Avenida Patricias Argentinas 435, Ciudad Autonoma de Buenos Aires C1405BWE, Argentina.; Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA.; Instituto de Biologia Molecular y Celular de Plantas, CSIC-Universitat Politecnica de Valencia, C/Ingeniero Fausto Elio s/n, Valencia 46022, Spain.
B-Box-containing zinc finger transcription factors (BBX) are involved in light-mediated growth, affecting processes such as hypocotyl elongation in Arabidopsis thaliana. However, the molecular and hormonal framework that regulates plant growth through BBX proteins is incomplete. Here, we demonstrate that BBX21 inhibits the hypocotyl elongation through the brassinosteroid (BR) pathway. BBX21 reduces the sensitivity to 24-epiBL, a synthetic active BR, principally at very low concentrations in simulated shade. The biosynthesis profile of BRs showed that two active BR-brassinolide and 28-homobrassinolide-and 8 of 11 intermediates can be repressed by BBX21 under white light (WL) or simulated shade. Furthermore, BBX21 represses the expression of CYTOCHROME P450 90B1 (DWF4/CYP90B1), BRASSINOSTEROID-6-OXIDASE 1 (BR6OX1, CYP85A1) and BR6OX2 (CYP85A2) genes involved in the BR biosynthesis in WL while specifically promoting DWF4 and PHYB ACTIVATION TAGGED SUPPRESSOR 1 (CYP2B1/BAS1) expression in WL supplemented with far-red (WL + FR), a treatment that simulates shade. In addition, BBX21 represses BR signaling genes, such as PACLOBUTRAZOL RESISTANCE1 (PRE1), PRE3 and ARABIDOPSIS MYB-LIKE 2 (MYBL2), and auxin-related and expansin genes, such as INDOLE-3-ACETIC ACID INDUCIBLE 1 (IAA1), IAA4 and EXPANSIN 11 in short-term shade. By a genetic approach, we found that BBX21 acts genetically upstream of BRASSINAZOLE-RESISTANT 1 (BZR1) for the promotion of DWF4 and BAS1 gene expression in shade. We propose that BBX21 integrates the BR homeostasis and shade-light signaling, allowing the fine-tuning of hypocotyl elongation in Arabidopsis.
PMID: 37847120
BMC Genomics , IF:3.969 , 2024 Nov , V25 (1) : P1047 doi: 10.1186/s12864-024-10966-z
Molecular cloning and characterization of a brassinosteriod biosynthesis-related gene PtoCYP90D1 from Populus tomentosa.
College of Tobacco Sciences, Guizhou University, Guiyang, 550025, China.; College of Tobacco Sciences, Guizhou University, Guiyang, 550025, China. yliu21@gzu.edu.cn.
Brassinosteroids (BRs), one of the major classes of phytohormones are essential for various processes of plant growth, development, and adaptations to biotic and abiotic stresses. In Arabidopsis, AtCYP90D1 acts as a bifunctional cytochrome P450 monooxygenase, catalyzing C-23 hydroxylation in the brassinolide biosynthetic pathway. The present study reports the functional characterizations of PtoCYP90D1, one of the AtCYP90D1 homologous genes from Populus tomentosa. The qRT-PCR analysis showed that PtoCYP90D1 was highly expressed in roots and old leaves. Overexpression of PtoCYP90D1 (PtoCYP90D1-OE) in poplar promoted growth and biomass yield, as well as increased xylem area and cell layers. Transgenic plants exhibited a significant increase in plant height and stem diameter as compared to the wild type. In contrast, the CRISPR/Cas9-generated mutation of PtoCYP90D1 (PtoCYP90D1-KO) resulted in significantly decreased biomass production in transgenic plants. Further studies revealed that cell wall components increased significantly in PtoCYP90D1-OE lines but not in PtoCYP90D1-KO lines, as compared to wild-type plants. Overall, the findings indicate a positive role of PtoCYP90D1 in improving growth rate and elevating biomass production in poplar, which will have positive implications for its versatile industrial or agricultural applications.
PMID: 39506673
Plants (Basel) , IF:3.935 , 2024 Oct , V13 (21) doi: 10.3390/plants13213051
Research on the Mechanisms of Phytohormone Signaling in Regulating Root Development.
Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Research Center of the Basic Discipline of Cell 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, Shijiazhuang 050024, China.; Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang 050051, China.
Phytohormones are organic compounds produced in trace amounts within plants that regulate their physiological processes. Their physiological effects are highly complex and diverse. They influence processes ranging from cell division, elongation, and differentiation to plant germination and rooting. Therefore, phytohormones play a crucial regulatory role in plant growth and development. Recently, various studies have highlighted the role of PHs, such as auxin, cytokinin (CK), and abscisic acid (ABA), and newer classes of PHs, such as brassinosteroid (BR) and peptide hormone, in the plant responses toward environmental stresses. These hormones not only have distinct roles at different stages of plant growth but also interact to promote or inhibit each other, thus effectively regulating plant development. Roots are the primary organs for water and mineral absorption in plants. During seed germination, the radicle breaks through the seed coat and grows downward to form the primary root. This occurs because the root needs to quickly penetrate the soil to absorb water and nutrients, providing essential support for the plant's subsequent growth. Root development is a highly complex and precisely regulated process influenced by various signals. Changes in root architecture can affect the plant's ability to absorb nutrients and water, which in turn impacts crop yield. Thus, studying the regulation of root development is of great significance. Numerous studies have reported on the role of phytohormones, particularly auxins, in root regulation. This paper reviews recent studies on the regulation of root development by various phytohormones, both individually and in combination, providing a reference for researchers in this field and offering perspectives on future research directions for improving crop yields.
PMID: 39519969
J Plant Physiol , IF:3.549 , 2024 Nov , V302 : P154318 doi: 10.1016/j.jplph.2024.154318
NHX5/NHX6/SPY22 complex regulates BRI1 and brassinosteroid signaling in Arabidopsis.
Academy of Plateau Science and Sustainability, School of Life Sciences, Qinghai Normal University, Xining, Qinghai, 810000, China.; MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China.; MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China; College of Life Science and Technology, Tarim University, Alar, 843300, China.; MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, 730000, China. Electronic address: qiuqsh@lzu.edu.cn.
NHX5 and NHX6, Arabidopsis endosomal antiporters, play a vital role in facilitating ion and pH homeostasis in endosomal compartments. Studies have found that NHX5 and NHX6 are essential for protein trafficking, auxin homeostasis, and plant growth and development. Here, we report the role of NHX5 and NHX6 in brassinosteroid (BR) signaling. We found that hypocotyl growth was enhanced in nhx5 nhx6 under epibrassinolide (eBR) treatment. nhx5 nhx6 bri1 was insensitive to eBR treatment, indicating that NHX5 and NHX6 are downstream of the BRI1 receptor in BR signaling. Moreover, confocal observation with both hypocotyls and root tips showed that BRI1-YFP localization in the plasma membrane (PM) was reduced in nhx5 nhx6. Interestingly, brefeldin A (BFA) treatment showed that formation of the BFA bodies containing BRI1 and their disassembling were disrupted in nhx5 nhx6. Further genetic analysis showed that NHX5/NHX6 and SYP22 may act coordinately in BR signaling. NHX5 and NHX6 may regulate SYP22 function by modulating cellular K(+) and pH homeostasis. Importantly, NHX5 and NHX6 colocalize and interact with SYP22, but do not interact with BRI1. In summary, our findings indicate that NHX5/NHX6/SYP22 complex is essential for the regulation of BRI1 recycling and PM localization. The H(+)-leak facilitated by NHX5 and NHX6 offers a means of controlling BR signaling in plants.
PMID: 39059150
Plant Signal Behav , IF:2.247 , 2024 Dec , V19 (1) : P2404807 doi: 10.1080/15592324.2024.2404807
Crosstalk among plant hormone regulates the root development.
Ministry of Education Key Laboratory of Molecular and Cellular Biology; Hebei Research Center of the Basic Discipline of Cell 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, Shijiazhuang, China.; College of Life Sciences, Hengshui University, Hengshui, China.
The plant root absorbs water and nutrients, anchors the plant in the soil, and promotes plant development. Root is developed from root apical meristem (RAM), which is formed during embryo stage and is maintained by dividing stem cells. Plant hormones have a predominant role in RAM maintenance. This review evaluates the functional crosstalk among three major hormones (auxin, cytokinin, and brassinolide) in RAM development in Arabidopsis, integrating a variety of experimental data into a regulatory network and revealing multiple layers of complexity in the crosstalk among these three hormones. We also discuss possible directions for future research on the roles of hormones in regulating RAM development and maintenance.
PMID: 39279500
Plant Commun , 2024 Nov : P101181 doi: 10.1016/j.xplc.2024.101181
Structural insights into brassinosteroid export mediated by the Arabidopsis ABC transporter ABCB1.
MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027 Hefei, China.; University Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.; Department of Organic and Macromolecular Chemistry, Ghent University, 9000 Ghent, Belgium.; Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Palacky University, 77900 Olomouc, Czech Republic.; Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.; MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027 Hefei, China. Electronic address: sttan@ustc.edu.cn.; University Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium. Electronic address: sttan@ustc.edu.cn.
Brassinosteroids (BRs) are steroidal phytohormones indispensable for plant growth, development, and responses to environmental stresses. The export of bioactive BRs to the apoplast is essential for BR signalling initiation, which requires binding of BR molecule to the extracellular domains of the plasma membrane-localized receptor complex. We have previously shown that the Arabidopsis thaliana ATP-binding cassette (ABC) transporter, ABCB19, functions as a BR exporter, and together with its close homologue, ABCB1, positively regulate BR signalling. Here, we demonstrate that ABCB1 is another BR transporter. The ATP hydrolysis activity of ABCB1 was stimulated by bioactive BRs, and its transport activity was confirmed in proteoliposomes and protoplasts. Structures of ABCB1 in substrate-unbound (apo), brassinolide (BL)-bound, and ATP plus BL-bound states were determined. In the BL-bound structure, BL was bound to the hydrophobic cavity formed by the transmembrane domain, and triggered local conformational changes. Together, our data provide additional insights into the ABC transporter-mediated BR export.
PMID: 39497419