Wang Fuxiang, Zhang Ling, Cui Lili, Zhao Yongchao, Huang Yi, Jiang Minrong, Cai Qiuhua, Lian Ling, Zhu Yongsheng, Xie Hongguang, Chen Liping, Xiao Yanjia, Xie Huaan, Zhang Jianfu
Rice Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350019, China; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops/Key Laboratory of Germplasm Innovation and Molecular Breeding of Hybrid Rice in South China/Fujian Engineering Laboratory of Crop Molecular Breeding/Fujian Key Laboratory of Rice Molecular Breeding/Fuzhou Branch, National Center of Rice Improvement of China/National Engineering Laboratory of Rice/South Base of National Key Laboratory of Hybrid Rice of China, Fuzhou 350003, China; College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Rice Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350019, China; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops/Key Laboratory of Germplasm Innovation and Molecular Breeding of Hybrid Rice in South China/Fujian Engineering Laboratory of Crop Molecular Breeding/Fujian Key Laboratory of Rice Molecular Breeding/Fuzhou Branch, National Center of Rice Improvement of China/National Engineering Laboratory of Rice/South Base of National Key Laboratory of Hybrid Rice of China, Fuzhou 350003, China.
Plant Commun. 2025 Mar 10;6(3):101236. doi: 10.1016/j.xplc.2024.101236. Epub 2024 Dec 26.
Leaf angle is a major agronomic trait that determines plant architecture, which directly affects rice planting density, photosynthetic efficiency, and yield. The plant phytohormones brassinosteroids (BRs) and the MAPK signaling cascade are known to play crucial roles in regulating leaf angle, but the underlying molecular mechanisms are not fully understood. Here, we report a rice WRKY family transcription factor gene, OsWRKY72, which positively regulates leaf angle by affecting lamina joint development and BR signaling. Phenotypic analysis showed that oswrky72 mutants have smaller leaf angles and exhibit insensitivity to exogenous BRs, whereas OsWRKY72 overexpression lines show enlarged leaf angles and are hypersensitive to exogenous BRs. Histological sections revealed that the change in leaf inclination is due to asymmetric cell proliferation and growth at the lamina joint. Further investigation showed that OsWRKY72 binds directly to the promoter region of BR receptor kinase (OsBRI1), a key gene in the BR signaling pathway, and activates its expression to positively regulate rice BR signaling. In addition, we discovered that OsWRKY72 interacts with and is phosphorylated by OsMAPK6, and this phosphorylation event can enhance OsWRKY72 activity in promoting OsBRI1 expression. Genetic evidence confirmed that OsMAPK6, OsWRKY72, and OsBRI1 function in a common pathway to regulate leaf angle. Collectively, our findings clarify the critical role of the OsWRKY72 transcription factor in regulating rice leaf angle. These results provide valuable insights into the molecular regulatory networks that govern plant architecture in rice.
叶夹角是决定植株形态的主要农艺性状，直接影响水稻种植密度、光合效率和产量。已知植物激素油菜素甾醇（BRs）和丝裂原活化蛋白激酶（MAPK）信号级联在调节叶夹角中起关键作用，但其潜在分子机制尚未完全清楚。在此，我们报道了一个水稻WRKY家族转录因子基因OsWRKY72，它通过影响叶片关节发育和BR信号传导正向调节叶夹角。表型分析表明，oswrky72突变体叶夹角较小，对外源BRs不敏感，而OsWRKY72过表达系叶夹角增大，对外源BRs超敏感。组织学切片显示，叶片倾斜度的变化是由于叶片关节处细胞不对称增殖和生长所致。进一步研究表明，OsWRKY72直接结合到BR信号通路中的关键基因BR受体激酶（OsBRI1）的启动子区域，并激活其表达以正向调节水稻BR信号传导。此外，我们发现OsWRKY72与OsMAPK6相互作用并被其磷酸化，这一磷酸化事件可增强OsWRKY72促进OsBRI1表达的活性。遗传证据证实，OsMAPK6、OsWRKY72和OsBRI1在一条共同途径中发挥作用来调节叶夹角。总的来说，我们的研究结果阐明了OsWRKY72转录因子在调节水稻叶夹角中的关键作用。这些结果为调控水稻植株形态的分子调控网络提供了有价值的见解。
