Zhang Mingxing, Zhao Ranran, Huang Kai, Wei Zhiqi, Guo Boya, Huang Shuangzhan, Li Zhao, Jiang Wenzhu, Wu Tao, Du Xinglin
Jilin Province Engineering Laboratory of Plant Genetic Improvement, College of Plant Science, Jilin University, Changchun, China.
Front Plant Sci. 2023 Apr 5;14:1168723. doi: 10.3389/fpls.2023.1168723. eCollection 2023.
Drought stress is a major environmental threat that limits plant growth and crop productivity. Therefore, it is necessary to uncover the molecular mechanisms behind drought tolerance in crops. Here, OsWRKY76 positively regulated drought stress in rice. expression was induced by PEG treatment, dehydration stress, and exogenous MeJA rather than by no treatment. Notably, knockout weakened drought tolerance at the seedling stage and decreased MeJA sensitivity. was significantly induced by drought stress, and its expression was significantly higher in -knockout mutants than in wild-type ZH11 under drought stress. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsWRKY76 interacted with OsJAZ12. OsWRKY76 weakened the interaction between OsbHLH148 and OsJAZ12 in yeast cells. The OsJAZ12 protein repressed the transactivation activity of OsbHLH148, and this repression was partly restored by OsWRKY76 in rice protoplasts. Moreover, expression was lower in -knockout mutants than in wild-type ZH11 under drought stress, but it was upregulated under normal growth conditions. Yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase assays showed that OsWRKY76 and OsbHLH148 bound directly to the promoter and activated expression in response to drought stress. These results suggest that OsWRKY76 confers drought tolerance through OsbHLH148-mediated jasmonate signaling in rice, offering a new clue to uncover the mechanisms behind drought tolerance.
干旱胁迫是限制植物生长和作物生产力的主要环境威胁。因此,有必要揭示作物耐旱性背后的分子机制。在此,OsWRKY76正向调控水稻的干旱胁迫。其表达由聚乙二醇(PEG)处理、脱水胁迫和外源茉莉酸甲酯(MeJA)诱导,而非未经处理时诱导。值得注意的是,敲除该基因会削弱幼苗期的耐旱性并降低对MeJA的敏感性。干旱胁迫显著诱导该基因表达,且在干旱胁迫下其在敲除突变体中的表达显著高于野生型ZH11。酵母双杂交和双分子荧光互补试验表明OsWRKY76与OsJAZ12相互作用。在酵母细胞中,OsWRKY76减弱了OsbHLH148与OsJAZ12之间的相互作用。OsJAZ12蛋白抑制OsbHLH148的反式激活活性,而在水稻原生质体中,OsWRKY76部分恢复了这种抑制作用。此外,在干旱胁迫下,敲除突变体中该基因的表达低于野生型ZH11,但在正常生长条件下其表达上调。酵母单杂交、电泳迁移率变动分析和双荧光素酶试验表明,OsWRKY76和OsbHLH148直接结合到该基因的启动子上,并在干旱胁迫下激活其表达。这些结果表明,OsWRKY76通过水稻中OsbHLH148介导的茉莉酸信号传导赋予耐旱性,为揭示耐旱机制提供了新线索。