Luo Guangyu, Li Lin, Yang Xiaoyu, Yu Yu, Gao Lei, Mo Beixin, Chen Xuemei, Liu Lin
Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong 518060, China.
College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060, China.
Plant Physiol. 2024 Jun 28;195(3):1954-1968. doi: 10.1093/plphys/kiae127.
Due to climate change, drought has become a major threat to rice (Oryza sativa L.) growth and yield worldwide. Understanding the genetic basis of drought tolerance in rice is therefore of great importance. Here, we identified a microRNA, miR1432, which regulates rice drought tolerance by targeting the CALMODULIN-LIKE2 (OsCaML2) gene. Mutation of MIR1432 or suppression of miR1432 expression significantly impaired seed germination and seedling growth under drought-stress conditions. Molecular analysis demonstrated that miR1432 affected rice drought tolerance by directly targeting OsCaML2, which encodes an EF-hand chiral calcium-binding protein. Overexpression of a miR1432-resistant form of OsCaML2 (OEmCaML2) phenocopied the mir1432 mutant and miR1432 suppression plants. Furthermore, the suppression of miR1432 severely affected the expression of genes involved in responses to stimulation, metabolism and signal transduction, especially the mitogen-activated protein kinase (MAPK) pathway and hormone transduction pathway in rice under drought stress. Thus, our findings show that the miR1432-OsCaML2 module plays an important role in the regulation of rice drought tolerance, suggesting its potential utilization in developing molecular breeding strategies that improve crop drought tolerance.
由于气候变化，干旱已成为全球水稻（Oryza sativa L.）生长和产量的主要威胁。因此，了解水稻耐旱性的遗传基础至关重要。在此，我们鉴定出一种微小RNA，即miR1432，它通过靶向类钙调蛋白2（OsCaML2）基因来调节水稻的耐旱性。MIR1432的突变或miR1432表达的抑制在干旱胁迫条件下显著损害种子萌发和幼苗生长。分子分析表明，miR1432通过直接靶向OsCaML2影响水稻的耐旱性，OsCaML2编码一种EF手型钙结合蛋白。过表达一种对miR1432具有抗性的OsCaML2形式（OEmCaML2）模拟了mir1432突变体和miR1432抑制植株的表型。此外，miR1432的抑制严重影响了干旱胁迫下水稻中参与刺激反应、代谢和信号转导的基因表达，特别是丝裂原活化蛋白激酶（MAPK）途径和激素转导途径。因此，我们的研究结果表明，miR1432-OsCaML2模块在调节水稻耐旱性中起重要作用，表明其在开发提高作物耐旱性的分子育种策略中的潜在应用价值。
