张大兵教授Nature子刊解析遗传发育新机制

　　

3月20日，《Nature Communications》在线发表了张大兵教授团队在水稻花器官发育方面的最新进展《Jasmonic acid regulates spikelet development in rice》。

这项工作发现水稻EG1编码茉莉素合成关键酶，EG2/OsJAZ1编码茉莉素信号途径中的抑制因子；依赖于EG1合成的茉莉素信号可以促进水稻花器官的发育，茉莉素受体OsCOI1b在感应到茉莉素信号后，与信号抑制因子EG2/OsJAZ1结合，并将其带到26S蛋白降解复合体中进行降解反应，从而释放茉莉素响应基因OsMYC2，OsMYC2蛋白可直接结合到E类花器官发育调控基因OsMADS1的启动子区域，激活水稻小花的发育进程。

这项研究首次证明了植物激素茉莉酸信号途径可调控水稻花器官发育，为阐明水稻花器官发育的分子机理提供了新的机制。

水稻具有独特的花序、穗和小花结构，它们和水稻产量密切相关，但是调控其形成的分子机理尚不清楚。张大兵团队十五年来在水稻生殖发育方面开展系统研究工作，克隆了多个控制水稻花序、花器官形成的重要基因。

此前，《Annual Review of Plant Biology》特邀张大兵教授撰写综述《Molecular Control of Grass Inflorescence Development》，提出了禾本科植物穗发育的基因调控网络，并探讨了这些控制花序发育的基因在农业生产中的应用。

原文摘要：

Jasmonic acid regulates spikelet development in rice

The spikelet is the basal unit of inflorescence in grasses, and its formation is crucial for reproductive success and cereal yield. Here, we report a previously unknown role of the plant hormone jasmonic acid (JA) in determining rice (Oryza sativa) spikelet morphogenesis. The extra glume 1 (eg1) and eg2 mutants exhibit altered spikelet morphology with changed floral organ identity and number, as well as defective floral meristem determinacy. We show that EG1 is a plastid-targeted lipase that participates in JA biosynthesis, and EG2/OsJAZ1 is a JA signalling repressor that interacts with a putative JA receptor, OsCOI1b, to trigger OsJAZ1’s degradation during spikelet development. OsJAZ1 also interacts with OsMYC2, a transcription factor in the JA signalling pathway, and represses OsMYC2’s role in activating OsMADS1, an E-class gene crucial to the spikelet development. This work discovers a key regulatory mechanism of grass spikelet development and suggests that the role of JA in reproduction has diversified during the flowering plant evolution.