组蛋白去甲基化酶OsJMJ706对温度介导的水稻穗发育的调控

Rice is not only the most important stable food source in the world, but also one of the best experimental systems for monocots. The stability of rice yield is directly related to the national food security. Panicle development is one of the critical factors to determine rice yield, and the booting stage is very sensitive to temperature. Epigenetic regulation play a key role in the booting process in response to environmental temperature. It is therefore critically important to understand the functions of epigenetic pathways in regulating rice panicle development. Previous studies showed that mutations in OsJMJ706 lead to pleiotropic panicle developmental defects including abnormal panicle and more sensitive to low temperature, which drastically decreases yield. Here, we propose to identify genome-wide alterations in epigenetic modifications and gene expression patterns at a genome-wide level, using the Osjmj706 mutant that we previous isolated. We are particularly interested in identifying genes for which transcriptional misregulation is directly correlated with phenotypic changes that affect yield. It is expected that the results will significantly broaden our understanding of the regulatory roles of epigenetic pathways in temperature mediated rice panicle development, and provide valuable insights for the improvement of rice breeding.

水稻是全球最重要的粮食作物和单子叶模式植物，其产量的稳定直接关系着国家粮食安全。穗发育过程是影响水稻产量的关键因素之一，水稻在孕穗期对温度极其敏感，研究表明表观遗传调控在水稻孕穗期对环境温度的响应过程中具有重要作用。因此，揭示调控水稻穗发育时期响应低温过程的表观遗传机制对于稻米产量的提高至关重要。前期研究表明：当控制组蛋白去甲基化的关键因子OsJMJ706突变后，水稻穗发育出现异常，而且突变体在孕穗期对低温更加敏感，结实率显著下降。因此，本研究拟利用前期获得的水稻Osjmj706突变体，通过表观遗传组学研究手段解析OsJMJ706的功能，系统鉴定受组蛋白去甲基化酶OsJMJ706调控直接参与水稻穗发育的基因位点，揭示温度介导水稻穗发育调控的表观遗传机制，最终为水稻育种奠定理论基础。

水稻是全球最重要的粮食作物和单子叶模式植物，其产量的稳定直接关系着国家粮食安全。穗发育过程是影响水稻产量的关键因素之一，水稻在孕穗期对温度极其敏感，研究表明表观遗传调控在水稻孕穗期对环境温度的响应过程中具有重要作用，但我们对相关分子机制了解十分有限。本研究以一个控制组蛋白去甲基化的关键因子OsJMJ706的突变体（Osjmj706-2）为出发点，通过表观遗传组学研究手段解析了OsJMJ706的功能，酶活和遗传互补实验确定OsJMJ706是一个H3K27me3去甲基化酶；表型分析表明Osjmj706-2突变体穗发育出现异常，而且在孕穗期对低温更加敏感，结实率显著下降；进一步分析发现OsJMJ706的表达受到低温诱导；最后我们结合RNA-seq和ChIP-seq测序数据，鉴定到多个受组蛋白去甲基化酶OsJMJ706调控直接参与水稻穗发育的候选基因位点。这些结果为揭示温度介导水稻穗发育调控的表观遗传机制和辅助水稻育种奠定了理论基础。