组蛋白脱甲基化酶JMJ704调控水稻抗白叶枯病的分子机理研究

水稻是我国最重要的粮食作物。组蛋白的脱甲基化修饰可以激活或抑制基因的表达，进而调控水稻对病原菌侵染的抗性。申请人已发表的研究数据表明水稻组蛋白脱甲基化酶基因JMJ704的两个等位缺失突变体均对白叶枯病原菌( Xanthomonas oryzae pv. oryzae, Xoo)的抗性减弱，但该基因能否增强水稻的抗性以及其调控的分子机理仍然未知。本项目前期研究工作揭示超量表达JMJ704可显著增强水稻对Xoo的抗性。本项目拟在上述JMJ704详实的生物学功能数据的基础上，通过离体和活体的脱甲基化酶活实验鉴定JMJ704蛋白作用的组蛋白底物和位点，明确其生化功能；通过ChIP-seq、ChIP-PCR、qRT-PCR实验探索JMJ704调控的下游基因和方式，明晰其调控的基因网络；从而全面阐明JMJ704在水稻防御白叶枯病中的分子调控机理，从表观遗传这个全新的领域为水稻抗病育种储备优良基因资源。

Rice is one of the most important food crops in China. Emerging evidences have shown that histone demethylation plays essential roles in rice defense against pathogen infection by activating or repressing gene transcription. JmjC domain-containing protein gene JMJ704 encodes a histone Lys demethylase in rice. Our published results demonstrated that jmj704 lines were more susceptible to bacterial blight disease pathogen (Xanthomonas oryzae pathovar oryzae, Xoo) infection than the wild-type. However, the potential of JMJ704 to improve rice disease resistance and the underlying regulation mechanism remain unclear. In this proposal, our preliminary data showed that over-expression of JMJ704 significantly enhanced rice resistant against Xoo infection. This proposal aims to confirm the biological role of JMJ704 in rice defense, investigate the specific histone substrate and sites of JMJ704 by demethylase activity assay in vivo and in vitro, as well as the regulatory networks by ChIP-seq、ChIP-PCR、qRT-PCR. In summary, the above proposal will shed light on the role of JMJ704 during pathogen infection, and elucidate the molecular mechanism of JMJ704 in rice defense response to Xoo, and provide novel gene resources for resistance breeding.