水稻泛素连接酶基因MIE2介导的抗稻瘟病分子机理研究

The ubiquitin proteasome is a principal regulator of many biological processes in all eukayotes. The best characterized components of the ubiquitination cascade are E3 ubiquitin(Ub)-ligase enzymes, which have been shown to be involved in all steps of plant immune responses. E3 Ub-ligase protein appear to modulate perception of pathogen, are also involved in regulation of the signaling responses downstream of pathogen perception. In our preliminary work, we got the E3 Ub-ligase gene MIE2, which negatively regulates resistance to rice blast fungus Magnaporthe oryzae in rice. In this project, a yeast-two hybrid will be performed to screen interacting protein of MIE2, and was designated as MIPs (MIE2 interacting protein). Then, the relationship and function of MIE2 and MIPs in rice innate immunity will be elucidated. Secondly, in the MIE2-RNAi and wild-type rice plants, the expression of defense-related genes and ROS generation after flg22 and chitin treatments will be tested to judge if MIE2 is involved in the PAMP-triggered immunity (PTI). Thirdly, the expression level of major regulatory components of disease resistance triggered by the R protein will be detected to figure out whether MIE2 is involved in effector-triggered immunity (ETI). Finally, the expression level of some marker genes in the signal pathways of SA/JA/ET will also be tested in the MIE2-RNAi plants. A better understanding of the rice resistance mechanism to rice blast mediated by MIE2 in this project will provide the new strategies for disease control.

泛素蛋白酶体系统是真核生物体内许多生物学进程的主要调节因子。而其中的E3泛素连接酶在植物的抗病反应中起着重要的作用，几乎涉及到植物免疫响应的每一个步骤。它不但参与了植物对病原菌的识别，还负责调控下游信号响应。在前期工作中，我们筛选到一个负调控水稻抗稻瘟病的E3泛素连接酶MIE2基因。本研究将通过酵母双杂交系统筛选MIE2的互作蛋白MIPs，明确它们之间的相互关系，以及互作蛋白在水稻抗稻瘟病过程中的功能。其次，在MIE2-RNAi和野生型植株中，利用PAMPs处理检测活性氧的迸发量以及相关防御基因的表达量，确定其是否参与水稻PTI反应；此外，检测R基因所介导的抗病信号途径中的重要调节基因的表达量，来确定其是否参与ETI反应。最后，分析SA/JA/ET信号途径中标记基因的表达情况，明确其是否参与以上抗病信号途径。本研究解析MIE2介导的水稻抗稻瘟病分子机理，将为稻瘟病的防控提供新策略。