水稻乙烯信号传导途径转录因子OsEIL2介导的抗病分子机理解析

Plants typically respond to pathogen infection or herbivore attack with a complex scenario of sequential, antagonistic, or synergistic action of different hormone signals leading to defense gene expression. This interplay or so-called crosstalk among individual hormone pathways enables plants to adjust their inducible defense arsenal to the type of attacker encountered. Previous research showed that a transcript factor, OsEIL2, played an important role in rice innate immunity. Our preliminary results demonstrated that OsEIL2 negatively regulates resistance to the rice blast (Magnaporthe oryzae) and rice bacterial leaf blight (Xanthomonas oryzae), but positively regulates resistance to rice sheath blight (Rhizoctonia solani). In this project, first, we will check the marker gene expression level in the signal pathways of SA/JA/ET and determine which signal pathway OsEIL2 is involved. The content of hormones in OsEIL2 transgenic rice will be evaluated. Second, we will check its transcript factor activity using subcellular localization and yeast one-hybrid. Third, we will use a ChIP-Seq to identify the OsEIL2 interaction proteins and elucidate the function of its interaction genes in rice innate immunity. Last, we will compare all the above data and find out the signaling networks regulated by OsEIL2. A better understanding of the rice resistance mechanism to pathogen regulated by OsEIL2 from this project will provide new knowledge and strategies for rice disease

植物面临生物胁迫时会调动、布局激素分子做出一系列顺序的、拮抗的、协同的反应。利用不同激素信号传导途径间的交织交错，帮助其不同的防卫反应元件抵抗不同类型的植物病原菌。在前期工作中，我们筛选到了一个负调控水稻抗稻瘟病和白叶枯病、正调控纹枯病的乙烯信号传导途径转录因子OsEIL2 基因。本研究旨在解析OsEIL2 调控的抗病分子机理。首先，通过测定SA、JA、ET信号通路的标记基因以及测定OsEIL2转基因材料中激素含量的变化确定其所参与的激素信号通路；其次，本项目将通过亚细胞定位和酵母单杂交等方法确定其转录活性；再次，采用Chip-Seq的方法确定其作用的靶基因，并研究靶基因在水稻抗病中的作用。综合以上结果解析OsEIL2调控水稻抗病信号网络，研究结果将为水稻稻瘟病的防控提供新思路。

植物面临生物胁迫时会调动、布局激素分子做出一系列有序的、拮抗的、协同的反应。利用不同激素信号传导途径间的交叉互作，帮助其不同的防卫反应元件抵抗不同类型的植物病原菌。本项目利用生物化学、分子生物学和细胞生物学等方法研究了OsEIL2对水稻三种重要病害的抗病分子机制。OsEIL2作为转录因子，在细胞核行使其转录调控功能。抗病性分析发现，OsEIL2正调控水稻对纹枯菌的抗性，而负调控水稻对稻瘟菌和白叶枯菌的抗性。进一步筛选获得OsEIL2的下游靶标基因 OsERF083和OsWRKY67，并发现OsEIL2可分别激活OsERF083和抑制OsWRKY67的表达。当纹枯菌侵染时OsEIL2特异性调控OsWRKY67，而稻瘟菌和白叶枯菌侵染时OsEIL2特异性调控OsERF083。此外，进一步解析了OsEIL2所介导的激素信号通路调控水稻抗病分子机制。OsEIL2可调控ET和JA信号途径的协同作用，促进水稻对死体营养型病菌的抗性反应，与SA调控水稻对活体营养型病菌的抗性反应相拮抗。同时本研究还开展了OsEIL2互作蛋白的研究工作，筛选到两个互作蛋白：14-3-3蛋白GF14e和丝氨酸苏氨酸蛋白激酶OsAFC3，并且证明OsAFC3可磷酸化修饰OsEIL2。