泛素蛋白降解途径参与植物防御信号传导，已有研究表明RING泛素连接酶参与水稻生物胁迫和非生物胁迫调控。我们前期研究了一个U-box泛素连接酶OsPUB57的功能,本项目将对另一个RING型泛素连接酶（RING6）展开重点研究。我们已获得了RING6的基因敲除和增强突变体，体外表达及纯化了RING6蛋白以及确定了其泛素连接酶活性，并获得了RING6的超表达和RNA沉默转基因株系。本项目将分析这些转基因株系及突变体材料的抗生物胁迫（稻瘟病及白叶枯病）及非生物胁迫（干旱及盐碱）状况，利用酵母双杂交体系，分离和克隆水稻泛素连接酶RING6的互作蛋白基因，筛选可能的泛素化底物，并研究RING6及其互作蛋白的亚细胞定位，探索RING6介导的抗逆机制。

The ubiquitin degradation pathway has been involved in plant defense signaling, and studies have shown that RING ubiquitin ligases regulate biotic and abiotic stresses in rice. The function of a U-box ubiquitin ligase OsPUB57 has been analyzied in our group, and another RING-type ubiquitin ligases (RING6) was picked up for functional studies in this project. We have obtained knockout and enhanced mutants for RING6, expressed and purificated RING6 in vitro, determined its ubiquitin ligase activity, and generated overexpression or RNA silencing transgenic lines for RING6. In this project, we will analyze these transgenic and mutant lines for their responses to biotic ( rice blast /bacterial blight ) or abiotic stresses ( drought/salinity). In addition, we will isolate and clone RING6-interacting protein genes using the yeast two-hybrid system, identified potential ubiquitinated substrates of RING6, determine subcellular localization of RING6 and its interacting proteins. These data will be useful to explore RING6-mediated resistance mechanisms against biotic and abiotic stresses.