RNA沉默通路新蛋白的作用机制及抗性功能研究

RNA silencing plays essential roles in plant development and pathogen resistance. However, many genes that involved in RNA silencing machinery remain unknown. Agronaute 2 (AGO2), as an essential component of the RNA-induced silencing complex (RISC), plays central roles in virus resistance of plant. Recently, the applicants have identified a novel protein AGOBP that interacts with AGO2 using IP-MS technique. The overexpression of AGOBP induced typical RNA silencing-like phenotype to plant, and the overexpression of AGOBP enhanced the plant resistance to virus, indicating AGOBP may participate into plant resistance to virus as functioning in RNA silencing pathway. In this project, we propose to study the function of AGOBP in RNA silencing and the mechanism of AGOBP in plant resistance to virus. The interaction between AGOBP and AGO, as well as the effect of AGOBP on sRNA accumulation will be determined. In addition, the effect of AGOBP on virus genome accumulation, virus-derived sRNA accumulation will be determined to investigate the mechanism of AGOBP on plant resistance. The study of this project will extend people's knowledge on RNA silencing and its function in plant resistance.

RNA沉默在植物抗性反应过程中具有重要作用，然而目前仍有许多参与RNA沉默的重要基因未知。AGO2作为RISC复合体的重要组成部分，是植物抵御病毒侵染的重要抗性蛋白。申请人以AGO2蛋白为切入点，通过免疫沉淀与质谱分析技术，筛选出与AGO2相互作用的蛋白AGOBP。此基因的过表达导致植物呈现典型的RNA沉默突变体表型，并导致对病毒抗性的增强，暗示该基因可能通过RNA沉默参与对病毒抗性反应。本项目拟在此基础上，对AGOBP进行深入研究：1、解析AGOBP对sRNA积累和AGO结合sRNA能力的影响，阐明AGOBP在RNA沉默中的功能及作用机制；2.探索AGOBP抗病毒作用与AGO2抗病毒之间的关系，揭示其抗病毒作用机制。研究结果将进一步完善人们对于RNA沉默发生机制和抗性作用机制的认识。

RNA沉默在植物抗性反应过程中具有重要作用，然而目前仍有许多参与RNA沉默的重要基因未知。申请人聚焦于RNA沉默抗性领域，发现了一类与AGO蛋白结合的新蛋白AGOBP。AGOBP通过调节AGO1及AGO2蛋白对小分子RNA的结合能力，参与植物的RNA沉默通路。此外，AGOBP参与了AGO蛋白介导的植物的抗性功能，其突变体植物对丁香假单胞杆菌Pst DC3000、Pst (avrRpt2) 以及黄瓜花叶病毒CMV的抗性增强，而过表达植物的抗性减弱。这些结果表明，AGOBP是一类参与RNA沉默通路的重要蛋白，并在植物对病原体的抗性中发挥着重要的功能。申请人拟进一步寻找此蛋白在水稻中的同源蛋白，并探索水稻中AGOBP蛋白的抗性作用，研究结果将为提高水稻的抗病性提供策略和依据。