芜菁花叶病毒（TuMV）是危害我国主要油料作物油菜和十子花科作物最严重的病毒，常造成重大经济损失。利用抗性基因培育抗病毒品种已成为防治病毒病最有效的方法，但目前抗病毒基因的研究仍较少。前期研究发现TSN是参与P1蛋白酶切割的最佳寄主蛋白，TSN是应激颗粒（SGs）和RNA诱导沉默复合体（RISC）的必要组分，与AGO2互作参与siRNA降解，但TSN在植物病毒侵染中的功能和机理仍不清楚。本项目通过融合标签表达TSN和病毒诱导基因沉默技术明确TSN的细胞定位和对TuMV侵染的响应。分析TSN、SGs和TuMV的互作关系和细胞定位，明确三者互作对TuMV致病力及P1蛋白酶切割活性的影响。解析TSN与AGO2的互作关系和对AGO2功能的干扰机制，明确二者互作对TuMV致病力的影响。本项目通过解析TSN在TuMV侵染中的作用和机理，以期挖掘油菜中TuMV的新抗性基因，为植物病毒病的防治提供新靶标。

Turnip mosaic virus (TuMV) is the most devastating RNA virus in oil-bearing crops (Brassica napus) and cruciferous crops, whose infection usually leads to enormous economic losses worldwide. One of the most effective strategy of prevention and control of plant viruses is to adopt resistance gene in breeding antivirus varieties. However, it is still scarce on the study of resistance genes against plant viruses. Our preliminary study revealed that Tudor staphylococcal nuclease (TSN, Tudor-SN, SND1 or p100) is the most likely candidate participating P1 proteolytic cleavage. TSN is an indispensable factor for the formation of stress granules (SGs), RNA-induced silencing complex (RISC) and interacting with Argonaute 2 (AGO2) protein to participate the degradation of small interference RNA (siRNA). However, it is still a mystery that how TSN works in TuMV infection. Therefore, we attempt to obtain the following results: 1) Define the subcellular localization of TSN and analyze the role of TSN in response to TuMV infection by knocking out or over-expressing TSN gene. 2) Detect the interacting domains and subcellular localization of TSN-SGs-TuMV to explore the influence on the infection of TuMV and P1 proteolytic cleavage. 3) Analyze the interaction and subcellular localization of TSN and AGO2 and determine their potential influence on the infection of TuMV. The objective of this project is expected to unveil the function and mechanism of TSN in the infection of TuMV, which may provide a novel TuMV resistance gene in B.napus and a new target for the prevention and control of TuMV.