马铃薯是世界第三大粮食作物，然而由致病疫霉所引起的晚疫病严重威胁着马铃薯生产。为了成功侵染植物，病原菌会分泌效应蛋白以干扰寄主植物抗病免疫系统。前期研究发现致病疫霉RxLR效应蛋白SFI7是一个重要效应蛋白，超量表达后显著促进致病疫霉侵染本氏烟草。此外，SFI7除抑制RxLR效应蛋白PITG_22798介导的细胞死亡反应外，还能通过与马铃薯磷酸酶StBSL1互作进而抑制AVR2激发过敏反应。本项目拟以SFI7基因为突破口，通过转基因技术明确SFI7基因的毒性功能。结合Pull down、免疫共沉淀、等温滴定量热法等技术鉴定SFI7与AVR2竞争互作StBSL1蛋白，同时分析SFI7对磷酸酶StBSL1活性的影响，初步解析SFI7抑制马铃薯ETI免疫反应机制，最终为揭示致病疫霉的致病机理提供重要线索。

Potato is the third most important food crop in the world. However, it suffers from one of the most destructive diseases late blight that is caused by oomycete pathogen Phytophthora infestans. To successfully infect plants, plant pathogens secrete arsenal of effectors to interfere with plant immunity. Previous studies showed that the RxLR effector SFI7 from P. infestans is an important effector protein. Transient expression of the SFI7 in Nicotiana benthamiana enhances susceptibility to P. infestans. Moreover, SFI7 could suppress AVR2-triggered immunity by the interaction between SFI7 and phosphatase StBSL1. And the SFI7 can also suppress the cell death triggered by the RxLR effector PITG_22798 from P. infestans. In this project, we focus on SFI7. Genetic modification technology will be used to identify the virulence function of SFI7 in potato. Pull-down, co-immunoprecipitation, isothermal titration calorimetry assays will be utilized to explore if the SFI7 binds to StBSL1 more tightly than AVR2. And the effect of SFI7 on phosphatase activity will be analyzed. Base on these studies, we are able to illuminate the mechanism of SFI7 to suppress effector-triggered immunity in potato. This project will provide important clues for the pathogenesis of P. infestans.