大豆疫霉效应子Avh238激活大豆免疫的分子机制

大豆疫霉引起的大豆疫病给我国大豆生产造成严重损失。效应子是大豆疫霉攻击植物的重要武器，以效应子为切入点，解析植物免疫发生机制，是利用植物抗性防控大豆疫病的关键。申请人前期鉴定到一个能激活植物免疫反应的大豆疫霉RXLR类效应子Avh238，发现其在疫霉菌种间具有广谱保守性，并鉴定到能与Avh238互作的大豆NLR蛋白GmNLR1，但是Avh238激活大豆免疫的机制尚不清楚。本项目拟通过敲除大豆GmNLR1编码基因，探究其对Avh238的识别作用及在植物抗性中的功能；利用免疫共沉淀方法鉴定GmNLR1结合Avh238的关键结构域和关键位点；探究Avh238对GmNLR1定位和功能的影响；通过改造GmNLR1，以期提高大豆对大豆疫霉的广谱抗性。研究结果有望阐明Avh238激活植物免疫的分子机制，为合理利用植物自身抗性、通过基因工程改良植物对疫霉菌的抗性提供理论依据和抗性资源。

Soybean root rot caused by Phytophthora sojae results in serious losses in soybean production every year in China. P. sojae secretes distinct RXLR effector proteins into host cells to modulate plant immunity. Elucidation of plant resistance mechanisms by using effectors as probes is critical for preventing P. sojae-caused plant disease. Our previous work discovered Avh238, a conserved RXLR effector in Phytophthora pathogens that triggered immunity in soybean. Further study identified a soybean NLR protein (named GmNLR1) interacted with Avh238. However, the molecular mechanisms involved in Avh238-triggered plant immunity are largely unknown. In this project, we will knockout the soybean GmNLR1-encoding gene to verify its role in the recognition of Avh238, and in soybean resistance. The key domain and sites of GmNLR1 that are responsible for association with Avh238 will be identified by using co-immunoprecipitation assay. The effect of Avh238 on the localization and function of GmNLR1 will be further investigated. Modification and expression of GmNLR1 will be performed to improve the broad-spectrum resistance of soybean towards P. sojae. These results will help to understand the molecular mechanisms involved in the recognition of Avh238 by plants, and will provide theoretical guidance for the modification of plant resistance to prevent Phytophthora-caused disease.