水稻条纹病毒逃避介体灰飞虱血淋巴免疫的机制

Rice stripe virus (RSV), causing rice stripe disease which is one of the most serious virus diseases in rice-growing area, is mainly transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a persisent-propagative manner. The success and efficiency of virus transmission is the main reason for of disease epidemics. Thus, to understand the transmission mechanism of RSV by SBPH is a critical step to understand the disastrous rules of rice stripe. Our previous work provided evidence that a novel cuticular protein of SBPH, CPR1, is essential for RSV transmission. CPR1 binds the nucleocapsid protein (pc3) of RSV both in vivo and in vitro, also colocalizes with RSV in the hemocytes. Further study showed evidence that viruses can use CPR1 to aid their survival in the hemolymph. However, the mechanism of RSV using CPR1 of SBPH to escape immune response is not clear. Based on the existing research, we try to verify the domain and amino acids of CPR1 which interact with RSV pc3. Meanwhile, the molecular structure of CPR1 and RSV pc3 will be analyzed by their crystal structure. It will be verified the binding site of the two proteins, and localization of amino acid in virus transmission. Finally, it was studied RSV acquisition and transmission of SBPH which was knocked out CPR1 key amino acid as the target. We will elucidate that how the virus uses of insect’s protein CPR1 to escape immune response by revealing their combined mechanism, which is conducive to the survival and spread of the virus. All of the results will help us to provide new approach for rice stripe disease and other new type of virus disease control.

水稻条纹病毒（RSV）主要通过介体灰飞虱以持久增殖的方式在寄主植物间传播，灰飞虱带毒率高和有效传播是导致条纹叶枯病暴发成灾的主要因素，阐明灰飞虱传毒机制是理解病害成灾规律最重要的基础。申请人前期研究发现RSV通过与灰飞虱的一种表皮蛋白CPR1在血淋巴中结合而逃避介体昆虫的免疫反应，但是二者究竟是怎样结合的，以及病毒是如何利用CPR1逃避免疫反应的机制还不清楚。本项目拟从验证CPR1与RSV核衣壳蛋白pc3互作的关键氨基酸及解析这两个蛋白的分子结构入手，对二者的互作与结合机制进行深入研究，并对传毒关键氨基酸进行定位，再以CPR1与病毒互作的关键氨基酸为靶标，通过体内定点敲除后研究其对RSV的获毒和传毒能力，阐明病毒是通过如何利用介体昆虫蛋白来逃避免疫反应的机制，研究结果将为切断病毒的介体昆虫传播来控制植物病毒病流行危害的新策略提供理论依据。

水稻条纹病毒（rice stripe virus, RSV）主要通过介体灰飞虱以持久增殖的方式在寄主植物间传播，灰飞虱带毒率高和有效传播是导致条纹叶枯病暴发成灾的主要因素，阐明灰飞虱传毒机制是理解病害成灾规律最重要的基础。申请人对介体灰飞虱蛋白参与RSV逃避免疫攻击的机制进行了研究。前期研究发现RSV通过与灰飞虱CPR1在血淋巴中结合而逃避介体昆虫的免疫反应，本项目验证了CPR1与RSV外壳蛋白互作的结构域和传毒关键氨基酸。此外，揭示了病毒通过与囊泡相关膜蛋白互作可以进入到细胞的囊泡中，并利用介体的囊泡运输系统跨越消化道屏障和逃避介体的免疫攻击。同时还发现了RSV可以通过其外壳蛋白与介体灰飞虱的囊泡相关膜蛋白相关蛋白B互作，进而抑制细胞内自噬前体的形成，从而逃避了灰飞虱利用自噬对病毒的降解作用。灰飞虱可以传播多种植物病毒，研究明确了水稻黑条矮缩病毒的获取可能通过诱导灰飞虱自噬而激活了介体昆虫的免疫反应，抑制了RSV的获取和增殖。同时还筛选获得了ribavirin可以抑制灰飞虱传播RSV。研究结果将为设计阻断介体昆虫传播植物病毒来控制病害流行的新策略提供科学依据。同时这些研究结果先后发表了8篇学术论文，其中SCI论文6篇，中文核心期刊论文2篇。