草莓镶脉病毒移动蛋白P1与热激蛋白DnaJ互作对病毒侵染的影响

Strawberry vein banding virus (SVBV) is one of the important viruses that endanger the production of strawberries. It was demonstrated in our research that protein P1 of SVBV is a movement protein, which closely related to the metastasis and diffusion of virus. However, it has not been reported that how the interaction of P1 protein with the host factors influence the intercellular movement and system infection of viruses. The cDNA library of the Fragaria vesca was constructed in our research, and protein P1 was used as a bait to screen out a host factor strawberry heat shock protein DnaJ. Heat shock protein DnaJ is an important molecular chaperone, participating in many physiological processes of plant cells, and it is likely to be an extremely important host factor regulating the functions of P1. In this project, on the basis of determining the interaction of P1 with DnaJ, the effect of DnaJ on the subcellular localization of P1 was analyzed, the effects of DnaJ on the P1 protein promoting local spread and systemic infection of virus were explored, and the effect of DnaJ on systemic movement of viruses was conformed. Finally, the mechanism of DnaJ on the infection of SVBV in F. vesca was clarified. This study has great significance in enriching the basic theory of plant double stranded DNA viruses and controlling strawberry virus disease.

草莓镶脉病毒（SVBV）是危害草莓生产的重要病毒之一。本课题组已鉴定SVBV P1蛋白是移动蛋白（MP），与病毒的转移和扩散密切相关，但P1蛋白如何与寄主因子互作影响病毒的胞间移动和系统侵染尚未见报道。本课题组构建森林草莓cDNA文库，以P1蛋白为诱饵筛选出与其互作的热激蛋白DnaJ。DnaJ蛋白是重要的分子伴侣，参与植物细胞的众多生理过程，可能是调控P1蛋白功能的重要寄主因子。本课题在确定P1蛋白和DnaJ蛋白互作的基础上，分析DnaJ蛋白对P1蛋白亚细胞定位的影响，探究DnaJ蛋白对P1蛋白自身胞间移动能力以及对P1蛋白促进病毒局部扩展和系统侵染的影响，明确DnaJ对SVBV在森林草莓中系统移动的影响，最终解析DnaJ蛋白在SVBV侵染过程中的作用机制。本研究的开展对丰富植物双链DNA病毒基础理论和防控草莓病毒病害均具有极重要的意义。

草莓镶脉病毒（strawberry vein banding virus, SVBV）是草莓种植业中最主要的一种病害，严重危害草莓的产量和质量。前期研究证明SVBV P1蛋白是移动蛋白，与病毒的转移和扩散密切相关。但P1蛋白如何与寄主因子互作影响病毒的胞间移动和系统侵染尚未见报道。本课题组构建森林草莓cDNA文库，以P1蛋白为诱饵筛选出与其互作的热激蛋白DnaJ。DnaJ蛋白是重要的分子伴侣，参与植物细胞的众多生理过程，可能是调控P1蛋白功能的重要寄主因子。本研究首先利用酵母双杂交、双分子荧光互补（BiFC）、免疫共沉淀（Co-IP）和萤火虫荧光素酶互补成像（LCI）试验证明P1能与DnaJ在植物体外和体内互作。亚细胞定位发现P1与DnaJ共定位与细胞边缘，DnaJ不影响P1定位于内质网和胞间连丝。SVBV侵染森林草莓能诱导DnaJ下调表达，说明DnaJ参与病毒的侵染过程。DnaJ蛋白能抑制P1蛋白回补运动缺陷型PVX胞间运动能力，而且DnaJ还能抑制P1蛋白回补运动缺陷型CMV系统移动能力。在森林草莓中瞬时过表达DnaJ，接种SVBV侵染性克隆发现，SVBV侵染速率减慢。