草莓镶脉病毒致病因子P6蛋白与草莓RD21蛋白互作机制研究

草莓镶脉病毒（SVBV）是一种严重危害草莓的DNA病毒，SVBV P6蛋白是病毒致病因子。前期研究发现，P6蛋白能与森林草莓RD21蛋白互作，且RD21蛋白可降解P6蛋白。RD21蛋白是一种半胱氨酸蛋白酶，在植物生长发育、抗逆和抗病方面发挥重要作用，推测RD21蛋白可能是调控P6蛋白功能的重要免疫因子。本项目拟进一步验证P6与RD21体内、体外互作及互作的关键结构域，明确二者互作的亚细胞定位。再分析RD21与P6互作对P6蛋白功能的影响，测定RD21蛋白体内、体外降解P6蛋白的效率，并确定RD21蛋白催化水解关键功能域以及P6蛋白被降解的关键氨基酸，分析RD21蛋白对P6蛋白抑制子活性的影响。最终解析RD21蛋白降解P6蛋白的分子机制，明确草莓RD21蛋白对SVBV侵染的影响。本研究的开展对揭示寄主和病毒之间防御和反防御机理具有重要意义。

Strawberry vein banding virus (SVBV) is a kind of DNA virus bringing serious harms to strawberry, and SVBV P6 protein is a virus pathogenic factor. The previous researches showed that P6 protein could interact with RD21 protein, and RD21 protein could degrade P6 protein. RD21 protein of Fragaria vesca is a kind of cysteine protease, playing an important role in plant growth and development, stress tolerance and disease resistance. We speculate that RD21 protein may be an important immune factor regulating the function of P6 protein. Our study intends to further verify the interaction of P6 and RD21 in vivo and in vitro, identify the key domains of interaction, and determine the subcellular localization of the interaction of the two proteins. Then we will analyze the effect of the interaction to the function of P6 protein, determine the degradation efficiency of RD21 protein to P6 protein in vitro and in vivo, identify the key functional domains about proteolysis of RD21 and the key amino acids related to degradation of P6 protein, and analyze the influence of RD21 protein to the suppressor activity of P6 protein. Finally, we will explore the molecular mechanism of degradation of P6 protein by RD21 protein, and determine the influence of strawberry RD21 protein to SVBV infection. The development of this study is of great significance to reveal the defense and anti-defense mechanisms between hosts and viruses.