利用一种高效遗传筛选研究RNAi介导的植物抗病毒免疫

RNA interference (RNAi) -mediated gene silencing preserves genome integrity and modulates gene expression for the normal development in diverse organisms. RNAi-mediated antiviral immunity also provides one of primary defenses against virus infection in plants, and in mammals. However, the antiviral RNAi pathway has not been well understood since the published studies have only characterized the shared core RNAi factors such as DCLs, AGOs which have already been elucidated to silence endogenous or transgenic genes. Recently, we developed a robust genetic screen to isolate avi mutants in Arabidopsis using mutant Cucumber Mosaic Virus (CMV) deficient of its viral suppressor of RNA silencing (VSR) 2b protein. Dozens of avi mutants have been successfully obtained through the genetic screen. And several new components in antiviral RNAi pathway, such as lipid flippases and AVI2, have been identified from these mutants and been found to regulate antiviral RNAi. We proposed that, further studying the mechanism of these identified components and characterization of the rest mutants will greatly contribute to our understanding of antiviral RNAi, which could eventually help to discover new strategies for preventing viral diseases in plants and animals.

RNA干扰（RNAi）介导的基因沉默不仅调控真核生物的生长发育，也为动植物抵抗病毒侵害提供极其重要的防御。已知的RNAi途径中的核心因子，如DCLs和AGOs，在RNAi介导的抗病毒免疫中也起着关键作用。然而，新的抗病毒RNAi因子知之甚少，抗病毒RNAi途径亟待研究。最近，我们利用RNA沉默抑制子（VSR）2b蛋白缺陷的黄瓜花叶病毒（CMV），建立了一种有效的遗传筛选体系来分离植物中的抗病毒RNAi（avi）突变体。成功获得了15个avi突变体，并从这些突变体中发现了几个新的抗病毒RNAi因子，如磷脂翻转酶和AVI2。该项目拟分离并鉴定更多的avi突变体并研究这些新的抗病毒RNAi因子的作用机理，为我们进一步阐明抗病毒RNAi途径，和探索新的预防动植物病毒性疾病的策略奠定基础。

病毒严重危害人类和动植物健康。RNA干扰（RNAi）介导的抗病毒是真核生物中一种高度保守的天然抗病毒免疫，而且几乎对所有的动植物病毒都起作用。然而，抗病毒RNAi的具体作用机理仍不清楚，亟待研究。我们利用RNA沉默抑制子（VSR）2b蛋白缺陷的黄瓜花叶病毒（CMV）建立了一种高效的遗传筛选体系分离拟南芥抗病毒RNAi免疫缺陷（avi）突变体并发掘植物抗病毒RNAi新基因，进而深入阐明抗病毒RNAi作用机理。我们成功发掘了多个新的抗病毒RNAi因子，并首次揭示不同的磷脂在植物抗病毒免疫中的重要功能。我们还通过发掘新型水稻病毒并利用它们建立有效体系探索研究重要粮食作物水稻中的抗病毒RNAi作用机理。研究发现不仅进一步深入阐明了抗病毒RNAi的作用机理，而且为利用抗病毒RNAi探索发展广谱抗病毒方法提供重要理论基础。