水稻AGO2调控宿主抗水稻矮缩病毒病害的机制研究

RNA silencing is an evolutionarily conserved, sequence-specific gene inactivation system which plays an essential role in many biological processes, and functions as a powerful antiviral system in plants. Antiviral silencing is triggered by double-strand viral RNAs that are processed into 21-24 nt virus-derived small RNAs (vsiRNAs) by RNase III type DICER enzymes. These vsiRNAs guide a multiprotein effector complex, the RNA induced silencing complex (RISC). Argonaute protein (AGO) is the slicer component of RISC and, targets complementary viral RNA to promote defense. .Insect vector transmitted viral diseases are the most severe rice diseases，which cause heavy yield loss in rice production. Rice dwarf virus (RDV) the pathogen of rice common dwarf disease, transmitted in nature by leafhopper in a propagative manner. In this proposal, we plan to use RDV as a model system to address the mechanisms of AGO2 involved in antiviral defense in the following aspects: expression regulation of AGO2 during RDV infection; small RNA profiling of AGO2.

RNA沉默通路是重要的抗病毒防御机制，病毒侵染植物后，在复制过程中形成双链RNA，诱发RNA沉默通路产生vsiRNA (virus derived small RNA)，进而与AGO蛋白结合形成RISC复合物，特异的识别并抑制病毒RNA的复制。水稻矮缩病毒(Rice dwarf virus, RDV)是双链RNA病毒，由叶蝉以持久方式传播，严重影响水稻产量。研究RDV与水稻之间的作用机制，对于开发抗病毒水稻具有重要的启发意义。我们前期的研究发现，RDV可诱导AGO2蛋白高表达，ago2突变体高度感病，但其作用机制尚不清楚。本课题以观察到的表型为基础，继续深入研究AGO2作用机理：1）初步明确AGO2在抗RDV过程中的功能；2）检测RDV染病水稻中AGO2结合小RNA特征；3）探索AGO2结合小RNA的靶基因在抗病毒中的作用。