水稻是维持世界过半人口生存的重要粮食作物，而由各种水稻病毒引起的病害却对水稻产量造成巨大损失，对国家粮食安全构成直接威胁。水稻草矮病毒（RGSV），一个单链RNA病毒，侵染水稻后造成严重减产，甚至绝收。目前，对于RGSV如何诱导水稻发病尚不清楚。我们前期研究发现，RGSV的侵染显著抑制了水稻内源24nt Small RNA的产生和Pol VI基因的转录和表达；水稻全基因组甲基化水平显著降低。深入研究揭示RGSV 编码的P3蛋白通过与Pol VI的互作从而调控DNA甲基化水平，进而参与病毒致病过程。该项目为建立RNA病毒参与调控植物表观遗传修饰，影响水稻生长发育的一种新的病毒致病机制，为有效进行该病毒病害的防控提供理论依据。

Rice is an essential food crop which can support the living for half of the world’s population. However, diseases caused by a wide variety of rice viruses have resulted in enormous losses for the rice production, posing a direct threat on the national food security. Rice grassy stunt virus (RGSV), a single-strand RNA virus, will not only damage the production of the infected rice, it will also make total crop failure of rice. At present, we still don’t know the pathogenesis mechanism induced by RGSV in rice. We previously found that rice 24 nt small RNA as well as the transcription and expression of Pol VI gene, is highly repressed by RGSV infection. The genome-wide DNA methylation level is significantly reduced in the RGSV infection rice plants. Further work has revealed that RGSV-encoding P3 interacted with Pol VI to regulate DNA methylation of rice genome and facilitate virus infection and symptom development. This project is for the purpose of building a new virus pathogenic mechanism in which RNA virus will participate in regulating the epigenetic modification to affect the growth and development of the rice, thus finally providing a theoretical basis to prevent and control this virus disease.