MicroRNAs调控植物受病毒侵染后花叶形成机理的研究

植物花叶病是一种普遍发生的病毒病害，花叶中深绿色的区域（DGIs）是植物转录后基因沉默的结果，是植物抵抗病毒侵染的一种表现，但其发生、形成及调控的机制尚不明确。本项目拟利用黄瓜花叶病毒（CMV）、烟草花叶病毒（TMV）与烟草构成的两类花叶病互作体系，从以下3个方面研究miRNAs调控植物受病毒侵染后花叶形成的机理：1. 通过全面测定花叶不同组织中的小RNAs，研究miRNAs与花叶病症的相关性；2. 依据花叶中深绿色组织的代谢结果，探查与花叶及DGIs形成密切相关的miRNAs；3. 利用烟草脆裂病毒（TRV）的基因沉默（VIGS）系统以及农杆菌介导的RNA干扰和过表达技术使烟草花叶病相关的miRNAs沉默或过表达，研究miRNAs在调控花叶及DGIs形成中的作用。本项目的研究结果不仅能为植物恢复抗性的作用机理研究提供新的论据，而且有望为农业生产中植物病毒病的防治提供新的理论和实践策略。

Mosaic disease of plants is one kind of common disease caused by plant viruses. Dark green islands （DGIs）in pathogenetic mosaic leaves are the result of posttranscriptional gene silencing and a phenomenon of recovery and resistance. To date, however, the regulation mechanism of the occurrence of mosaic disease and the formation of DGIs remains elusive. In this proposal, the regulation mechanism of miRNAs on the formation of mosaic disease will be investigated by using two typical mosaic disease systems composed of Cucumber mosaic virus (CMV) and Nicotiana tobacum, Tobacco mosaic virus (TMV) and Nicotiana tobacum respectively, and the following works will be performed：1. To investigate the correlation between miRNAs with mosaic disease by large scale sequence of small RNAs in different tissues of mosaic leaves. 2. To investigate and find miRNAs closely related to the formation of mosaic disease and DGIs through the metabolic substances of DGIs. 3. To investigate the roles of miRNAs in the formation of mosaic disease and DGIs by silencing related miRNAs in tobacco through the techniques of TRV-VIGS, RNAi and over-expression mediated by agrobacterium. The prospective results may provide new data for the machanism study of plant recovery post pathogens’ infection. It may also give some new guidance and strategy on the control of plant viruses in agricultural production.