光对植物受病毒侵染后叶片绿岛形成的影响

植物受病毒侵染后在叶片上形成绿岛（Dark green islands, DGIs）是花叶病的一种常见症状。绿岛被认为是一种转录后基因沉默现象，是植物抵抗病毒侵染的一种表现，但其发生、形成的机理目前仍不清楚。本项目拟利用黄瓜花叶病毒（CMV）与烟草、烟草花叶病毒（TMV）与烟草构成的花叶症亲和互作体系，分别从以下2个方面来研究光对植物受病毒侵染后叶片绿岛形成的影响：1、通过不同的光周期、不同的光照强度、不同光质、病毒接种前后不同的黑暗处理、一个光周期中不同的病毒接种时间以及接种后不同的光照时间长短来研究光在绿岛发生、形成中的作用；2、利用烟草脆裂病毒（TRV）病毒诱导的基因沉默（VIGS）系统以及RNA干扰技术使烟草的不同光受体沉默，研究光受体在绿岛形成中的作用。本项目的研究结果不仅能为植物恢复抗性的作用机制研究提供新的论据，而且有望为农业生产中植物病毒病的防治提供理论和实践指导。

Dark green islands（DGIs）are a common symptom of plants systemically infected with a mosaic virus. DGIs are regarded as the result of posttranscriptional gene silencing and a phenomenon of recovery and resistance. To date, however, the mechanism of the occurrence and formation of DGIs remains elusive. In this proposal, the effects of light on the formation of DGIs will be investigated by using the compatible 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 function of light in the appearance of DGIs by applying different photoperiod, different light intensity, different light spectral, different dark incubation before and after viruses inoculation, different time of inoculation in one photoperiod and different exposure to light after infection. ② To investigate the roles of photoreceptors in the formation of DGIs by silencing different photoreceptors in tobacco through the techniques of TRV-VIGS and RNAi. The prospective results may provide new data for the machanism study of plant recovery post pathogens' infection. It may also give some new guidance on the control of plant viruses in agriculantural production.