甘蔗花叶病是甘蔗生产上一类重要的病毒病害。我们前期研究发现，高粱花叶病毒（Sorghum mosaic virus, SrMV）和甘蔗线条花叶病毒（Sugarcane streak mosaic virus, SCSMV）混合侵染同种甘蔗时花叶症状较单亲侵染时明显加重，但其互作的分子机制尚不明确。本研究拟在实验室接种培养和田间自然发生两种条件下，通过比较分析SrMV和SCSMV单侵染和混合侵染时的症状变化、病毒浓度积累差异确定其互作方式；通过比较单侵染和混合侵染时小RNA及病毒基因表达水平的差异，在小RNA水平上探讨SrMV和SCSMV混合侵染致病的分子机制。通过本研究的实施，可明确SrMV和SCSMV混合侵染甘蔗时的互作方式，确定SrMV和SCSMV混合侵染加重甘蔗花叶病危害的作用机制，为有效的进行甘蔗花叶病病害防治提供理论依据，并能够促进解析植物病毒混合侵染的致病机制。

Sugarcane mosaic disease is one of economically important viral diseases on sugarcane. In our previous study, the mosaic symptoms of same sugarcane cultivar caused by Sorghum mosaic virus (SrMV) and Sugarcane streak mosaic virus (SCSMV) are more significantly serious than by each of the two viruses. However, at present the molecular mechanism of mixed infection by SrMV and SCSMV is still obscure. In this project, we will investigate the interaction pattern of the two viruses’ co-infection through comparing the variations of symptoms and accumulation between single and mixed infections; dissect the molecular mechanism of mixed infection in aspect of small RNA by analyzing the variations of small RNA and viral gene express level, under both laboratory and natural field conditions. From this project, we could clarify the interaction pattern of SrMV and SCSMV co-infection, the molecular mechanism of increasing significantly hazards on sugarcane caused by SrMV and SCSMV mixed-infection. These could provide the basis to controlling the sugarcane mosaic disease, and to understand the molecular mechanism of plant virus mixed infection.