Alphasatellite总是与双生病毒病害复合体相伴随，但目前对alphasatellite的研究仍集中在田间的分离鉴定，其生物学功能不清。项目拟以与双生病毒病害复合体伴随的alphasatellite为对象，在完善核酸数据库的基础上，明确其编码的唯一蛋白Rep抑制PTGS和TGS的功能；构建双生病毒各DNA分子的侵染性克隆，分析其对双生病毒致病及病毒DNA、卫星beta积累量的影响，明确其与双生病毒各DNA分子之间的互作。筛选可能与Rep互作的寄主因子，沉默或过表达寄主因子后接种病毒，观察其对病毒致病及植物防御途径的影响，探索其与寄主植物的互作。比较烟粉虱在有/无卫星alpha的植物上获毒、持毒及传毒效率的差异，明确alphasatellite对介体传毒能力的影响。项目的开展将明确alphasatellite在双生病毒病害复合体致病、植物防御反应及介体传播中的生物学功能。

Alphasatellites are circular single-stranded molecules associated with begomovirus / betasatellite complexes. Studies on alphasatellites mainly focus on molecular characterization, while the function of alphasatellites is not known. Our preliminary work showed the types and molecular variation of alphasatellites in China. In this project, the post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) suppressor activity of the Rep protein encoded by the alphasatellite were tested. In order to evaluate the interaction among the alphasatellite, begomovirus and betasatellite, the infectious clones of begomovirus, alphasatellite and betasatellite molecules of typical geminiviruses will be constructed and the influence of alphasatellite in viral pathogenicity will also be analyzed. To assess the interaction between the alphasatellite and the host, the host factor will be screened, and the begomovirus / alphasatellite / betasatellite complexes will be agro-infected in host factor silenced-plants or over expressed-plants, and the function of alphasatellite in plant defense will be studied. The difference of whiteflies acquisition, retention and inoculation in alphasatellite-infected or no alphasatellite-infected plants will be compared to dertermine the influence on alphasatellite in virus transmission. With these above research work, it will expand our knowledge of the functions of alphasatellite associated with begomovirus / betasatellite complexes in viral pathogenicity, plant defense and virus transmission.