番茄Ty-1调控TYLCV-V2影响双生病毒侵染的分子机制研究

TYLCV是全球最具危害性的十大植物病毒之一，一旦侵染番茄，便造成毁灭性危害。在田间，TYLCV常与其他双生病毒混合侵染造成更严重的损失。因此，寻找双生病毒广谱抗性因子是迫切需要解决的科学问题，根据报道TYLCV抗性基因Ty-1具有这种潜力。申请者前期发现Ty-1可以调控TYLCV编码V2（TYLCV-V2）的表达，但调控机制还不明确。本项目拟通过关键位点或终止突变解析Ty-1调控TYLCV侵染对V2的依赖性；通过分析Ty-1，TYLCV-V2和SGS3/RDR6三者亚细胞定位及共定位，酵母双杂交和免疫共沉淀研究三者互作关系，阐明Ty-1调控TYLCV-V2的分子机制；通过超表达，VIGS和转基因Ty-1植株对双生病毒早期及系统侵染的精细观察，通过分析超表达Ty-1对双生病毒V2的调控，揭示Ty-1对双生病毒侵染调控与其对V2调控的相关性。本项目研究结果将为防控双生病毒提供新的理论依据。

Tomato yellow leaf curl virus (TYLCV) is one of the top 10 plant viruses in the world, which causes great loss to global tomato industry. In field, co-infections between TYLCV and other Geminiviruses occurred frequently, which caused greater economic loss. Thus, seeking resistant factors against several Geminiviruses at the seme time is an urgent issue to be addressed in tomato industry, and it seems that Ty-1, one of the TYLCV resistant genes, is a candidate. Previously, we found that the expression level of TYLCV encoded V2, which is a viral suppressor of RNA silencing (VSR), was greatly decreased when co-expression with Ty-1 in Nicotiana benthamiana. On the other hand, V2 VSR activity was also greatly disturbed by Ty-1. We therefore hypothesis that Ty-1 defends against TYLCV by regulating V2, but the regulating mechanisms remain unknown. In this study, confocal microscopy, site mutations, Y2H and Co-IP will be used to analyze the subcellular localization, colocalization and interactions among Ty-1, TYLCV-V2 and SGS3/RDR6, which will clarify the mechanisms of Ty-1 regulating V2. Transient over-expression, VIGS and Ty-1 transgenic plants will be utilized to analyze the impacts of Ty-1 on the infection of Geminiviruses, Ty-1 will be transient co-expressed with V2 derived from several Geminiviruses to analyze the regulations of Ty-1 on Geminiviruses V2. Results from our project will help to understand the molecular mechanisms of Ty-1 regulating V2, which probably will provide new theories and strategies to control Geminiviruses.