番茄黄化曲叶病毒协同烟粉虱传播番茄褪绿病毒的效应与机制

Insect vectors can always play a key role in the expansion of many plant diseases. In recent years, epidemics of Tomato chlorosis virus in many regions of China inland could be attributed to the outbreaks of its vector Bemisia tabaci. The cases of mixed infection of ToCV and Tomato yellow leaf curl virus (TYLCV) in tomato plants was detected by field investigation. The previous studies also found that bringing TYLCV could obviously improve the acquisition ability of B. tabaci for ToCV. However, the influence on the B. tabaci transmission of ToCV brought by TYLCV and the mechanism still remain unknown. This study focus on the above questions, using behavior, physiology, biochemistry and molecular biology technologies to conduct the following researches: 1) Assess the effect on the transmission ability of B. tabaci Q brought by TYLCV, and further clarify the feeding behavior; 2) Examine the host adaptability change of B. tabaci Q caused by the mixed infection of TYLCV and ToCV; 3) Reveal the physiological response of both plant and B. tabaci Q to the mixed infection of two virus through chromatography, determination of enzyme activity and real-time quantity PCR. The results will increase our knowledge about B. tabaci transmission characteristics of ToCV, facilitate our exploration of the interaction mechanism of plant virus-plant-insect. Furthermore, this study also will provide basic information for the scientific prevention of multiple plant virus and effective management of vector insects.

媒介昆虫在许多植物病害的蔓延过程中起到关键作用。近年来番茄褪绿病毒（ToCV）在中国内陆的暴发成灾与其传播媒介烟粉虱具有直接联系。田间调查发现发病地区番茄存在ToCV与番茄黄化曲叶病毒（TYLCV）复合侵染现象，并且前期研究发现Q烟粉虱携带TYLCV明显促进了其对ToCV的获取。本项目围绕“TYLCV协同烟粉虱传播ToCV的效应与机制”这一科学问题，明确TYLCV对Q烟粉虱传播ToCV能力的影响，进一步通过刺吸电位技术研究其取食行为机制；解析TYLCV和ToCV复合侵染对Q烟粉虱寄主适应性的影响；利用色谱、酶活性测定、实时荧光定量等技术揭示植物和Q烟粉虱应对TYLCV和ToCV复合侵染的内在生理响应机理。研究结果将增强对于烟粉虱传播新入侵病毒ToCV特性的认识，深化对植物病毒-植物-昆虫三者互作机理的探索，为新形势下开展多病毒流行的科学防控和媒介昆虫的有效治理提供理论依据。

媒介昆虫在许多植物病害的蔓延过程中起到关键作用。近年来番茄褪绿病毒（ToCV）在中国内陆的暴发成灾与其传播媒介烟粉虱具有直接联系，并且田间发病地区普遍存在ToCV与番茄黄化曲叶病毒（TYLCV）复合侵染现象。本项目围绕“TYLCV协同烟粉虱传播ToCV的效应与机制”这一科学问题，综合运用行为学、生理生化及分子生物学技术展开了系列研究。主要研究结果如下：（1）构建了ToCV的实时荧光定量PCR检测技术体系，实现了植物、单头媒介昆虫体内ToCV的高灵敏度、准确检测。（2）TYLCV在一定程度上提高了Q烟粉虱传播ToCV的效率；TYLCV&ToCV复合侵染和ToCV侵染均能通过直接和间接方式对Q烟粉虱的取食行为进行修饰，并且二者在韧皮部和非韧皮阶段多个参数均存在显著差异。（3）Q烟粉虱取食TYLCV&ToCV复合侵染和ToCV侵染番茄植株后，存活率均显著下降，但二者差异不明显；而取食TYLCV&ToCV复合侵染植株Q烟粉虱的产卵量显著低于取食ToCV侵染植株。（4）TYLCV&ToCV复合侵染番茄植株体内水解氨基酸总含量、14种氨基酸比例以及总糖含量均显著低于ToCV侵染植株；TYLCV&ToCV复合侵染和ToCV侵染均能显著抑制番茄JA信号通路关键基因FAD7和PI II的表达量，且TYLCV&ToCV复合侵染对番茄JA信号通路的抑制作用显著强于ToCV侵染；两种侵染方式对SA信号通路关键基因NPR1和PR1的表达具有一定的诱导作用，但诱导程度不同。（5）取食TYLCV&ToCV复合侵染和ToCV侵染番茄植株后，Q烟粉虱体内海藻糖含量显著降低，前者略低于者；取食TYLCV&ToCV复合侵染植株的Q烟粉虱体内海藻糖酶活性和海藻糖酶基因表达水平均明显低于取食ToCV侵染植株；取食TYLCV&ToCV复合侵染番茄植株后，Q烟粉虱P450s活性显著低于取食ToCV侵染植株，而CarEs活性相反。（6）取食TYLCV&ToCV复合侵染和ToCV侵染植株后Q烟粉虱体内分别有60和221个基因的表达水平发生显著变化；二者在解毒、胁迫响应、转运和能量代谢等类别基因表达模式存在显著差异。本项目研究结果丰富了植物病毒-昆虫-植物的互作理论体系，为进一步探索病毒复合侵染条件下烟粉虱的传毒机制奠定基础，为实现虫媒植物病毒的有效阻隔防控提供科学指导。