烟粉虱诱导番茄吸引寄生蜂活性成分鉴定及植物调控机制研究

Upon herbivore attack, plant can rapidly release complex blends of volatiles that attract natural enemies of the herbivore, and consequently, reduce herbivory damage. This is called indirect plant defense. With the studies on indirect plant defense are accumulating, it has become a promising topic in bio-control filed to identify the effective components of volatile blends and investigate the involved mechanisms. Bemisia tabaci has been recently recognized as an important invasive pest in China. Compared with chemical and physiological methods, biological control of B. tabaci by exploiting the natural enemies of whitefly has more broad perspective in application field. However, until now little is known about the composition of plant volatile blends induced by B. tabaci feeding and the underlying mechanisms. In the present study, we employ B. tabaci, host plant tomato, and parasitoid Encarsia formosa as a model system. By examining insect behavior, plant volatiles, and plant signaling pathway, we will analyze the composition of volatile blends emitted from whitefly-infested tomato, indentify the effective components in attracting parasitoids, and investigate the key signaling pathway involved in mediating volatile emission.

植物受到植食者攻击后会迅速的释放出一些挥发性化合物，通过这类挥发性物质吸引植食者的天敌，达到控制虫害的目的，这一性状称为植物间接防御。随着对植物间接防御的研究深入，明确植物挥发物中的活性成分，探索植物释放挥发物的内在机制，成为农业害虫生物防治领域的研究热点。烟粉虱Bemisia tabaci是近年来快速入侵我国的重要农业害虫。相较于化学和物理防治方法，利用天敌昆虫进行烟粉虱生物防治具有更广阔的应用前景。但是，目前关于烟粉虱诱导植物释放挥发物的化学指纹谱及其内在机制的研究仍是空白。本研究以烟粉虱及其寄主番茄作为研究模式系统，从昆虫行为、植物挥发物变化，植物防御信号路径三方面，综合分析烟粉虱诱导番茄释放挥发物的化学指纹谱，鉴定其中吸引寄生蜂的活性成分，并初步探讨植物体内调控相关挥发物释放的信号路径。

烟粉虱Bemisia tabaci是近年来快速入侵我国的重要农业害虫。相较于化学和物理防治方法，利用天敌昆虫进行烟粉虱生物防治具有更广阔的应用前景。但是，目前关于烟粉虱诱导植物释放挥发物的化学指纹谱及其内在机制的研究仍是空白。本项目结合行为学、化学分析、分子生物学方法，系统的研究了烟粉虱为害番茄后对丽蚜小蜂寄主搜寻行为的影响，并深入研究了烟粉虱诱导番茄释放挥发物吸引天敌的内在机制。我们的试验结果表明，烟粉虱需要以较高的取食密度（100头/株），取食时间超过 5d，虫害植株才能够显著吸引丽蚜小蜂；烟粉虱取食番茄5d后，能够显著诱导番茄释放更多的β-myrcene、ρ-cymene和β-caryophyllene，这些化合物可能是吸引丽蚜小蜂的关键挥发物。利用番茄不同信号突变体及外源激素处理，我们发现烟粉虱诱导番茄释放挥发物是由水杨酸信号路径调控的。本研究结果首次较为全面的证实了水杨酸信号路径在调控植物间接防御中的关键作用，对于利用寄生蜂实现烟粉虱的生物防治具有重要的指导意义。