扶桑绵粉蚧瓦解寄主植物防御反应的行为及分子机制研究

The mealybug, Phenacoccus solenopsis, has been recently recognized as an aggressively invasive pest in China. However, little is understood about the mechanisms involved in the rapid invasion and eruption of P. solenopsis, especially from the perspectives of its ecological, physiological, and molecular mechanisms co-evolved with host plant. In the present study, we will use P. solenopsis and its two suitable host plants (cotton and tomato) as model systems. And we will integrate electrophysiological, ecological, and molecular biological technologies to investigate 1) the behavioral responses of P. solenopsis when facing with different defensive responses mediated by diverse signal transduction pathways; 2) the effects of infestation by P. solenopsis on kinetic expression of marker genes regulated by jasmonic acid (JA) or salicylic acid (SA), as well as the changes in defensive metabolites; and 3)the intensity of suppression of JA pathway when P. solenopsis feeding on SA-deficient or ethylene-deficient mutant of tomato. Base on these results, we will discuss on the behavioral and molecular mechanism involved in disarming host defense responses by mealybugs. Our expected findings will further exploit the underlying mechanism on the rapid invasion and eruption of mealybugs, and lay the foundation for the biological control of mealybugs in the future.

扶桑绵粉蚧是近年来入侵我国的又一主要农业害虫。但目前尚缺乏从内因，即从扶桑绵粉蚧与寄主植物协同进化所形成的生理、生态和分子机理来充分认识其灾变的机理。本项目将以两种寄主植物棉花和番茄、扶桑绵粉蚧为研究模式系统，综合运用昆虫电生理学、生态学以及分子生物学等多学科的研究技术与分析方法，研究扶桑绵粉蚧应对不同植物防御反应的取食行为电生理信号的变化情况；其取食行为对寄主植物体内的茉莉酸及水杨酸路径不同阶段调控基因及其代谢产物的影响；以及利用番茄突变体，研究当水杨酸或乙烯路径沉默时，扶桑绵粉蚧对茉莉酸防御路径的抑制效果，综合探讨扶桑绵粉蚧瓦解寄主有效防御反应的行为及分子机制。预计所得研究结果不但可以阐明扶桑绵粉蚧快速入侵、繁殖的行为及分子机制，而且还可以对未来制定扶桑绵粉蚧生物防治计划提供科学依据。

扶桑绵粉蚧是近年来入侵我国的又一主要农业害虫。但目前尚缺乏从内因，即从扶桑绵粉蚧与寄主植物协同进化所形成的生理、生态和分子机理来充分认识其灾变的机理。本项目以两种寄主植物棉花和番茄、扶桑绵粉蚧为研究模式系统，综合运用昆虫电生理学、生态学以及分子生物学等多学科的研究技术与分析方法，研究扶桑绵粉蚧应对不同植物防御反应的取食行为电生理信号的变化情况；其取食行为对寄主植物体内的茉莉酸及水杨酸路径不同阶段调控基因及其代谢产物的影响。获得以下研究结果：一、茉莉酸信号路径调控的防御反应在棉花防御扶桑绵粉蚧过程中发挥重要作用，但粉蚧能够通过其取食行为抑制茉莉酸防御反应的发生，包括抑制防御基因的表达和挥发物的释放，进而对其种群发育有利；二、 茉莉酸防御反应同样是番茄防御扶桑绵粉蚧的重要防御反应，茉莉酸防御反应的激活能显著抑制粉蚧若虫在番茄韧皮部的取食效率，进而抑制其发育；利用番茄茉莉酸、水杨酸及乙烯突变体，研究发现粉蚧激活的水杨酸信号路径在其抑制茉莉酸防御反应中发挥关键作用，且水杨酸路径的激活能够促进其个体发育。综合分析后，我们认为，该行为机制可能是扶桑绵粉蚧在我国主要棉花产区快速繁殖、入侵的重要原因之一。