Adaptation of insect herbivores to plant defense: Genome-wide transcriptional responses of the lepidopteran midgut to changes in plant defense chemistry

高等植物产生无数的蛋白质和专门的代谢物，针对昆虫消化生理的各个方面。与我们对这些宿主防御机制的了解相反，我们对昆虫克服植物防御的策略知之甚少。这项建议的主要目标是采用现代测序和转录谱分析技术来研究昆虫食草动物通过重新配置中肠生理来适应叶化学变化的假设。本项目的具体目标是：（i）对鳞翅目通性粉纹夜蛾Trichoplusia ni的中肠转录组进行深度测序，并利用这些序列信息设计一个全面的中肠表达的T. ni基因;（ii）使用该微阵列平台鉴定T. ni幼虫在不同寄主植物上生长; ni基因，这些基因在拟南芥和番茄中响应于基于茉莉酸的防御系统而差异表达;以及（iv）鉴定T.这些基因响应于单个植物防御化合物而差异表达。从这些实验的结果将提供一个前所未有的，全基因组的观点，昆虫中肠生理学是如何调制在响应寄主植物化学变化，并将建立一个基础，为未来的功能分析的基因和信号事件，控制昆虫适应植物防御化合物。由于依赖于“内置”植物防御的害虫控制策略通常受到昆虫有效适应这些化合物的能力的限制，因此鉴定由叶片化学变化触发的昆虫基因可能有助于发现害虫控制的新方法。

Higher plants produce myriad proteins and specialized metabolites that target various aspects of insect digestive physiology. In contrast to our knowledge about these host defense mechanisms, relatively little is known about the strategies employed by insects to overcome plant defenses. The major objective of this proposal is to employ modern sequencing and transcriptional profiling technologies to investigate the hypothesis that insect herbivores adapt to changes in leaf chemistry by reconfiguring their midgut physiology. The specific aims of the project are: (i) to perform deep sequencing of the midgut transcriptome of the lepidopteran generalist Trichoplusia ni, and to use this sequence information to design a comprehensive microarray of midgutexpressed T. ni genes; (ii) to use this microarray platform to identify global changes in the midgut transcriptome of T. ni larvae reared on diverse host plants; (iii) to identify T. ni genes that are differentially expressed in response to the jasmonate-based defense system in Arabidopsis thaliana and Solanum lycopersicum; and (iv) to identify T. ni genes that are differentially expressed in response to individual plant defense compounds. Results from these experiments will provide an unprecedented, genome-wide view of how insect midgut physiology is modulated in response to changes in host plant chemistry, and will establish a foundation for future functional analyses of genes and signaling events that control insect adaptation to plant defense compounds. Because pest control strategies that rely on “built-in” plant defenses are often limited by the ability of insects to effectively adapt to these compounds, the identification of insect genes that are triggered by changes in leaf chemistry may facilitate the discovery of novel approaches for pest control.