Insect Espionage: Molecular Mechanisms of Caterpillar Subversion of Host Plant Defenses

尽管大量使用农业杀虫剂，但由于昆虫食草性疾病造成的全球农作物损失超过13%。在加拿大，产量损失预计会随着全球变暖的进展而恶化，因为预计将建立新的迁徙害虫物种，再加上由于夏季较长和冬季较暖和而虫害死亡率较低，世代较多，虫害增加。因此，在预测的未来气候条件下，虫害压力将增加，并进一步挑战农业系统。植物有内源性的物理和化学手段来保护自己免受毛虫食草性疾病的侵袭，然而，昆虫食草动物也有策略来对抗这些植物防御。我们的研究计划侧重于了解这些复杂的植物-昆虫相互作用背后的机制，目标是制定策略，最大限度地提高内源植物的防御能力，同时最大限度地减少毛虫的欺骗行为，从而在不断变化的气候条件下实现可持续的害虫管理。这个研究计划的一个主要主题是了解植物如何调节对毛虫食草性反应诱导的防御途径，以及毛虫唾液效应器如何激活相反的植物激素调节途径来削弱植物发起有效防御反应的能力。翻译后修饰(PTM)是一种动态而强大的细胞调节机制，可以改变蛋白质的活性(活性、定位、调节、蛋白质-蛋白质相互作用、稳定性)。我们之前已经确定了植物蛋白是根据毛毛虫唾液中分泌的效应物进行修饰的。在此基础上，我们提出，一些夜蛾通过唾液，通过关键调节蛋白的PTM改变植物信号通路，抑制植物防御反应的诱导。这项研究将导致可持续的农业实践，并通过以下方式加强加拿大的农业生物技术产业：1)进一步了解植物对毛虫食草性疾病的防御机制；2)了解昆虫抑制植物防御诱导的策略，以开发在害虫管理中操纵昆虫表现的策略。该项目的资金将用于培训研究生(2.5名博士，1名硕士)、本科生(2年制)和一名兼职研究助理，培训领域涉及加拿大具有高就业潜力的领域，如分子生物技术、植物和昆虫生物化学和生理学。这样的背景和培训对包括农业生物技术在内的加拿大工业至关重要。

Despite heavy agricultural pesticide use, global crop losses due to insect herbivory exceed 13%. In Canada, yield losses are expected worsen as global warming progresses as new migrant insect pest species are predicted to become established coupled with increases in pest infestations due to more generations because of longer summers and lower pest mortality due to milder winters. Therefore, under predicted future climatic conditions, insect pest pressure will increase and further challenge agricultural systems. Plants have endogenous physical and chemical means to protect themselves against caterpillar herbivory, however, insect herbivores also have strategies to counteract these plant defenses. Our research program focuses on understanding the mechanisms underlying these complex plant-insect interactions with the goal of defining strategies to maximize endogenous plant defenses while minimizing caterpillar subterfuge to lead to sustainable pest management practices under changing climatic conditions. A main theme of this research program is to understand how plants regulate defensive pathways induced in response to caterpillar herbivory and how caterpillar salivary effectors activate opposing plant hormone-regulated pathways to weaken the plant's ability to mount an effective defense response. Post-translational modification (PTM) is a dynamic and powerful cellular regulatory mechanism to alter protein activity (activity, localization, regulation, protein-protein interactions, stability). We have previously identified plant proteins that are modified in response to effectors secreted in the caterpillar's saliva. Based on this, we propose that, through their saliva, some noctuid caterpillar pests alter plant signaling pathways through the PTM of key regulatory proteins and dampen the induction of plant defense responses. This research will lead to sustainable agricultural practices and strengthen Canada's agricultural biotechnology industries by 1) furthering our understanding of the regulation of plant defenses against caterpillar herbivory 2) understanding insect strategies of suppressing the induction of plant defenses to develop strategies to manipulate insect performance in pest management. Funding for this project will support the training of graduate students (2.5 PhD, 1 MSc), undergraduates (2/yr) and a part-time research assistant in areas of high employment potential in Canada, such as molecular biotechnology and plant and insect biochemistry and physiology. Such background and training is vital for Canadian industries including agricultural biotechnology.