Untangling the Complex Network of BIK1 Mediated Immune Response Signaling Pathways

植物病原体对全球作物生产构成持续威胁。扩大植物与病原体相互作用机制的基础知识的研究将最终有助于设计更好的疾病控制策略。尽管进行了广泛的研究，但调节病原体识别、信号转导和植物防御激活的机制尚不清楚，特别是涉及真菌杀死宿主组织以获得植物营养物质的相互作用。这些所谓的坏死性病原体通过分泌各种疾病促进因子来促进其植物宿主的破坏。该项目的目标是确定植物如何识别感染被启动，以及植物采用的分子和细胞过程来激活适当的防御。该项目还将为学生和博士后科学家提供培训。拟南芥botrytis诱导的KINASE1 （BIK1）在植物对坏死性真菌和细菌病原体的免疫中起核心作用。BIK1促进对坏死性真菌的抗性，但抑制对生物营养细菌病原体丁香假单胞菌的毒力菌株的抗性。有趣的是，BIK1促进PAMP触发免疫（PTI）对细菌和真菌病原体。BIK1的PTI功能取决于乙烯信号和与其他免疫反应调节因子的相互作用。因此，BIK1对植物免疫和激素反应的影响是普遍存在的，体现了其功能的复杂性。目前还不清楚BIK1的多功能性和调控作用的分子和生化基础。连接BIK1与下游免疫反应的下游靶点，有助于其对比抗性功能，尚未得到很好的研究。本项目以BIK1为重点，旨在剖析植物免疫应答信号转导的分子机制。首先，我们将研究BIK1向下游传播信号的靶点与BIK1和其他植物免疫调节因子的作用机制。BIK1及其相互作用伙伴之间的调控关系将通过遗传学，分子和生化方法进行研究。目的是确定BIK1及其相互作用伙伴和免疫应答信号传导层次中下游其他靶标之间的生化和功能联系。其次，将研究BIK1与其他PTI调控因子和效应触发免疫（effector triggered immunity， ETI）之间的生化和分子相互作用，以确定BIK1在ETI-PTI界面上的作用。BIK1和受体样激酶介导对坏死性真菌的反应的关系将被研究。该项目将为不同背景的学生和博士后科学家提供培训，为多样化的科学队伍做出贡献。此外，坏死性真菌是一种广泛存在的病原体，对作物生产产生了巨大的影响。坏死性致病菌的毒力策略和相应的植物免疫反应与生物营养致病菌有显著差异。该项目将产生有关调控蛋白和控制植物免疫机制的基本知识，从而为更聪明的遗传抗性策略铺平道路。

Plant pathogens pose continued threat to global crop production. Studies that expand fundamental knowledge on mechanisms of plant-pathogen interaction will ultimately help design better disease control strategies. Despite extensive studies, mechanisms regulating pathogen recognition, signal transduction and activation of plant defenses are poorly understood, particularly for interactions involving fungi that kill host tissue in order to gain access to a plant's nutrients. These so-called necrotrophic pathogens promote the destruction of their plant hosts by secreting a variety of disease promoting factors. The goal of this project is to determine how plants recognize that an infection was initiated and the molecular and cellular processes plants employ to activate appropriate defenses. This project will also provide training for students and postdoctoral scientists.Arabidopsis BOTRYTIS-INDUCED KINASE1 (BIK1) plays a central role in plant immunity to necrotrophic fungi and bacterial pathogens. BIK1 promotes resistance to necrotrophic fungi but suppresses resistance to virulent strains of the biotrophic bacterial pathogen Pseudomonas syringae. Intriguingly, BIK1 promotes PAMP triggered immunity (PTI) to bacterial and fungal pathogens. The PTI function of BIK1 hinges upon ethylene signaling and interactions with other immune response regulators. Thus, BIK1 is pervasive in its impact on plant immune and hormone responses, epitomizing the complexity of its functions. The molecular and biochemical bases of BIK1's functional versatility and regulatory role are not understood. The downstream targets that connect BIK1 to downstream immune responses that contribute to its contrasting resistance functions are not well studied. By taking BIK1 as a focal point, the project aims to dissect the molecular mechanisms of plant immune response signaling. First, targets of BIK1 that propagate signals downstream will be studied for their mechanisms of function in relation to BIK1 and other regulators of plant immunity. The regulatory relationship between BIK1 and its interacting partners will be studied through genetic, molecular and biochemical approaches. The goal is to determine biochemical and functional linkage between BIK1, its interacting partners and other targets further downstream in the immune response signaling hierarchy. Second, the biochemical and molecular interactions between BIK1 and other regulators of PTI and effector triggered immunity (ETI) will be studied to determine the role of BIK1 at the ETI-PTI interface. The relationship of BIK1 and receptor like kinases mediating responses to necrotrophic fungi will be investigated. This project will provide training to students and post-doctoral scientists of different backgrounds to contribute to a diverse scientific workforce. In addition, necrotrophic fungi are widespread pathogens with tremendous impacts on crop production. Virulence strategies of necrotrophs and the corresponding plant immune responses show significant differences from biotrophic pathogens. The project will pave the way for smarter genetic resistance strategies by generating fundamental knowledge on regulatory proteins and mechanisms that control plant immunity.