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-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，但对调节病原体识别、信号转导和植物防御激活的机制知之甚少，特别是对于涉及杀死宿主组织以获得植物营养的真菌的相互作用。这些所谓的坏死营养型病原体通过分泌多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的启动以及植物用于激活适当防御的分子和细胞过程。拟南芥BOTRYTIS-INDUCED KINASE 1（BIK 1）在植物对坏死性真菌和细菌病原体的免疫中起着核心作用。BIK 1促进对坏死营养型真菌的抗性，但抑制对活体营养型细菌病原体假单胞菌的强毒株的抗性。有趣的是，BIK 1促进PAMP触发的对细菌和真菌病原体的免疫（PTI）。BIK 1的PTI功能取决于乙烯信号传导和与其他免疫应答调节剂的相互作用。因此，BIK 1在其对植物免疫和激素反应的影响中是普遍的，集中体现了其功能的复杂性。BIK 1的功能多样性和调节作用的分子和生物化学基础尚不清楚。将BIK 1连接到下游免疫反应的下游靶标，这些下游免疫反应有助于其对比抗性功能，但尚未得到充分研究。该项目以BIK 1为重点，旨在剖析植物免疫反应信号传导的分子机制。首先，将研究下游传播信号的BIK 1靶点与BIK 1和其他植物免疫调节剂相关的功能机制。BIK 1及其相互作用伙伴之间的调节关系将通过遗传，分子和生物化学方法进行研究。目标是确定BIK 1、其相互作用伴侣和免疫应答信号传导层级中更下游的其他靶标之间的生物化学和功能联系。其次，将研究BIK 1与PTI和效应触发免疫（ETI）的其他调节剂之间的生物化学和分子相互作用，以确定BIK 1在ETI-PTI界面的作用。BIK 1和受体样激酶介导的反应，坏死营养真菌的关系将进行调查。该项目将为不同背景的学生和博士后科学家提供培训，以促进多样化的科学工作队伍。此外，坏死营养型真菌是广泛分布的病原体，对作物生产具有巨大的影响。坏死营养型病原菌的致病策略和相应的植物免疫反应与活体营养型病原菌有很大的不同。该项目将通过产生关于控制植物免疫的调节蛋白和机制的基础知识，为更智能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.