Characterization of XopN, a Heat-Repeat TTSS Effector Required for Xanthomonas Pathogenesis in Tomato

该项目旨在确定细菌致病过程中受影响的关键植物过程，为发现控制或消除植物病害的替代方法打开大门。研究人员将使用遗传、生化和细胞生物学方法来确定病原菌如何抑制植物防御以促进定居。拟研究的病害是由野油菜黄单胞菌致病变种泡囊变种(Xcv)引起的番茄细菌性斑点病。XCV已经进化出一种特殊的分泌系统(称为III型分泌系统(TTSS))，在感染过程中将30-35种蛋白质输送到植物细胞中。这个项目的研究目标是确定XopN的生化功能，XopN是一种独特的XCV蛋白，在不同的Xanthomonas物种中高度保守。中心假说是，XopN干扰番茄中的蛋白质-蛋白质相互作用，从而抑制防御激活。本研究的具体目的是：(1)鉴定番茄XCV致病所需的XopN蛋白结构域；(2)鉴定XopN在植物质膜上与XopN结合的蛋白；(3)鉴定和表征XopN在XCV侵染过程中特异调控的植物途径。在此获得的知识将有助于从机理上理解微生物的发病机制，并调节植物的防御途径。更广泛的影响：从长远来看，在此获得的知识将被学术界、工业界和政府用于解决农业生产、疾病预防和根除问题。短期内，研究人员将与加州弗里蒙特的K-12教师和他们的学生合作，介绍这一植物主题。目前，没有教授植物生物学课程。重点将是培训学生和教师有关植物生物学、疾病和农业的知识--强调植物科学的重要性及其对社会的影响。

This project seeks to identify critical plant processes affected during bacterial pathogenesis, opening the door to the discovery of alternative methods to control or eliminate plant disease. The investigators will use genetic, biochemical, and cell biological approaches to determine how pathogenic bacteria suppress plant defenses to promote colonization. The disease that will be studied is bacterial spot disease of tomato caused by Xanthomonas campestris pathovar vesicatoria (Xcv). Xcv has evolved a specialized secretion system (referred to as the type III secretion system (TTSS)) to transport 30-35 proteins into the plant cell during infection. The intellectual goal of this project is to determine the biochemical function of XopN, a unique Xcv protein that is highly conserved amongst different Xanthomonas species. The central hypothesis is that XopN interferes with protein-protein interactions in tomato to suppress defense activation. The specific aims are to: (1) characterize XopN protein domains required for Xcv pathogenesis in tomato; (2) characterize a tomato protein that XopN binds to at the plant plasma membrane; and (3) identify and characterize plant pathways specifically modulated by XopN during Xcv infection. Knowledge gain herein will contribute to the mechanistic understanding of microbial pathogenesis and the regulation of defense pathways in plants. Broader Impacts: In the long-term, knowledge gained herein will be used by academia, industry, and the government to address agricultural production, disease prevention, and eradication. In the short-term, the investigators will work with K-12 teachers in Fremont CA and their students to introduce this plant topic. Currently, a plant biology curriculum is not being taught. Emphasis will be to train students and teachers about plant biology, disease, and agriculture - highlighting the importance of the plant sciences and its impact on society.