Dissection of AvrBsT-BST defense pathway in Arabidopsis

拟南芥 AvrBsT-BST 防御途径的剖析

• 批准号: 7283041
• 负责人: Mary Beth MUDGETT
• 金额: $ 25.89万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-30 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7283041
• 关键词: Affect; Animals; Arabidopsis; Bacteria; Bacterial Proteins; Cell Communication; Cells; Cleaved cell; Cysteine Protease; Data; Disease; Disease Resistance; Dissection; Endopeptidases; Family; Genes; Genetic Screening; Goals; Growth; Infection; Maps; Microbe; Molecular; Numbers; Pathogenesis; Pathway interactions; Peptide Hydrolases; Physiology; Plant Physiology; Plants; Post-Translational Protein Processing; Protein Isoforms; Proteins; Proteolysis; Resistance; Role; Signal Transduction; Signal Transduction Pathway; Specificity; Staging; Stress; Symptoms; System; Type III Secretion System Pathway; Ubiquitin; Virulence; Work; Xanthomonas; Xanthomonas campestris; base; defense response; genetic analysis; genetic regulatory protein; insight; mutant; pathogen; response

DESCRIPTION (provided by applicant): This project will further dissect the molecular and cellular basis of Xanthomonas campestris pathovar vesicatoria (Xcv) pathogenesis in plants. This bacterium uses a specialized secretory system to orchestrate cell-to-cell communication during the early stages of plant infection. The type III secretion system (TTSS) enables direct secretion and translocation of bacterial proteins into host plant cells. Once inside the host, TTSS effectors, acting presumably as virulence proteins, collectively modulate the cell to initiate disease symptoms in susceptible plants and to activate defense responses in resistant plants. To date, the mechanisms by which XcvTTSS effectors modulate plant physiology are virtually unknown. However, our work has provided important insights to the potential mechanisms used by the YopJ-like effectors, a family that is prevalent in Xanthomonas and conserved amongst plant and animal bacterial pathogens. Such conservation implies that pathogenic microbes use a specific mechanism to interfere with host cell signaling. We have shown that Xcv effectors in the YopJ and XopD family function as cysteine proteases inside plant and animal cells. The substrates for these effectors are highly conserved small ubiquitin-like modifiers (SUMO) that are covalently added to a number of regulatory proteins. Thus, we predict that YopJ-like effectors exert their pathogenic effect on host cells by disrupting posttranslational SUMO modification of proteins. The overall goal of this study is to identify and study the plant signal transduction pathways that are affected by the YopJ-like effector AvrBsT during Xanthomonas pathogenesis. Specifically, we will: (1) explore the effect of AvrBsT proteolysis on the SUMO pathway in Arabidopsis by isolating SUMOylated plant targets, (2) isolate the Arabidopsis bst disease resistance gene that provides protection against AvrBsT, and (3) use genetic screens to dissect the AvrBsTBST disease resistance signal transduction pathway in Arabidopsis. We believe our findings will reveal common mechanisms used by SUMO proteases conserved in both plant and animal pathogens to control eukaryotic physiology during bacterial-host interactions.

项目描述（申请人提供）：本项目将进一步研究野油菜黄单胞菌水疱致病变种（Xcv）在植物中致病的分子和细胞基础。这种细菌在植物感染的早期阶段使用专门的分泌系统来协调细胞与细胞的通信。III型分泌系统（TTSS）能够将细菌蛋白直接分泌和转运到宿主植物细胞中。一旦进入宿主，TTSS效应物，可能作为毒力蛋白，共同调节细胞，在易感植物中引发疾病症状，并激活抗性植物的防御反应。迄今为止，XcvTTSS效应子调节植物生理的机制几乎是未知的。然而，我们的工作为YopJ样效应子使用的潜在机制提供了重要的见解，YopJ样效应子是一个在黄单胞菌属中普遍存在并在植物和动物细菌病原体中保守的家族。这种保守性意味着病原微生物使用特定的机制来干扰宿主细胞信号传导。我们已经表明，Xcv效应在YopJ和XopD家族的功能作为半胱氨酸蛋白酶内的植物和动物细胞。这些效应物的底物是高度保守的小泛素样修饰物（SUMO），它们共价连接到许多调节蛋白上。因此，我们预测YopJ样效应子通过破坏蛋白质的翻译后SUMO修饰对宿主细胞发挥其致病作用。 本研究的总体目标是鉴定和研究黄单胞菌致病过程中受YopJ样效应子AvrBsT影响的植物信号转导途径。具体而言，我们将：（1）通过分离SUMO化的植物靶标来探索AvrBsT蛋白水解对拟南芥中SUMO途径的影响，（2）分离提供针对AvrBsT的保护的拟南芥bst抗病基因，以及（3）使用遗传筛选来剖析拟南芥中AvrBsTBST抗病信号转导途径。我们相信我们的研究结果将揭示植物和动物病原体中保守的SUMO蛋白酶在细菌与宿主相互作用期间控制真核生物生理学的共同机制。