Molecular basis underlying type III effector evolution: discovering the recognition specificity of the diversified HopZ1 alleles in Pseudomonas syringae

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”病原体和宿主正在进行一场无休止的致命战争。III型分泌系统（T3SS）和分泌效应物（T3SEs）是革兰氏阴性细菌病原体必不可少的毒力因子，其中一些是造成植物和动物最具破坏性疾病的原因。在与细菌病原体的军备竞赛中，植物进化出了抗性(R)基因来检测特定的病原体t3se并诱导防御反应。然而，这种免疫可以通过效应序列的变化被病原体有效地击败。该项目旨在为病原体中关键毒力因子和相应宿主防御策略之间高度动态的共同进化军备竞赛的机制提供重要见解。研究重点是广泛分布于模式植物病原体丁香假单胞菌T3SE家族的HopZ1。当类似祖先的HopZ1等位基因触发植物防御反应时，序列多样化允许进化的等位基因逃避宿主检测，同时保留毒力功能。研究人员将采用遗传筛选和生化分析来比较HopZ1等位基因变异的宿主蛋白相互作用谱，并确定参与军备竞赛的重要植物参与者，以努力理解序列多样化激活的效应进化。从这项研究中获得的新知识将有助于开发可持续的方法来控制细菌疾病和提高食品安全。该项目将对教育、推广和科学研究产生广泛影响。它将为本科生、研究生和博士后研究人员提供全面的培训和教育活动，特别是对少数民族和第一代大学生。本项目产生的新知识将以期刊文章、会议论文集和网站发布的形式及时传播给科学界，并通过研究者对本科生和研究生的教学活动传播给广泛的受众。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Pathogens and hosts are engaged in an endless and deadly warfare. Type III secretion system (T3SS) and secreted effectors (T3SEs) are essential virulence factors of gram negative bacterial pathogens, some of which are responsible for the most devastating diseases of plants and animals. During the arms race with bacterial pathogens, plants have evolved resistance (R) genes to detect specific pathogen T3SEs and induce defense responses. However, this immunity can be efficiently defeated by the pathogen through effector sequence variation. This project seeks to offer important insights into the mechanisms underlying the highly dynamic co-evolutionary arms races between key virulence factors in pathogens and the corresponding host defense strategies. The research will focus on HopZ1, a widely distributed T3SE family of the model plant pathogen Pseudomonas syringae. While the ancestor-like HopZ1 allele triggers plant defense response, sequence diversification has allowed evolved alleles to evade host detection while retaining virulence functions. The investigators will employ genetic screens and biochemical analyses to compare the host protein interaction spectrums of HopZ1 allelic variants and identify important plant players involved in the arms race in an effort to understand sequence diversification-enabled effector evolution. Novel knowledge obtained from this research will contribute to the development of sustainable means to control bacterial diseases and improve food safety. This project will have broad impacts on education, outreach and scientific research. It will offer comprehensive training and educational activities for undergraduates, graduate and postdoctoral researchers, especially for underrepresented minority groups and first-generation college students. Novel knowledge generated from this project will be disseminated in a timely manner to the scientific community in the forms of journal articles, conference proceedings and website postings, and also to a broad audience through teaching activities of the investigator to undergraduate and graduate students.