RUI: Characterization of Arabidopsis Defense Responses to the Agrobacterium tumefaciens Type VI Secretion System

植物细菌性病原体可造成粮食生产力的重大损失，从而对农业构成严重威胁。植物免疫系统研究的一个目标是了解植物如何自然地识别和保护自己免受致病菌的侵害，从而有可能将有效的抗病途径引入易感植物。虽然某些细菌识别系统已在植物中广泛表征，但并非所有植物都具有感知所有微生物病原体所需的成分；某些细菌已经进化到至少在某些植物的监视机制的“雷达之下”。该项目最近发现，农杆菌（Agrobacterium tumefaciens）的一个鲜为人知的特征——“6型分泌系统”（Type 6 secretsystem, T6SS）可以激活植物的防御系统，该项目将使用生化和遗传方法来研究植物如何检测细菌上的T6SS，以及植物在感知到T6SS后如何做出反应。这些研究将阐明植物用来抵御细菌的一种以前未知的保护策略。由于许多细菌具有T6SS，引入T6SS特异性识别系统可以增强植物对细菌性疾病的抗性，减少与通常用于控制田间细菌感染的化学农药相关的不利生态和健康影响。该项目充分整合了研究和教育，因为实验将主要由本科生进行，并由一名博士后提供连续性。通过PI教授的独立研究和长达一个学期的调查项目，40多名本科生将有机会为植物免疫系统的前沿研究做出贡献。本项目以植物抗病性为范例，培养学生的批判性思维能力，培养他们在实验设计中的独立性，无论他们是否从事研究工作，这都将使学生受益。

Bacterial pathogens of plants can pose a serious agricultural threat by causing substantial losses in food productivity. One goal of research into plant immune systems is to understand how plants naturally recognize and defend themselves against pathogenic bacteria, with the possibility of introducing effective disease resistance pathways into susceptible plants. Although certain bacteria-recognition systems have been extensively characterized in plants, not all plants have the components necessary to sense all microbial pathogens; certain bacteria have evolved to stay "below the radar" of at least some of the plant's surveillance mechanisms. Having recently discovered that a little-studied feature of the pathogenic bacterium Agrobacterium tumefaciens, the "Type 6 Secretion System" (T6SS), activates plant defenses, the project will use biochemical and genetic approaches to investigate how the plant detects the T6SS on the bacterium, and how the plant responds once it has perceived the T6SS. These studies will elucidate a previously unknown protection strategy used by plants to defend themselves against bacteria. Since many bacteria have a T6SS, introducing a T6SS-specific recognition system could conceivably enhance the resistance of plants to bacterial diseases, with fewer of the adverse ecological and health effects associated with the chemical pesticides typically used to control bacterial infection in the field. The project fully integrates research and education, in that the experiments will be performed primarily by undergraduate students, with one post-doctoral fellow providing continuity. Through independent research and investigative semester-long projects in courses taught by the PI, more than 40 undergraduates will have the opportunity to contribute to cutting-edge research on the plant immune system. This project uses the paradigm of plant disease resistance to inculcate critical thinking skills and foster independence in experimental design that will benefit students, whether or not they pursue a career in research.