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

Williams College, Williamstown MA

Investigators

Abstract

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.