Higher organisms have developed effective mechanisms to protect themselves against microbial infection. Host defense responses must be tightly regulated: if hosts are unable to induce defenses, microbes take hold of them. If responses are continuously activated, host cells divert valuable resources from growth to defense resulting in host growth penalty. Some eukaryotic cells use ligand-induced endocytosis as a means for down-regulating receptor concentration from the cell surface to desensitize cells to stimuli and attenuate signaling responses. In this project, the investigator uses the FLS2/flagellin system to delineate roles of endocytosis in regulating immunity against bacteria. FLAGELLIN SENSITIVE 2 (FLS2) is the plant cell surface receptor that perceives bacterial flagellin to initiate defense signaling. FLS2 is the only plant immune receptor known to undergo ligand-induced endocytosis. Roles of FLS2 endocytosis in regulating responses and immunity, however, remain unknown. The investigator has identified the vesicular trafficking proteins Dynamin-Related Protein DRP2A and DRP2B as novel positive regulators of basal resistance against the bacteria Pseudomonas syringae. In this project, the investigator uses a combination of biochemical, live-cell imaging, proteomics, pathology and genetics approaches to address roles of DRP2s in regulating defense signaling, FLS2 endocytosis and immunity against bacteria.
In addition to enhancing the knowledge of DRP2 functions in cellular processes, this project could lead to novel strategies for enhancing innate immunity in plants and contributing to improved food, fiber, and biofuel production. The project also provides training opportunities for a postdoctoral researcher, graduate and undergraduate students. Furthermore, the investigator's group participates in outreach efforts by developing and presenting hands-on biological experiments to K-5 elementary school students. Undergraduate and elementary students will learn to gather, analyze, and interpret data. Society will profit from scientifically literate citizens with intellectual background crucial in making educated decisions about applications for science in their everyday lives.
