The pathogenic bacterium Ralstonia solanacearum is very successful in the vascular tissue of its plant hosts even though this habitat contains few nutrients and little oxygen. This project's central hypothesis is that R. solanacearum uses inorganic nitrogen, one of the few abundant nutrients in plant sap, not just for food but also to generate energy and to sense and manipulate plant defenses. The investigators will use genetic and biochemical experiments to identify the specific adaptations that allow this pathogen to use inorganic nitrogen in multiple ways as it causes plant disease. Expected results include a better understanding of how R. solanacearum grows at low oxygen levels and a definition of the role(s) in virulence of nitric oxide, a common biological signal molecule that also has antimicrobial properties. R. solanacearum is a widely distributed pathogen with many hosts, so these results are likely to be relevant to diverse plant-associated microbes. Plant vascular systems are home to many microbes, ranging from destructive pathogens like R. solanacearum to valuable mutualists that can increase plant stress tolerance or growth.
This project will generate basic biological knowledge about the biochemical mechanisms used by plant-inhabiting microbes. In addition, this project will contribute to the nation's scientific workforce by training a postdoctoral researcher and a doctoral student in laboratory research, teaching and mentoring, which are all key skills for future faculty. Three undergraduate students will also receive independent research experiences in microbiology.
