CAREER: The molecular basis of abortive symbiosis

Brigham Young University, Provo UT

Investigators

Abstract

The overall goal of this work is to identify molecular mechanisms that determine whether a given bacterial strain will be harmful or beneficial to the organism in which it lives. Rhizobia are soil bacteria that are known to greatly benefit plants in the legume family by providing them with nitrogen-rich nutrients. Rhizobia are of great agricultural importance, since they dramatically reduce the need for synthetic fertilizers on legume crops such as soybean and alfalfa. This project investgates naturally occurring strains of rhizobia that behave like pathogens on some legume species, and like beneficial symbionts on others. This variation in outcome is dictated by a limited set of genes that have been detected but not fully sequenced. These genes define an important but mysterious biological process that determines whether rhizobia will harm or help the plants that harbor them. The investigators are using molecular-level analysis to define the precise biochemical process that is governed by these genes. The research goals are integrated with an educational plan that will allow undergraduate and high school students to participate in the discovery of more of these outcome-determining genes, through a combination of outdoor collection activities and laboratory-based molecular analysis of bacterial isolates. The project will support the training of high school, undergraduate, graduate, and postdoctoral students and will inform directly the development of more effective strategies for using rhizobia to enhance crop productivity. At a more fundamental level, it will result in a clearer understanding of how closely related bacteria may have radically different effects on the plants or animals in which they reside.