Collaborative Research: Revealing the vast diversity within the legume-rhizobia mutualism

University Of North Carolina Greensboro, Greensboro NC

Investigators

Abstract

This project will examine partnerships between plants in the bean and pea family (legumes) and bacteria that live within their roots. Rhizobial bacteria take nitrogen from the air and turn it into a form that makes it available to plants. Nitrogen is a fundamental element for life on Earth. Legumes provide most of the natural inputs of nitrogen into soil because of their beneficial relationship with rhizobial bacteria. Because of this, legumes are important plants in agriculture as both a food source and a way to naturally fertilize soils. Although the legume plant family has many species, for many of these species, there is no information about their partnerships with rhizobial bacteria. This project will look at the diversity of partnerships between legumes and rhizobial bacteria to solve whether legume species can have few or many bacterial types living within their roots. This research is important for sustainable agriculture and the bioeconomy. The project will also provide training to students underrepresented in STEM. As a team of community and ecosystem ecologists, the researchers will assess the diversity of compatible rhizobial strains associated with a wide variety of legume species that naturally occur in the tallgrass prairie ecosystem of the United States. The identities of rhizobial strains nodulating with each legume species will be determined in a two-stage process. First, a subset of rhizobial strains will be collected from legume roots, cultured, and whole genome sequences obtained. These strains will then be tested in a greenhouse assay to determine the ability of each legume species to form associations with each rhizobial strain. In addition to assessing the rhizobial diversity associated with each legume species tested, the researchers will identify genetic markers that can be used to identify rhizobial diversity in future. This information will directly improve ecosystem theory on the drivers of nitrogen fixation, eco-evolutionary theory on the maintenance of mutualisms, and community theory on coexistence and the relationship between biodiversity and ecosystem function. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.