Mississippi State University
Date of Degree
Graduate Thesis - Open Access
Department of Biological Sciences
The legume-rhizobia relationship is an important symbiosis. Studies have found variation in specificity and the functionality of symbiotic specificity can vary among plants of the same species and among rhizobia, as well as in concert with geographical variation. Here, we examined the diversity and geographic structure of rhizobia nodulating Chamaecrista fasciculata, which grows throughout the east-central U.S. and is symbiotic with Bradyrhizobium species. We investigated the association of geography and soil variables on rhizobial diversity by sampling plant nodules and soil across Mississippi and evaluated variation in rhizobia housed in different nodules of individual plants. Using nifH and truA, we conducted phylogenetic analyses and mantel tests but did not find that geography correlates with genetic diversity. However, soil variables and genetic distance were significantly correlated. Lastly, we found that rhizobia across nodules of the same plant varied substantially. These results contribute to the knowledge of rhizobial assemblages in natural populations.
Dorman, Hanna Elizabeth, "Genetic Structure of Rhizobia Associated with Chamaecrista Fasciulata" (2015). Theses and Dissertations. 2398.