A proposal for Georgia Gwinnett College faculty-mentored undergraduate student research on the microbial ecology of the Kudzu (Pueraria spp.)-rhizobia symbiotic relationship.

James Russell, Lee Kurtz

Abstract:

The goal of the proposed research is to engage undergraduate students in active learning with a tractable, comprehensive, and long-term research project that utilizes a locally abundant biological resource- the microbial ecosystem associated with the invasive plant species, Kudzu (Pueraria spp.). Kudzu belongs to the pea family (Fabaceae) of plants and is considered highly invasive in the southeastern United States. The spread of Kudzu through the eastern United States has been facilitated by microbial symbioses between Kudzu roots and soil bacteria called rhizobia. Rhizobia are soil-dwelling bacteria characterized by their ability to form beneficial nitrogen-fixing intracellular infections in plants (mainly in the family Fabaceae). Nitrogen is an essential element for plant growth. The bacterial population from which rhizobia are sampled consists of a wide range of symbionts- cooperative, commensal, parasitic, and pathogenic; including so-called “cheater” rhizobia that acquire nutrients from host plants yet fail to fix nitrogen.

The proposed undergraduate research into the Kudzu-rhizobia interaction would allow students with interests in ecology, microbiology, botany, and molecular biology to participate in directed field and lab-based learning experiences. Kudzu is a well-documented invasive species with available historical records. Most students will have some lifetime experience with Kudzu and have interest in the research subject. The rhizobia-plant symbiosis is considered a model system for the scientific study of symbiotic mutualism. Students engaged in the proposed research would have the benefit of working with excellent biological models for both microbial symbiosis and invasive species. Research and educational experience will extend into the fields of agriculture, conservation biology, soil science, genomics, and bioinformatics. Students would participate in field collection of microbial samples, microbiological laboratory techniques, genomic analysis, population genetic analysis, hypothesis-driven experimental research, and ecological impact studies. The long-term future for research would include the impact of rhizobia diversity on the spread of Kudzu, the influence of Kudzu invasiveness on the soil microbial community, effects on native plant populations, and the population genetics of both Kudzu (host) and rhizobia (symbiont).