Seminars – Center for Microbial Dynamics and Infection

Current schedule here. This trainee-run seminar series focused on new research in CMDI. It’s Fridays at 3pm and includes coffee and cookies. Most seminars are in College of Computing 017 for Spring 2025.

Upcoming seminar:

Abstract:

Cable bacteria are sulfide-oxidizing bacteria that spatially separate sulfide and oxygen by long-distance electron transfer. They often live in the rhizosphere of aquatic plants, where they perform electrogenic sulfide oxidation and protect the plants from toxic sulfide. Recently, cable bacteria were investigated at established transects in a saltmarsh on Sapelo Island, GA, USA, where the cordgrass Spartina alterniflora dominates the ecosystem. Across the transects, Spartina biomass declines with distance from tidal creeks in parallel with geochemical gradients that indicate plant stress (porewater anoxia, dissolved sulfide, and salinity). We hypothesized that sulfide and oxygen concentrations are the main selective forces controlling the distribution of cable bacteria and expected to find different species with niche differentiations associated with the contrasting rhizospheres of the tall vs. short Spartina. Initial results showed that cable bacteria are more abundant in the short Spartina rhizosphere, while the tall Spartina rhizosphere seems to select for species with a c-type cytochrome oxidase complex (COX). This suggests that oxygen availability selects for cable bacteria with COX, while abundance is determined by sulfide concentration. Metagenome-assembled genomes (MAGs) from both types of sediment corroborate this hypothesis, as the only MAG containing COX genes was retrieved from tall Spartina sediment. Further studies along the Spartina biomass/redox-gradient will improve our understanding of cable bacteria adaptation to contrasting environmental conditions.