Dedman College of Humanities and Sciences Dedman College Research Earth Sciences Faculty News

Nature Portfolio highlights research by Earth Sciences professor, Alexander Chase

Nature Portfolio – Chemical Communication Drive Microbial Community Structure

Microbial communities are assemblages organized by various ecological and evolutionary processes that contribute to the different types and number of species across environments. At broad biogeographic patterns, certain microbial taxa are largely associated with particular environments (e.g., Cyanobacteria in marine systems) due to conserved phylogenetic traits. Just as certain plant species live in tropical forests vs. temperate forests, microbial taxa disperse and differentially establish in environments afforded by their physiological traits, which are evolutionary constrained. While neutral processes like dispersal may contribute at these large spatial scales, microbial communities are largely composed of a subset of the regional species pool that have passed through environmental filtering due to adaptive differentiation of various abiotic factors. At smaller spatial scales at the local community, ecological theory predicts that biotic filters, such as predation, competition, and species interactions, further reduce these species pools resulting in the observed community. In our paper published in The ISME Journal (link), we examine the effects of these biotic interactions, as measured through the production of specialized metabolites, and their influence on microbial community structure in marine sediments (pictured above is co-author Dr. Alyssa Demko, currently a postdoc at the Smithsonian Institute, deploying our gridded plots for sample collection in Mo’orea, French Polynesia).

In these marine environments, chemistry is the language of choice for microbes. All organisms, including microbes, produce chemical compounds to interact with the environment. These may be for internal signaling, environmental responses, resource acquisition, or for antagonistic interactions like antibiotic production. In microbiomes, these metabolites perform a variety of ecological roles, with many mediating species interactions. Thus, they are classified as biotic filtering in classical ecological theory. However, we know little about the production of these metabolites in natural communities, their concentrations in natural systems, or even the roles most of these molecules perform in mediating interspecies relationships within these complex communities. This is due in part to the focus on these specialized metabolites for pharmaceutical exploitation, with most of the current drugs derived directly from these natural products.

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