D 9 - Andreas Brune
Environmental drivers of microbial community structure in termite guts
Prof. Dr. Andreas Brune
Max Planck Institute for Terrestrial Microbiology
Phone: +49 - 6421 - 178701
The microbiota in the hindguts of termites plays essential roles in symbiotic digestion. In higher termites, whose gut microbiota is exclusively prokaryotic, the loss of flagellates was accompanied by an enormous dietary diversification. We have hypothesized that the pronounced axial dynamics of oxygen status, pH, and redox potential, together with the continuous influx of oxygen across the gut wall, creates various microenvironments with characteristic microbial communities. In the first project phase, we could show that the characteristic patterns in the microbial communities colonizing the guts are strongly correlated with the diet of different host groups and the distinct environmental conditions in individual gut compartments. In the next project phase, we want to identify the specific environmental drivers of microbial community structure in the individual gut compartments and to elucidate the adaptations in major microbial lineages that make them particularly suitable for the colonization of the respective microhabitat. Using a selection of wood-, humus- and soil-feeding termites, we will correlate community structures in the different microhabitats with the prevailing abiotic and biotic factors in the respective microenvironments. This approach will combine amplicon sequencing and microsensor techniques established in the first project phase with high-resolution profiles of microbial metabolites. Comparative metagenomics of individual gut compartments and reconstruction of composite genomes of important lineages will be used to characterize important genomic features of the mostly uncultivated microbial lineages and to compare their functional potentials and their adaptations to particular ecological niches. Responses of the microbiota to the constant influx of oxygen and other environmental factors will be tested by metatranscriptomic analyses and ecophysiological characterization of selected isolates.
Our long-term objective is to obtain a fundamental understanding of the ecological processes that shape the intestinal microbiota of higher termites and to provide tenable explanations that reconcile the structure of the intestinal communities with the dynamics of microhabitats and ecological niches manifested in the course of host evolution.