The bacterial gut microbiota of wood- and humus-feeding termites: Diazotrophic populations and compartment-specific response of bacterial communities to environmental factors

Wood-feeding termites thrive on a diet with an extremely low nitrogen content, and N₂ fixation by their intestinal microbiota is an important factor in the nitrogen economy of the host. We selected the nifH gene (dinitrogenase reductase) as a molecular marker to study abundance, diversity, and community structure of potential diazotrophs, combining qPCR with amplicon sequencing and metagenomics. The lack of N₂ fixation in humivorous species prompted a detailed study of gut microenvironment and intestinal microbiota in litter- and soil-feeding termites. We found a clear correlation between bacterial community structure and diet and identified the microenvironment as an important driver in the different gut compartments.