Molecular investigation of Australian termites and their gut symbionts

From our initial amplicon survey, we hypothesised that dietary fluctuations caused shifts in the gut community structure and function. We directly tested this hypothesis through a series of feeding experiments performed on the most basal polyphagous termite species Mastotermes darwiniensis. Here, using amplicon community profiling and proteome analyses, we investigated the M. darwiniensis gut microbial community compositional changes in response to wood (complex lignocellulose), sugarcane mulch (C4 grass) and cotton (pure cellulose) diet over a period of seven days. Shifts in relative abundance of some gut microbial populations were noted with compositionally different feedstocks but most of the changes are likely due to response to stress as an effect of small colonies. While laboratory conditions can influence the termite gut microbiome, the bulk of prokaryotic communities of Mastotermes gut profiles were comparably consistent in all diets. In addition, zymograhy coupled with mass spectrometry sequencing of M darwiniensis gut extracts identified highly expressed protist-derived cellulases. Thus, our findings have contributed to the understanding of community structure and function of gut microbiota in lower termites and suggest that the contribution of prokaryotic symbionts to lignocellulose digestion is more complex than previously appreciated.