The importance of symbiotic, prokaryotic groups in termite digestion of lignocellulose

Lower termites feed on a nitrogen-poor diet of lignocellulose that they cannot survive on without the aid of eukaryotic and prokaryotic symbionts living in their guts. The eukaryotic protists are credited with the majority of cellulolytic activity, but we show that prokaryotes also contribute significantly to this process. Using four different antimicrobial treatments, we successfully reduced the prokaryotic diversity in the gut of Reticulitermes flavipes workers in a 7-day feeding period (p<0.0001, aerobic; p=0.0119, anaerobic). As a result, the liberation of glucose and pentose from lignocellulose was significantly reduced (p<0.0001; p=0.0459). The V3 hypervariable region of the 16s rRNA gene was used to estimate prokaryotic diversity from whole gut samples in a culture independent manner. Approximately 300 cloned 16s rRNA gene amplicons were sequenced from each of five treatment groups: water (control), 5% ampicillin, 5% kanamycin, 5% metronidazole, and 2.5% tetracycline. Each of these groups has a unique prokaryotic profile which allows for inference of the importance of specific groups in lignocellulose digestion. This study provides insight into the role bacteria play in the digestion of wood and aims to elucidate which prokaryotic groups most appreciably impact this process.