The Wood-Eating Termite Hindgut: Diverse Cellular Symbioses in a Microoxic to Anoxic Environment

Abstract

The wood-eating termites evolved 140 million years ago in the early Cretaceous. Symbiotic microbial communities developed in their hindguts that allowed them to survive on a diet of lignocelluloses, and co-evolved into an obligate association that was horizontally transmitted through the colony. A typical gut's microbial community consists of several types of anaerobic protists and hundreds of pro-karyotes, many of which are specialized to the gut, and include novel chemoautotrophic forms. Gut-inhabiting protists harbour ecto-and endosymbiotic prokaryotes that have been studied as analogs of early cellular evolution. Genomic studies have revealed a great deal more molecular genetic diversity in the community than was previously known, and are producing the first complete genomes of the bacterial endosymbionts. Experimental studies of the community have lagged because many of the organisms have proven difficult to culture.