The Microbial Metagenome of the Termite Hindgut

Arizona State University, Scottsdale AZ

Investigators

Abstract

Termites have the remarkable ability to survive on a diet of wood. From one perspective, this can be a big problem, costing billions in damage repair to man-made structures and termite eradication. On the other hand, it is also an opportunity to understand how energy can be efficiently extracted from wood. Termites rely on a complex community of microorganisms in their hindgut to break down wood and provide energy for themselves. However, the identity of many of these organisms, and the specific roles they each play in wood digestion, are still unknown. This research focuses on a highly invasive and destructive subterranean species of termite, and aims to identify the community diversity of their associated microorganisms and to understand their specific roles in the wood digestion process. This can be achieved in part through genome sequencing, as each microorganism's metabolic capabilities can be predicted from its genome sequence. This information is fundamentally important for science and society as it may enable exploring alternative approaches to biological termite control as well as biofuel and biomaterial production. In addition to providing research training for students, this project also develops an interactive outreach module for K-12 students to help spark appreciation for science, technology, and engineering research. The Coptotermes formosanus hindgut community includes large, complex eukaryotic microbes called hypermastigotes. Their genomes are unexplored but are expected to be very large, necessitating deep sequencing. The hindgut community also includes bacteria, archaea, and viruses, at highly variable abundances. To adequately sequence microbes from each of these "domains" of life, enrichment steps will be performed before sequencing, namely isolation of hypermastigote nuclei, isolation of viral particles, and rolling-circle amplification of lower abundance bacterial genomes. Assembled microbial genomes will be identified by 16S or 18S ribosomal RNA genes, so that carbohydrate active enzyme genes can be assigned to microbial species. Nitrogen fixing capability will also be inferred by quantitative real-time PCR of nifH genes. For the most abundant bacteria, their symbiotic status (ectosymbiont, endosymbiont, or free swimming) will be determined through fluorescent in-situ hybridization. By identifying and inferring the metabolic capabilities of each microbe in the hindgut bioreactor, this project will lay the groundwork for a deeper understanding of efficient wood digestion. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.