Microbial Genome Sequencing: Genomics of Treponema primitia and T. Azotonutricium: H2 Metabolizing, N2 Fixing Termite Gut Symbionts

California Institute Of Technology, Pasadena CA

Investigators

Abstract

The genomes of two beneficial microbes will be sequenced. In nature, these two species live in a mutually beneficial symbiosis with their termite host. Termites are among the most abundant animals living in many tropical ecosystems and have been shown to play important roles in global cycles of methane, carbon dioxide, and nitrogen. Their gut microbes play critical but incompletely understood roles in several of these processes and improve the health and vitality of their host (as many of our own gut microbes improve our own). The two subjects of this study belong to a group of microbes called spirochetes. Treponema primitia lives by eating and gaining nutrition and energy from hydrogen gas, an important intermediate generated during the degradation of wood in termites. Treponema azotonutricium is known to convert the nitrogen gas found in air (which has no nutritional benefit to animals) into protein-grade nutrient of great benefit to animal nutrition. Whereas other spirochetes are known for their roles in causing diseases such as Syphilis and Lyme Arthritis, these bacteria benefit the health of their animal host. These will be the first genomes of beneficial spirochetes to be so examined, allowing for important comparisons and contrasts between the symbiotic and disease-causing forms to be cast. Several novel features of these beneficial bacteria appear to have been patched together using genes acquired from quite distantly related organisms. This natural process has generated novel combinations found no where else in nature. Gaining the genomic blueprints of these spirochetes will help us to piece together these intriguing past events and to reach an improved understanding of the historical development and current details of a fascinating symbiosis having a great, global, modern-day impact. The knowledge that will be gained during the course of this study holds the promise of providing significant aid to current and future efforts concomitantly aimed at improving animal nutrition and reducing greenhouse emissions generated from agriculture in this nation and abroad. For example, it has long been known that termites emit less methane (a potent greenhouse gas and product of their gut microbes) and gain more nutrition mouthful for mouthful than do cattle because of their superior gut microbes, even though, at first blush, both face nearly the same, challenging diet. The genomic data and blueprints generated during the research will be made widely available via the World Wide Web including web-accessible, open-access, and archival databases. The data will serve the interests of many user groups, including those studying microbial disease & animal health, improved agricultural methods, symbiosis, biotechnology, and global environmental science. The research will continue to stimulate the researchers outreach activities, which include presenting material on the biology of termites to school teachers and other public groups ranging from senior citizen's groups to children's science day camps. Because termites and the visually intriguing shape of their microbes can generate great interest in 6 and 77 year old citizens alike, the investigators have been involved in and will continue to be involved in the development of media materials for mass dissemination.