The process by which ammonia or ammonium is reduced to nitrate or nitrite is known as nitrification. The nitrogen cycle is considered to be one of the most impacted by humans, with factors such as industrially produced fertilizers and nitrogen-fixing crops adding more nitrogen to the terrestrial system than natural sources. Ammonia-oxidizing bacteria (AOB) help mediate the first step of the nitrification process, and in this project researchers focus on the genomes of two of these microbes: Nitrosomonas cryotolerans and Nitrosospira briensis. The role of AOB in the production of nitrous oxide (N2O) remains an important international concern and this sequencing project will improve our ability for comparative and functional analysis for both terrestrial and marine systems and will provide two crucial reference genomes for molecular ecologists.
Isolated from a soil sample, N. briensis C-128 is sensitive to salt and represents a commonly detected, globally-abundant soil AOB. In contrast, N. cryotolerans was isolated off the coast of Alaska and can grow at extremely low temperatures. Studies have shown N. cryotolerans cultures can produce nitrous oxide at subfreezing temperatures, which is thought to explain the abnormally high N2O levels in ice cores from Lake Vostok. Having the genome sequences of both bacteria will allow researchers to do both genus and intergeneric comparison of ammonia-oxidizing bacteria.
Principal Investigators: Jeannette Norton, Utah State University
Program: CSP 2010