Agricultural Microbes Genome 2 Conference

Session: Functional Genomics & Applications
S01_02.html

INSIGHTS FROM THE GENOME OF Nitrosomonas europaea, AN OBLIGATE CHEMOLITHOAUTOTROPH

Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, OR 97331, USA

Nitrosomonas europaea is an obligate chemolithoautotroph that obtains all its energy for growth from the oxidation of ammonia. Like other ammonia-oxidizing bacteria, this bacterium participates in the process of nitrification. It's genome is being sequenced by the DOE-supported Joint Genome Institute. The gapped genome resulting from the sequences of random clones (8X coverage) currently consists of about 70 contigs containing about 2200 genes, about 1200 of which can be identified based on similarity searches. The results have revealed insights to the physiology of this organism. A CO₂ uptake system, carbonic anhydrase, and type I RuBP carboxylase feed a complete Calvin cycle. All central biosynthetic pathways are essentially complete and include genes for synthesis of amino acids, nucleotides, cofactors, sugars, and lipids. In contrast, catabolic pathways are strikingly absent. Uptake is possible for a range of Fe-siderophores, but production of siderophores is limited to citrate. Ammonia assimilation may occur by glutamate dehydrogenase or GS/GOGAT. The basis for obligate autotrophy remains unclear given the genetic basis for a complete TCA cycle. The sequences can be accessed at http://spider.jgi-psf.org/JGI_microbial/html/nitrosomonas_homepage.html