Why Sequence Hyperthermophilic Archaea?

The hyperthermophile genus Pyrobaculum represents a unique clade among the archaea because its cultured members respire toxic metals such as arsenic and selenium, sulfur compounds, ferric (Fe(III)) iron, nitrate, and oxygen. Pyrobaculum species are also capable of chemolithotrophic and organotrophic growth. In contrast to the emerging crenarchaeal model Sulfolobus, which is an acidophilic obligate aerobe, Pyrobaculum provides an alternative archaeal system to investigate biological processes in non-acidic, aerobic/anaerobic, high-temperature environments. This project involves sequencing multiple Pyrobaculum genomes, which will significantly advance the genus's establishment as a model system. Unfortunately, the first member of this genus to be sequenced, P. aerophilum, is not easily cultured, which has slowed research with this compelling genus. With the isolation of additional Pyrobaculum species that are easily handled and maintained, there is now an opportunity to rapidly advance the biological understanding of these microbes.

JGI will sequence five related species, three from the genus Pyrobaculum (P. calidifontis, P. arsenaticum, and P. islandicum), and two other closely-related species (Caldivirga maquilingensis and Thermoproteus neutrophilus) with unique comparative significance. This project will expand the biological value of the existing P. aerophilum genome sequence and explore additional metabolic diversity in related species. The sequence and resulting science will likely enhance our understanding of several challenging areas of research, including alternate modes of transcription and transcription regulation, DNA repair, biofilm formation, respiration and its role in hydrothermal ecosystems, microbial reduction of arsenic, and the origins of life.

CSP project participants: Todd M. Lowe (proposer) and Chad Saltikov (UC Santa Cruz), Christopher H. House (Pennsylvania State Univ.), and Sorel T. Fitz-Gibbon (UC Los Angeles).