Why Sequence Crenarchaeota?

Earth's microbiota is remarkably pervasive, thriving at extremely high temperature, low and high pH, high salinity, and low water availability. One major evolutionary lineage of microbial life, the Archaea, is especially adept at exploiting environmental extremes. Despite their success in these challenging habitats, the Archaea may now also be viewed as cosmopolitan. Archaea are now known to exist in a wide variety of more pedestrian terrestrial, freshwater, and marine habitats, sometimes in very high abundance. The marine planktonic Crenarchaeota, for example, rival total bacterial biomass in ocean waters from 100 m to 5000 m, from temperate regions to Antarctica. As such, they represent one of the most abundant microbial groups in the oceans. Surprisingly, evidence is now mounting that deep-sea planktonic Crenarchaeota may be autotrophic (i.e., they may synthesize the organic molecules they need from inorganic ones). Since no isolates of these unique Archaea are currently available, however, little is known of their genetics, biochemistry, physiology, or ecology.

Because of their high biomass, ubiquity, and limited overall diversity, it is now feasible to consider characterizing uncultivated planktonic Crenarchaeota via whole-genome shotgun sequence analyses. This project will apply whole-community shotgun sequencing to characterize the deep-sea Crenarchaeota, and co-existing bacterial species, that are predominant in the deep Pacific Ocean. The goal is to assemble large genomic scaffolds representative of planktonic Crenarchaeota, to facilitate a deeper biological and ecological understanding of these abundant oceanic microbes. In conjunction with ongoing large-insert DNA analyses, this shotgun sequencing project will greatly advance our knowledge of planktonic Crenarchaeota and other deep-sea bacteria. In addition, it will facilitate the development and utilization of microbial ‘metagenomic’ data, to better characterize the naturally occurring microbial world.

CSP project participants: Edward F. DeLong (proposer, M.I.T.), Steve Hallam (postdoc, M.I.T.), and Dave Karl (PI, University of Hawaii).