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Insights into Archaeal Evolution and Symbiosis from the Genomes of a Nanoarchaeon and its Inferred Crenarchaeal Host from Obsidian Pool, Yellowstone National Park
Biology Direct
  • Mircea Podar, University of Tennessee - Knoxville
  • Kira S. Makarova, National Institutes of Health
  • David E. Graham, University of Tennessee - Knoxville
  • Yuri L. Wolf, National Library of Medicine
  • Eugene V. Koonin, National Library of Medicine
  • Anna-Louise Reysenbach, Portland State University
Document Type
Article
Publication Date
4-1-2013
Subjects
  • Evolution (Biology),
  • Polymerase chain reaction,
  • Sequence alignment (Bioinformatics)
Disciplines
Abstract
Background: A single cultured marine organism, Nanoarchaeum equitans, represents the Nanoarchaeota branch of symbiotic Archaea, with a highly reduced genome and unusual features such as multiple split genes. Results: The first terrestrial hyperthermophilic member of the Nanoarchaeota was collected from Obsidian Pool, a thermal feature in Yellowstone National Park, separated by single cell isolation, and sequenced together with its putative host, a Sulfolobales archaeon. Both the new Nanoarchaeota (Nst1) and N. equitans lack most biosynthetic capabilities, and phylogenetic analysis of ribosomal RNA and protein sequences indicates that the two form a deepbranching archaeal lineage. However, the Nst1 genome is more than 20% larger, and encodes a complete gluconeogenesis pathway as well as the full complement of archaeal flagellum proteins. With a larger genome, a smaller repertoire of split protein encoding genes and no split non-contiguous tRNAs, Nst1 appears to have experienced less severe genome reduction than N. equitans. These findings imply that, rather than representing ancestral characters, the extremely compact genomes and multiple split genes of Nanoarchaeota are derived characters associated with their symbiotic or parasitic lifestyle. The inferred host of Nst1 is potentially autotrophic, with a streamlined genome and simplified central and energetic metabolism as compared to other Sulfolobales. Conclusions: Comparison of the N. equitans and Nst1 genomes suggests that the marine and terrestrial lineages of Nanoarchaeota share a common ancestor that was already a symbiont of another archaeon. The two distinct Nanoarchaeota-host genomic data sets offer novel insights into the evolution of archaeal symbiosis and parasitism, enabling further studies of the cellular and molecular mechanisms of these relationships.
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© 2013 Podar et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

DOI
10.1186/1745-6150-8-9
Persistent Identifier
http://archives.pdx.edu/ds/psu/10407
Citation Information
Podar, M., Makarova, K., Graham, D., Wolf, Y., Koonin, E., & Reysenbach, A. (2013). Insights into archaeal evolution and symbiosis from the genomes of a nanoarchaeon and its inferred crenarchaeal host from Obsidian Pool, Yellowstone National Park. Biology Direct, 89. doi:10.1186/1745-6150-8-9