The Genome of Salinibacter Ruber: Convergence and Gene Exchange Among Hyperhalophilic Bacteria and Archaea

Proc Natl Acad Sci U S A. 2005 Dec 13;102(50):18147-52. doi: 10.1073/pnas.0509073102. Epub 2005 Dec 5.

Abstract

Saturated thalassic brines are among the most physically demanding habitats on Earth: few microbes survive in them. Salinibacter ruber is among these organisms and has been found repeatedly in significant numbers in climax saltern crystallizer communities. The phenotype of this bacterium is remarkably similar to that of the hyperhalophilic Archaea (Haloarchaea). The genome sequence suggests that this resemblance has arisen through convergence at the physiological level (different genes producing similar overall phenotype) and the molecular level (independent mutations yielding similar sequences or structures). Several genes and gene clusters also derive by lateral transfer from (or may have been laterally transferred to) haloarchaea. S. ruber encodes four rhodopsins. One resembles bacterial proteorhodopsins and three are of the haloarchaeal type, previously uncharacterized in a bacterial genome. The impact of these modular adaptive elements on the cell biology and ecology of S. ruber is substantial, affecting salt adaptation, bioenergetics, and photobiology.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adaptation, Physiological / genetics
  • Archaea / genetics*
  • Bacteroidetes / enzymology
  • Bacteroidetes / genetics*
  • Base Composition
  • Base Sequence
  • Evolution, Molecular*
  • Gene Transfer, Horizontal / genetics*
  • Genome, Bacterial / genetics*
  • Likelihood Functions
  • Models, Genetic
  • Molecular Sequence Data
  • Phylogeny*
  • Rhodopsins, Microbial / genetics*
  • Sequence Analysis, DNA

Substances

  • Rhodopsins, Microbial