NSF Award
0333190
Hypersaline environments were considered to be the exclusive preserve of halophilic archaea, specialists at coping with these extreme conditions. It has recently been discovered however, that many of the prokaryotic inhabitants of crystallizer ponds are actually bacteria of the Cytophaga cluster. Representative strains of this cluster have now been isolated from several locales, and have been described as the new species Salinibacter ruber, an aerobic heterotroph that grows readily in pure culture and exhibits many "haloarchaeal" physiological properties. These properties are likely the result of remarkable convergence, extensive inter-domain gene transfer, or most likely a combination of both of these events. Salinibacter, has turned out to be a significant player in an extreme and highly productive microbial ecosystem, and as far as we know, is the only halophilic bacterium that, rather than producing compatible solutes and excluding salt, has adapted each of its proteins to function at very high internal ionic concentrations. In addition to these interesting physiological aspects, S. ruber belongs to a complex and genomically under-sampled lineage (the Cytophaga-Flexibacter- Bacteroides group). The main goal of this research project is to sequence, annotate and analyze the entire genome of S. ruber. In addition, the genome sequence will be closely examined for evidence of gene transfer events and convergent evolution. It is anticipated that S. ruber will prove to be one of the extraordinary contributors to the understanding of evolution and molecular biology, and at the gene and protein level will demonstrate a mix of independently achieved (convergent) and laterally acquired adaptations.
