Deferribacter desulfuricans SSM1^T is thermophilic (optimal temperature 60-65℃) and strictly anaerobic heterotroph capable of using versatile organic compounds. The strain SSM1^T has been isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the Izu-Bonin Arc, JAPAN¹. Thermophilic microorganisms living on hydrothermal vents are exposed to physically and chemically fluctuating environments. It has also been shown, depending on the hydrothermal vent chimney environment, that Deferribacter-related species are the dominant species in these locations².

The genome of D. desulfuricans SSM1 contains a single circular chromosome of 2,234,389 bp and a megaplasmid (pDF308) of 308,544 bp. Among the 2374 ORFs identified in the D. desulfuricans genome, ~30% of them showed high similarity to those of the species from Deltaproteobacteria, although D. desulfuricans is phylogenetically distant from Deltaproteobacteria. D. desulfuricans especially revealed orthologous relationships to bacteria that possesses sulphur or sulphate-reducing properties. The reconstructed central metabolic pathways from the D. desulfuricans genome showed that various organic acids could be utilize as carbon and energy sources. In addition, numerous genes for chemoreceptors, chemotaxis-like systems and signal transduction machineries encoded in the genome could be linked to the adaptation mechanisms required to survive in variable environments. The genome sequence of D. desulfuricans SSM1 should provide many insights for the better understanding of bacterial life in harsh environments around hydrothermal vents. This is the first complete genome sequence from the phylum Deferribactares.