Vulcanimicrobium alpinus gen. nov. sp. nov., the first cultivated representative of the candidate phylum “Eremiobacterota”, is a metabolically versatile aerobic anoxygenic phototroph

• Published in: ISME Communications Vol. 2; no. 1; p. 120
• Main Authors: Yabe, Shuhei, Muto, Kiyoaki, Abe, Keietsu, Yokota, Akira, Staudigel, Hubert, Tebo, Bradley M
• Format: Journal Article
• Language: English
• Published: London Springer Nature B.V 01.12.2022; Nature Publishing Group UK; Oxford University Press
• Subjects: Bacteriochlorophyll; Candidatus Eremiobacterota; Carbon dioxide; Carbon dioxide fixation; Caves; Chemical synthesis; Cloning; Filaments; Genomes; Geobiology; Laboratories; Metabolic pathways; Metabolism; New species; Oligotrophic environments; PCB; Photochemical reactions; Photochemicals; Photosynthesis; Polychlorinated biphenyls; Reaction centers; Sediments; Soil contamination; Taxonomy; Volcanoes; Vulcanimicrobium alpinus; United States > US; Japan; Antarctica
• ISSN: 2730-6151; 2730-6151
• DOI: 10.1038/s43705-022-00201-9

Abstract The previously uncultured phylum “Candidatus Eremiobacterota” is globally distributed and often abundant in oligotrophic environments. Although it includes lineages with the genetic potential for photosynthesis, one of the most important metabolic pathways on Earth, the absence of pure cultures has limited further insights into its ecological and physiological traits. We report the first successful isolation of a “Ca. Eremiobacterota” strain from a fumarolic ice cave on Mt. Erebus volcano (Antarctica). Polyphasic analysis revealed that this organism is an aerobic anoxygenic photoheterotrophic bacterium with a unique lifestyle, including bacteriochlorophyll a production, CO2 fixation, a high CO2 requirement, and phototactic motility using type IV-pili, all of which are highly adapted to polar and fumarolic environments. The cells are rods or filaments with a vesicular type intracytoplasmic membrane system. The genome encodes novel anoxygenic Type II photochemical reaction centers and bacteriochlorophyll synthesis proteins, forming a deeply branched monophyletic clade distinct from known phototrophs. The first cultured strain of the eighth phototrophic bacterial phylum which we name Vulcanimicrobium alpinus gen. nov., sp. nov. advances our understanding of ecology and evolution of photosynthesis.