title: Complete genome sequence of 'Halanaeroarchaeum sulfurireducens' M27-SA2, a sulfur-reducing and acetate-oxidizing haloarchaeon from the deep-sea hypersaline anoxic lake Medee.
abstract: Strain M27-SA2 was isolated from the deep-sea salt-saturated anoxic lake Medee, which represents one of the most hostile extreme environments on our planet. On the basis of physiological studies and phylogenetic positioning this extremely halophilic euryarchaeon belongs to a novel genus 'Halanaeroarchaeum' within the family Halobacteriaceae. All members of this genus cultivated so far are strict anaerobes using acetate as the sole carbon and energy source and elemental sulfur as electron acceptor. Here we report the complete genome sequence of the strain M27-SA2 which is composed of a 2,129,244-bp chromosome and a 124,256-bp plasmid. This is the second complete genome sequence within the genus Halanaeroarchaeum. We demonstrate that genome of 'Halanaeroarchaeum sulfurireducens' M27-SA2 harbors complete metabolic pathways for acetate and sulfur catabolism and for de novo biosynthesis of 19 amino acids. The genomic analysis also reveals that 'Halanaeroarchaeum sulfurireducens' M27-SA2 harbors two prophage loci and one CRISPR locus, highly similar to that of Kulunda Steppe (Altai, Russia) isolate 'H. sulfurireducens' HSR2(T). The discovery of sulfur-respiring acetate-utilizing haloarchaeon in deep-sea hypersaline anoxic lakes has certain significance for understanding the biogeochemical functioning of these harsh ecosystems, which are incompatible with life for common organisms. Moreover, isolations of Halanaeroarchaeum members from geographically distant salt-saturated sites of different origin suggest a high degree of evolutionary success in their adaptation to this type of extreme biotopes around the world.
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Messina
authors.affiliation: Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia ; Department of Biotechnology, Deft University of Technology, Delft, The Netherlands.
authors.forename: Dimitry Y
authors.initials: DY
authors.lastname: Sorokin
authors.affiliation: Winogradsky Institute of Microbiology, Russian Academy of Sciences, Moscow, Russia.
authors.forename: Ilya V
authors.initials: IV
authors.lastname: Kublanov
authors.affiliation: Immanuel Kant Baltic Federal University, Kaliningrad, Russia.
authors.forename: Stepan
authors.initials: S
authors.lastname: Toshchakov
authors.affiliation: Institute of Molecular Genetics and Gene Biology, Russian Academy of Sciences, Moscow, Russia.
authors.forename: Anna
authors.initials: A
authors.lastname: Lopatina
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Arcadi
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Smedile
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Gina
authors.initials: G
authors.lastname: La Spada
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Violetta
authors.initials: V
authors.lastname: La Cono
authors.affiliation: Institute for Coastal Marine Environment, CNR, Messina, Italy.
authors.forename: Michail M
authors.initials: MM
authors.lastname: Yakimov
keywords: Anoxic habitats; Extremely halophilic archaea; Hypersaline lake; Strictly anaerobic; Sulfur reduction