An aerobic, Gram-negative, non-motile, non-spore-forming, rod-shaped, and pale yellow-colored bacterial strain, designated TS118T, was isolated from a sand sample obtained from a coastal sand dune after exposure to 3 kGy of gamma radiation. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was a member of the genus Spirosoma and most closely related to Spirosoma metallicum PR1014kT (95.1% similarity). The genome of strain TS118T is constituted by one chromosome (5,691,492 bp) and one plasmid (28,440 bp) and has a G + C content of 52.7%. The genome contains 4641 protein coding sequences (CDSs), 38 tRNAs, and 11 rRNAs. The predominant fatty acids of strain TS118T were C16:1 ω5c, iso-C15:0, C16:0, summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), and iso-C17:0 3-OH. The major polar lipids were phosphatidylethanolamine, an unidentified amino lipid and an unidentified aminophospholipid. The main respiratory quinone was menaquinone-7 (MK-7). The novel strain showed resistance to gamma radiation with a D10 value (i.e., the dose required to reduce the bacterial population by tenfold) of 4.3 kGy. Based on the phylogenetic, physiological, and chemotaxonomic characteristics, strain TS118T represents a novel species, for which the name Spirosoma taeanense sp. nov. is proposed. The type strain is TS118T (=KCTC 72898T =JCM 34024T).
Keywords: Bacteroidetes; Coastal sand dune; Gamma radiation; Phylogenetic analysis; Spirosoma; Taxonomy.