Planococcus halocryophilus sp. nov., an extreme sub-zero species from high Arctic permafrost

Abstract

A novel aerobic, Gram-positive, motile, coccoid bacterial strain, designated Or1T, was isolated from permafrost active-layer soil collected from the Canadian high Arctic. Strain Or1T was capable of growth over a broad temperature range, including sub-zero growth (below −10 to 37 °C), and at high salinity (0–19 % NaCl), growing optimally at 25 °C, at pH 7.0–8.0 and in the presence of 2 % NaCl. Its taxonomic and phylogenetic position was determined by using a polyphasic approach, which indicated that strain Or1T was a member of the genus Planococcus . Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Or1T belonged to the genus Planococcus , differing by 0.4–3.6 % from the type strains of all recognized Planococcus species, and was related most closely to Planococcus antarcticus CMS 26orT (98.8 % similarity) and Planococcus donghaensis JH1T (99.6 %). However, DNA–DNA hybridization experiments showed that strain Or1T had low genomic relatedness to Planococcus antarcticus CMS 26orT (18 %) and Planococcus donghaensis JH1T (46 %). The major menaquinones of strain Or1T were MK-7 (55 %), MK-8 (36 %) and MK-6 (9 %) and the major fatty acids were anteiso-C15 : 0, C16 : 1ω7c alcohol and anteiso-C17 : 0. The DNA G+C content of strain Or1T was 40.5 mol%. Differential phenotypic, phylogenetic and genomic data suggest that strain Or1T represents a novel species of the genus Planococcus , for which the name Planococcus halocryophilus sp. nov. is proposed. The type strain is Or1T ( = DSM 24743T = JCM 17719T).