Pseudorhodobacter psychrotolerans sp. nov., a psychrotolerant bacterium isolated from terrestrial soil, and emended description of the genus Pseudorhodobacter

Abstract

A Gram-stain-negative, facultatively aerobic, cream-coloured, ovoid-shaped, non-motile and psychrotolerant bacterial strain, PAMC 27389^T, was isolated from terrestrial soil collected on King George Island, Antarctica. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain PAMC 27389^T belongs to the genus Pseudorhodobacter, sharing highest similarities with the type strains of Pseudorhodobacter wandonensis (96.9 %), Pseudorhodobacter antarcticus (96.8 %), Pseudorhodobacter ferrugineus (96.5 %) and Pseudorhodobacter aquimaris (95.4 %). Average nucleotide identity values between strain PAMC ^T and the type strains of P. wandonensis, P. antarcticus, P. ferrugineus and P. aquimaris were 70.8, 70.9, 71.0 and 70.5 %, respectively and the genome-to-genome distances were 18.4 - 19.1 %, indicating PAMC 27389T is clearly distinguished from the most closely related Pseudorhodobacter species. The genomic DNA G+C content was 60.1 mol%. Strain PAMC ^T grew at 0 - 37 8C (optimally at 15 - 20 8C), at pH 5.5 - 9.0 (optimally at pH 6.5 - 7.0) and in the presence of 0.5 - 3.0 % (w/v) sea salt (optimally with 0.5 %). It lacked bacteriochlorophyll a. The major fatty acids (.5 %) were summed feature 8 (C18 : 1v7c and/or C18 : 1v6c) and C18 : 1v7c 11-methyl. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid, an unidentified lipid and three unidentified aminophospholipids. The major respiratory quinone was Q-10. Based on the phenotypic, chemotaxonomic and genomic data presented, we propose the name Pseudorhodobacter psychrotolerans sp. nov. with the type strain PAMC 27389^T (=KCTC42640^T=JCM 30764^T)