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 27389T, was isolated from terrestrial soil collected on King George Island, Antarctica. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain PAMC 27389T 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 27389T 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 27389T grew at 0-37 °C (optimally at 15-20 °C), 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 1ω7c and/or C18 1ω6c) and C18 1ω7c 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 27389T ( = KCTC 42640T = JCM 30764T).