Pseudopuniceibacterium antarcticum sp. nov., isolated from an Antarctic marine sponge

A Gram-negative, aerobic, rod-shaped, non-motile bacterium, designated strain HQ09^T, was isolated from a marine sponge off the coast of Fields Peninsula, West Antarctica. Strain HQ09^T grew at 4-35 °C (optimum, 25 °C), pH 5-9 (optimum, pH 7.0), and with 1-10% NaCl (optimum, 2 %). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain HQ09^T was affiliated with the genus Pseudopuniceibacterium in the family Rhodobacteraceae, sharing 99.64 % identity with the type strain of Pseudopuniceibacterium sediminis, the only known species in the genus. However, the low digital DNA-DNA hybridization (dDDH) (27.2 %) and average nucleotide identity (ANI) (83.63 %) values between strain HQ09^T and the type strain of Pseudopuniceibacterium sediminis indicated that they did not belong to the same species. Strain HQ09^T could also be differentiated from Pseudopuniceibacterium sediminis by many phenotypic characteristics. The major fatty acids (>5 %) of strain HQ09^T were summed feature 8 (C_18 : 1  ω7c/C_18 : 1 ω6c), 11-methyl C_18 : 1  ω7c, C_16 : 0 and C19 : 0 cyclo ω8c. The polar lipids included phosphatidylglycerol, phosphatidylcholine, two unidentified aminolipids and one unidentified phospholipid. The predominant respiratory quinone was ubiquinone 10 (Q-10). The genomic DNA G+C content was 62.63 mol%. Four secondary metabolite biosynthetic gene clusters were detected in the genome, potentially producing ectoine and three types of unknown compounds. On the basis of the polyphasic evidences obtained in this study, strain HQ09^T represents a novel species of the genus Pseudopuniceibacterium, for which the name Pseudopuniceibacterium antarcticum sp. nov. is proposed, with the type strain being HQ09^T (=KCTC 52229^T=CGMCC 1.15538^T).