Algoriphagus algorifonticola sp. nov., a marine bacterium isolated from cold spring area of South China Sea

Abstract

A Gram-stain-negative, aerobic, non-motile, short-rod-shaped bacterium, designated strain hg1^T, was isolated from marine sediment within the cold spring area of South China Sea and subjected to a polyphasic taxonomic investigation. Colonies were circular and 1.0-2.0 mm in diameter, coral in colour, convex and smooth after growth on marine agar at 28 °C for 3 days. Strain hg1^T was found to grow at 4-40 °C (optimum, 35-37 °C), at pH 6.5-9.0 (optimum, pH 7.5) and with 0-8 % (w/v) NaCl (optimum, 1.5-2 %). Chemotaxonomic analysis showed the sole respiratory quinone was MK-7, and the principal fatty acids are iso-C_{15 : 0}, summed feature 3 (C_{16 : 1} ω7c and/or C_{16 : 1} ω6c), and iso-C_{16 : 0}. The major polar lipids are phosphatidylethanolamine, an unidentified phospholipid and five unidentified glycolipids. The DNA G+C content of strain hg1^T was 39.6 mol% based on the genome sequence. The comparison of 16S rRNA gene sequence similarities showed that hg1^T was closely related to Algoriphagus ornithinivorans DSM 15282^T (98.6 % sequence similarity), Algoriphagus zhangzhouensis MCCC 1F01099^T (97.9 %) and Algoriphagus vanfongensis DSM 17529^T (97.2 %); it exhibited 97.0 % or less sequence similarity to the type strains of other species of the genus Algoriphagus with validly published names. Phylogenetic trees reconstructed with the neighbour-joining, maximum-parsimony and maximum-likelihood methods based on 16S rRNA gene sequences showed that strain hg1^T constituted a separate branch with A. ornithinivorans, A. zhangzhouensis, A. vanfongensis in a clade of the genus Algoriphagus. OrthoANI values between strain hg1^T and A. ornithinivorans, A. zhangzhouensis and A. vanfongensis were 94.3, 74.1, 73.2 %, respectively, and in silico DNA-DNA hybridization values were 56.2, 18.5 and 18.3 %, respectively. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain hg1^T is clearly distinct from recognized species of genus Algoriphagus. On the basis of these features, we propose that strain hg1^T (=MCCC 1K03570^T=KCTC 72111^T) represents a novel species of the genus Algoriphagus with the name Algoriphagus algorifonticola sp. nov.

Keywords: Algoriphagus algorifonticola sp. nov.; marine bacterium; polyphasic taxonomy.