Oceaniglobus ichthyenteri sp. nov., isolated from the gut microflora of sea bass (Dicentrarchus labrax L.) and emended description of the genus Oceaniglobus.

ABSTRACT

A Gram-stain-negative, non-flagellated, catalase-positive, oxidase-positive bacterial strain, designated YLY08T, was isolated from the gut microflora of sea bass (Dicentrarchus labrax L.) collected from the coast of Yuanyao Wharf, Weihai, PR China, and subjected to a polyphasic taxonomic study. Strain YLY08T grew optimally at 28-30 °C, at pH 7.0-7.5 and in the presence of 2.0-3.0 % (w/v) NaCl. Poly-ß-hydroxybutyrate granules were produced. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain YLY08T clustered with the type strain of Oceaniglobus indicus, with which it exhibited 95.3 % sequence similarity, while the similarity to other genera was below 95.0 %. Genomic analyses, including average nucleotide identity and the digital DNA-DNA hybridization, clearly separated YLY08T from O. indicus MCCC 1A11863T with values below the thresholds for species delineation. The major cellular fatty acid was summed feature 8 (C18  1ω7c and/or C18  1ω6c). The sole respiratory quinone detected was Q-10. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine, diphosphatidylglycerol, one unidentified aminolipid and one unidentified phospholipid. The genome of strain YLY08T, with 38 assembled contigs, was 3.9 Mb long with a G+C content of 59.0 mol%. The results of the phenotypical, phylogenetic and biochemical analyses between the strain YLY08T and the related type strain indicated that this strain represents a novel species in genus Oceaniglobus within the family Rhodobacteraceae, for which the name Oceaniglobus ichthyenteri sp. nov. is proposed. The type strain is YLY08T (=MCCC 1H00318T=KCTC 62182T).