Croceicoccus hydrothermalis sp. nov., isolated from shallow-sea hydrothermal system off Kueishantao Island

A Gram-stain-negative, strictly aerobic, non-motile, ovoid or short-rod shaped, orange-pigmented bacterial strain, designated as strain JLT1^T, was isolated from seawater of the shallow-sea hydrothermal system, near Kueishantao Islet. Growth was observed at 5-45°C (optimum, 30 °C) and pH 5.0-11.0 (optimum, pH 7.0). The salinity range for growth was 0-12 % (optimum, 2-4 %) (w/v) NaCl. JLT1^T contained ubiquinone-10 as the main respiratory quinone. Iso-C_12 : 0, summed feature 3 (C_16 : 1ω7c/ω6c) and summed feature 8 (C_18 : 1ω6c/ω7c) were identified as the major cellular fatty acids. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unidentified phospholipids, eight unidentified glycolipids and an unidentified lipid. The 16S rRNA gene of JLT1^T shared the greatest similarity (96.31 %) with those of Croceicoccus pelagius Ery9^T and Croceicoccus ponticola GM-16^T. The draft genome size of JLT1^T is 3.56 Mb, with 3578 potential genes and a genomic DNA G+C content of 63.24 mol %. Average nucleotide identity and digital DNA-DNA hybridization values of JLT1^T compared with C. pelagius Ery9^T, C. ponticola GM-16^T, Croceicoccus sediminis S2-4-2^T, Croceicoccus mobilis Ery22^T and Croceicoccus marinus E4A9^T were 74.5, 73.9, 74.4, 74.3 and 74.8 % and 20.6, 19.2, 20.0, 20.5 and 19.8%, respectively. On the basis of these phylogenetic, chemotaxonomic and phenotypic features, JLT1^T is concluded to represent a novel species of the genus Croceicoccus, for which the name Croceicoccus hydrothermalis sp. nov. is proposed. The type strain is JLT1^T (=CGMCC 1.15786^T =JCM 31508^T).