Staphylospora marina gen. nov., sp. nov., a novel member of the family Thermoactinomycetaceae, isolated from a deep-sea hydrothermal vent in the Pacific Ocean

A novel bacterium, designated SCSIO 07575(T), was isolated from a deep-sea hydrothermal sediment sample collected from the western Pacific Ocean. Growth at 65 degrees C was observed, but not at 70 degrees C or below 37 degrees C. The optimum conditions for growth were at 55-65 degrees C, pH 7.0 and in the presence of 2% (w/v) NaCl. Strain SCSIO 07575(T) showed filamentous growth. Unstable formation of white aerial mycelia was observed, which disappeared after several times' subculture. Abundant substrate mycelia were observed with grape-like spores. No soluble pigment was observed. Phylogenetic analysis of 16S rRNA gene sequences showed that SCSIO 07575(T) belonged to the family Thermoactinomycetaceae and formed a distinct Glade in the phylogenetic tree. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Whole-cell hydrolysates contained ribose, xylose, glucose and galactose. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid and two unidentified phospholipids. The predominant menaquinone was MK-7. Major fatty acids were iso-C-15.0, iso-C-17.0 and iso-C-16.0. Based on the whole genome sequence analysis, the genome size was 2 751 094 bp with a DNA G+C value of 57.2 mol%, including one circular chromosome and one plasmid. On the basis of polyphasic data, strain SCSIO 07575(T) represented a novel species of a new genus within the family Thermoactinomycetaceae, for which the name Staphylospora gen. nov. is proposed with the type species Staphylospora marina sp. nov. and the type strain SCSIO 07575(T) (=DSM 106793(T) =CGMCC 1.15879(T)).