Psychrosphaera ytuae sp. nov., isolated from the deep-sea cold seep sediment of South China Sea

Abstract

In this study, we report a Gram-stain-negative, rod-shaped, non-pigmented, motile and aerobic bacterium named strain MTZ26^T, which was isolated from deep-sea sediment sampled at a cold seep in the South China Sea. Growth of strain MTZ26^T occurred at 4-40 °C (optimum, 25-30 °C), pH 6.0-10.0 (optimum, 7.0-8.0) and with 1.0-11.0 % (w/v) NaCl (optimum, 6.0-8.0 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MTZ26^T belonged to the genus Psychrosphaera and was closely related to Psychrosphaera aestuarii PSC101^T (97.5 % sequence similarity) and Psychrosphaera haliotis KDW4^T (97.5 %). Genomic analysis indicated that strain MTZ26^T contains a circular chromosome of 3 331 814 bp with G+C content of 42.2 mol%. The predominant respiratory quinone of MTZ26^T was ubiquinone-8. The polar lipids of MTZ26^T contained phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid and one unidentified phospholipid. The major fatty acids of strain MTZ26^T contained C_15:0, C_16:0, C_17:0, C_{17 : 1} ω8c, C_{10 : 0} 3-OH, C_{11 : 0} 3-OH, C_{15 : 1} ω8c and summed feature 8 (C_{18 : 1} ω7c or/and C_{18 : 1} ω6c). Results of phylogenetic, physiological, biochemical and morphological analyses suggested that strain MTZ26^T represents a novel species of the genus Psychrosphaera, and the name Psychrosphaera ytuae sp. nov. is proposed with the type strain MTZ26^T (=MCCC 1K05568^T=JCM 34321^T).

Keywords: Alphaproteobacteria; Psychrosphaera; cold seep; sediment.