Sphingomonas radiodurans sp. nov., a novel radiation-resistant bacterium isolated from the north slope of Mount Everest
Yang Liu, Tuo Chen, Xiaowen Cui, Yeteng Xu, Shixin Hu, Yidan Zhao, Wei Zhang, Guangxiu Liu, Gaosen Zhang
Abstract
A bacterial strain, designated S9-5 T , was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5 500 m above sea level. A polyphasic study confirmed the affiliation of the strain with the genus Sphingomonas . Strain S9-5 T was an aerobic, Gram-stain-negative, non-spore-forming, non-motile and rod-shaped bacterium that could grow at 10–40 °C, pH 5–8 and with 0–9 % (w/v) NaCl. Q-10 was its predominant respiratory menaquinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and eight unidentified lipids comprised the polar lipids of strain S9-5 T . Its major fatty acids were summed feature 8 (C 18 : 1 ω 7 c and/or C 18 : 1 ω 6 c ) and C 16 : 0 . The G+C content was 65.75mol%. Phylogenetic analysis based on 16S rRNA sequences showed that strain S9-5 T was phylogenetically closely related to Sphingomonas panaciterrae DCY91 T (98.17 %), Sphingomonas olei K-1-16 T (98.11 %) and Sphingomonas mucosissima DSM 17494 T (97.39 %). The average nucleotide identity values among strain S9-5 T and Sphingomonas panaciterrae DCY91 T , Sphingomonas olei K-1-16 T and Sphingomonas mucosissima DSM 17494 T were 78.82, 78.87 and 78.29 %, respectively. Based on the morphological, physiological and chemotaxonomic data, strain S9-5 T (=JCM 34750 T =GDMCC 1.2714 T ) should represent a novel species of the genus Sphingomonas , for which we propose the name Sphingomonas radiodurans sp. nov.