Aquabacter Cavernae Sp. Nov., A Bacterium Isolated From Cave Soil

A Gram-stain-negative, rod-shaped, non-motile, aerobic, catalase-negative and oxidase-positive bacterium, designated strain Sn-9-2(T), was isolated from a cave soil sample collected from Tiandong cave, Guizhou Province, south-west PR China. Growth occurred at 15-40 degrees C (optimum, 30 degrees C), at pH 5.0-9.0 (optimum, pH 7.0-8.0) and with 0-1 % NaCl (w/v). The predominant respiration quinone was ubiquinone-10 (0-10). The major cellular fatty acids were summed feature 8 (C-18:1 omega 7c or C-18:1 omega 6c; 83.9 %) and C-16:0 (5.8 %). The major polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, three unidentified phospholipids, two unidentified glycolipids, two unidentified polar lipids and one unidentified aminolipid. The DNA G+C content of strain Sn-9-2(T) was 67.5 mol%. Based on the results of 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain Sn-9-2(T) (MF958452) were identified as Aquabacter spiritensis (FR733686) DSM 9035(T) (97.5 %), Xanthobacter autorophicus (jgi.1053054) DSM 432(T) (97.2 %) and Xanthobacter tagetidis ATCC 700314(T) RCTF01000015 (96.9 %). The average nucleotide identity values were 78.0, 77.4 and 77.6 % and the digital DNA-DNA hybridization values were 21.8, 22.0 and 18.8 % between strain Sn-9-2(T) and A. spiritensis DSM 9035(T), X. autotrophicus DSM 432(T) and X. tagetidis DSM 11105(T), respectively. The DNA-DNA hybridization data indicated that strain Sn-9-2(T) represented a novel genomic species. On the basis of the results of phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain Sn-9-2(T) should represent a novel species of the genus Aquabacter, for which the name Aquabacter cavernae sp. nov. is proposed. The type strain is Sn-9-2(T) (=KCTC 62308(T)=CCTCC AB 2018270(T)).