Description of Sinomonas soli sp. nov., reclassification of Arthrobacter echigonensis and Arthrobacter albidus (Ding et al. 2009) as Sinomonas echigonensis comb. nov. and Sinomonas albida comb. nov., respectively, and emended description of the genus Sinomonas

Abstract

A novel actinomycete strain, designated CW 59T, was isolated from a polluted forest soil sample in Anhui Province, China. Cells were strictly aerobic, non-motile, bent rods. The strain grew optimally at 30–37 °C and pH 6.0–8.0. The major fatty acids were ai-C15 : 0 (34.7 %), i-C15 : 0 (11.6 %) and ai-C17 : 0 (14.9 %); the predominant respiratory quinone was MK-9(H2), with MK-8(H2) present as a minor component. The polar lipid composition of strain CW 59T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two glycolipids and phosphatidylmonomethylethanolamine (minor component). The whole-cell sugars contained galactose, mannose, ribose and glucose; the major amino acids of the cell-wall were lysine, alanine and glutamic acid. The genomic DNA G+C content was 66.9 mol%. Phylogenetic analysis showed that CW 59T belonged to the genus Sinomonas and grouped with members of the species Sinomonas atrocyanea, Sinomonas flava, Arthrobacter echigonensis and Arthrobacter albidus. 16S rRNA gene sequence similarities of CW 59T to S. atrocyanea DSM 20127T, S. flava CW 108T, A. echigonensis LC10T and A. albidus LC13T were 99.5, 99.3, 98.2 and 98.0 %, respectively. DNA–DNA hybridization of the isolate showed relatedness values of 58.3 % (DSM 20127T), 41.8 % (CW 108T), 21.6 % (LC10T) and 25.5 % (LC13T) with its four closest neighbours. The taxonomic relationships of strains LC10T and LC13T with the genus Sinomonas were further clarified by means of a direct experimental comparison; results showed that strains LC10T and LC13T showed the same major fatty acid, polar lipid, cell-wall amino acid, whole-cell sugar and respiratory quinone compositions as members of the genus Sinomonas. Based on phenotypic, chemotaxonomic and phylogenetic analysis, it is proposed that: strain CW 59T represents a novel species of the genus Sinomonas, Sinomonas soli sp. nov., with CW 59T ( = CCTCC AB 207193T = KCTC 19389T) as the type strain; and the type strains of A. echigonensis and A. albidus should be reclassified as Sinomonas echigonensis comb. nov. and Sinomonas albida comb. nov., respectively. An emended description of the genus Sinomonas is given.