Streptomyces durbertensis sp. nov., isolated from saline-alkali soil.

A novel strain of actinobacteria, designated NEAU-S1GS20, was isolated from a saline-alkali soil collected from Heilongjiang Province, north-east China, and characterized using a polyphasic approach. Strain NEAU-S1GS20 exhibited morphological, cultural and chemotaxonomic features consistent with its classification as representing a member of the genus Streptomyces. Growth occurred at 18‒45 °C, at pH 6.0‒10.0 and in the presence of 10 % (w/v) NaCl. Whole-cell hydrolysates mainly contained glucose and ribose. The predominant menaquinones were MK-9(H4) and MK-9(H6). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and two unidentified phospholipids. The major cellular fatty acids (>10 %) were iso-C16 : 0, iso-C17 : 0, anteiso-C17 : 0 and C16 : 0. The G+C content of the DNA was 72.8 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain NEAU-S1GS20 formed a distinct clade within the genus Streptomyces and was closely related to Streptomyces xinghaiensis CCTCC AA 208049 (98.4 % similarity), Streptomyces chumphonensis JCM 18522 (98.1 %) and Streptomyces palmae JCM 31289 (98.1 %). Multilocus sequence analysis (MLSA) using five housekeeping genes (atpD, gyrB, recA, rpoB and trpB) showed that the MLSA distance of strain NEAU-S1GS20 to the most closely related species was greater than the 0.007 threshold. A combination of DNA-DNA hybridization results and differences in certain phenotypic characteristics demonstrated that strain NEAU-S1GS20 could be distinguished from its closest phylogenetic relatives. Therefore, strain NEAU-S1GS20 represents a novel species of the genus Streptomyces, for which the name Streptomyces durbertensis sp. nov. is proposed. The type strain is NEAU-S1GS20 (=CCTCC AA 2017006=DSM 104538).