Streptomyces indoligenes sp. nov., isolated from rhizosphere soil of Populus euphratica

A novel actinobacterium, designated TRM 43006T, was isolated from the rhizosphere soil of Populus euphratica in Xinjiang Province, north-west China. Phylogenetic and phenotypic analysis demonstrated that strain TRM 43006T belongs to the genus Streptomyces. The strain was aerobic and Gram-stain-positive; the aerial mycelium branched monopodially, forming chains of arthrospores. The spores were oval to cylindrical with smooth surfaces. The whole-cell sugar pattern of strain TRM 43006T consisted of xylose, mannitol, galactose and ribose. The menaquinones were MK-9(H6), MK-9(H8) and MK-9(H10). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidylinositol mannosides and four unknown phospholipids. Major fatty acids were iso-C16 : 0, iso-C16 : 1, iso-C14 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 69.0 mol%. Comparative 16S rRNA gene sequence analysis indicated that strain TRM 43006T was phylogenetically most closely related to Streptomyces roseolilacinus NBRC 12815T (98.6 % similarity) and Streptomycessudanensis SD 504T (98.3 %); however, DNA-DNA hybridization studies between S. roseolilacinus NBRC 12815T, S. sudanensis SD 504T and TRM 43006T showed only 30.28 and 30.65  % relatedness, respectively. Based on the evidence from this polyphasic study, strain TRM 43006T represents a novel species of the genus Streptomyces, for which the name Streptomyces indoligenes sp. nov. is proposed. The type strain is TRM 43006T (=KCTC 39611T=CCTCC AA 2015010T).