Streptomyces qaidamensis sp. nov., isolated from sand in the Qaidam Basin, China.

A novel actinobacterial strain, designated S10T, was isolated from a sand sample collected from the Qaidam Basin in Qinghai province, China. The strain S10T exhibited antibacterial activity against MRSA. The taxonomic position of the strain S10T was determined by a polyphasic approach. There were six copies of 16S rDNA in S10T which were not same exactly (MH257693-MH257698). Phylogenetic analysis of 16S rRNA gene sequences indicated the strain belonging to the genus Streptomyces and it showed high sequence similarities with Streptomyces chartreusis NBRC 12753T (99.31%), Streptomyces phaeoluteigriseus DSM 41896T (99.24%), Streptomyces variegatus NRRL B-16380T (99.17%) and Streptomyces flavovariabilis NRRL B-16367T (99.17%) comparing with MH257693, MH257695, MH257696, MH257697, and MH257698. Similarities with Streptomyces kunmingensis NBRC14463T (98.82%), Streptomyces bungoensis DSM 41781T(98.76%), S. chartreusis NBRC 12753T (98.69%) and S. phaeoluteigriseus DSM 41896T (98.62%) with MH257694. Whole-genome average nucleotide identity (ANI) values between strain S10T and S. chartreusis NBRC 12753T, S. phaeoluteigriseus DSM 41896T, S. variegatus NRRL B-16380T, S. flavovariabilis NRRL B-16367T, S. kunmingensis NBRC 14463T, S. bungoensis DSM 41781T were 83.63%, 82.89%, 92.55%, 92.51%, 79.29, and 82.87%, respectively, suggesting that the strain S10T represented a new species. A phylogenetic analysis comparing the S10T genome with those of 336 other sequenced Streptomyces genomes confirmed its relatedness with Streptomyces variegatus NRRL B-16380T and Streptomyces flavovariabilis NRRL B-16367T. Strain S10T contained LL-diaminopimelic acid in the cell wall. The predominant menaquinones were MK-9(H6) and MK-9(H8) and the major fatty acids were iso-C15:0, anteiso-C15:0, iso-C16:0, and anteiso-C17:0. Phospholipids detected were diphosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl choline, three unknown phospholipids, an unknown aminophospholipid and an unknown phosphatidyl glycolipid. On the basis of these genotypic and phenotypic data, it is proposed that isolate S10T (=JCM 31184T =CGMCC 4.7315T) should be classified in the genus Streptomyces as Streptomyces qaidamensis sp. nov.