Streptomyces gobiensis sp. nov., an antimicrobial producing actinobacterium isolated from soil under black Gobi rocks

A novel actinomycete, strain 1_25^T, was isolated from soil under a black Gobi rock sample from Shuangta, PR China, and characterized using a polyphasic taxonomic approach. The results of comparative analysis of the 16S rRNA gene sequences indicated the 1_25^T represented a member of the genus Streptomyces. Chemotaxonomic data revealed that 1_25^T possessed MK-9(H₈) as the major menaquinone. The cell wall contained ll-diaminopimelic acid (ll-DAP) and the whole-cell sugar pattern consisted of ribose, glucose and galactose. Major fatty acid methyl esters were observed to be iso-C_16 : 0 (23.6 %), and anteiso-C_15 : 0 (10.4 %). The genomic DNA G+C content of 1_25^T was 69 mol %. The results of phylogenetic analysis based on 16S rRNA gene sequence indicated that 1_25^T had high sequence similarity with Streptomyces qinglanensis 172205^T (98.1 %), Streptomyces lycii TRM 66187^T (98 %), and Streptomyces griseocarneus JCM4580^T (98 %). In addition to the differences in phenotypic characters, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between 1_25^T and closely related species were below the recommended threshold values for assigning strains to the same species. The fermentation product of 1_25^T in ISP2 had an inhibitory effect on Staphylococcus aureus. On the basis of these genotypic and phenotypic characteristics, strain 1_25^T (=JCM 34936^T=GDMCC 4.216^T) represents a novel species of the genus Streptomyces, for which the name Streptomyces gobiensis sp. nov. is proposed.