Streptomyces maremycinicus sp. nov. and its secondary metabolite-biosynthetic gene clusters

Streptomyces strain TP-A0890^T, isolated from a soil sample, is a producer of FR-900452 and A-74863a. The taxonomic status was clarified by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain was closely related to Streptomyces coriariae, with similarity of 99.7%. Strain TP-A0890^T comprised LL-diaminopimelic acid, glutamic acid, glycine and alanine in its peptidoglycan. The predominant menaquinones were MK-9(H₈) and MK-9(H₆), and major fatty acids were anteiso-C_17:0, anteiso-C_15:0, iso-C_16:0 and iso-C_17:0. The chemotaxonomic features matched those described for the genus Streptomyces. The genome size and G + C content were 8.72 Mb and 71.5%, respectively. The results of digital DNA-DNA hybridization along with differences in phenotypic characteristics between the strains suggested strain TP-A0890^T to assign to a novel species, for which Streptomyces maremycinicus sp. nov. is proposed; the type strain is TP-A0890^T ( = NBRC 110468^T). We also show that Streptomyces strain B9173, a producer of FR-900452 and maremycins that was isolated from coastal sediment in Chile, belonged to S. maremycinicus. Twenty-two to 23 secondary metabolite-biosynthetic gene clusters (smBGCs) were present in the genomes of S. maremycinicus strains. Seventeen of them were conserved in the genome of S. coriariae CMB-FB^T but the others were not.