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

Streptomyces strain TP-A0890, 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 comprised LL-diaminopimelic acid, glutamic acid, glycine and alanine in its peptidoglycan. The predominant menaquinones were MK-9(H) and MK-9(H), and major fatty acids were anteiso-C, anteiso-C, iso-C and iso-C. 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 to assign to a novel species, for which Streptomyces maremycinicus sp. nov. is proposed; the type strain is TP-A0890 ( = NBRC 110468). 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 but the others were not.