Discovery and biosynthetic assessment of 'Streptomyces ortus' sp. nov. isolated from a deep-sea sponge

The deep sea is known to host novel bacteria with the potential to produce a diverse array of undiscovered natural products. Thus, understanding these bacteria is of broad interest in ecology and could also underpin applied drug discovery, specifically in the area of antimicrobials. Here, we isolate a new strain of Streptomyces from the tissue of the deep-sea sponge Polymastia corticata collected at a depth of 1869 m from the Gramberg Seamount in the Atlantic Ocean. This strain, which was given the initial designation A15ISP2-DRY2(T), has a genome size of 9.29 Mb with a G+C content of 70.83 mol%. Phylogenomics determined that A15ISP2-DRY2(T) represents a novel species within the genus Streptomyces as part of the Streptomyces aurantiacus clade. The biosynthetic potential of A15ISP2-DRY2(T) was assessed relative to other members of the S . aurantiacus clade via comparative gene cluster family (GCF) analysis. This revealed a clear congruent relationship between phylogeny and GCF content. A15ISP2-DRY2(T) contains six unique GCFs absent elsewhere in the clade. Culture-based assays were used to demonstrate the antibacterial activity of A15ISP2-DRY2(T) against two drug-resistant human pathogens. Thus, we determine A15ISP2-DRY2(T) to be a novel bacterial species with considerable biosynthetic potential and propose the systematic name 'Streptomyces ortus' sp. nov.