Whole genome sequencing of Streptomyces actuosus ISP-5337, Streptomyces sioyaensis B-5408, and Actinospica acidiphila B-2296 reveals secondary metabolomes with antibiotic potential

Streptomycetes are bacteria of biotechnological importance since they are avid producers of secondary metabolites, including antibiotics. Progress in genome mining has recently shown that Streptomyces species encode for many biosynthetic gene clusters which are mostly unexplored. Here, we selected three Actinomycetes species for whole genome sequencing that are known to produce potent thiopeptide antibiotics. Streptomyces actuosus biosynthesizes nosiheptide, Streptomyces sioyaensis produces siomycin, and Actinospica acidiphila is a member of the Actinomycete subfamily. Bioinformatic analyses demonstrated diverse secondary metabolomes with multiple antibiotic-encoding gene clusters. Detailed mass spectrometry analysis of metabolite extracts verified the active expression of nosiheptide and siomycin from S. actuosus and S. sioyaensis while fractionation of the bacterial extracts and subsequent challenge against Staphylococcus aureus demonstrated potent antibiotic activity of fractions containing these compounds. Whole genome sequencing of these species facilitates future bioengineering efforts for thiopeptides and characterization of relevant secondary metabolites.