Abstract

Actinobacteria have been a valuable source of secondary metabolites as novel natural products (NPs). Most microbial metabolites are products of the metabolic pathways encoded by biosynthetic gene clusters (BGCs). Now we know that actinobacteria could harbor silent or cryptic BGCs capable of producing new NPs yet to be discovered. Rare non-explored Actinobacteria isolated from Antarctica could allow the discovery of new BGCs with biotechnological potential. In this work, we aimed to isolate rare Antarctic Actinobacteria and mined their genomes to study BGCs. To do this, we applied different protocols to selectively isolate rare-Actinobacteria from Antarctic soil samples. The complete genome of eight isolates was obtained and analyzed for taxonomic identification and BGCs predictions. The phylogenetic analysis and taxonomic classification based on 16S rRNA comparison ANI, AAI and dDDH values suggest that seven out of eight strains are new species belonging to the genera Lapillicoccus sp., Pseudarthrobacter sp., Micrococcus sp., Allobranchiibius sp., and Paenarthrobacter sp. The identified specie was Janibacter terrae. Forty-five BGCs belonging to the identity of the sequenced strains, of which three groups showed 100% similarity, four groups showed >50% genetic similarity and 38 BGCs showed <50% similarity to other known secondary metabolites. All the strains presented BGCs whose metabolites could be candidates for NPs discovery with antimicrobial, antitumoral, and antioxidant properties. Our results confirm the relevance of selective isolation protocols for rare-Actinobacteria during bioprospection. Also, here we provide evidence of novel actinobacteria taxa inhabiting the Antarctic environment.