Diversity of bacterial biosynthetic genes in maritime antarctica

Bacterial natural products (NPs) are still a major source of new drug leads. Polyketides (PKs) and non-ribosomal peptides (NRP) are two pharmaceutically important families of NPs and recent studies have revealed Antarctica to harbor endemic polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, likely to be involved in the production of novel metabolites. Despite this, the diversity of secondary metabolites genes in Antarctica is still poorly explored. In this study, a computational bioprospection approach was employed to study the diversity and identity of PKS and NRPS genes to one of the most biodiverse areas in maritime Antarctica—Maxwell Bay. Amplicon sequencing of soil samples targeting ketosynthase (KS) and adenylation (AD) domains of PKS and NRPS genes, respectively, revealed abundant and unexplored chemical diversity in this peninsula. About 20% of AD domain sequences were only distantly related to characterized biosynthetic genes. Several PKS and NRPS genes were found to be closely associated to recently described metabolites including those from uncultured and candidate phyla. The combination of new approaches in computational biology and new culture-dependent and -independent strategies is thus critical for the recovery of the potential novel chemistry encoded in Antarctica microorganisms.

Fundação para a Ciência e a Tecnologia (FCT) funded this study through the grant PTDC/CTA- AMB/30997/2017 to CM, the IF research contract IF/01358/2014 to PNL, a PhD scholarship to AR (SFRH/BD/140567/2018) and within the scope of UIDB/04423/2020 and UIDP/04423/2020. The authors acknowledge the Portuguese Polar Program (PROPOLAR) and the Chilean Antarctic Institute (INACH) for providing logistics and traveling financial support during CONTANTARC-3 campaign in Maxwell Bay/King George Island.