Great diversity of KSα sequences from bat-associated microbiota suggests novel sources of uncharacterized natural products

Polyketide synthases (PKSs) are multidomain enzymes in microorganisms that synthesize complex, bioactive molecules. PKS II systems are iterative, containing only a single representative of each domain: ketosynthase alpha (KSα�⁠), ketosynthase beta and the acyl carrier protein. Any gene encoding for one of these domains is representative of an entire PKS II biosynthetic gene cluster (BGC). Bat skin surfaces represent an extreme environment prolific in Actinobacteria that may constitute a source for bioactive molecule discovery. KSα� sequences were obtained from culturable bacteria from bats in the southwestern United States. From 467 bat bacterial isolates, we detected 215 (46%) had KSα� sequences. Sequencing yielded 210 operational taxonomic units, and phylogenetic placement found 45 (21%) shared α� homology and total BGC novelty within each fully sequenced strain. We propose amplification and detection of KSα� could predict a strain's global biosynthetic capacity.