Genome mining of one of the protective symbionts ( Burkholderia gladioli ) of the invasive beetle Lagria villosa revealed a cryptic gene cluster coding for the biosynthesis of a novel antifungal polyketide with a glutarimide pharmacophore. Targeted gene inactivation, metabolic profiling and bioassays led to the discovery of the gladiofungins as yet overlooked components of the antimicrobial armory of the beetle symbiont, specifically against the entomopathogenic fungus Purpureocillium lilacinum . By mutational analyses, isotope labeling and in silico analyses of the modular polyketide synthase, we found that the rare butenolide moiety of gladiofungins derives from an unprecedented polyketide chain termination reaction involving a glycerol-derived C3 building block. The key role of an A-factor synthase (AfsA)-like offloading domain was corroborated by CRISPR-Cas-mediated gene editing, which facilitated the precise excision within a PKS domain.
PubMed ID: 32588959
Publication type: Not specified
Journal: Angew Chem Int Ed Engl
Citation: Angew Chem Int Ed Engl. 2020 Jun 26. doi: 10.1002/anie.202005711.
Date Published: 26th Jun 2020
Registered Mode: Not specified
Created: 23rd Sep 2020 at 15:14