Functional Characterization of Polyketide Synthase Clusters in Streptomyces anandii J6

Abstract

<i>Streptomyces</i> species are well-known for their antifungal properties and the production of diverse secondary metabolites, including non-ribosomal peptides and polyketides. These metabolites can be identified through various genetic techniques, allowing for the investigation of gene functions using whole-genome databases. Numerous studies have explored the genetic functions of <i>Streptomyces</i> using advanced techniques, such as CRISPR-Cas9 mutagenesis, to generate site-specific mutant strains. In this study, we re-identified <i>Streptomyces</i> sp. J6 as <i>Streptomyces anandii</i> J6 through whole-genome sequencing and average nucleotide identity (ANI) analysis. The type II and type III polyketide synthase clusters (PKS: clusters 9, 10, and 12) were further studied using CRISPR-Cas9 for functional analysis, revealing the role of <i>srsA</i> in the biosynthesis of alkylresorcinols, which are phenolic lipids with antifungal properties. These results indicate that metabolites belonging to the polyketide family produced by <i>Streptomyces</i> plays a significant role in the biocontrol activity of microorganisms against plant diseases. Furthermore, the findings suggest that specific PKS profiling enables the rapid and efficient screening of a large number of microbial candidates, thereby facilitating the selection of promising biocontrol agents.