Application of Transcription Factor Decoys for Avermectin and Lycopene Overproduction in Streptomyces avermitilis

Here, we applied a transcription factor (TF) decoy strategy to enhance avermectin (AVE) production and activate the cryptic lycopene biosynthetic gene cluster (BGC) in industrial species Streptomyces avermitilis. Two decoy systems based on multicopy plasmid pKC1139 for repressors AfsR and AveI significantly increased AVE titers by 526.1% and 417.6%, respectively, compared to the wild-type (WT) strain. We further constructed a series of integrative decoy plasmids harboring varying numbers of AfsR decoys to demonstrate the dose-dependent effect, followed by a pKC1139-based AfsR decoy library to screen for optimal AVE-producing sequences. Three top-performing sequences were identified, increasing AVE titers by up to 1040.2% in the WT strain and 36.1% in an industrial strain. Finally, we successfully activated lycopene production (45.5 μg/mL) by using the crtY-crtE intergenic region as a decoy. These findings demonstrate that the simple, easy-to-implement TF decoy strategy can be applied to Streptomyces metabolic engineering for the overproduction of secondary metabolites.