An optimized CRISPR/Cas9-based genome editing platform enhances bacteriocin production in Lactiplantibacillus...

Efficient genetic engineering of lactic acid bacteria remains technically challenging due to their thick peptidoglycan cell wall, low transformation efficiency, strain-specific restriction-modification systems, and sensitivity to Cas9-induced double-strand breaks. In this study, we adapted an established CRISPR/Cas9 approach for the targeted disruption of plnD, a key negative regulatory gene within the plantaricin quorum-sensing network of Lactiplantibacillus plantarum 8P-A3 through extensive optimization of transformation and genome-editing conditions. The genetically modified strain exhibited upregulation of plnA, plnE, and plnF, accompanied by elevated antimicrobial activity. These findings underscore the feasibility of rationally reconfiguring a quorum-sensing-associated regulatory circuit and provide a practical strategy for successful genetic engineering in L. plantarum for elevated bacteriocin production.