Construction of prcK and prcR Mutant Strains of Lactobacillus paracasei HD1.7 and the Impact on the Production of Paracin 1.7

Gene knockouts of prcK, prcR and both together were constructed in L. paracasei HD1.7. The antimicrobial activities of the prcK, prcR and prcKprcR mutant strains against B. subtilis were 23.6%, 21.9% and 36.6% lower than that of the parental strain, respectively, indicating that these genes affect production of bacteriocin antimicrobial peptides. qRT-PCR assays showed that the relative transcription levels of prcK and prcR mRNA in the ΔK and ΔR strains were 0.36 and 0.33 times of that in parental bacteria, respectively. Our data suggest that prcK and prcR are quorum sensing related genes that influence production of the bacteriocin Paracin 1.7. This research provides the basis for exploring the functions of these genes in the production of Paracin 1.7 and more generally for the exploration of the biological preservatives instead of chemical preservatives.