A ‘bacteriocin PCR array’ for identification of bacteriocin-related structural genes in lactic acid bacteria

Abstract

Bacteriocins have been identified in many strains of lactic acid bacteria (LAB) which are a source of natural food preservatives and microbial inhibitors. Our objectives were to use a PCR array of primers to identify bacteriocin structural genes in Bac+ LAB. DNA sequence homology at the 5′- and 3′-ends of the various structural genes indicated that non-specific priming may allow PCR amplification of heterologous bacteriocin genes. Successful amplification was obtained by real-time PCR and confirmed by melting curve and agarose gel analysis. Sequence information specific to targeted bacteriocin structural genes from the intra-primer regions of amplimers was compared to sequences residing in GenBank. The bacteriocin PCR array allowed the successful amplification of bacteriocin structural genes from strains of Lactobacillus, Lactococcus, and Pediococcus including one whose amino acid sequence was unable to be determined by Edman degradation analysis. DNA sequence analysis identified as many as 3 bacteriocin structural genes within a given strain, identifying ten unique bacteriocin sequences that were previously uncharacterized (partial homology) and one that was 100% identical to sequences in GenBank. This study provides a rapid approach to sequence and identify bacteriocin structural genes among Bac+ LAB using a microplate bacteriocin PCR array.