Strain-specific barcode PCR and quantitative PCR assay for identification and enumeration of kimchi starter, Leuconostoc mesenteroides DRC1506

Abstract

Leuconostoc mesenteroides DRC1506 has been used as a starter to ferment commercial kimchi products for good organoleptic quality in Korea. Monitoring the starter during kimchi fermentation is essential for maintaining its quality. In this study, L. mesenteroides DRC1506 strain-specific barcodes PCR method was developed by comparative pan-genome analysis, and it was applied to the rapid and accurate detection and quantification of starter during kimchi fermentation. As a result, four nucleotide sequences, 788 bp, 585 bp, 319 bp, and 161 bp, were chosen as unique sequences for specific primers to detect DRC1506. Of these, the three primer sets, for 788 bp, 585 bp, and 319 bp, showed specific binding and barcode pattern bands with the genomic DNA of DRC1506 when tested against the genomic DNA of various lactic acid bacteria. In addition, a standard curve for quantitative PCR analysis of DRC1506 was established using the 161bp primer set, and it was accurately used to quantify the L. mesenteroides DRC1506 during kimchi fermentation. In conclusion, newly developed PCR method can be applied to rapidly and accurately monitor the population changes of L. mesenteroides DRC1506 during the kimchi fermentation process.