Cloning of a novel specific SCAR marker for species identification in Lactobacillus pentosus

Identifying Lactobacillus species using only phenotypic and genotypic (16S rDNA sequence analysis) techniques yields inaccurate results. The objective of this study was to develop species-specific primers based on randomly amplified polymorphic DNA (RAPD) fingerprinting to distinguish species within the closely related Lactobacillus plantarum group. One of these primers, OPD-3, produced a species-specific band that was found only in the tested Lactobacillus pentosus. This specific fragment was isolated from agarose gel and ligated into a vector for DNA sequencing. A pair of primers, SpOPD3Lpen-F1/R1, that were highly specific sequence-characterized-amplified-regions (SCARs) were designed according to the nucleotide sequences of the specific RAPD marker. These primers were used for PCR analysis of the template DNA of the Lactobacillus strains, and a single 542 bp species-specific band was found only in L. pentosus. Using PCR, a novel species-specific primer pair is shown to rapidly, accurately and effectively distinguish L. pentosus from other species in the L. plantarum group of probiotic bacteria.