Institute of Life Sciences and Resources and Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea.
Institute of Life Sciences and Resources and Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea.
Food Microbiol. 2020 Sep;90:103485. doi: 10.1016/j.fm.2020.103485. Epub 2020 Mar 13.
The Lactobacillus casei group, which includes the closely related species L. casei, L. paracasei, L. rhamnosus, and L. chiayiensis, has been under debate regarding its taxonomy because of the difficulty in distinguishing the species from each other. In the present study, we developed a novel real-time PCR assay for distinguishing the L. casei group species. The pan-genome, as determined by the genomes of 44 strains, comprised 6789 genes, comparative genomic analysis showed that L. casei group strains were classified by species. Based on these results, species-specific genes were identified, and primers were designed from those genes. Real-time PCR clearly distinguished each species of the L. casei group and specifically amplified only to the target species. The method was applied to 29 probiotic products, and the detected results and label claims were compared. Total 23 products were in accordance with the label claims, and the remaining products contained species different from those stated in the label claims. Our method can rapidly and accurately distinguish the L. casei group species in a single reaction. Hence, our assay can be applied to identify L. casei group species from food or environmental samples and to accurately determine the nomenclature of the species.
干酪乳杆菌组包括密切相关的物种干酪乳杆菌、副干酪乳杆菌、鼠李糖乳杆菌和干酪乳杆菌，由于难以区分彼此，其分类学一直存在争议。在本研究中，我们开发了一种用于区分干酪乳杆菌组物种的新型实时 PCR 检测方法。通过对 44 株菌基因组的全基因组分析，确定了包含 6789 个基因的泛基因组，比较基因组分析表明，干酪乳杆菌组菌株按物种分类。基于这些结果，鉴定了种特异性基因，并从这些基因中设计了引物。实时 PCR 能够清楚地区分干酪乳杆菌组的每个物种，并且仅特异性地扩增目标物种。该方法应用于 29 种益生菌产品，比较了检测结果和标签声称。共有 23 种产品与标签声称相符，其余产品中含有的物种与标签声称的不同。我们的方法可以在单个反应中快速准确地区分干酪乳杆菌组的物种。因此，我们的检测方法可用于从食品或环境样本中鉴定干酪乳杆菌组的物种，并准确确定物种的命名。
