Abstract: In this study, we aimed to establish a qualitative and quantitative method for the potential probiotic strain of Lactobacillus plantarum HNU082 using traditional selective isolation and culture method and genomic technology. For the purpose of qualitative analysis, the specific DNA fragment of the strain was selected by comparative genomics based on its whole genome sequence. Primers were designed targeting this DNA fragment and validated by using it to co-amplify L. plantarum HNU082 with other strains of L. plantarum. Subsequently, based on the annotation of antibiotic resistance genes from the whole genome of strain HNU082, the corresponding antibiotics were selected for verification, which made it easier to isolate L. plantarum HNU082 from the intestinal contents of the host. The qualitative analysis of the strain was accomplished by bacterial isolation using a selective medium and verification of the specific primers. Besides, using the specific primers of the strain, the quantitative analysis of the copy number of the strain was performed by quantitative real-time PCR. Finally, we validated the feasibility and accuracy of this method through a rat experiment. The qualitative and quantitative method will provide important methodological support for the in vivo study of priobiotic Lactobacillus.

Key words: Lactobacillus plantarum; intestinal tract; antibiotic resistance gene; specific gene sequence; real-time polymerase chain reaction