Abstract
Background:
Gut microbiota are the potential sources of probiotics, playing an essential role in maintaining intestinal health. Limosilactobacillus reuteri PSC102 (L. reuteri PSC102), which was isolated from feces of healthy pigs, exhibited health-beneficial properties.

Aim:
We aimed to conduct the whole genome sequencing analysis of L. reuteri PSC102 to determine its molecular characteristics as a probiotic strain.

Methods:
L. reuteri PSC102 was cultured in a De Man-Rogosa-Sharpe medium, followed by DNA extraction for genomic analysis using the PacBio-Illumina sequencing platform. The EzBioCloud software was used to carry out the gene assembly, and the genes were interpreted by the National Center for Biotechnology Information (NCBI) and the Glimmer program. Core and pan-genomic analyses were performed to assess the extent of functional conservation in the genomic sequence. Moreover, the NCBI database and the Basic Local Alignment Search Tool (BLAST) software were used to determine the antimicrobial resistance genes and virulence factors.

Results:
L. reuteri PSC102 consists of a single circular chromosome possessing 2,048,626 bp with a GC of 38.9% and encodes 18 rRNA genes and 69 tRNA genes. Among the 1846 protein-coding sequences, genes associated with probiotic characteristics were found, including genes involved in host-microbe interactions, stress tolerance, biogenesis, and defense mechanisms. Furthermore, the genome of L. reuteri PSC102 comprises 2,446 pan-genome and 1,222 core-genome orthologous gene clusters. A total of 74 unique genes were identified in the genome of L. reuteri PSC102. These genes mostly encoded proteins potentially involved in transport and the metabolism of amino acids and carbohydrates. Moreover, the antibacterial resistance genes and virulence factors were absent in L. reuteri PSC102.

Conclusion:
Taken together, the results of the molecular insight into L. reuteri PSC102 corroborates its use as a probiotic in humans and other animals.

Key words: Antimicrobial resistance genes, Genomic feature, Phylogenetic tree, Probiotic, Virulence genes.