Pan-Genomics of Revealed Group-Specific Genomic Profiles without Habitat Association.

is a lactic acid bacterium that promotes animal intestinal health as a probiotic and is found in a wide variety of habitats. Here, we investigated the genomic features of different clusters of strains via pan-genomic analysis. We compared the genomes of 108 strains that were available from the NCBI GenBank database. These genomes were 2.9-3.7 Mbp in size and 44-45% in G+C content. A total of 8,847 orthologs were collected, and 1,709 genes were identified to be shared as core genes by all the strains analyzed. On the basis of SNPs from the core genes, 108 strains were clustered into five major groups (G1-G5) that are different from previous reports and are not clearly associated with habitats. Analysis of group-specific enriched or depleted genes revealed that G1 and G2 were rich in genes for carbohydrate utilization (-arabinose, -rhamnose, and fructooligosaccharides) and that G3, G4, and G5 possessed more genes for the restriction-modification system and MazEF toxin-antitoxin. These results indicate that there are critical differences in gene content and survival strategies among genetically clustered strains, regardless of habitats.