Comparative genomics and functional analysis of a highly adhesive dairy Lactobacillus paracasei subsp. paracasei IBB3423 strain

arious Lactobacillus paracasei strains are found in diverse environments, including dairy and plant materials and the intestinal tract of humans and animals, and are also used in the food industry or as probiotics. In this study, we have isolated a new strain L. paracasei subsp. paracasei IBB3423 from samples of raw cow milk collected in a citizen science project. IBB3423 showed some desired probiotic features such as high adhesion capacity and ability to metabolize inulin. Its complete genome sequence comprising the chromosome of 3,183,386 bp and two plasmids of 5986 bp and 51,211 bp was determined. In silico analysis revealed numerous genes encoding proteins involved in carbohydrate metabolism and of extracellular localization likely supporting interaction with host tissues. In vitro tests confirmed the high adhesion capacity of IBB3423 and showed that it even exceeds that of the highly adhesive L. rhamnosus GG. Curing of the larger plasmid indicated that the adhesive properties depend on the plasmid and thus could be determined by its pilus-encoding spaCBA genes.