A Peek into the Relationship Between Probiotic Characteristics of Lactiplantibacillus plantarum Strains and Sortase A Gene Expression

Abstract

This study investigates the correlation between the expression of the sortase A gene and the probiotic characteristics of Lactiplantibacillus plantarum strains, with a focus on adhesion capabilities, acid tolerance, and bile salt resistance. Seven L. plantarum strains were isolated from traditional dairy products, including yogurt, doogh, cheese, butter, sour cream, kashk, and Lighvan cheese, and evaluated for their probiotic potential. Using real-time PCR, the expression of the sortase A gene was assessed, and the adhesion of these strains to Caco-2 cells-a model for human intestinal epithelial cells-was evaluated. Among the strains, L. plantarum MK08 exhibited the highest resistance to acidic conditions (pH 2.0) and bile salts (0.3%), along with the highest sortase A gene expression. While sortase A expression was not directly correlated with acid and bile tolerance, it was associated with enhanced adhesion capabilities, suggesting its role in probiotic colonization and persistence in the gastrointestinal tract. All L. plantarum strains demonstrated superior adhesion to Caco-2 cells compared to the non-pathogenic control strain Escherichia coli ATCC 25922. Phylogenetic analysis revealed that the sortase gene is conserved across Lactobacillus strains, with no significant differences between probiotic and non-probiotic strains. These findings provide valuable insights into the probiotic potential of L. plantarum, highlighting the functional role of sortase A in adhesion mechanisms and its evolutionary significance. This study underscores the potential of L. plantarum strains as promising probiotic candidates and lays the groundwork for further exploration of sortase-mediated adhesion in probiotic development.