Compositional and functional features of the intestinal lactobacilli associated with different long-term diet types

It is well known that diet is one of the most important factors in shaping the host's intestinal microbiota. Lactobacillus, a common group of probiotic bacteria, is widely distributed in the host gut, and studies have linked changes in lactobacilli in the gut to differences in dietary habits. Different dietary habits may affect not only the structural composition but also the function of lactobacilli in the intestine. Therefore, we dissected 283 metagenomes from samples collected from individuals with different dietary habits, investigating the presence of different species of lactobacilli. We demonstrated that the highest abundance of lactobacilli was found in stool samples from omnivorous populations and that Ligilactobacillus ruminis (L. ruminis) and Lactiplantibacillus plantarum (L. plantarum) were more prevalent in these samples than in vegetarian and vegan samples. In addition, we determined that different dietary structures affected the functional potential of lactobacilli by reconstructing the metagenome-assembled genomes (MAGs) of L. ruminis (highest abundance) in the samples. L. ruminis strains associated with a vegetarian diet had a higher "replication, recombination and repair" functional potential and may also have a greater capacity for glutathione (GSH) synthesis and metabolism. The results of our analysis provide evidence for the possibility of a specific selection of lactobacillus strains for people with different dietary habits.