Sucrose metabolism is a fitness determinant of Lactobacillus plantarum in the digestive tract

We previously showed Lactobacillus plantarum WCFS1 (a single colony isolate of L. plantarum NCIMB 8826) survived in significantly higher numbers in mice fed high-fat, high-sucrose diet (HFHSD) compared to low-fat, polysaccharide-rich diet (LFPPD). However, the importance individual dietary components in the HFHSD on L. plantarum intestinal survival is unknown. To investigate the contribution of dietary sucrose on L. plantarum in vivo, we constructed a mutant of L. plantarum NCIMB 8826 deficient in sucrose utilization (strain LM0187). Strain LM0187 survived in 2.6-fold higher numbers compared to wild-type cells in the mouse digestive tract (P=0.0002). Neither strain changed the intestinal microbiota composition according to 16S rRNA gene sequencing of the mouse stools. However, co-occurrence analysis identified different microbial interactions upon ΔscrB feeding including new negative correlations between Cetenibacterium and Dialister as well as Clostridiales and Coprococcus. Fecal metabolome measurements identified modest but non-overlapping changes upon NCIMB8826-R and LM0187 feeding compared to the PBS-fed controls. Notably, fecal glycerol concentration in LM0187-fed mice were significantly higher than both NCIMB8826-R and control mice accompanied with reduced quantities of the predicted glycerol metabolism gene (K04069, pyruvate formate lyase activating enzyme) in this group. Taken together, we found that sucrose metabolism lowers L. plantarum in vivo fitness, likely as a result of changed interactions and metabolism of the intestinal microbiota.