AcrR and Rex Control Mannitol and Sorbitol Utilization through Their Cross-Regulation of Aldehyde-Alcohol Dehydrogenase (AdhE) in Lactobacillus plantarum

The function and regulation of AdhE in the important probiotic genus Lactobacillus are rarely reported. Here we demonstrated that AdhE is responsible for sorbitol and mannitol utilization and is cross-regulated by two transcriptional regulators in L. plantarum NF92, which had not been reported previously. This is important for L. plantarum to compete and survive in some harsh environments in which sorbitol or mannitol could be used as carbon source. A novel transcriptional regulator AcrR was identified to be important to promote the expression of adhE , which was unknown before. The cross-regulation of adhE by AcrR and Rex is important to balance the level of NADH in the cell during sorbitol or mannitol utilization.