The yesN gene encodes a carbohydrate utilization regulatory protein in Lactobacillus plantarum

The gene yesN encodes a putative carbohydrate utilization response regulator in Lactobacillus plantarum. In order to determine the regulatory function of the yesN in L. plantarum, a yesN null mutant strain, L. plantarum ΔyesN, was constructed and confirmed by PCR and sequencing analyses. Using glucose, sucrose, and inulin as the sole carbon source, the mutant strain displayed a lower growth rate than the wild type. The transcriptions of genes in media containing glucose, sucrose, and inulin were analyzed by reverse-transcription quantitative polymerase chain reaction (RT-qPCR). The results indicated that, compared to the basal level, the transcription of yesN was increased from 3.73-fold to 4.33-fold by the test sugars, and the expressions of yesM, dexB, and sacK were increased by test sugars in L. plantarum WT, but decreased in L. plantarum ΔyesN. Simultaneously, the transcriptions of the genes scrA, scrR, and sacK1 with sucrose and inulin as carbon sources were decreased from 81.0 % to 88.8 % in L. plantarum ΔyesN compared to the wild-type strain. These results indicated that yesN plays significant roles in the utilization of carbohydrates such as glucose, sucrose, and inulin, and shed lights on the carbohydrate metabolic pathways of the bacterium.