Le Trung-Son, Nguyen Phu-Tho, Nguyen-Ho Song-Hao, Nguyen Tang-Phu, Nguyen Thi-Tho, Thai My-Ngan, Nguyen-Thi To-Uyen, Nguyen Minh-Chon, Hoang Quoc-Khanh, Nguyen Huu-Thanh
Biotechnology Research and Development Institute, Can Tho University, Can Tho City, Vietnam.
Graduate University of Sciences and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam.
Arch Microbiol. 2021 Oct;203(8):4941-4950. doi: 10.1007/s00203-021-02479-0. Epub 2021 Jul 13.
Environmental factors can alter exopolysaccharide biosynthesis in lactic acid bacteria (LAB). To further clarify this potential relationship, the mRNA expression of genes involved in exopolysaccharide synthesis such as glmU, pgmB1, cps4E, cps4F, cps4J, and cps4H in Lactiplantibacillus plantarum VAL6 under different conditions including temperature, pH, sodium chloride (NaCl), and carbon dioxide (CO) intensification culture was studied. The transcriptomic data revealed that the exposure of L. plantarum VAL6 at pH 3 increased the expression level of cps4H but decreased the expression levels of pgmB1 and cps4E. Under pH 8, cps4F and cps4E were significantly upregulated, whereas pgmB1 was downregulated. Similarly, the expression levels of cps4F, cps4E, and cps4J increased sharply under stresses at 42 or 47 °C. In the case of NaCl stress, glmU, pgmB1, cps4J, and cps4H were downregulated in exposure to NaCl at 7 and 10% concentrations while cps4E and cps4F were upregulated at 1 h of 10%-NaCl treatment and at 5 h of 4%-NaCl treatment. Remarkably, CO intensification culture stimulated the expression of all tested genes. In addition, simultaneous changes in expression of cps4E and cps4F under environmental challenges may elicit the possibility of an association between the two genes. These findings indicated that the expression level of eps genes is responsible for changes in the yield and monosaccharide composition of exopolysaccharides under environmental stresses.
环境因素可改变乳酸菌（LAB）中胞外多糖的生物合成。为进一步阐明这种潜在关系，研究了植物乳杆菌VAL6在不同条件下（包括温度、pH值、氯化钠（NaCl）和二氧化碳（CO）强化培养）参与胞外多糖合成的基因（如glmU、pgmB1、cps4E、cps4F、cps4J和cps4H）的mRNA表达。转录组数据显示，植物乳杆菌VAL6在pH 3条件下培养会增加cps4H的表达水平，但会降低pgmB1和cps4E的表达水平。在pH 8条件下，cps4F和cps4E显著上调，而pgmB1下调。同样，在42或47°C胁迫下，cps4F、cps4E和cps4J的表达水平急剧增加。在NaCl胁迫情况下，当暴露于浓度为7%和10%的NaCl时，glmU、pgmB1、cps4J和cps4H下调，而在10% NaCl处理1小时和4% NaCl处理5小时时，cps4E和cps4F上调。值得注意的是，CO强化培养刺激了所有测试基因的表达。此外，在环境挑战下cps4E和cps4F表达的同时变化可能引发这两个基因之间存在关联的可能性。这些发现表明，在环境胁迫下，eps基因的表达水平决定了胞外多糖产量和单糖组成的变化。
