Uridine diphosphate glucose pyrophosphorylase (UGPase) plays an important role in glucose metabolism, catalyzing the reversible formation and decomposition of UDP-glucose (UDPG). However, its function and regulatory mechanism in the freeze-drying stress response of Lactobacillus acidophilus are unknown. In this work, the genes LBA0625 and LBA1719 encoding UGPase of L. acidophilus ATCC4356 were overexpressed in Staphylococcus carnosus(S. carnosus) TM300. Compared with the control group, the UGPase activities increased by 41.66% and 35.49%, respectively, while the lyophilization-survival rates of the recombinant S. carnosus increased by 17.94% and decreased by 11.17%, respectively, indicating that the two UGPase genes respond differently to lyophilization stress. Over-expression of LBA1719 decreased the expression of genes gapA, gapB, and pgiA in carbohydrate metabolism and dapA, dapB, and dapE in amino acid metabolism, significantly changing the physiological characteristics of S. carnosus and decreasing its lyophilization survival rate. However, over-expression of LBA0625 did not affect these genes and led to an increase in survival rate. Our findings indicate that LBA0625, LBA1719, gapA, gapB, pgiA, dapA, dapB, and dapE are key genes for freeze-drying protection in lactic acid bacteria and provide a theoretical basis for analyzing the regulatory and molecular mechanisms of lyophilization resistance in Lactobacillus.
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