Transcriptome Analysis and Functional Gene Identification Reveals Potential Mechanisms of Heat Stress Response of Lactiplantibacillus Plantarum CGMCC8198

Lactiplantibacillus plantarum is an important probiotic bacterium and extensively applied to functional food. Its survival is strongly affected by the heat-shock process during manufacture. Acclimation is thought to be able to enhance bacteria resistance to heat stress. In this study, the results of transcriptomics and bioinformatics analysis showed that alcohol dehydrogenase adhE-like, phosphoribose-ATP pyrophosphatase hisE, flavodoxin ykuN, and dihydropterin aldolase folB might be related with heat resistance of L. plantarum CGMCC8198. Furthermore, after these genes were expressed in Escherichia coli, survival rate, hydrophobicity and membrane integrity of the recombinant bacteria under high temperature were also significantly improved. Besides, by screening the strains after multiple rounds of acclimation, a strain (XH) with better heat tolerance was obtained, and the results of qRT-PCR showed that these four genes, especially hisE, were upregulated in the acclimated strain when it was treated with high temperature. These findings indicated that adhE-like and some other potential genes could improve the heat resistance of lactic acid bacteria, and might be used as indicators for screening of heat-tolerant probiotics strains.