Abstract:In recent years, the formation mechanism of bacterial biofilms has been frequently investigated by researchers locally and abroad, but the formation mechanism of probiotic biofilms remains unclear. In our laboratory, Lactobacillus plantarum GIM1.648 has been used as a model strain to explore the effects of biofilm formation on stress resistance and antibacterial properties. However, the mechanism of biofilm formation has not been elucidated. Understanding the mechanism of probiotic biofilm formation will aid in promoting the formation of biofilms through molecular methods in the future, thereby enhancing the efficacy of probiotics. Therefore, the formation mechanism of the L. plantarum GIM1.648 biofilm was investigated in this study. Gene Ontology (GO) function enrichment analysis showed that the differentially expressed genes between the biofilm and planktonic state were annotated to 338 GO entries. The synthesis and metabolism of proteins and polysaccharides were found to affect the biofilm formation of L. plantarum GIM1.648 on the surface of electrospun fiber membranes. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the differentially expressed genes were annotated to 56 pathways; pyrimidine metabolism, the two-component system, and tryptophan biosynthesis of L. plantarum GIM1.648 were identified as key factors in promoting biofilm formation. In addition, the expression levels of genes related to the regulation of fatty acid biosynthesis, peptidoglycan synthesis, and ABC transport were upregulated, which beneficial for enhancing the tolerance of the bacteria to adverse environmental conditions. The luxS gene expression level of the biofilm cells was 8.7 times that of the planktonic cells. This study provides a preliminarily clarification of the formation mechanism of L. plantarum GIM1.648 biofilm, thus establishing a basis for utilizing biofilms to improve the stability of probiotics.
