The maltose transporter subunit IICB of the phosphotransferase system: An important factor for biofilm formation of Cronobacter.

Cronobacter is a common food-borne opportunistic pathogen, which is easily to form biofilm and difficult to remove. The regulation mechanism on the biofilm formation of Cronobacter has drawn more and more attention. In here, transcriptomic sequencing of free and biofilm states of Cronobacter was performed, and analyzed to identify the differential gene expression through Gene Ontology (GO) function, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Based on sequencing analysis of the results, the malX gene encoding maltose transporter subunit IICB in the phosphotransferase system (PTS) might be involved in the formation of Cronobacter biofilm and thus selected for gene knockout. Hereafter, the changes in biofilm formation ability, extracellular polymer and biofilm-related gene expression of malX gene knockout strains were detected to explore the potential mechanism of malX gene on biofilm formation of Cronobacter. From the result, weaken biofilm formation ability of Cronobacter, decreased extracellular polysaccharide content and down-regulated expression of cellulose-related genes were obtained after knockout of malX gene, which verified our deduction. This study is the first to elucidates the regulation mechanism of the PTS on the biofilm formation of Cronobacter, which lays a foundation for the further prevention and control of food contamination caused by Cronobacter.