The role of the phoP transcriptional regulator on biofilm formation of avian pathogenic Escherichia coli

PhoP plays an important role as a transcriptional regulator in the two-component phoP/phoQ regulatory system, which is widely present in Gram-negative bacteria. In this study, we used DNA microarray-based technology to evaluate the role of phoP in biofilm formation in avian pathogenic Escherichia coli (APEC). Differences in gene transcription between APEC wild-type and phoP mutant strains were determined. Mutation of the phoP transcriptional regulator affects the expression profile of genes involved in processes such as flagellar assembly, ABC transporters, quorum sensing, and bacterial chemotaxis. Deletion of phoP in APEC reduced biofilm formation, as indicated by crystal violet staining and scanning electron microscopy (SEM). In addition, the phoP gene was found to be associated with changes in bacterial drug resistance and cell-membrane-related properties. This study shows that phoP plays an important regulatory role in APEC biofilm formation, and provides new insights into strategies for preventing and controlling APEC infection.