Methyl anthranilate: A novel quorum sensing inhibitor and anti-biofilm agent against Aeromonas sobria

Quorum sensing (QS), bacterial cell-to-cell communication, is a gene regulatory mechanism that regulates virulence potential and biofilm formation in many pathogens. Aeromonas sobria, a common aquaculture pathogen, was isolated and identified by our laboratory from the deteriorated turbot, and its potential for virulence factors and biofilm production was regulated by QS system. In view of the interference with QS system, this study was aimed to investigate the effect of methyl anthranilate at sub-Minimum Inhibitory Concentrations (sub-MICs) on QS-regulated phenotypes in A. sobria. The results suggested that 0.5 μL/mL of methyl anthranilate evidently reduced biofilm formation (51.44%), swinging motility (74.86%), swarming motility (71.63%), protease activity (43.08%), and acyl-homoserine lactone (AHL) production. Furthermore, the real-time quantitative PCR (RT-qPCR) and in silico analysis showed that methyl anthranilate might inhibit QS system in A. sobria by interfering with the biosynthesis of AHL, as well as competitively binding with receptor protein. Therefore, our data indicated the feasibility of methyl anthranilate as a promising QS inhibitor and anti-biofilm agent for improving food safety.