Inhibitory effects of 2-phenylacrylic acid on the virulence factors of Erwinia amylovora

Abstract:

Background Fire blight, caused by Erwinia amylovora, is a devastating bacterial disease affecting the global fruit plant industry of Rosaceae.Objective Explored the inhibitory effect of 2-phenylacrylic acid at subinhibitory concentrations against the quorum sensing of E. amylovora, aiming to underpin the development of novel control agents.Methods The minimum inhibitory concentration (MIC) of 2-phenylacrylic acid against strain Ea-213 was determined. The effects of 2-phenylacrylic acid at subinhibitory concentrations on the biofilm formation, extracellular polysaccharide production, motility, and activities of various cell wall-degrading enzymes were evaluated via crystal violet staining and the anthrone-sulfuric acid assayResults The MIC of 2-phenylacrylic acid was determined to be 1 mg/mL against strain Ea-213 and 0.5 mg/mL against the Gram-negative biosensor strain CV026. At subinhibitory concentrations, 2-phenylacrylic acid did not affect the growth of strain Ea-213 but exhibited pronounced quorum-quenching activity against CV026. At 1/2 MIC, 2-phenylacrylic acid significantly inhibited the biofilm formation, extracellular polysaccharide production, and motility of strain Ea-213. Furthermore, the compound markedly suppressed the activities of cellulase, xylanase, pectin lyase, and polygalacturonase secreted by E. amylovora. Particularly, 2-phenylacrylic acid exerted the most significant inhibitory effect on polygalacturonase, with an inhibition rate reaching 53.8% at 1/2 MIC.Conclusion 2-Phenylacrylic acid can effectively attenuate multiple key virulence factors of E. amylovora by interfering with its quorum sensing system, demonstrating considerable potential as a novel biocontrol agent against fire blight.