Impact of salicylic acid on biofilm formation by plant pathogenic bacteria

Abstract

The biofilm lifestyle gives bacteria distinct advantages over the planktonic lifestyle, as bacteria in such multicellular assemblages are protected from fluctuations in environmental conditions, antibiotics and host defenses. Biofilm formation, as well as motility, is controlled by density-dependent regulatory mechanism of cell-to-cell communication called quorum-sensing (QS). In this study we have shown that salicylic acid (SA), a plant-produced phenolic compound inhibits biofilm formation, motility and N-Acyl homoserine lactone production by Pectobacterium carotovorum and Pseudomonas syringae pv syringae at subinhibitory concentrations. We’ve also provided evidence that SA induces biofilm formation by Pseudomonas corrugata while inhibiting its motility. SA had no effect on biofilm formation by Xanthomonas campestris pv campestris and slightly increased its motility. Erwinia amylovora was insensitive to SA treatment.