Varronia curassavica Jarq. Essential Oils Inhibit the Formation of the Biofilm of Xanthomonas campestris pv. campestris in vitro.

Abstract The aim of this study was to investigate the anti-biofilm activity of two essential oils from Varronia curassavica Jaq. Two genotypes (VCUR-202 and VCUR-302), previously identified as exhibiting high antimicrobial activity against Xanthomonas campestris, were selected for this study. Use of Crystal Violet (CV) and Phenol Red (PR) staining of biofilm biomass demonstrated that both Essential Oils (EOs) had strong effect on both biofilm formation and preformed biofilm. The EOs effects on biofilm was confirmed with scanning electron microscopy where the changes in biofilm structure were noticed. Furthermore, results obtained show that sub-inhibitory concentrations of EOs were able to inhibit biofilm formation. Our findings show that EOs from V. curassavica exhibit strong anti-biofilm activity and might be used as a potential agent to controlX. campestris biofilm. Significance and Impact of the Study: This study provides useful information for the development of natural treatments for black rot caused by X.campestris. Studies on the cellular mechanisms involved in antimicrobial and antibiofilm activities are ongoing. These steps are essential for future in vivo tests using these essential oils to control black rot caused by Xcc.