Dickeya zeae, Pantoea ananatis, and Xanthomonas vasicola pv. vasculorum: Control with the use of nanoparticles

Abstract

ABSTRACT Metal oxide nanoparticles (NPs) possess antibacterial activities and can be used for the control of phytopathogenic bacteria. The objective of this work was to evaluate the antibacterial activity of pure and doped NPs against Dickeya zeae, Pantoea ananatis, and Xanthomonas vasicola pv. vasculorum in vitro, and to assess the efficacy of preventive and curative application of zinc oxide (ZnO), nickel oxide (NiO), and silver-doped zinc oxide (ZnO:Ag) NPs for the control of white spot (WS) and bacterial leaf streak (BLS) in vivo. Bacterial growth inhibition was first evaluated by measuring the diameter of the inhibition zone formed in Petri dishes. Subsequently, the severity of WS and BLS diseases was evaluated in a greenhouse calculating the area under the disease progress curve. The in vitro antibacterial activity was not influenced by the increase in the concentration of doping elements for most NPs. ZnO NPs doped with Ag, K, and Mo; ZnOCl doped with Ag, and pure NPs (Ag2O, CuO, and NiO) showed antibacterial activity against D. zeae, P. ananatis, and X. vasicola pv. vasculorum with relatively similar inhibition zones at different concentrations. Commercial copper showed antibacterial activity only against D. zeae. NiO NPs in preventive and curative applications reduced WS and BLS severities, whereas commercial copper application increased WS severity and reduced BLS severity. The use of NPs has promising applications and further evaluation of their formulation, application form, and timing is necessary for new strategies to control the activity of phytopathogenic bacteria.