Assessment of Different Antibacterial Effects of Fe and Cu Nanoparticles on Xanthomonas campestris Growth and Expression of Its Pathogenic Gene hrpE

Plant diseases cause severe damage to agricultural production and need to be effectively managed. The economic importance of the plant diseases and lack of effective control measures have led to many research in this field. Nanotechnology is one of the new techniques for disease control. The purpose of this study was to evaluate the antibacterial effects of copper and iron Nano­Particles (NPs) against a Xanthomonas campestris strain, as well as the study of these nanoparticles’ effects on expression of the pathogenic gene hrpE. The Zero-Valent Iron (ZVI) and copper nanoparticles were synthesized by chemical reduction method. Different concentration of nanoparticles of Fe and Cu were used in bacteria plate culture and the Minimum Inhibitory Concentrations (MIC) as well as Minimum Bactericidal Concentration (MBC) were determined using colony count and optical density methods. The effect of nanoparticles on pathogenic gene expression hrpE was studied using Real- Time PCR. Xanthomonas campestris strain exposed to zero-valent iron nanoparticles showed that the growth rate was increased with increase in the concentration of nano-iron. But, the growth percentage of bacteria Xanthomonas campestris was reduced with increase in the concentration of nano-copper. The expression levels of pathogenic gene expression hrpE were increased 9 and 3 fold for copper and iron, respectively. Copper and iron nanoparticles showed different effects on Xanthomonas growth.