Antibacterial Activity of Synthesized Silver Nanoparticles Using Sumac Aqueous Extract and Silver-Chitosan Nanocomposite against Xanthomonas perforans

One of the applications of nanotechnology is the use of different nanoparticles in the management of plant diseases. Bacterial spot of tomato caused by Xanthomonas perforans is a devastating disease of tomato that can reduce the quality and quantity of crop. This study aimed to evaluate the antibacterial effects of silver nanoparticles (AgNPs) and silver-chitosan nanocomposite against X. perforans. The nanoparticles were synthesized with sumac extract and the antibacterial activity of different concentrations of biosynthesized nanoparticles was evaluated with minimum inhibitory concentration method. The structure and physical properties of nanoparticles were investigated by scanning electron microscope and X-ray diffraction. The results showed that the AgNPs and nanocomposite had quasi-spherical shape in a uniform distribution with the average size about 35 and 50 nm respectively. Minimum inhibitory concentrations of green biosynthesized AgNPs and silver-chitosan nanocomposite were at concentrations of 17 mg/L, and 3 mg/L AgNPs/6.94 mg/L chitosan respectively. Also, in greenhouse experiments, nanoparticles at 10, 50 and 100 mg/L concentrations reduced the disease severity of the bacterial spot on seedlings when compared to the control. The greatest decrease in the disease severity was caused using 100 mg/L concentration of AgNPs (91.11%). The results of this study showed that synthesized nanoparticles had effective antibacterial activity against the causal agent of tomato bacterial spot.