Antibacterial efficacy of iron oxide and silver nanoparticles against bacterial wilt pathogen Ralstonia solanacearum

The security of vegetable plants worldwide is threatened by bacterial wilts, one of the most infectious soil-borne bacterial plant diseases. This is caused by R. Solanacearum. Overuse of bactericides and antibiotics to combat bacterial wilt results in pesticide resistance and toxicity to beneficial living organisms. Consequently, nanoparticles are more beneficial, safe for the environment, and have strong antibacterial properties than conventional pesticides. In the present work, iron oxide nanoparticles (IONPs) and silver nanoparticles (AgNPs) were prepared by simple chemical, eco-friendly procedures, and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), size distribution, zeta potential, ultraviolet-visible (UV-vis) absorption spectra, and Fourier transform infrared spectra (FTIR). In vitro and in vivo tests were also used to assess the nanoparticles' antibacterial effectiveness against the phytopathogen R. solanacearum. The findings showed that NPs (nanoparticles) had strong antibacterial properties that changed according to concentration. The greenhouse toxicity study indicated that the NPs significantly impacted tomato bacterial wilt. The disease severity was successfully decreased by 27 and 67%, respectively, when IONPs and AgNPs were contrasted with the untreated infected plants that entirely wilted and died (100% disease severity). Therefore, as compared to infected plants, IONPs and AgNPs enhanced shoot and root length, fresh and dry weight, and chlorophyll content of tomato plants by two to five times. The findings show that the bacterial cell membranes were physically harmed by the direct attachment of NPs to their surfaces, as shown by transmission electron microscopy (TEM). In conclusion, this study provides evidence and strategies for preventing and controlling soil-borne bacterial wilt disease with an efficient and environmentally friendly metal oxide NPs. Furthermore, vegetable plant's nutritional value is enhanced by iron, which is essential for all living things.