Management of Ralstonia solanacearum in tomato using ZnO nanoparticles synthesized through Matricaria chamomilla
Matricaria chamomilla flower extract was used as a biocompatible material for synthesis of zinc oxide nanoparticles (ZnONPs). The synthesized NPs were evaluated for their antibacterial potential in vitro and in vivo against Ralstonia solanacearum that causes devastating bacterial wilt disease in tomato and other crops. Synthesized ZnONPs were further analyzed by UV-Visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The synthesized polydisperse ZnONPs were found to be in the size range of 8.9 to 32.6 nm, and at 18.0 µg ml-1 exhibited maximum in vitro growth inhibition of R. solanacearum. SEM analysis of affected bacterial cells showed morphological deformation such as disruption of cell membrane, cell wall and leakage of cell contents. Results of in vivo studies also showed that application of ZnONPs to the artificially inoculated tomato plants with R. solanacearum significantly enhanced the plant growth by reducing bacterial soil population and disease severity as compared to untreated control. Biosynthesized ZnONPs could be an effective approach to control R. solanacearum.