Protective role of biosynthesized silver nanoparticles synthesized using sesame oil as biocontrol approach against Erwinia amylovora causing fire blight in pears (Pyrus communis L.)

Abstract

Erwinia amylovora, the primary cause of fire blight, is thought to be one of the most difficult crop diseases to eradicate. The study aimed to evaluate the performance of essential sesame oil (SO) and silver nanoparticle synthesized by sesame oil SO-AgNPs against E. amylovora. Using GC-MS, it was found that essential sesame oil contains the main component of the oil was sesamin, asarninin, heptane, c-Sitosterol, anethol, and trimethyl -6- ((s) - 4-methylcyclohexan – 3 – en-1-yl)) tetrahydro -2H-pyran. The diluted sesame oil (SO) was used as a reducing agent in synthesis of AgNPs in aqueous solution. By using UV-Visible spectrophotometry (UV–Vis), Dynamic Light Scattering (DLS), High Resolution Transmission Electron Microscopy (HRTEM), and Fourier Transformer InfraRed (FTIR) analysis, the produced Ag NPs were studied. The average particle size of the spherical Ag NPs was determined to be 54.98 nm using data from HRTEM and DLS. SO-Ag NPs (20 µg/ml) showed a promising antibacterial against E. amylovora, producing a 22.9 mm Zone of Inhibition (ZOI) against E. amylovora, followed by SO-Ag NPs (10 ug/ml) that gave 18.2 mm ZOI., compared to gentamicin that produced 13.2 mm ZOI. The most effective inducers were SO-Ag NPs at 10 ug/ml, which decreased the percentage of disease severity by 27.5 and increased the percentage of protection against disease infection by 68.39%. SO-Ag NPs was the most effective inducers which decreased the contents of Malonaldehyde (MDA) and H2O2 by 41.3% and 77.1%. Applying SO-Ag NPs or SO lowered the level of malondialdehyde (MDA) and hydrogen peroxide (H2O2) and improved the fruit set and yield in infected trees. We could assume that, to prevent E. amylovora fire blight disease in pears, SO-Ag NPs, SO are safe, effective, and environmentally friendly alternatives to conventional antibiotics.

Keywords

• biocontrol agents
• Erwinia amylovora
• nanoparticles
• sesame oil