Management of Botrytis Grey mold of tomato using bio-fabricated silver nanoparticles.

• Green synthesis of silver nanoparticles using extract of Amaranthus viridus and their characterization. • Growing of tomato plants and induction of infection (Botrytis cinerea) in them. • Application of green synthesized silver nanoparticles on infected plants along with positive and negative controls. • Mitigation of biotic stress of fungal infection in tomato plants by silver nanoparticles treatment. Lycopersicum esculentum Mill. commonly known as tomato is an important crop grown all over the world. Tomato crops are badly affected by various abiotic and biotic stresses and one of the biotic stressors that harm L. esculentum is Botrytis cinerea causing grey mold disease. Botrytis grey mold can badly disturb all above-ground parts of the tomato plant. In this study, silver nanoparticles were used to mitigate the negative effects of B. cinerea on tomato growth. These nanoparticles were produced from the leaf extract of Amaranthus viridis L. and characterization was done using UV-Visible spectroscopy, Particle size analysis, X-ray diffraction analysis (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectrophotometer (FTIR). Characterization confirmed the synthesis of silver nanoparticles with an average size of 11.4 -25 nm and a spherical shape. XRD analysis exhibited diffracted intensities at the 2θ values of 38.5°, 44.65°, 63.2°, and 77.25° which is significant for silver nanoparticles. An in vivo pot experiment was performed to evaluate various physiological and biochemical parameters of tomato plants, including chlorophyll, proline, sugar, protein, and growth parameters like fresh, and dry weight of plants. The experiment revealed that all the physiological and biochemical parameters improved after the application of silver nanoparticles as compared to the control groups e.g., chlorophyll content was 39.69 µg/g after NPs' treatment whereas in control it was 30.44 µg/g. Similarly, carotenoids were 10.05 µg/g in control and 12.68 µg/g with NP treatment whereas membrane stability was 51.34 % in control and 59.26 % with NPs-treated plants. Protein, sugar, and proline content were 0.31 mg/g, 0.68 µg/g, and 0.19 µg/g in control as compared to 0.59 mg/g, 1.11 µmol/g, and 0.07 µg/g respectively in NPs-treated plants. Disease occurrence was significantly reduced to 0% in plants treated with 0.03-0.05% silver NPs. Therefore, this study suggested that bio-fabricated silver nanoparticles reduced the harmful effects of B. cinerea in tomatoes. [ABSTRACT FROM AUTHOR]