A new technique for using gamma irradiation to enhance silver nanoparticles synthesized by chemical reduction and their effect on tomato early blight disease under field conditions

Early blight disease causes a significant loss in tomato production. This study focuses on the effective suppression of Alternaria solani, which causes huge losses in tomato yield. This research was conducted at the Egyptian Atomic Energy Authority Nuclear Research Centre. Infected plants were treated with silver nanoparticles (AgNPs). Two chemical materials, sodium borohydride and trisodium phosphate, were used for the synthesized silver nanoparticles. 1% polyvinylpyridine (PVP) was used as a stabilizer agent. AgNPs were exposed to several doses of gamma irradiation (0, 1.5, 3, 6, 12, and 24) kilo Gray (kGy) in order to enhance and maximize the effect of AgNPs on Alternaria solani. UV-Vis spectroscopy (UV), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were used to characterize AgNPs; sodium borohydride and trisodium citrate were used for the chemical reduction. AgNPs and AgNPs + gamma irradiation led to increases in shoot fresh weight and shoot dry weight; they also elevated the antioxidant enzymes, as well as peroxides and catalase, when compared with control (untreated) plants. AgNPs and AgNPs + gamma irradiation decreased the disease severity compared with the control untreated. Our study not only corroborates established trends in nanoagriculture but also introduces novel insights into the specific effects of gamma irradiation on AgNP that led to a decrease in this size in the quantum dot range (3-10) nm, as shown in Tem. By drawing parallels with the work of esteemed researchers in the field.