Silver nanoparticles elicited physiological, biochemical, and antioxidant modifications in rice plants to control Aspergillus flavus

This study was carried out to analyze the effects of biogenic silver nanoparticles (AgNPs) on physiological, biochemical, and enzymatic attributes of rice plants against Aspergillus flavus. The plant-based AgNPs were synthesized by using the aqueous extract of Moringa oleifera leaves. The characterization of AgNPs was accomplished through UV-visible spectrophotometry, SEM, and energy-dispersive X-ray (EDX) analysis, which confirmed that the nanoparticles are crystalline and are less than 100 nm in size. The exogenous applications of different concentrations of AgNPs (25, 50, 75, and 100 mg/L) on rice plants in field experiments were used to control the proliferation of A. flavus. The effects of biosynthesized AgNPs were evaluated for physiological (relative water content, membrane stability index, and chlorophyll content), nonenzymatic metabolites (total phenolic, total flavonoid, proline, soluble sugar, and protein contents), and enzymatic metabolites (superoxide dismutase, peroxidase, and catalase) in rice plants under biotic stress, and 50 mg/L concentration of AgNPs was found to be effective to elicit biochemical modifications to reduce biotic stress. The 50 mg/L concentration of AgNPs was also effective in controlling the proliferation of fungal pathogen. The applications of AgNPs reduced the biotic stress by decreasing the production level of osmolytes, enzymatic, and nonenzymatic compounds but significantly increased the protein content.