Targeted Silencing of Multiple Fusarium graminearum Genes via Graphene Quantum Dots Enhances RNAi-Based Control of Fusarium Head Blight in Wheat

Fusarium head blight (FHB), caused by the fungus Fusarium graminearum , is a devastating disease of wheat resulting in substantial yield loss and grain contamination with mycotoxins. While chemical fungicides are currently the primary control method, they carry significant risks to human and environmental health. The use of exogenous double-stranded RNA (dsRNA) to induce RNA interference (RNAi) against fungal genes is an effective and sustainable alternative for the control of FHB. In this study, we investigated the in - vitro and in - vivo effects of dsRNA targeting eights F. graminearum genes ( FgMGV1 , FgRAS1 , FgCOT1 , FgPp2A , FgCAK1 , FgTRI5 , FgGMK1 , and FgYCK1 ) that are responsible for growth and pathogenicity of Fusarium. To enhance delivery and stability of dsRNA, we utilized Graphene Quantum Dots functionalized with branched Polyethyleneimine as a nanocarrier. This surface modification provided a positive charge to facilitate more and stable dsRNA loading. Supplementation of dsRNA in liquid culture showed a range of inhibitory effects, with fungal biomass reductions of 60% to 90% relative to the control. In greenhouse assays, the spray application of GQD-dsRNA conjugate achieved a 75% reduction in the percentage of symptomatic spikelets, significantly outperforming naked dsRNA, which resulted in a 50% reduction compared to the water-treated control. Furthermore, treatment with the all-dsRNA mixture reduced the accumulation of the mycotoxin deoxynivalenol by 72% to 86% across the genotypes tested. Analysis of transcript abundance for FgRAS1 and FgPP2A confirmed the molecular mechanism, showing a reduction in gene expression in treated cultures by approximately one-third compared to controls. These results demonstrate that GQD-mediated spray induced gene silencing could offer efficient, target-specific, and environmentally friendly plant disease management strategy.