Control of <i>Fusarium graminearum</i> Infection in Wheat by dsRNA-Based Spray-Induced Gene Silencing

Spray-induced gene silencing (SIGS) has become a new technology for pest and disease control in plants. This study synthesized three double-strand RNAs (dsRNAs) targeting <i>Fusarium graminearum</i> (<i>F. graminearum</i>), the major pathogen causing <i>Fusarium</i> head blight (FHB). Co-incubation showed weak uptake of dsRNA by <i>F. graminearum</i>, and some dsRNAs influence spore germination and hyphae growth. In contrast, exogenous dsRNA quickly and efficiently penetrates wheat leaves. Treatment of wheat leaves and detached wheat heads with these dsRNAs has a negative effect on the pathogenicity of <i>F. graminearum</i>. Foliar spraying of ds<i>CHS3b</i> or ds<i>MGV1</i> decreased the amount of artificially inoculated <i>F. graminearum</i>, the incidence rate, and disease severity in the field. Under natural conditions, spraying dsRNAs significantly decreased the FHB disease index and deoxynivalenol content. Twice spray achieved more than 90% control of FHB. In conclusion, SIGS effectively prevents the infection of <i>F. graminearum</i> in wheat, providing a green way for FHB control.