Effects of Double-Stranded RNAs Targeting on Fusarium Head Blight and Mycotoxins.

is the causal agent of Fusarium head blight (FHB), which reduces crop yield and contaminates grains with poisonous trichothecene mycotoxins, including deoxynivalenol (DON). DON functions as an important virulence factor that promotes FHB spread in wheat; therefore, reducing DON production will decrease yield losses to FHB and increase food safety. Recent progress in the topical application of double-stranded RNA (dsRNA) to reduce infection has provided encouraging results. In this study, we designed and synthesized dsRNA targeting the transcription factor (-dsRNA), which is a key regulator of DON biosynthesis. The expression of was significantly lower in detached wheat heads treated with -dsRNA solution compared with the controls. Furthermore, -dsRNA treatments reduced disease and DON accumulation in inoculated detached wheat heads. Therefore, topical applications of dsRNA on wheat heads of intact plants were assessed for their ability to reduce FHB and DON under growth chamber and greenhouse conditions. When wheat heads were treated with -dsRNA solution in growth chamber conditions, -dsRNA treatments failed to prevent FHB spread. However, when wheat heads were treated with -dsRNA solution under greenhouse conditions, FHB and DON were significantly reduced, and infection was restricted to the inoculated floret. In addition, addition of -dsRNA to toxin induction liquid media had no effect on 15-ADON production. Our study demonstrates that the efficacy of dsRNA applications is strongly dependent on application methods and environmental conditions.