Fusion dsRNA Enhances RNAi Efficiency and Broadens the Insecticidal Spectrum

Abstract RNA interference (RNAi) technology provides a precise strategy for green control of agricultural pests; however, its low efficiency and high cost still constrain its application. Constructing multitarget fusion dsRNA can significantly improve insecticidal efficiency. Using Tribolium castaneum as a model organism, three highly efficient silencing genes (RpS3, VhaSFD, and EF1) were screened. The results showed that the fusion dsRNA construct dsRVE–3 × 200 bp (200 bp per gene) had the most stable silencing performance, with an LD50 significantly lower than that of the single-gene dsRpS3. Based on the optimized parameters, a fusion dsRNA (named dsNLS) targeting Nilaparvata lugens, Locusta migratoria, and Sogatella furcifera was constructed. dsNLS was significantly superior to naked dsRNA in controlling these three pests, with mortality rates of 69.1%, 71.3%, and 93.4%, respectively, and was safe for nontarget organisms. This study confirms that fusion dsRNA can improve the insecticidal efficiency of RNAi and provides new perspectives for dsRNA design.