Targeted silencing of resistance-associated genes by specific double-stranded RNA (dsRNA) is an attractive strategy for overcoming insecticide resistance in insect pests. However, silencing target genes of insect pests by feeding on dsRNA transported via plants remains challenging. Herein, a codelivery system of insecticide and dsRNA is designed by encapsulating imidacloprid and dsNlCYP6ER1 within zeolitic imidazolate framework-8 (ZIF-8) nanoparticles to improve the susceptibility of Nilaparvata lugens (Stål) to imidacloprid. With an average particle size of 195 nm and a positive surface charge, the derived imidacloprid/dsNlCYP6ER1@ZIF-8 demonstrates good monodispersity. Survival curve results showed that the survival rates of N. lugens treated with imidacloprid and imidacloprid@ZIF-8 were 82 and 62%, respectively, whereas, in the imidacloprid/dsNlCYP6ER1@ZIF-8 treatment group, the survival rate of N. lugens is only 8%. Pot experiments demonstrate that the survival rate in the imidacloprid/dsNlCYP6ER1@ZIF-8 treatment group was much lower than that in the imidacloprid treatment group, decreasing from 54 to 24%. The identification of NlCYP6ER1 expression and the fluorescence tracking of ZIF-8 demonstrate that ZIF-8 can codeliver dsRNA and insecticide to insects via rice. Safety evaluation results showed that the dsNlCYP6ER1@ZIF-8 nanoparticle had desirable biocompatibility and biosafety to silkworm. This dsRNA and insecticide codelivery system may be extended to additional insecticides with potential resistance problems in the future, greatly enhancing the development of pest resistance management.
Keywords: Nilaparvata lugens (Stål); NlCYP6ER1; ZIF-8; codelivery; imidacloprid.