Overcoming resistance in insect pest with a nanoparticle-mediated dsRNA and insecticide co-delivery system

The cotton aphid Aphis gossypii Glover (Homoptera: Aphididae) is a notorious agricultural pest that has evolved high levels of resistance to various insecticides. Innovative RNA insecticides, as potential green plant protection products, are anticipated to alleviate the significant issue of pest resistance. Herein, a rough-surface hollow mesoporous silica (RHMS)-based gene/insecticide delivery system was constructed for the co-delivery of CYP6CY13 double-stranded RNA (dsRNA) and the chemical insecticide imidacloprid for the effective control of A. gossypii. The hollow mesoporous structure of RHMS facilitates insecticide loading and further combines with dsRNA through electrostatic interactions to form nanoscale complexes, while protecting the dsRNA from complete degradation by nucleases. The screened dsCYP6CY13 fragment was successfully expressed in the L4440-HT1115 (DE3) RNaseIII- system and inhibiting CYP6CY13 expression by RNA interference (RNAi) significantly increased the susceptibility of A. gossypii adults to imidacloprid. The toxicity of the RHMS/IMI/dsCYP6CY13 complex was significantly higher (1.95-fold) than that of imidacloprid. The results of the pot test showed that the effectiveness of the RHMS/IMI/dsCYP6CY13 complex against A. gossypii improved by 19.95 % in 5 days. Therefore, this nanoparticle-mediated gene/insecticide co-delivery system is expected to be an effective tool for pest control.