A co-delivery nanosystem of dsRNA and nitenpyram for insecticide resistance management in Nilaparvata lugens.

Nilaparvata lugens has evolved high resistance to neonicotinoid insecticides such as nitenpyram (NTP), driven by detoxification-associated genes. RNA interference (RNAi) can suppress these genes and restore insecticide susceptibility, but delivering double-stranded RNA (dsRNA) in the field remains a major challenge because naked dsRNA degrades within hours. To overcome this barrier, a layered double hydroxide (LDH)-based nanocarrier for co-delivery of dsRNA and NTP (dsRNA@NTP@LDH) was developed. The nanoplatform was synthesized by one-step co-precipitation and electrostatic dsRNA adsorption, then characterized for size, charge, morphology, loading efficiency, and dsRNA protection. Optimal loading occurred at a 1:4 dsRNA:NTP@LDH mass ratio. LDH encapsulation protected dsRNA from RNase A degradation (retaining ∼160-fold more intact dsRNA than free dsRNA) and promoted its foliar uptake, systemic translocation, and retention in rice plants. Microinjection confirmed that silencing NlCYP6ER1 or NlERK significantly enhanced NTP susceptibility, raising mortality from 15.0% to 91.7% and 58.3%, respectively. Foliar spray of dsNlCYP6ER1@NTP@LDH and dsNlERK@NTP@LDH achieved 4.6-fold and 1.7-fold synergistic effects, respectively. This work establishes the integrated dsRNA-insecticide co-delivery nanoplatform that enables field-applicable foliar spray RNAi to combat neonicotinoid resistance in N. lugens, offering a highly specific and environmentally compatible resistance management strategy.