Characterization and potential mechanism of resistance to double-stranded RNA in willow leaf beetle, Plagiodera versicolora

Abstract

Abstract RNAi-based pesticides have emerged rapidly in recent decades and are believed to be the third generation of pesticides. Although two case studies of the resistance to RNA pesticides have been reported in western corn rootworm and Colorado potato beetle, whether RNAi-resistance is general phenomena in other coleopteran insects and the underlying mechanism of resistance to RNA pesticides are largely unknown. Here we report the development of a highly (> 4110-fold) dsRNA-resistant population (Pv-30R) of Plagiodera versicolora by feeding a laboratory-rearing susceptible population (Pv-S) with the leaves of willow plants after seven episodes of selection using foliar coating dsRNA targeting a signal recognition particle protein 54k gene. We showed that Pv-30R was cross-resistant to another dsRNAs (dsActin and dsSnap) but susceptible to the Cry3Bb protein from Bacillus thuringiensis, and the resistance was an autosomal and recessive trait. Although no significant differences of the dsRNA stability in the midgut of larvae between Pv-S and Pv-30R were observed, uptake of dsRNA in the midgut tissue of larvae from Pv-30R was impaired. Overall, these results demonstrate that high-levels of resistance to RNA pesticides can developed quickly in P. versicolora in laboratory condition. These findings highlight the requirements to counter the potential rapid evolution of insect resistance to dsRNA in the field.