RNA Interference as a Method for Target-Site Screening in the Western Corn Rootworm,Diabrotica Virgifera Virgifera

To test the efficacy of RNA interference (RNAi) as a method for target-site screening in Diabrotica virgifera virgifera LeConte (Coleptera: Chrysomelidae) larvae, genes were identified and tested for which clear RNAi phenotypes had been identified in the Coleopteran model, Tribolium castaneum . Here the cloning of the D. v. vergifera orthologs of laccase 2 (DvvLac2) and chitin synthase 2 (DvvCHS2) is reported. Injection of DvvLac2 -specific double-stranded RNA resulted in prevention of post-molt cuticular tanning, while injection of DvvCHS2- specific dsRNA reduced chitin levels in midguts. Silencing of both DvvLac2 and DvvCHS2 was confirmed by RT-PCR and quantitative RT-PCR. As in T. castaneum , RNAi-mediated gene silencing is systemic in Diabrotica . The results indicate that RNAi-induced silencing of D. v. vergifera genes provides a powerful tool for identifying potential insecticide targets.