RNA interference is induced in the glassy winged sharpshooter Homalodisca vitripennis by actin dsRNA

The glassy winged sharpshooter, Homalodisca vitripennis, is an unusually robust and efficient leafhopper vector of Xylella fastidiosa. X. fastidiosa is the causative agent of Pierce's disease, almond scorch, citrus variegated chlorosis and other serious plant diseases. The present study was conducted to establish whether RNA interference (RNAi) was induced in nymphal H. vitripennis that were injected with actin dsRNAs and other dsRNAs.

A dramatic reduction in target H. vitripennis actin mRNAs and the formation of small interfering RNAs (siRNAs), hallmarks of RNAi, were found following the injection of actin dsRNAs. Quantitative reverse transcription PCR indicated an 80% reduction in actin mRNA levels by 5 days post-injection. Western blot analysis showed a dramatic drop in actin protein levels by 3 days post-injection. Biological effects such as incomplete nymphal-adult ecdysis and > 95% mortality were also found following the injection of fifth-instar nymphs with actin dsRNA. Dramatic reductions in target mRNA levels were also found following the injection of other dsRNAs into fifth-instar H. vitripennis.

The findings indicate that RNAi is induced in post-embryonic leafhoppers by dsRNA. The present system can be used to screen potential gene-silencing targets that can be used for reducing the vector competence of H. vitripennis and other leafhoppers.