RNA interference (RNAi) in Homalodisca vitripennis.

Several very important plant diseases are caused by Xylella fastidiosa, a Gram-negative bacterium vectored by xylem feeding leafhoppers, including the very robust and efficient vector, Homalodisca vitripennis. The glassy winged sharpshooter, H. vitripennis, invaded California in the late 1980’s and was associated with X. fastidiosa epidemics. Here, we investigated RNA interference (RNAi) activity in H. vitripennis from a fundamental and practical perspective. Candidate RNAi inducers (double-stranded RNAs) were delivered to H. vitripennis nymphs via intrathoracic injection. Real-time RT-PCR, RNA hybridization, protein immunoblotting and microscopic analyses were employed to assess RNAi effects. Real-time RT-PCR showed significant decreases in 7 Homalodisca vitripennis target mRNAs. Altered phenotypic effects, including death, also were evident in 5th instar H. vitripennis nymphs injected with dsRNAs against the H. vitripennis actin, and siRNAs, hallmarks of RNAi, were observed. This whole insect-based RNAi approach offers new opportunities to research hemipterans, the most important insect vectors of plant pathogens, and potentially to find alternatives in controlling insect vectors of plant diseases.