1a. Objectives (from AD-416):
Molecular-based research identifying protein and RNAi molecules that have insect deterrent activity when ingested by the insect pests (Asian citrus psyllid Diaprepes, root weevil and Whitefly) of citrus.
1b. Approach (from AD-416):
Use of insect bioassays and development of transgenic plants to study the activity of protein and RNAi molecules against pest insects of agriculture. Specific methods include dsRNA and peptide synthesis, mRNA and protein characterization insect feeding bioassays and development of transgenic plants.
3. Progress Report:
This project is related to Objective 3b: Develop novel control methods based on disrupting key processes in pest biology. We previously identified that we could induce mortality in the psyllid by ingestion of dsRNAs composed of sequences that match the sequence of an essential gene within the psyllid. This mortality is sequence specific and linked to specific down regulation of the targeted gene through a mechanism termed RNA interference (RNAi). Through collaboration with University of Florida researchers, we have now shown that this can be incorporated into a psyllid control strategy. This was achieved by using a Citrus tristeza virus expression vector to produce infected citrus plants that synthesize these dsRNAs. When adult psyllid were allowed to feed on leaves of these plants, psyllid survival was significantly reduced. This new strategy for psyllid control was further advanced by screening for dsRNA gene targets using a feeding bioassay incorporating an artificial diet. Also, fifty different psyllid genes were targeted representing 10 major gene ontology classes of biological function. This research showed the importance of targeting specific biological systems as a means of obtaining sustainable control.