1a. Objectives (from AD-416):
Develop Asian citrus psyllid control strategy based on inhibition of crucial psyllid feeding processes used to locate the phloem tissue.
1b. Approach (from AD-416):
Use artificial diet for the Asian citrus psyllid (AsCP) to study molecular mechanism of highly specialized feeding process of the AsCP. Analysis will be through protein and genomic studies targeting the salivary glands and secreted salivary proteins. Use artificial diets to screen for chemicals/transgenic strategies that will inhibit the AsCP ability to form salivary sheaths that are needed for successful phloem feeding.
3. Progress Report:
First round screening of a 10-amino combinatorial peptide library provided by Torrey Pines Institute for Molecular Studies was completed and results show specific decameric peptide mixtures influence adult psyllid mortality/behavior when fed to the psyllids in an artificial diet. Different decameric peptide mixtures were identified that induced either higher or low mortality. This supported our hypothesis that decameric peptides can be identified that have oral toxicities in the psyllid, and that such peptides could be identified and incorporated into a psyllid control strategy. The next year will be spent completing the combinatorial library screen to identify individual decameric peptide sequences within the current mixes that are responsible for the observed affects. A novel methods for psyllid salivary sheath isolation was developed using soluble membranes through which psyllids would pierce and produce a salivary sheath that remained attached to the membranes. Large quantities of pure salivary sheaths were obtained using this method, Furthermore, this method was shown to work for numerous plant feeding hemipteran insects. Salivary sheath composition analysis revealed unique composition. This information was used to identify inhibitors of sheath formation and has opened to door to development of new hemipteran insect control strategies based on inhibition of this process.