1a. Objectives (from AD-416):
The objective of this project is to determine which stress response proteins or detoxification enzymes are expressed in response to codling moth exposure to “reduced-risk” insecticides and granulosis virus, as well as to evaluate potential compounds that inhibit pheromone production by codling moth females.
1b. Approach (from AD-416):
We will: 1) clone gene transcripts encoding codling moth heat shock proteins and detoxification enzymes. Quantify expression levels of codling moth heat shock proteins and detoxification enzymes from untreated eggs, neonates, and adults or those exposed to heat, cold, or sub-lethal doses of Altacor, Delegate, Calypso and granulosis virus; and 2) Clone gene transcripts encoding for codling moth PBAN receptors (PBANR). Express cloned receptors in mammalian cell lines. Verify PBANR activity and determine if PBAN antagonists block receptor activity. Test compounds on female codling moth to determine biological activity in pheromone biosynthesis inhibition.
3. Progress Report:
Work summarized in this progress report relates to objectives number 1 and 2 in the Project Plan for 001-00D: 1. Develop new knowledge of the behavior, genetics, systematic, physiology, ecology, and biochemistry of the insect pests of apple, pear, and cherry, and their natural enemies, that will aid in the discovery, development, and application of management methods and technologies. 2. Identify genes, receptor proteins, and respective ligands that are critical to codling moth development and reproduction. To reduce the environmental and safety concerns associated with organophosphates and other harsh insecticides, orchardists have switched to the newer, “reduced-risk” chemistries (Altacor® - rynaxypyr, Delegate® - spinetoram, and Calypso® - thiacloprid) for codling moth control. These new chemistries have been effective in codling moth control; however, orchardists are concerned about the potential development of resistance to these agents. The overall goal of this project is to study the molecular mechanisms the codling moth may use to develop resistance to these “reduced-risk” insecticides. These molecular mechanisms will include target modifications (nicotinic acetylcholine receptors - spinetoram and thiacloprid; ryanodine receptor –rynaxypyr) and expression of detoxification enzymes (cytochrome P450s, esterases, and glutathione S-transferases). Our first objective was to obtain the sequences for gene transcripts encoding for the targets and potential detoxification enzymes for the “reduced-risk” insecticides. Through a codling moth transcriptome, we have identified transcripts encoding for nicotinic acetylcholine receptors (20 including splice variants), the ryanodine receptor (1), cytochrome P450s (76), esterases (50) and glutathione S-transferases (20). We are currently in the process of cloning each transcript to verify their expression and nucleotide sequence.