Functional characterization of a female-biased chemoreceptor of the codling moth (Cydia pomonella) responding to aldehydes and other volatile compounds

Authors: CATTANEO, ALBERTO - Swedish University Of Agricultural Sciences; KWADHA, CHARLES - North Carolina State University; PULLMANN-LINDSLEY, HEIDI - Baylor University; ERDEI, ANNA - Swedish University Of Agricultural Sciences; PITTS, RONALD - Baylor University; Walker Iii, William

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2025
Publication Date: 2/25/2025
Citation: Cattaneo, A.M., Kwadha, C.A., Pullmann-Lindsley, H., Erdei, A.L., Pitts, R.J., Walker Iii, W.B. 2025. Functional characterization of a female-biased chemoreceptor of the codling moth (Cydia pomonella) responding to aldehydes and other volatile compounds. Journal of Chemical Ecology. 51(2);28. https://doi.org/10.1007/s10886-025-01579-1.
DOI: https://doi.org/10.1007/s10886-025-01579-1

Interpretive Summary: The codling moth, Cydia pomonella, is a globally established and prominent pest of apple, pear and walnut. For most insects, including the codling moth, the sense of smell, or olfaction, has a large influence on most vital behaviors. Decades of research on the sense of smell of the codling moth has led to innovative odorant-based pest management strategies that target the codling moth's olfactory system. This approach, however, is mainly aimed at male moths that react strongly to female-produced pheromones. Substantial gaps in our knowledge exist concerning the underlying mechanisms of olfaction for female moths. Odorant molecules are detected by a class of proteins known as odorant receptors, and previous research on codling moth olfactory system revealed several odorant receptors that are predominantly found in the female moth nose, the antennae, compared to male antennae. It is hypothesized that these female-biased receptors may be underlying female-specific behaviors, such as egg-laying. Researchers at the USDA-ARS in Wapato, WA, the Swedish University of Agricultural Sciences and Baylor University studied the function of one female-biased odorant receptor. They discovered that this odorant receptor is strongly activated by several odorants commonly found in apples, but it also responded to other chemically-similar odorants that were not previously known to affect codling moth's behavior. These results will drive further research on the role of these odorants in mediating female codling behaviors with the aim to augment pest management strategies by targeting female codling moths as well as males.

Technical Abstract: With the advent of semiochemical-based control strategies used to mitigate damage of agricultural pest moths, many studies have focused on the function of male-specific putative pheromone receptors (PRs). In this investigation, we instead isolated, heterologously expressed, and functionally characterized a female-biased candidate PR, CpomOR22, from the codling moth, Cydia pomonella. Using transgenic Drosophila melanogaster for single sensillum recording (SSR) and gas-chromatographic SSR, we tested both synthetic ligands and various apple headspace extracts, identifying saturated and unsaturated aldehydes (nonanal, decanal, undecanal, dodecanal; (Z)-4-undecenal and (Z)-6-undecenal) among the most active ligands. Parallel experiments expressing CpomOR22 in Xenopus oocytes confirmed the binding of nonanal, decanal and undecanal and revealed lactones ('-undecalactone and d-dodecalactone) and several carboxylic acids as additional active compounds. The renowned ecological importance of aldehydes for the codling moth and the potential for newly identified ligands, such as lactones, may inform innovative control strategies based on novel semiochemicals to interfere with the female-specific chemosensory systems of this insect.