Reverse chemical ecology approach for the identification of a mosquito oviposition attractant

Authors: CHOO, YOUNG-MOO - University Of California, Davis; XU, PINGXI - University Of California, Davis; TAN, KAIMING - University Of California, Davis; BHAGAVATHY, GANGA - University Of Kentucky; Chauhan, Kamlesh; LEAL, WALTER - University Of California, Davis

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2017
Publication Date: 1/8/2018
Citation: Choo, Y., Xu, P., Tan, K., Bhagavathy, G., Chauhan, K.R., Leal, W. 2018. Reverse chemical ecology approach for the identification of a mosquito oviposition attractant. Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.1718284115.

Interpretive Summary: Certain volatile chemicals play a crucial role in today’s integrated pest and vector management strategies for controlling populations of insects causing loses to agriculture and vectoring diseases to humans. These chemicals are typically discovered by bioassay-guided approaches. Here, we applied a reverse chemical ecology approach, ie, we used insect proteins to lead us to putative attractant chemicals. Egg laying mosquito females and dual-choice assays demonstrated that acetaldehyde is an attractant in a wide range of concentrations and thus of potential practical applications.

Technical Abstract: Pheromones and other semiochemicals play a crucial role in today’s integrated pest and vector management strategies for controlling populations of insects causing loses to agriculture and vectoring diseases to humans. These semiochemicals are typically discovered by bioassay-guided approaches. Here, we applied a reverse chemical ecology approach, ie, we used olfactory proteins to lead us to putative semiochemicals.CquiOR36, which showed the highest transcript levels of all OR genes in female antennae, was also silent to all odorants in the tested panel, but yielded robust responses when it was accidentally challenged with an old sample of nonanal in ethanol. After confirming that fresh samples were inactive and through a careful investigation of all possible “contaminants” in the old nonanal samples, we identified the active ligand as acetaldehyde. That acetaldehyde is activating CquiOR36 was further confirmed by electroantennogram (EAG) recordings from antennae of fruit flies engineered to carry CquiOR36. Antennae of female mosquitoes also responded to acetaldehyde. Cage oviposition and dual-choice assays demonstrated that acetaldehyde is an oviposition attractant in a wide range of concentrations and thus of potential practical applications.