Olfactory Molecular Targets for Reverse Chemical Ecology

Since the landmark characterization of bombykol more than five decades ago, bioassay-guided isolation of natural products led chemical ecologists to the discovery of hundreds of insect pheromones. These semiochemicals in turn paved the way for novel, environmentally friendly strategies for controlling agricultural pests. These green chemistry-based approaches are sorely needed in medical entomology to reduce mosquito bites and, consequently, mitigate transmission of devastating diseases like malaria, dengue, West Nile virus, etc. To circumvent the complex behavior of mosquitoes, we have devised a “reverse chemical ecology” approach to screen for potential attractants (and repellents) based on their binding affinity to olfactory proteins. With the advent of genome sequences we are now able to characterize the entire repertoire(s) of olfactory genes and study their function in olfactory tissues. I n this presentation, I will first describe the identification of odorant-binding proteins and odorant receptors from the Southern House mosquito Culex quinquefasciatus. Then, I will discuss their use as “molecular targets” for the identification of oviposition attractants, some of which will soon become commercially available for West Nile virus surveillance and to monitor and/or control populations of the Southern House mosquito.