Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/30/2009
Publication Date: 1/13/2010
Publication URL: http://hdl.handle.net/10113/40573
Citation: Wanner, K.W., Nichols, A.S., Allen, J.E., Bunger, P., Garczynski, S.F., Linn, C.J., Robertson, H.M., Luetje, C.W. 2010. Sex Pheromone Receptor Specificity in the European Corn Borer Moth, Ostrinia nubilalis. PLoS One. 5(1):e8685. doi:10.1371/journal.pone.0008685. Interpretive Summary: Larvae of moth species are among the most destructive pests of agriculture. To reduce chemical insecticide contamination of the environment, agriculturalists need non-pesticidal methods to control lepidopteran pests. Scientists at the USDA-ARS Yakima Agricultural Laboratory in Wapato, WA in conjunction with Researchers at the Montana State University are conducting research to better understand the sense of smell in insect pests, including major pests of tree fruit such as the codling moth, obliquebanded leafroller and light brown apple moth. Pheromones are currently used for mating disruption, wherein synthetic sex pheromones are used to interfere with male moths finding females, reducing pest reproduction and the use of insecticides. Researchers identified pheromone receptors in the European corn borer, a major moth pest of agriculture. This new information provides scientists a better understanding of the sense of smell in insect pests, and a potential biochemical assay method for developing superior disruptants.
Technical Abstract: The European corn borer (ECB), Ostrinia nubilalis, exists as two separate sex pheromone races. ECB(Z) females produce a 97:3 blend of Z11- and E11-14:OAc whereas ECB(E) females produce an opposite 1:99 ratio of the Z and E isomers. Males of each race respond specifically to their conspecific female’s blend. A closely related species, the Asian corn borer (ACB), O. furnacali, uses a 3:2 blend of Z- and E-12:14:OAc, and is believed to have evolved from an ECB-like ancestor. To understand better the molecular mechanisms of pheromone detection and their evolution among closely related species we identified and characterized 5 sex pheromone receptors from ECB Z-race males. The transcripts of OnOrs1 and 3-6 are 14-100 times more abundant in male compared to female antennae. When expressed in Xenopus oocytes, OnOr6 was highly selective for Z11-14:OAc (EC50 = 0.86 ± 0.27 µM) and was at least three orders of magnitude less responsive to E11-14:OAc. Surprisingly, OnOr1, 3 and 5 responded to all four pheromones (Z11-14:OAc, E11-14:OAc, Z12-14:OAc and E12-14:OAc) and to Z9-14:OAc, a behavioral antagonist for both ECB and ACB males. OnOr1 was selective for E12-14:OAc based on an efficacy that was at least 5-fold greater compared to the other four components. This mix of broadly- and specifically-responsive pheromone receptors corresponds to published results of sensory neuron activity in vivo. Receptors broadly-responsive to a class of pheromone components may provide a mechanism for variation in male moth response that enables population level shifts in pheromone blend use.