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Sex Pheromone Receptor Specificity in the European Corn Borer Moth, Ostrinia nubilalis

Permanent URL:
http://handle.nal.usda.gov/10113/40573
Abstract:
Background: The European corn borer (ECB), Ostrinia nubilalis (Hubner), exists as two separate sex pheromone races. ECB(Z) females produce a 97:3 blend of Z11- and E11-tetradecenyl acetate 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. furnacalis, uses a 3:2 blend of Z12- and E12-tetradecenyl acetate, and is believed to have evolved from an ECB-like ancestor. To further knowledge of the molecular mechanisms of pheromone detection and its evolution among closely related species we identified and characterized sex pheromone receptors from ECB(Z). Methodology: Homology-dependent (degenerate PCR primers designed to conserved amino acid motifs) and homology-independent (pyrophosphate sequencing of antennal cDNA) approaches were used to identify candidate sex pheromone transcripts. Expression in male and female antennae was assayed by quantitative real-time PCR. Two-electrode voltage clamp electrophysiology was used to functionally characterize candidate receptors expressed in Xenopus oocytes. Conclusion: We characterized five sex pheromone receptors, OnOrs1 and 3–6. Their transcripts were 14–100 times more abundant in male compared to female antennae. OnOr6 was highly selective for Z11-tetradecenyl acetate (EC50 = 0.86±0.27 µM) and was at least three orders of magnitude less responsive to E11-tetradecenyl acetate. Surprisingly, OnOr1, 3 and 5 responded to all four pheromones tested (Z11- and E11-tetradecenyl acetate, and Z12- and E12-tetradecenyl acetate) and to Z9-tetradecenyl acetate, a behavioral antagonist. OnOr1 was selective for E12-tetradecenyl acetate based on an efficacy that was at least 5-fold greater compared to the other four components. This combination of specifically- and broadly-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 the male moth response that enables population level shifts in pheromone blend use.
Author(s):
Wanner, Kevin W. , Nichols, Andrew S. , Allen, Jean E. , Bunger, Peggy L. , Garczynski, Stephen F. , Linn, Charles E. Jr. , Robertson, Hugh M. , Luetje, Charles W.
Subject(s):
Ostrinia nubilalis , Ostrinia furnacalis , insect pests , sex pheromones , races , isomers , chemical composition , males , females , smell , chemoreceptors , electroantennography
Note:
Includes references
Source:
PloS one 2010 Jan., v. 5, no. 1
Language:
English
Year:
2010
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.