Article

Single mutation to a sex pheromone receptor provides adaptive specificity between closely related moth species

Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 08/2012; 109(35):14081-6. DOI: 10.1073/pnas.1204661109
Source: PubMed

ABSTRACT

Sex pheromone communication, acting as a prezygotic barrier to mating, is believed to have contributed to the speciation of moths and butterflies in the order Lepidoptera. Five decades after the discovery of the first moth sex pheromone, little is known about the molecular mechanisms that underlie the evolution of pheromone communication between closely related species. Although Asian and European corn borers (ACB and ECB) can be interbred in the laboratory, they are behaviorally isolated from mating naturally by their responses to subtly different sex pheromone isomers, (E)-12- and (Z)-12-tetradecenyl acetate and (E)-11- and (Z)-11-tetradecenyl acetate (ACB: E12, Z12; ECB; E11, Z11). Male moth olfactory systems respond specifically to the pheromone blend produced by their conspecific females. In vitro, ECB(Z) odorant receptor 3 (OR3), a sex pheromone receptor expressed in male antennae, responds strongly to E11 but also generally to the Z11, E12, and Z12 pheromones. In contrast, we show that ACB OR3, a gene that has been subjected to positive selection (ω = 2.9), responds preferentially to the ACB E12 and Z12 pheromones. In Ostrinia species the amino acid residue corresponding to position 148 in transmembrane domain 3 of OR3 is alanine (A), except for ACB OR3 that has a threonine (T) in this position. Mutation of this residue from A to T alters the pheromone recognition pattern by selectively reducing the E11 response ∼14-fold. These results suggest that discrete mutations that narrow the specificity of more broadly responsive sex pheromone receptors may provide a mechanism that contributes to speciation.

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    • "When the male moths detect the pheromone, they fly to the pheromonereleasing females and land near one of them to initiate a series of courtship behaviors (Nakano et al., 2006). The repertoire of genes involved in chemoreception in this species has been identified (Yang et al., 2015), including nine pheromone receptors (Miura et al., 2009, 2010; Wanner et al., 2010; Leary et al., 2012). Among them, the odorant receptor co-receptor, OfurOrco, is considered to serve as a common subunit of odorant receptor complex receptors involved in the recognition of a wide range of odorants (Vosshall et al., 1999; Larsson et al., 2004; Xia and Zwiebel, 2006; Stengl, 2010). "
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