The fall armyworm Spodoptera frugiperda is a worldwide serious agricultural pest, and recently invaded South China. Sex pheromone can be employed to monitor its population dynamics accurately in the field. However, the pheromone components previously reported by testing different geographic populations and strains are not consistent. On the basis of confirming that the S. frugiperda population from Yunnan Province belonged to the corn strain, we analyzed the potential sex pheromone components in the pheromone gland extracts of females using gas chromatography coupled with electroantennographic detection (GC‐EAD), gas chromatography coupled with mass spectrometry (GC‐MS) and electroantennography (EAG). The results show that (Z)‐9‐tetradecenal acetate (Z9‐14:Ac), (Z)‐11‐hexadecenyl acetate (Z11‐16:Ac), (Z)‐7‐dodecenyl acetate (Z7‐12:Ac) or (E)‐7‐dodecenyl acetate (E7‐12:Ac) with a ratio of 100 : 15.8 : 3.9 induced EAD responses to varying degrees: Z9‐14:Ac elicited a strong EAD response, Z7‐12:Ac or E7‐12:Ac elicited a small but clear EAD response, while Z11‐16:Ac elicited a weak EAD response. Further single sensillum recording (SSR) showed that Z9‐14:Ac and Z7‐12:Ac induced dose‐dependent activities in two types (A and B) of sensilla in male antennae, respectively, while the sensilla in response to E7‐12:Ac and Z11‐16:Ac was not recorded. Finally, wind tunnel tests reveal that Z9‐14:Ac and Z7‐12:Ac are two principal sex pheromone components of the tested population.
BACKGROUND The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a polyphagous moth species that is spreading all around the globe. It uses (Z)‐9‐tetradecenyl acetate (Z9‐14:Ac) and (Z)‐7‐dodecenyl acetate (Z7‐12:Ac) (100:3.9) as essential sex pheromone components. However, our understanding of the molecular basis of pheromone detection of S. frugiperda is still incomplete. RESULTS Herein, we identified six PRs, i.e. SfruOR6, 11, 13, 16, 56, and 62, by transcriptome sequencing. Subsequently, we heterologously expressed them in Drosophila OR67d neurons and determined their response spectra with a large panel of sex pheromones and analogs. Among them, SfruOR13‐expressing neurons strongly respond to the major sex pheromone component Z9‐14:Ac, but also comparably to (Z,E)‐9,12‐tetradecadienyl acetate (Z9,E12‐14:Ac) and weakly to (Z)‐9‐dodecenyl acetate (Z9‐12:Ac). Both SfruOR56 and SfruOR62 are specifically tuned to the minor sex pheromone component Z7‐12:Ac with varying intensities and sensitivities. In addition, SfruOR6 is activated only by Z9,E12‐14:Ac, and SfruOR16 by both (Z)‐9‐tetradecenol (Z9‐14:OH) and (Z)‐9‐tetradecenal (Z9‐14:Ald). However, the OR67d neurons expressing SfruOR11 remain silent to all compounds tested, a phenomenon commonly found in the OR11 clade of Noctuidae species. Next, using single sensillum recording, we characterized four sensilla types on the antennae of males, namely A, B, C and D types that are tuned to the ligands of PRs, thereby confirming that S. frugiperda uses both SfruOR56 and SfruOR62 to detect Z7‐12:Ac. Finally, using wind tunnel assay, we demonstrate that both Z9,E12‐14:Ac and Z9‐14:OH act as antagonists to the sex pheromone. CONCLUSION We have deorphanized five PRs and characterized four types of sensilla responsible for the detection of pheromone compounds, providing insights into the peripheral encoding of sex pheromones in S. frugiperda.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.