A moth odorant receptor highly expressed in the ovipositor is involved in detecting host-plant volatiles

Abstract

Antennae are often considered to be the nostrils of insects. Here, we sequenced the transcriptome of the pheromone gland-ovipositor complex of Helicoverpa assulta and discovered that an odorant receptor (OR) gene, HassOR31, had much higher expression in the ovipositor than in antennae or other tissues. To determine whether the ovipositor was involved in odorant detection, we co-expressed HassOR31 and its co-receptor, HassORco, in a Xenopus oocyte model system, and demonstrated that the OR was responsive to 12 plant odorants, especially Z-3-hexenyl butyrate. These odorants elicited electrophysiological responses of some sensilla in the ovipositor, and HassOR31 and HassORco were co-expressed within ovipositor sensilla. Two oviposition preference experiments showed that female moths lacking antennae still preferentially selected oviposition sites containing plant volatiles. We suggest that the expression of HassOR31 in the ovipositor of H. assulta helps females to determine precise egg-laying sites in host plants.

Comparative transcriptomic analysis reveals female-biased olfactory genes potentially involved in plant volatile-mediated oviposition behavior of Bactrocera dorsalis

“…Therefore, we inferred that abdomen cuticles may contain many sensilla, especially on the ovipositor. A recent study showed that HassOR31 highly expressed in ovipositor was involved in detecting host-plant volatiles for determining precise oviposition sites [ 25 ]. This gene may exert a function associated with host-plant volatile detection or stimulation of egg lay.…”

Ultrastructure of the Olfactory Sensilla across the Antennae and Maxillary Palps of Bactrocera dorsalis (Diptera: Tephritidae)

“…The antennae and the maxillary palps, covered by numerous sensilla, are primary olfactory organs. With the sensilla, the insects can perceive and accurately recognize various odorants from the surrounding environment, which trigger insect behaviors, such as host selection and oviposition decisions [ 3 , 4 , 5 ]. Furthermore, olfaction-based behavioral manipulation has been frequently used for the monitoring and prevention of oriental fruit flies.…”

Identification and Functional Characterization of Two Putative Pheromone Receptors in the Potato Tuber Moth, Phthorimaea operculella

“…A recent study into Helicoverpa assulta found that an odorant receptor gene, HassOR31 which was highly expressed in the ovipositor rather than in antennae, was related to the determination of oviposition in host plants in females. This finding reveals that some ORs located outside the antenna might also have a functional role in vivo ( Li et al, 2020 ). Therefore, further studies are needed to uncover the function of PopeOR3 in the wings of P. operculella .…”

“…For example, Bastin-Heline et al (2019) found SlitOR5, a PR from the cotton leafworm Spodoptera littoralis , grouped with a novel PR clade. With a typical structure of seven transmembrane domains, PRs are more abundantly expressed in male antennae ( He et al, 2014 ; Zhang and Löfstedt, 2015 ; Ke et al, 2017 ), whilst some PRs are also found in female antennae and other tissues such as the wings and ovipositor ( Chang et al, 2015 ; Li et al, 2020 ).…”