Identification of an odorant receptor responding to sex pheromones in Spodoptera frugiperda extends the novel type‐I PR lineage in moths

Abstract

In moths, pheromone receptors (PRs) are crucial for intraspecific sexual communication between males and females. Moth PRs are considered as an ideal model for studying the evolution of insect PRs, and a large number of PRs have been identified and functionally characterized in different moth species. Moth PRs were initially thought to fall into a single monophyletic clade in the odorant receptor (OR) family, but recent studies have shown that ORs in another lineage also bind type‐I sex pheromones, which indicates that type‐I PRs have multiple independent origins in the Lepidoptera. In this study, we investigated whether ORs of the pest moth Spodoptera frugiperda belonging to clades closely related to this novel PR lineage may also have the capacity to bind type‐I pheromones and serve as male PRs. Among the 7 ORs tested, only 1 (SfruOR23) exhibited a male‐biased expression pattern. Importantly, in vitro functional characterization showed that SfruOR23 could bind several type‐I sex pheromone compounds with Z‐9‐tetradecenal (Z9‐14:Ald), a minor component found in female sex pheromone glands, as the optimal ligand. In addition, SfruOR23 also showed weak responses to plant volatile organic compounds. Altogether, we characterized an S. frugiperda PR positioned in a lineage closely related to the novel PR clade, indicating that the type‐I PR lineage can be extended in moths.

The novel function of an orphan pheromone receptor reveals the sensory specializations of two potential distinct types of sex pheromones in noctuid moth

“…Moth PRs are highly conserved and form a dedicated subfamily of ORs in the phylogenetic trees of moth ORs [69]. Recent studies have revealed novel lineages within OR clades responsible for detecting moth sex pheromones [26,[83][84][85][86][87], indicating multipe orgins of moths PRs. This perspective is resonable given the diverse structures of sex pheromones in moths.…”

Chemosensory Receptor Expression in the Abdomen Tip of the Female Codling Moth, Cydia pomonella L. (Lepidoptera: Tortricidae)

“…With the exception of OR69, all of these are found, phylogenetically, scattered across various non-PR clades; it may be hypothesized that they would function in mediating female behaviors related to oviposition. On the other hand, OR69 clusters within the recently expanded novel PR clade [8,62]. Multiple ORs within this clade display sex-biased antennal expression in codling moth [27] and may play a role in mediating intra-species communication.…”

“…Three of these ORs presented as putative paralogues of previously identified ORs (OR11, OR12, and OR37), and were thus named respectively (OR11.2, OR12.2, and OR37.2). With the exception of OR69, all of the newly named ORs clustered with putative general odorant receptors; OR69 grouped within the newly expanded novel PR clade [62]. Of the 29 OR transcripts previously annotated, only 2 contained complete ORFs, and another 2 contained ORFs of at least 80% completeness.…”