Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid‐Producing Plants

Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol (1) and (4aS,7S,7aR)-nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction 8-oxogeranial into reactive enol (S)-8-oxocitronellal, cyclization this intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) yields nepetalactols. In study, we investigated biosynthesis vivo 1 2 pea aphid, Acyrthosiphon pisum, using library isotopically-labelled monoterpenoids as molecular probes. Topical application deuterium-labelled probes synthesized from geraniol nerol resulted production 2H4−lactol 2H4−lactone 2. However, deuterium incorporation was not evident labelled (S)-citronellol. These results suggest animals, specifically aphids, may follow broadly similar route to characterised for plants.