Pheromone biosynthetic pathways in the moths Heliothis subflexa and Heliothis virescens

Sex pheromones of many moth species have relatively simple structures consisting of a hydrocarbon chain with a functional group and one to several double bonds. These sex pheromones are derived from fatty acids through specific biosynthetic pathways. We investigated the incorporation of deuterium-labeled tetradecanoic, hexadecanoic and octodecanoic acid precursors into pheromone components of Heliothis subflexa and Heliothis virescens. The two species utilize (Z)11-hexodecenal as the major pheromone component, which is produced by Delta 11 desaturation of hexadecanoic acid. H. subflexa also produced (Z)11-hexadecanol and (Z)-11-hexadecenyl acetate via Delta 11 desaturation. In H. subflexa, octadecanoic acid was used to biosynthesize the minor pheromone components (Z)9-hexodecenal, (Z)9-hexadecenol, and (Z)9-hexadecenyl acetate. These minor components are produced by Delta 11 desaturation of octadecanoic acid followed by one round of chain-shoftening. In contrast, H. virescens used hexadecanoic acid as a substrate to form (Z)11-hexadecenal and (Z)11-hexodecenol and hexodecenal. H. virescens also produced (Z)9-tetradecenal by Delta 11 desaturation of the hexadecomoic acid followed by one round of chain-shortening and reduction. Tetradecanoic acid was not utilized as a precursor to form Z9-14:Ald in H. virescens. This labeling pattern indicates that the Delta 11 desaturase is the only active desaturase present in the pheromone gland cells of both species. (c) 2005 Wiley-Liss, Inc.