title: Pheromone biosynthetic pathways in the moths Helicoverpa zea and Helicoverpa assulta.
abstract: Sex pheromones of many Lepidopteran species have relatively simple structures consisting of a hydrocarbon chain with a functional group and usually one to several double bonds. The sex pheromones are usually derived from fatty acids through a specific biosynthetic pathway. We investigated the incorporation of deuterium-labeled palmitic and stearic acid precursors into pheromone components of Helicoverpa zea and Helicoverpa assulta. The major pheromone component for H. zea is (Z)11-hexadecenal (Z11-16:Ald) while H. assulta utilizes (Z)9-hexadecenal (Z9-16:Ald). We found that H. zea uses palmitic acid to form Z11-16:Ald via delta 11 desaturation and reduction, but also requires stearic acid to biosynthesize the minor pheromone components Z9-16:Ald and Z7-16:Ald. The Z9-16:Ald is produced by delta 11 desaturation of stearic acid followed by one round of chain-shortening and reduction to the aldehyde. The Z7-16:Ald is produced by delta 9 desaturation of stearic acid followed by one round of chain-shortening and reduction to the aldehyde. H. assulta uses palmitic acid as a substrate to form Z9-16:Ald, Z11-16:Ald and 16:Ald. The amount of labeling indicated that the delta 9 desaturase is the major desaturase present in the pheromone gland cells of H. assulta; whereas, the delta 11 desaturase is the major desaturase in pheromone glands of H. zea. It also appears that H. assulta lacks chain-shortening enzymes since stearic acid did not label any of the 16-carbon aldehydes.
authors.affiliation: Department of Entomology, Iowa State University, Ames, IA 50011-3222, USA.
authors.forename: Man-Yeon
authors.initials: MY
authors.lastname: Choi
authors.forename: Kyeung Sik
authors.initials: KS
authors.lastname: Han
authors.forename: Kyung Saeng
authors.initials: KS
authors.lastname: Boo
authors.forename: Russell A
authors.initials: RA
authors.lastname: Jurenka
mesh_terms: D000818:Animals; D003903:Deuterium; D005227:Fatty Acids / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005260:Female; D009036:Moths / Q000378:metabolism*; D010675:Pheromones / Q000096:biosynthesis*; D011865:Radioisotope Dilution Technique; D013045:Species Specificity
chemical_list: D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D010675:Pheromones; D003903:Deuterium