Sex pheromone biosynthetic pathway for disparlure in the gypsy moth, Lymantria dispar

Abstract

6 pages, 7 figures.-- PMID: 12533665 [PubMed].-- PMCID: PMC298683.-- Printed version published Feb 4, 2003.-- Full text version available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC298683/?tool=pubmedThe pheromone biosynthetic pathway for production of the sex pheromone disparlure, 2-methyl-7R,8S-epoxy-octadecane, was determined for the gypsy moth. Each step in the pathway was followed by using deuterium-labeled compounds that could be identified by using GC/MS. This approach provides unequivocal determination of specific reactions in the pathway. It was shown that the alkene precursor, 2-methyl-Z7-octadecene, is most likely made in oenocyte cells associated with abdominal epidermal cells. The pathway begins with valine contributing carbons for chain initiation, including the methyl-branched carbon, followed by chain elongation to 19 carbons. The double bond is introduced with an unusual Δ12 desaturase that utilizes a methyl-branched substrate. The resulting 18-methyl-Z12-nonadecenoate is decarboxylated to the hydrocarbon, 2-methyl-Z7-octadecene. The alkene is then transported to the pheromone gland through the hemolymph, most probably by lipophorin. At the pheromone gland, the alkene is unloaded and transformed into the epoxide disparlure for release into the environment. A chiral HPLC column was used to demonstrate that the (R,S)-stereoisomer of the epoxide, (+)-disparlure is found in pheromone glands.This work was supported by grants from the U.S. Department of Agriculture–National Research Initiative (2001-35302-10882) and the U.S.–Spain Joint Commission on Scientific and Technological Cooperation, and by Hatch Act and State of Iowa funds.Peer reviewe