title: A novel fatty acyl desaturase from the pheromone glands of Ctenopseustis obliquana and C. herana with specific Z5-desaturase activity on myristic acid.
abstract: Sexual communication in the Lepidoptera typically involves a female-produced sex pheromone that attracts males of the same species. The most common type of moth sex pheromone comprises individual or blends of fatty acyl derivatives that are synthesized by a specific enzymatic pathway in the female's pheromone gland, often including a desaturation step. This reaction is catalyzed by fatty acyl desaturases that introduce double bonds at specific locations in the fatty acid precursor backbone. The two tortricid moths, Ctenopseustis obliquana and C. herana (brown-headed leafrollers), which are endemic in New Zealand, both use (Z)-5-tetradecenyl acetate as part of their sex pheromone. In C. herana, (Z)-5-tetradecenyl acetate is the sole component of the pheromone. Labeling experiments have revealed that this compound is produced via an unusual Δ5-desaturation of myristic acid. Previously six desaturases were identified from the pheromone glands of Ctenopseustis and its sibling genus Planotortrix, with one differentially regulated to produce the distinct blends used by individual species. However, none were able to conduct the Δ5-desaturation observed in C. herana, and presumably C. obliquana. We have now identified an additional desaturase gene, desat7, expressed in the pheromone glands of both Ctenopseustis species, which is not closely related to any previously described moth pheromone desaturase. The encoded enzyme displays Δ5-desaturase activity on myristic acid when heterologously expressed in yeast, but is not able to desaturate any other fatty acid (C8-C16). We conclude that desat7 represents a new group of desaturases that has evolved a role in the biosynthesis of sex pheromones in moths.
authors.affiliation: Pheromone Group, Department of Biology, Lund University, Sölvegatan 37, 223 62, Lund, Sweden, asa.hagstrom@biol.lu.se.
authors.forename: Åsa K
authors.initials: ÅK
authors.lastname: Hagström
authors.forename: Jérôme
authors.initials: J
authors.lastname: Albre
authors.forename: Leah K
authors.initials: LK
authors.lastname: Tooman
authors.forename: Amali H
authors.initials: AH
authors.lastname: Thirmawithana
authors.forename: Jacob
authors.initials: J
authors.lastname: Corcoran
authors.forename: Christer
authors.initials: C
authors.lastname: Löfstedt
authors.forename: Richard D
authors.initials: RD
authors.lastname: Newcomb
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005260:Female; D042541:Intracellular Space / Q000378:metabolism; D007915:Lepidoptera / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000378:metabolism*; D010802:Phylogeny; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012724:Sex Attractants / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D012724:Sex Attractants; D019814:Myristic Acid; D044943:Fatty Acid Desaturases