Sex pheromone biosynthesis from radiolabeled fatty acids in the redbanded leafroller moth [Argyrotaenia velutinana]

Radiolabeled fatty acids in dimethyl sulfoxide were applied topically to sex pheromone glands of young adult female Argyrotaenia velutinana. Glands treated with sodium [1-14C]acetate incorporated radiolabel into the sex pheromone components and into dodecanoic, tetradecanoic, hexadecanoic, octadecanoic, (Z)-11-tetradecenoic, and (E)-11-tetradecenoic fatty acyl moieties. In contrast, very little radiolabel was incorporated into unsaturated 18-carbon fatty acyl moieties and almost none into unsaturated 18-carbon fatty acyl moieties, although these moieties were abundant in the gland. A similar pattern of incorporation was observed for glands treated with [U-14C]hexadecanoic acid. In glands treated with [1-14C]hexadecanoic acid, a smaller proportion of the label was incorporated into the 14-carbon fatty acyl moieties than in glands treated with [U-14C]hexadecanoic acid, indicating that 14-carbon fatty acyl moieties arose from chain-shortening of hexadecanoyl moieties. In glands treated with [1-14C]tetradecanoic acid, (Z)-11-tetradecenoyl and (E)-11-tetradecenoyl moieties incorporated the most label, implicating (Z)-11 and (E)-11 desaturases specific for the tetradecanoyl chain. In glands treated with (Z)-11-[1-14C]tetradecenoic acid or (E)-11-[1-14C]tetradecenoic acid, very little label was incorporated into the other geometric isomer, implying that Z/E isomerases do not occur in the gland. In glands treated with (E)-11-[1-14C]tetradecenoic acid, much more label was incorporated into (E)-11-tetradecenyl acetate than with the other substrates, showing that most of the labeled acetate arose from reduction and acetylation of the labeled fatty acyl moiety.