Biosynthesis of Unusual Moth Pheromone Components Involves Two Different Pathways in the Navel Orangeworm, Amyelois transitella

Abstract

The sex pheromone of the navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), consists of two different types of components, one type including (11Z,13Z)-11,13-hexadecadienal (11Z,13Z-16:Ald) with a terminal functional group containing oxygen, similar to the majority of moth pheromones reported, and another type including the unusual long-chain pentaenes, (3Z,6Z,9Z,12Z,15Z)-3,6,9,12,15-tricosapentaene (3Z,6Z,9Z,12Z,15Z-23:H) and (3Z,6Z,9Z,12Z,15Z)- 3,6,9,12,15-pentacosapentaene (3Z,6Z,9Z,12Z,15Z-25:H). After decapitation of females, the titer of 11Z,13Z-16:Ald in the pheromone gland decreased significantly, whereas the titer of the pentaenes remained unchanged. Injection of a pheromone biosynthesis activating peptide (PBAN) into the abdomens of decapitated females restored the titer of 11Z,13Z-16:Ald and even increased it above that in intact females, whereas the titer of the pentaenes in the pheromone gland was not affected by PBAN injection. In addition to common fatty acids, two likely precursors of 11Z,13Z-16:Ald, i.e., (Z)-11-hexadecenoic and (11Z,13Z)-11,13-hexadecadienoic acid, as well as traces of (Z)-6-hexadecenoic acid, were found in gland extracts. In addition, pheromone gland lipids contained (5Z,8Z,11Z,14Z,17Z)-5,8,11,14,17-icosapentaenoic acid, which also was found in extracts of the rest of the abdomen. Deuterium-labeled fatty acids, (16,16,16-D3)-hexadecanoic acid and (Z)-[13,13,14,14,15,15,16,16,16-D9]-11-hexadecenoic acid, were incorporated into 11Z,13Z-16:Ald after topical application to the sex pheromone gland coupled with abdominal injection of PBAN. Deuterium label was incorporated into the C23 and C25 pentaenes after injection of (9Z,12Z,15Z)- [17,17,18,18,18-D5]-9,12,15-octadecatrienoic acid into 1–2 d old female pupae. These labeling results, in conjunction with the composition of fatty acid intermediates found in pheromone gland extracts, support different pathways leading to the two pheromone components. 11Z,13Z-16:Ald is probably produced in the pheromone gland by Δ11 desaturation of palmitic acid to 11Z-16:Acid followed by a second desaturation to form 11Z,13Z-16:Acid and subsequent reduction and oxidation. The production of 3Z,6Z,9Z,12Z,15Z-23:H and 3Z,6Z,9Z,12Z,15Z-25:H may take place outside the pheromone gland, and appears to start from linolenic acid, which is elongated and desaturated to form (5Z,8Z,11Z,14Z,17Z)-5,8,11,14,17-icosapentaenoic acid, followed by two or three further elongation steps and finally reductive decarboxylation.

Receptor for detection of a Type II sex pheromone in the winter moth Operophtera brumata

“…Instead, members of the existing pheromone receptor subfamily can be recruited for detection of the new ligands. This is different to the production of the two types of pheromones in female moths, where distinct pathways and enzymes are involved 21 22 . Type II pheromones mainly appear in the advanced moth superfamilies Geometroidea and Noctuoidea 17 and we have not found any ObruOR1 orthologues outside Geometridae and Noctuidae among available sequences of PR candidate genes.…”

“…This type of compounds comprises about 15% of the identified lepidopteran pheromones 15 18 19 . The two major types of sex pheromones are produced through distinct pathways, including differences in the biosynthetic sites, the substrates and enzymes involved, as well as the endocrine regulation mechanism, but still serve the same role in moth mate recognition and attraction 20 21 22 23 .…”

Identification of the Female-Produced Sex Pheromone of the Leafminer Holocacista capensis Infesting Grapevine in South Africa

“…For chemical identification and electrophysiological experiments, ( Z )-5-tetradecenal (Z5-14:Ald), ( E )-5-tetradecenal (E5-14:Ald), ( Z )-7-tetradecenal (Z7-14:Ald), and ( E )-7-tetradecenal (E7-14:Ald) were prepared by oxidation of corresponding alcohols with pyridinium chlorochromate as described by Corey and Suggs ( 1975 ). The corresponding fatty acids and their methyl esters also were prepared from the respective alcohols as described in Wang et al ( 2010 ). Z5-14:Ald (chemical purity 99.6 %), Z7-14:Ald (chemical purity 98.2 %), and ( Z )-9-hexadecenal (Z9-16:Ald, chemical purity 99.0 %) used for field experiments were purchased from Pherobank (Wageningen, The Netherlands).…”

Sex Pheromones of Two Leafminer Species, Antispila oinophylla and Holocacista rivillei (Lepidoptera: Heliozelidae) Infesting Grapevine in Italy

“…For chemical identification and electrophysiological experiments, ( Z )-5-dodecenal (Z5–12:Ald), ( E )-5-dodecenal (E5–12:Ald), Z5–14:Ald, ( E )-5-tetradecenal (E5–14:Ald), Z7–14:Ald and ( E )-7-tetradecenal (E7–14:Ald) were prepared by oxidation of corresponding alcohols with pyridinium chlorochromate as described by Corey and Suggs ( 1975 ). The corresponding fatty acids and their methyl esters were also prepared from the respective alcohols as described in Wang et al ( 2010 ). For field experiments, Z5–14:Ald (chemical purity 99.6%) and Z7–14:Ald (chemical purity 98.2%) were purchased from Pherobank (Wageningen, The Netherlands), and Z5–12:Ald (chemical purity 98.7%) was prepared in our laboratory from the corresponding alcohol according to Corey and Suggs ( 1975 )…”