Effect of PBAN on Pheromone Production and Biosynthetic Pathway of the Major Sex Pheromone Component of Proeulia auraria Clarke (Lepidoptera: Tortricidae)

Proeulia auraria (Lepidoptera: Tortricidae) is a native Chilean moth and a significant pest of several fruit crops. Its sexual communication relies on pheromones, of which (E)-11-tetradecenyl acetate (E11-14:OAc) is the major component, but the mechanisms regulating its production and biosynthetic pathways are poorly understood. We studied the effect of pheromone-biosynthesis-activating neuropeptide (PBAN) on pheromone production and its biosynthesis through isotopic labeling using deuterated fatty acids, which were topically applied to the pheromone gland. Gas chromatography–mass spectrometry (GC-MS) analysis was then performed. PBAN application increased E11-14:OAc by up to eight times. In labeling experiments with [16,16,16-2H3]hexadecanoic acid (D3-16:acid), the mass spectrum of E11-14:OAc showed a shifted ion at m/z 197 and a natural ion at m/z 194. These results indicated the incorporation of three deuteriums into the terminal methyl group and that chain shortening from palmitic acid to the 14-carbon skeleton occurs through β-oxidation from the carboxyl end. Deuterium incorporation was also detected after D3-18:acid and D3-14:acid application. The findings provide the first direct evidence regarding the precursors and direction of chain shortening in the pheromone biosynthesis of P. auraria. The information contributes to our understanding of its chemical communication and could lay the foundation for the development of pheromone-based control tools.