Putative pheromone biosynthesis pathway in Maruca vitrata by transcriptomic analysis

Abstract

Pheromone biosynthesis in the pheromone gland is stimulated by pheromone biosynthesis activating neuropeptide (PBAN) produced in the suboesophageal ganglion. PBAN binds its receptor and transduces biological signal into the molecules for the pheromone biosynthesis. To understand pheromone biosynthesis pathway in legume pod borer, Maruca vitrata, total RNA from the pheromone gland was isolated and transcriptome of the pheromone gland was obtained. Total read bases from the transcriptome were 12.03billionbp and 62,604 contigs were identified. A total of 191 contigs involved in the pheromone biosynthesis such as PBAN receptor, PBAN, fatty acid transport proteins, fatty acid synthases, fatty acid desaturases (FADs), fatty acyl-CoA reductases (FARs), alcohol oxidase/dehydrogenases (AOXs) and β-oxidation enzymes, were identified. Putative pheromone biosynthetic pathways for sex pheromone components in M. vitrata were proposed through transcriptomic analysis. Biosynthesis pathway for E10,E12-16:Ald and E10,E12-16:OH may initiate from C16:CoA with FAD2-like enzyme found in Manduca sexta, which converts the substrate into E10,E12-16:CoA. This intermediate is subsequently reduced by pheromone gland-specific FAR (pgFAR) which modifies end moiety with alcohol or by AOX which convert end moiety into aldehyde. The production of E10-16:Ald can be initiated from C16:CoA by ∆10 desaturase or from C18:CoA by ∆12 desaturase followed by with β-oxidation, and the intermediate can be reduced by pgFAR.