Putative Pathway of Sex Pheromone Biosynthesis and Degradation by Expression Patterns of Genes Identified from Female Pheromone Gland and Adult Antenna of Sesamia inferens (Walker)

Abstract

The general pathway of biosynthesis and degradation for Type-I sex pheromones in moths is well established, but some genes involved in this pathway remain to be characterized. The purple stem borer, Sesamia inferens, employs a pheromone blend containing components with three different terminal functional groups (Z11-16:OAc, Z11-16:OH, and Z11-16:Ald) of Type-I sex pheromones. Thus, it provides a good model to study the diversity of genes involved in pheromone biosynthesis and degradation pathways. By analyzing previously obtained transcriptomic data of the sex pheromone glands and antennae, we identified 73 novel genes that are possibly related to pheromone biosynthesis (46 genes) or degradation (27 genes). Gene expression patterns and phylogenetic analysis revealed that one desaturase (SinfDes4), one fatty acid reductase (SinfFAR2), and one fatty acid xtransport protein (SinfFATP1) genes were predominantly expressed in pheromone glands, and clustered with genes involved in pheromone synthesis in other moth species. Ten genes including five carboxylesterases (SinfCXE10, 13, 14, 18, and 20), three aldehyde oxidases (SinfAOX1, 2 and 3), and two alcohol dehydrogenases (SinfAD1 and 3) were expressed specifically or predominantly in antennae, and could be candidate genes involved in pheromone degradation. SinfAD1 and 3 are the first reported alcohol dehydrogenase genes with antennae-biased expression. Based on these results we propose a pathway involving these potential enzyme-encoding gene candidates in sex pheromone biosynthesis and degradation in S. inferens. This study provides robust background information for further elucidation of the genetic basis of sex pheromone biosynthesis and degradation, and ultimately provides potential targets to disrupt sexual communication in S. inferens for control purposes.

Large number of putative chemoreception and pheromone biosynthesis genes revealed by analyzing transcriptome from ovipositor-pheromone glands of Chilo suppressalis

“…Unfortunately, we did not find an AO from the transcriptomic database, similar as studies with sex pheromone gland transcriptome analysis in other species using aldehyde(s) as sex pheromone component(s), such as H. virescens 47, Agrotis segetum 17 and A. ipsilon 48. In Sesamia inferens , 1 AO was found with very low expression level in the sex pheromone gland transcriptome49. Therefore, more sensitive approaches are needed to identify the possible AO genes in moths.…”

Identification of putative Type-I sex pheromone biosynthesis-related genes expressed in the female pheromone gland of Streltzoviella insularis

“…Labeling studies demonstrated that palmitic acid (C16) and stearic acid (C18) are the FAS products in most moth PGs [15,[66][67]. Herein, we identified five FASs with lengths ranging from 301 bp to 8170 bp in the S. insularis PG transcriptome (Table 2 and S1 Text), These results are similar to those reported for other insects, with six and three FASs in A. segetum [58] and Sesamia inferens [68], respectively. Among the five FASs, only SinsFAS2 has an intact ORF.…”

Antennal Transcriptome Analysis and Comparison of Chemosensory Gene Families in Two Closely Related Noctuidae Moths, Helicoverpa armigera and H. assulta

“…Previously, these studies have mostly been focused on model species with sequenced genome available, such as Drosophila melanogaster, Bombyx mori, Aphis gossypii and several other insect species [ 17 – 22 ]. With the development of the next generation sequencing (NGS) techniques, numerous chemosensory genes have been identified from various insect species, such as Manduca sexta [ 23 ], Helicoverpa armigera [ 24 ], Cydia pomonella [ 25 ], Spodoptera littoralis [ 26 – 28 ], Sesamia inferens [ 29 ], Chilo suppressalis [ 30 ] and Aphis gossypii [ 31 ], etc.…”