Evolution of the Integral Membrane Desaturase Gene Family in Moths and Flies

Abstract

Lepidopteran insects use sex pheromones derived from fatty acids in their species-specific mate recognition system. Desaturases play a particularly prominent role in the generation of structural diversity in lepidopteran pheromone biosynthesis as a result of the diverse enzymatic properties they have evolved. These enzymes are homologous to the integral membrane desaturases, which play a primary role in cold adaptation in eukaryotic cells. In this investigation, we screened for desaturase-encoding sequences in pheromone glands of adult females of eight lepidopteran species. We found, on average, six unique desaturase-encoding sequences in moth pheromone glands, the same number as is found in the genome database of the fly, Drosophila melanogaster, vs. only one to three in other characterized eukaryotic genomes. The latter observation suggests the expansion of this gene family in insects before the divergence of lepidopteran and dipteran lineages. We present the inferred homology relationships among these sequences, analyze nonsynonymous and synonymous substitution rates for evidence of positive selection, identify sequence and structural correlates of three lineages containing characterized enzymatically distinct desaturases, and discuss the evolution of this sequence family in insects.

Transcriptome analysis identifies candidate genes in the biosynthetic pathway of sex pheromones from a zygaenid moth, Achelura yunnanensis (Lepidoptera: Zygaenidae)

“…As the first step of pheromone biosynthesis, two enzymes of acetyl-CoA carboxylases (ACCs) and fatty acid synthases (FASs) are involved in the synthesis of saturated fatty acids, the precursors of sex pheromones ( Volpe & Vagelos, 1973 ; Pape, Lopez-Casillas & Kim, 1988 ; Foster & Anderson, 2012 ). Next, members of a key gene family encoding fatty acyl desaturases (FADs) determine the diversity of pheromone structures by introducing double bonds into specific positions of sex pheromones, largely contributing to the specificity of sex pheromone communication ( Hao et al, 2002 ; Knipple et al, 2002 ; Fujii et al, 2015 ; Xia et al, 2019 ). In some case, the long-chain unsaturated fatty acids are shortened by β -oxidation enzymes to further increase the diversity of species-specific pheromones ( Bjostad, Wolf & Roelofs, 1987 ).…”

Release of moth pheromone compounds from Nicotiana benthamiana upon transient expression of heterologous biosynthetic genes

“…The C. suppressalis FAD-like genes CsupYPAQ and CsupKPSE (following the nomenclature proposed by Knipple et al [ 13 ] naming desaturase genes based on the composition of 4 amino acid residues at a signature motif) displayed 1038 nt and 1059 nt ORFs that translated into 346 and 353 aa-proteins, respectively. In a phylogenetic analysis of lepidopteran FADs, CsupYPAQ clustered into the ∆11/∆10/multifunctional FAD subfamily, whereas CsupKPSE fell into the ∆9 (C 16 >C 18 ) FAD clade (Fig.…”

“…In insects, the acyl-CoA desaturase gene family has had a very dynamic evolutionary history [ 13 , 37 , 38 ]. As a result of gene duplication bursts, many opportunities have arisen for evolution to explore protein space and produce proteins with unique and novel functions.…”

“…In phylogenetic analysis, CsupYPAQ clusters in the Lepidoptera-specific XXXQ/E clade (the proteins contain an XXXQ/E amino acid motif 13 amino acids in front of the conserved histidine box of the desaturase sequences) (Fig. 1 ), which is a lineage that is composed of pheromone biosynthetic desaturases with diverse specificities [ 13 ]. With the exception of the ∆9 desaturase from the tortricid species Cydia pomonella [ 39 ], the FADs clustering in this clade are ∆11/∆10 FADs but in some cases, they have additional functions and are then classified as multifunctional.…”

Transcriptome analysis and identification of sex pheromone biosynthesis and transport related genes in Atrijuglans hetaohei (Lepidoptera: Gelechioidea)

“…Des has been proved to play a key role in the generation of structural diversity in Lepidopteran pheromone biosynthesis because of the diverse enzymatic properties they have evolved (G. Hao et al, 2002; Liénard et al, 2010; Liu et al, 2004; H. L. Wang et al, 2010), which gives rise to divergent patterns of expression and biological roles in Lepidoptera (Knipple et al, 2002). The current study found that Ahetdes12 was abundant in the female PG transcriptome, which was consistent with the results of RT‐qPCR analysis.…”