Suppression of pheromone biosynthesis and mating behavior by RNA interference of pheromone gland‐specific fatty acyl reductase in Maruca vitrata

Abstract

In moths, various enzymes, such as fatty acid synthases, fatty acyl desaturases, and fatty acyl reductases (FARs), are involved in pheromone biosynthesis. In particular, pheromone gland‐specific FAR (pgFAR) plays an important role in converting the functional group from carboxylic to alcohol during pheromone biosynthesis. A novel pgFAR of Maruca vitrata, Mvi‐pgFAR, was identified through transcriptome sequencing of its pheromone gland. To investigate the involvement of Mvi‐pgFAR in pheromone biosynthesis, Mvi‐pgFAR was cloned from the pheromone gland and suppressed by RNA interference (RNAi). Mvi‐pgFAR harbored several conserved motifs related to NAD(P)H‐binding, N‐glycosylation, and adenosine / guanosine triphosphate binding. Phylogenetic analysis revealed that Mvi‐pgFAR with other lepidopteran pgFARs formed an independent clade. Mvi‐pgFAR was specifically expressed only in the pheromone gland. Quantitative real‐time polymerase chain reaction showed that the diurnal expression levels of Mvi‐pgFAR in the pheromone gland were the highest at 2 h before the scotophase. After primarily confirming Mvi‐pgFAR suppression by RNAi, (E,E)‐10,12‐hexadecadienal (E10E12‐16:Ald), a major sex pheromone component, was quantified by gas chromatography. When Mvi‐pgFAR was successfully suppressed, E10E12‐16:Ald production was reduced by up to half of that of the control, and the mating rate was subsequently decreased. Our results demonstrate that Mvi‐pgFAR downregulation can suppress mating behavior by changing the relative sex pheromone component ratio, suggesting that Mvi‐pgFAR can be used as a novel control target.

Functional Analysis of Pheromone Biosynthesis Activating Neuropeptide Receptor Isoforms in Maruca vitrata

“…In this study, prior to RNAi treatment, we measured the diurnal expression of MviPBANR-C in response to MviPBAN in the pheromone glands of M. vitrata. The expression level of MviPBANR-C was the highest at 2 h before the scotophase (5 p.m.) (Figure 5), which coincides with MvipgFAR expression [26]. RNAi suppression of MviPBANR-C was performed 2 h before the scotophase (5 p.m.), and this suppression reduced sex pheromone production as well as mating behavior (Figure 5).…”

“…In addition, PBAN, which induces sex pheromone biosynthesis, was found in the heads of female adults of M. vitrata [25]. Functional analysis using RNA interference (RNAi) revealed that pheromone gland-specific fatty acyl reductase (pgFAR) was also involved in the sex pheromone biosynthesis of M. vitrata [26]. However, signal transduction studies on PBANR in M. vitrata remain insufficient.…”

Suppression of PBAN receptor expression reduces fecundity in the fall armyworm, Spodoptera frugiperda

“…Downregulation of Sf‐PBANr may lead to decrease pheromone production, which results in unsuccessful mating behaviour as mismatching with female and male during mating period in adult stage. Some studies have reported that suppression of genes, which are related with pheromone production, reduced mating rate in Maruca vitrata (Cha & Lee, 2022) and in P. xylostella (Lee et al, 2011). Therefore, silencing of PBANr gene by RNAi suggest that the gene is closely related with sex pheromone biosynthesis.…”

Burkholderia gut symbiont induces insect host fecundity by modulating Kr‐h1 gene expression

“…7.1.0.). Phylogenetic trees for the alignment were constructed using the Maximum likelihood method and the Jones–Taylor–Thornton model (Cha & Lee, 2022; Lee et al, 2022).…”