Gene-silencing reveals the functional significance of pheromone biosynthesis activating neuropeptide receptor (PBAN-R) in a male moth

Abstract

The role of pheromone biosynthesis activating neuropeptide (PBAN) in the regulation of pheromone biosynthesis of several female moth species is well elucidated, but its role in the males has been a mystery for over two decades since its discovery from both male and female central nervous systems. In previous studies we have identified the presence of the gene transcript for the PBAN-G-protein coupled receptor (PBAN-R) in Helicoverpa armigera male hair-pencil-aedaegus complexes (male complexes), a tissue structurally homologous to the female pheromone gland. Moreover, we showed that this transcript is up-regulated during pupal-adult development, analogous to its regulation in the female pheromone-glands, thereby indicating a likely functional gene. Here we argue in favor of PBAN's role in regulating the free fatty-acid components (myristic, palmitic, stearic, and oleic acids) and alcohol components (hexadecanol, cis-11 hexadecanol, and octadecanol) in male complexes. We demonstrate the diel periodicity in levels of male components, with peak titers occurring during the 7th-9th h in the scotophase, coincident with female pheromone production. In addition, we show significant stimulation of component levels by synthetic HezPBAN. Furthermore, we confirm PBAN's function in this tissue through knockdown of the PBAN-R gene using RNAi-mediated gene-silencing. Injections of PBAN-R dsRNA into the male hemocoel significantly inhibited levels of the various male components by 58%-74%. In conclusion, through gain and loss of function we revealed the functionality of the PBAN-R and the key components that are up-regulated by PBAN.aedaegus | hair-pencils | Helicoverpa armigera | male-produced components R eproductive behavior involves the integration of physiological and behavioral events that synchronize male and female encounters. Receptivity in female moths is broadcasted by the release of a blend of volatile sex-pheromones during specific times of the photoperiod when they assume typical calling behaviors.

Ant Trail Pheromone Biosynthesis Is Triggered by a Neuropeptide Hormone

“…PBAN-R RNAi has already been shown to inhibit PBAN-R transcription in moths [47], [51], [52], resulting in reduced sex pheromone production, which is similar to our results for SolinPBAN-R RNAi and reduced trail pheromone production in fire ants.…”

Functional impact of silencing the Helicoverpa armigera sex‐peptide receptor on female reproductive behaviour

“…RNAi silencing techniques have proven to be of great usefulness in functional analysis of genes (Ohnishi et al ., 2006; Bober & Rafaeli, 2010). In the present study, RNAi silencing of the HeaSP‐R gene has demonstrated the involvement of this receptor in aspects of reproductive behaviour including responses to mating and to injected synthetic Drm SP.…”

Diet-delivered RNAi in Helicoverpa armigera – Progresses and challenges

“…RNAi mediated by dsRNA ingestion requires higher dosage and multiple administrations until the onset of silencing in insects when compared to RNAi via injection in the haemolymph (Chen et al, 2008;Tian et al, 2009;Zhu et al, 2011), although dosages needed to elicit effect via injection in H. armigera remain measured in micrograms (Bober and Rafaeli, 2010;Cai et al, 2014;Du et al, 2012;Hou et al, 2012;Qiao et al, 2014;Sivakumar et al, 2007;Tang et al, 2012;Wang et al, 2010;Yang and Han, 2014a).…”