The pigment-dispersing factor receptor (PDFR) gene is involved in circadian rhythm and moulting in Hyphantria cunea.

Abstract

The pigment-dispersing factor neuropeptide receptor (PDFR) has a key role in establishing and maintaining the circadian rhythm, such as reproductive behaviour and ecdysone biosynthesis in numerous insect species. However, the functions of the PDFR gene are still unknown in Hyphantria cunea. In this study, the expression level of the HcPDFR gene during the 6th instar stage of larvae is higher than those in the other developmental stages. The HcPDFR gene is highly expressed in the testis compared to the other tissues. Additionally, a significant rhythmic expression of HcPDFR was observed in the head under the photoperiod of 16L:8D and 12L:12D, while it showed no rhythmicity under 24L:0D. The physiological function of the PDFR gene was identified by RNA interference (RNAi) technology. After the HcPDFR was silenced, the timing of moulting of the 5th instar larvae was disrupted, as the peak time of moulting moved forward under the photoperiod of 16L:8D and 12L:12D, and the moulting time completely lost rhythm under 24L:0D. Furthermore, interfering with HcPDFR leads to a decrease in pupation rate and an increase in the mortality rate. These findings suggested that targeting the HcPDFR could be a potential strategy to control the damage caused by the leaf-eating pest, H. cunea.