RNA interference-mediated knockdown of voltage-gated sodium channel (MpNav) gene causes mortality in peach-potato aphid, Myzus persicae

Kaleem Tariq,Maolin Hou,Asad Ali,Farman Ullah,Erum Naz,Summar Sohail,T G Emyr Davies,Laila Naz

doi:10.1038/s41598-019-41832-8

Abstract

Voltage-gated sodium channels (VGSC) are transmembrane proteins that generate an action potential in excitable cells and play an essential role in neuronal signaling. Since VGSCs play a crucial role in nerve transmission they have become primary targets for a broad range of commercial insecticides. RNA interference (RNAi) is a valuable reverse genetics tool used in functional genomics, but recently, it has also shown promise as a novel agent that could be used to control agricultural insect pests. In this study, we targeted the VGSC (MpNav) gene in the peach-potato aphid Myzus persicae, by oral feeding of artificial diets mixed with dsRNAs. Knock-down of MpNav gene expression caused up to 65% mortality in 3rd instar nymphs. Moreover, significantly lower fecundity and longevity was observed in adult aphids that had been fed with dsMpNav solution at the nymphal stage. Analysis of gene expression by qRT-PCR indicated that the aphid mortality rates and the lowered fecundity and longevity were attributable to the down-regulation of MpNav by RNAi. Taken together, our results show that MpNav is a viable candidate target gene for the development of an RNAi-based bio-aphicide.

Highlights

The peach-potato aphid Myzus persicae (Hemiptera: Aphididae) is a major sap-sucking insect pest that infest more than 400 species of plants belonging to 40 different families including Brassicaceae and Solanaceae
In M. persicae, the functioning voltage-gated sodium channel (VGSC) is encoded by two genes (NCBI Accessions FN601405 and FN601406)[12] with some unique properties that are not present in the VGSCs of other insects
Insect VGSCs are normally encoded by a single gene, that can generate a large number of transcriptional editing and splice variants that are differentially expressed at various developmental stages within the life cycle and in specific cell types[30]

Summary

Introduction

The peach-potato aphid Myzus persicae (Hemiptera: Aphididae) is a major sap-sucking insect pest that infest more than 400 species of plants belonging to 40 different families including Brassicaceae and Solanaceae. Synthetic chemical insecticides are considered the most effective way to combat M. persicae. It has developed resistance against several different insecticide classes[4], resulting in significant control failures and losses in protected crops. The insecticides that target the VGSC have broad spectrum effects, as the structure of the VGSC is highly conserved across the animal kingdom, so there is a consequential detrimental impact on non-target species including pollinators and other beneficial’s. In M. persicae (and other aphids), the functioning VGSC is encoded by two genes (NCBI Accessions FN601405 and FN601406)[12] with some unique properties that are not present in the VGSCs of other insects. Unlike the channels of other insects, the aphid has a unique heterodimeric channel (composed of two subunits, H1 and H2, encoding DI-II and DIII-IV of the VGSC respectively) with an atypical ion selectivity filter (similar that found in the mammalian sodium sensor channel Nax)[13], which, atypically for insect VGSCs, is extremely insensitive to tetrodotoxin

Methods

Results

Conclusion