Host Generated siRNAs Attenuate Expression of Serine Protease Gene in Myzus persicae

Varnika Bhatia,Rajendra Singh,Prem L Uniyal,Rampal S Niranjan,Ramcharan Bhattacharya,Zhengguang Zhang

doi:10.1371/journal.pone.0046343

Abstract

BackgroundSap sucking hemipteran aphids damage diverse crop species. Although delivery of ds-RNA or siRNA through microinjection/feeding has been demonstrated, the efficacy of host-mediated delivery of aphid-specific dsRNA in developing aphid resistance has been far from being elucidated.Methodology/Principal FindingsTransgenic Arabidopsis expressing ds-RNA of Myzus persicae serine protease (MySP) was developed that triggered the generation of corresponding siRNAs amenable for delivery to the feeding aphids. M. persicae when fed on the transgenic plants for different time intervals under controlled growth conditions resulted in a significant attenuation of the expression of MySP and a commensurate decline in gut protease activity. Although the survivability of these aphids was not affected, there was a noticeable decline in their fecundity resulting in a significant reduction in parthenogenetic population.Conclusions/SignificanceThe study highlighted the feasibility of developing host based RNAi-mediated resistance against hemipteran pest aphids.

Highlights

Loss in yield, especially due to insect pests, accounts almost 14% of global agricultural output [1] and incurs a cost of about 3000 million dollars towards the protection of five important crop species [2]
From here onwards Myzus persicae serine protease (MySP) refers to the serine protease gene in M. persicae
Bioinformatic analysis revealed 18 candidate gene sequences putatively coding for serine proteases in Acyrthosiphon pisum (Fig. S1)

Summary

Introduction

Especially due to insect pests, accounts almost 14% of global agricultural output [1] and incurs a cost of about 3000 million dollars towards the protection of five important crop species [2]. Sap sucking hemipteran aphid elicits multitude damaging effects on a large number of agriculturally important oilseed, cereal, fruit, timber and medicinally important crop species belonging to taxonomically diverse families including Poaceae, Anacardiaceae, Rosaceae, Brassicaceae, Pinaceae, and Asteraceae [3,4]. Since aphids feed through sucking the phloem sap and shelter beneath the leaf surface, only systemic chemical insecticides are effective against aphids. As a result, breeding efforts for developing resistant cultivars for minimizing the use of insecticides has not met with any success. Some efforts have been made towards developing transgenic plants expressing insecticidal proteins of plant origin such as lectins [7,8] and protease inhibitors [9,10], the success has been rather modest due to their non-specific mode of action. Sap sucking hemipteran aphids damage diverse crop species. Delivery of ds-RNA or siRNA through microinjection/feeding has been demonstrated, the efficacy of host-mediated delivery of aphid-specific dsRNA in developing aphid resistance has been far from being elucidated

Methods

Results

Conclusion