RNA Interference of Genes Encoding the Vacuolar-ATPase in Liriomyza trifolii

SIMPLE SUMMARY: Liriomyza trifolii is an important insect pest of many horticultural and vegetable crops, and it is also an important alien pest, which is increasingly harmful in most parts of China. Here, a dsRNA delivery method was established for L. trifolii and used to study two vacuolar-ATPase subunits (V-ATPase B and V-ATPase D) by microinjection. The dsRNA constructs reduced transcription of both V-ATPases, and the knockdown of these genes resulted in increased mortality. This study is the first report on the RNA interference (RNAi)-based approach for Liriomyza spp., internal feeders. The use of RNAi technology in L. trifolii will contribute to the functional analysis of critical genes and may potentially provide a new idea for control strategies. ABSTRACT: The leafminer fly, Liriomyza trifolii, is an invasive pest of vegetable and horticultural crops in China. In this study, a microinjection method based on dsRNA was developed for RNA interference (RNAi) in L. trifolii using genes encoding vacuolar-ATPase (V-ATPase). Expression analysis indicated that V-ATPase B and V-ATPase D were more highly expressed in L. trifolii adults than in larvae or pupae. Microinjection experiments with dsV-ATPase B and dsV-ATPase D were conducted to evaluate the efficacy of RNAi in L. trifolii adults. Expression analysis indicated that microinjection with 100 ng dsV-ATPase B or dsV-ATPase led to a significant reduction in V-ATPase transcripts as compared to that of the dsGFP control (dsRNA specific to green fluorescent protein). Furthermore, lower dsRNA concentrations were also effective in reducing the expression of target genes when delivered by microinjection. Mortality was significantly higher in dsV-ATPase B- and dsV-ATPase D-treated insects than in controls injected with dsGFP. The successful deployment of RNAi in L. trifolii will facilitate functional analyses of vital genes in this economically-important pest and may ultimately result in new control strategies.