RT Journal Article SR Electronic T1 RNAi gene knockdown in the poultry red mite, Dermanyssus gallinae (De Geer 1778), a tool for functional genomics JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.09.28.316380 DO 10.1101/2020.09.28.316380 A1 Wan Chen A1 Kathryn Bartley A1 Francesca Nunn A1 Alan S. Bowman A1 Jeremy M. Sternberg A1 Stewart T. G. Burgess A1 Alasdair J. Nisbet A1 Daniel R. G. Price YR 2020 UL http://biorxiv.org/content/early/2020/10/01/2020.09.28.316380.abstract AB Background The avian haematophagous ectoparasite, Dermanyssus gallinae or the poultry red mite, causes significant economic losses to the egg laying industry worldwide and also represents a significant welfare threat. Current acaricide-based controls are unsustainable due to the mite’s ability to rapidly develop resistance, thus developing a novel sustainable means of control for D. gallinae is a priority. RNA interference (RNAi) mediated gene silencing is a valuable tool for studying gene function in non-model organisms, but is also emerging as a novel tool for parasite control.Methods Here we use an in silico approach to identify core RNAi pathway genes in the recently sequenced D. gallinae genome. In addition we utilise an in vitro feeding device to deliver dsRNA to D. gallinae targeting the D. gallinae vATPase subunit A (Dg vATPase A) gene and monitor gene knockdown using quantitive PCR (qPCR).Results We identified core components of the small interfering RNA (siRNA) and micro RNA (miRNA) pathways in D. gallinae, which indicate these gene silencing pathways are likely functional. Strikingly, the Piwi-interacting RNA (piRNA) pathway was absent in D. gallinae. In addition, we demonstrate that feeding Dg vATPase A dsRNA to adult female D. gallinae results in silencing of the targeted gene compared to control mites fed non-specific lacZ dsRNA. In D. gallinae, dsRNA mediated gene knockdown is rapid, detectable 24 hours after oral delivery of dsRNA and persisted for at least 120 hours.Conclusions This study has shown the presence of core RNAi machinery components in the D. gallinae genome. In addition, we have developed a robust RNAi methodology for targeting genes in D. gallinae, which will be of value for studying genes of unknown function and validating potential control targets in D. gallinae.Competing Interest StatementThe authors have declared no competing interest.