RNA interference in the poultry red mite Dermanyssus gallinae

The avian haematophagous ectoparasite, Dermanyssus gallinae or the poultry red mite (PRM), 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 PRM is a priority. RNA interference (RNAi) represents a powerful method of pest control and works by selectively knocking-down genes, which are crucial to the mite’s survival and has been employed in pest management for decades. Here we describe the interrogation of the PRM genome, and subsequent identification of the key components of the small interfering RNA (si-RNA) and micro-RNA (miRNA) pathways, which indicate the likely presence of these mechanisms in PRM. In addition, we noted the absence of Aub and P-element induced wimpy testis (Piwi) genes indicating the absence of the Piwi-interacting RNA (piRNA) pathway in PRM. The function of the exo-siRNA pathway was confirmed by selective knock-down of the vATPase gene in PRM, using dsRNAs targeting two regions of the vATPase-subunit A. Successful gene knock-down was observed with a significant reduction in vATPase expression being observed. Gene knockdown was achieved within 24 hours, and persisted for at least 120 hours. The significance of gene knock-down in PRM has shown the potential of RNAi as a control measure for the poultry industry