RNA Interference in Ticks: A Functional Genomics Tool for the Study of Physiology

Ticks are an example of an efficient ectoparasite that feeds on a variety of hosts including humans, domestic and wild animals. Tick salivary glands are critical to the biological success of ticks both during extended periods off the host and during the feeding period on the host. The salivary glands are also the sites of pathogen development and saliva is the route of transmission. The importance of multifunctional salivary glands to tick survival and vector competency makes the glands potential targets for intervention. RNA interference (RNAi) has the potential to revolutionize genetic manipulation and enhance the development of therapeutic and control agents in many arthropod-borne diseases and vectors. This reverse genetics tool has already been successfully used to study tick host and tick pathogen interactions. The translation of RNAi from an effective functional genomics tool into field application has been hindered by the challenge of delivering RNAi molecules to their target tissues by systemic administration. This review highlights the current status of RNAi in defining the physiological role of tick molecules in vector competence and vector host interactions.