Identification and RNA binding characterization of plant virus RNA silencing suppressor proteins

Suppression is a common mechanism employed by viruses to evade the antiviral effects of the host's RNA silencing pathway. The activity of suppression has commonly been localized to gene products in the virus, but the variety of mechanisms used in suppression by these viral proteins spans nearly the complete biochemical pathway of RNA silencing in the host. This review describes the agrofiltration assay and a slightly modified version of the agro-infiltration assay called co-infiltration, which are common methods used to observe RNA silencing and identify viral silencing suppressor proteins in plants, respectively. In addition, this review will provide an overview of two methods, electrophoretic mobility shift assay and fluorescence polarization, used to assess the binding of a suppressor protein to siRNA which has been shown to be a general mechanism to suppress RNA silencing by plant viruses.