Acts as suppressor of RNA-mediated gene silencing, also known as post-transcriptional gene silencing (PTGS), a mechanism of plant viral defense that limits the accumulation of viral RNAs. Suppresses RNA silencing by direct perturbation of host AGO1 slicer activity and thus interfering with miRNA pathways. Homotetramer (Probable). Interacts with host AGO1; this interaction blocks AGO1 cleavage activity to attenuate RNA silencing and thus counter host defense (PubMed:17158744). Belongs to the cucumovirus/ilarvirus protein 2b family.