The present invention concerns the barley yellow dwarf virus (BYDV) and compositions and methods related thereto. In particular in the invention, identifies a movement protein (MP) of BYDV as being responsible for at least one symptom produced as a result of BYDV infection. In certain aspects, the invention concerns a target to inhibit BYDV and to inhibit at least one symptom of BYDV infection, for example, at least plant growth retardation. In particular aspects, the invention relates to screening methods for identifying suppressors of BYDV MP.