Grapevine fanleaf virus (GFLV) is a plant pathogenic virus of the family Secoviridae. It infects grapevines, causing chlorosis of the leaves and lowering the fruit quality. Because of its effect on grape yield, GFLV is a pathogen of commercial importance. It has an RNA genome contained on two RNA molecules, each of which is covalently attached to a small protein (the viral genome-linked protein, VPg) at the 5' end.