The present invention provides a method for reducing or inhibiting fucose modification to a N-linked sugar chain in a plant, and a transgenic plant, or the like, in which the fucose modification has been reduced or inhibited. Transcription or translation of a gene coding for an enzyme involved in synthesis of sugar nucleotide GDP-fucose is inhibited by post-transcriptional gene silencing (PTGS), virus-induced gene silencing (VIGS) or transcriptional gene silencing (TGS), and an amount of GDP-fucose in a plant cell is reduced, to reduce or inhibit fucose modification to a sugar chain including glycoprotein sugar chain, glycolipid sugar chain, oligosaccharide, polysaccharide, and the like, thereby enabling production of a glycoprotein, or the like, from which fucose modification, which may become an allergen, has been removed, and enabling clinical application of a medicinal glycoprotein produced with a plant.
