Provided is a polynucleotide encoding a protein having an activity to transfer a sugar to the hydroxy groups at the 4'- and 7-positions of a flavone. The polynucleotide is selected from the group consisting of: (a) a polynucleotide which comprises a base sequence represented by SEQ ID NO: 1, 3, or 12； (b) a polynucleotide which hybridizes to a polynucleotide comprising a base sequence complementary to a base sequence represented by SEQ ID NO: 1, 3, or 12 under high stringency conditions, and encodes a protein having an activity to transfer a sugar to the hydroxy groups at the 4'- and 7-positions of a flavone； (c) a polynucleotide which encodes a protein comprising an amino acid sequence represented by SEQ ID NO: 2, 4, or 13； (d) a polynucleotide which encodes a protein comprising an amino acid sequence in which one or more amino acids have been deleted, substituted, inserted, and/or added in an amino acid sequence represented by SEQ ID NO: 2, 4, or 13 and having an activity to transfer a sugar to the hydroxy groups at the 4'- and 7-positions of a flavone； etc.
