Disclosed are: a novel cineraria-derived polynucleotide which can act as a promoter for a coding region of flavonoid 3,5-hydroxylase (F35H) and a novel F35H gene construct which carries the polynucleotide. Specifically disclosed are: a cineraria-derived petal-specific promoter which is selected from the group consisting of (1) a polynucleotide having the nucleotide sequence depicted in SEQ ID NO:9 and (2) a polynucleotide which can hybridize with the polynucleotide having the nucleotide sequence depicted in SEQ ID NO:9 under stringent conditions and can act as a promoter for a coding region of flavonoid 3,5-hydroxylase (F35H) and a gene construct for inhibiting the expression of a gene in an RNAi method, which has, as a loop, a polynucleotide comprising the whole or a part of a first intron of the novel cineraria-derived polynucleotide.