Abstract: A novel Flavonoid-3′,5′-hydroxylase（F3′5′H）gene，named Ac-F3′5′H（The accession number in GenBank：JN635708）was cloned from the flower of Aconitum carmichaeli Debx. using RT-PCR and RACE approaches. The cDNA sequence was 1 720 bp and included a whole open reading frame，which encoded 506 amino acids. Sequence alignment results showed that the Ac-F3′5′H had three known motifs such as“PPGP”motif，I-helix，and P450 haem-binding. The amino acid sequence of the Ac-F3′5′H has higher similarity with other F3′5′H. Using the 18S rRNA（FJ748878）transcripts as an internal control，semi-quantitative RT-PCR analysis showed that the Ac-F3′5′H mRNA was highly transcribed in late phase of flowers development，which was concomitant with the appearance of anthocyanins in flower tissue. The transcript was abundant in the purple flowers but absent in leaves orroots. This indicated that the Ac-F3′5′H might play a role in regulating the forming of blue flowers in Aconitum carmichaeli Debx.

Key words: Aconitum carmichaeli Debx., flavonoid-3′,5′-hydroxylase, cloning, gene expression