关键词: 石蒜, 黄烷酮3–羟化酶, 基因克隆, 表达

Abstract: Flavanone 3-hydroxylase（F3H）is a crucial enzyme in the early stage of anthocyanins
biosynthesis which is important in regulating the formation of flower color. In the study，a full-length
cDNA sequence of F3H gene was cloned from petals of Lycoris radiate using RT-PCR and RACE
approaches. The cDNA sequence was 1 293 bp and included a whole open reading frame of 1098 bp
encoding 365 amino acids. The amino acid sequence of this gene shared up to 91% homology with F3H
from Narcissus tazetta，and then was named LrF3H. The predicted secondary structure indicated that
random coil was the most important structural element. However，alpha helix and extended strand
distributed in the whole protein. The conserved structural domain analysis revealed that LrF3H had the
typical functional domains of F3H protein，containing 2-oxoglutarate and iron ion combination sites and
belonging to the 2OG-Fe(Ⅱ)-dependent dioxygenase superfamily. Quantitative RT-PCR analysis showed
that LrF3H was expressed in the whole phases of flower development，and the expression level was
increasing concomitant with the growth of flower bud and pigmentation until the phase of blooming flower.
The transcript level was highest in anthocyanin-pigmented petals，moderate in cape and lower in root，
corm and leaf. Those indicated that LrF3H gene might play a role in flower pigmentation in Lycoris
radiate.

Key words: Lycoris radiate, flavanone 3-hydroxylase（F3H）, gene cloning, expression