采用RT-PCR和RACE方法从鹤望兰黄色花萼中克隆到类黄酮生物合成途径关键基因SrF3′5′H。该cDNA全长1 766 bp,具有完整的开放阅读框(ORF),共1 509个碱基,编码503个氨基酸。氨基酸同源性分析表明,SrF3′5′H编码的氨基酸序列与已报道的其他植物的F3′5′H蛋白具有很高的同源性。系统进化树分析显示,鹤望兰SrF3′5′H与非洲紫罗兰蛋白亲缘关系较近。应用半定量PCR分析表明,SrF3′5′H在始花期转录水平达到最高,且在蓝色花瓣中表达最高,在黄色花萼中几乎没有表达。 The key gene of flavonoid biosynthesis pathway SrF3’5’H was cloned from the yellow calyx of Strelitzia reginae by RT-PCR and RACE. The cDNA is 1 766 bp in length and has a complete open reading frame (ORF) of 1,509 bases coding for 503 amino acids. Amino acid homology analysis indicated that the deduced amino acid sequence of SrF3’5’H has high homology with other reported F3’5’H proteins. Phylogenetic tree analysis showed that the relationship between Strelitzia reginae SrF3’5’H and African violet protein was close. Semi-quantitative PCR analysis showed that SrF3’5’H reached the highest transcription level at the beginning of flowering stage and was the highest expressed in the blue petals and scarcely expressed in the yellow calyxes.