红肉火龙果 HpCYP76AD1 基因克隆与表达分析.

[Objective] The present paper aimed to provide theoretical basis for studying the molecular mechanism of betacyanin accumulation and improving the nutritional value of Hylocereus polyrhizus, the betacyanin content in fruits, cloned HpCYP76 AD1 gene are detected, and the relationship between gene expression and betacyanin content are analyzed.[Method] The betacyanin content during fruit maturation was measured using the colorimetric method. HpCYP76 AD1 gene was obtained based on fruit transcriptome sequencing data and RT-PCR clone. The physicochemical properties and phylogenetic relationship of protein encoding by HpCYP76 AD1 were analyzed and the gene expression pattern during fruit maturation was detected by qRT-PCR.[Result] The betacyanin accumulated rapidly during fruit ripening, whose content in mature fruit（30 days after pollination） was about 150 times higher than the one 20 days after pollination. The open reading frame of HpCYP76 AD1 gene was 1521 bp, which encoded a protein sequence of 506 amino acids. The relative molecular weight of HpCYP76 AD1 protein was 57.5 kDa and the predicted isoelectric point was 8.86. The HpCYP76 AD1 amino acid sequence had a highest similarity with pear cactus OfCYP76 AD8, which up to 89.96%. HpCYP76 AD1 and Beta vulgaris BvCYP76 AD1, Mirabilis jalapa MjCYP76 AD3 and Amaranthus cruentus belonged to the α class of CYP76 AD1 family, which suggested that HpCYP76 AD1 had a catalytic activity in the two hydroxylation reactions of betacyanin accumulation in fruits. The expression of HpCYP76 AD1 gene was significantly up-regulated during fruit ripening, which was positively correlated with the betacyanin accumulation pattern in fruits.[Conclusion] HpCYP76 AD1 gene from cytochrome P450 family member of H. polyrhizus belonged to the α class, which indicated that it may have a catalytic activity in the two-step hydroxylation reaction of betacyanin accumulation. The expression of HpCYP76 AD1 gene was greatly up-regulated during fruit ripening, which was involved in betacyanin accumulation. [ABSTRACT FROM AUTHOR]