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在植物中,类黄酮3-O-葡萄糖基转移酶(F3GT)将不稳定的花色素转变为稳定的花色素苷,是花色素苷形成的关键酶。本研究采样RT-PCR技术从滇牡丹中成功克隆获得一个完整的F3GT基因(Pd F3GT1),其含有1 371 bp的开放阅读框(ORF),编码456个氨基酸。该基因推断的蛋白与葡萄(Vitis vinifera)3GT蛋白的相似性为64%;与已知功能的3GT基因进行系统进化分析,结果显示Pd3GT1与葡萄3GT聚类到同一个分支。氨基酸比对显示Pd3GT1蛋白序列还有糖基转移酶家族特有的PSPG-box结构域。半定量PCR结果显示:Pd3GT1在花蕾,花开时期的花瓣中大量表达,在叶和花芽中有微弱表达;在根和茎中没有表达。说明Pd3GT基因表达具有组织表达特异性。该研究将为研究滇牡丹花色素形成机理,以及对滇牡丹类黄酮糖基转移酶的功能鉴定和利用基因工程手段改良花卉品质提供理论依据。
In plants, the flavonoid 3-O-glucosyltransferase (F3GT) converts unstable anthocyanidins to stable anthocyanins, a key enzyme in the formation of anthocyanins. In this study, a complete F3GT gene (Pd F3GT1) was cloned successfully from P. momordica by RT-PCR and contained a open reading frame (ORF) of 1 371 bp encoding 456 amino acids. The similarity between the deduced protein and the 3GV protein of Vitis vinifera was 64%. Phylogenetic analysis of the 3GT gene with known function showed that Pd3GT1 clustered into the same branch with grapevine 3GT. Amino acid alignments show that the Pd3GT1 protein sequence also has a PSPG-box domain that is unique to the glycosyltransferase family. Semi-quantitative PCR results showed that Pd3GT1 was highly expressed in the petals of flower buds and flowering stages, but weakly expressed in leaf and flower buds, but not in roots and stems. Pd3GT gene expression of tissue-specific expression. This research will provide a theoretical basis for studying the formation mechanism of the flower pigment of Peony, as well as the functional identification of the flavonoid glycosyltransferase of the peony tree and the improvement of flower quality by means of genetic engineering.