箭叶淫羊藿EsUF3GT基因的克隆及表达分析

类黄酮3-O-糖基转移酶(flavonoid 3-O-glucosyltransferase,UF3GT)可以把不稳定的花色素催化成花色素苷。本研究采用同源基因克隆技术获得箭叶淫羊藿Epimedium sagittatum(Sieb.and Zucc.)Maxim.UF3GT基因c DNA开放阅读框(Open Reading Frame,ORF)序列,命名为Es UF3GT(Gen Bank注册号为KJ648620)。序列分析表明,该基因ORF全长为1356 bp,编码451个氨基酸,与其它植物中UF3GT蛋白序列的相似性为40%~50%。进化树分析发现,Es UF3GT同催化类黄酮3-O糖基化的糖基转移酶聚为一枝。qRTPCR分析结果显示,Es UF3GT在花中的表达量最高,约为叶片、花蕾中表达水平的2.3倍,果实及根中表达水平的19倍。花青素含量检测表明,花蕾中的含量最高(130.4 mg/100 g),分别是叶片、花、果实及根中含量的3.5、5.2、72、87倍。我们推测Es UF3GT参与了箭叶淫羊藿花色素苷的生物合成,此结果为深入开展EsUF3GT的生化功能研究奠定了基础。

Cloning and Expression Analysis of the EsUF3GT Gene in Epimedium sagittatum (Sieb. and Zucc.) Maxim.

Flavonoid 3-O-glycosyltransferase (UF3GT) can catalyze unstable anthocyanidin into anthocyanin. In this study, the Open Reading Frame (ORF) sequence of a novel UF3GT gene, designated as EsUF3GT, was isolated from Epimedium sagittatum (Sieb. and Zucc.) Maxim. using homologous gene cloning. The sequence was logged into the GenBank database with an accession No. of KJ648620. Its cDNA sequence contained a 1356 bp complete ORF, encoding 451 amino acids, and the deduced amino acid showed 40%-50% homology with other plant UF3GTs. Phylogenetic analysis revealed that EsUF3GT had a close relationship with glycosyltransferases (GTs) that catalyze the flavonoid 3-O glycosylation from various species. qRT-PCR analysis indicated that EsUF3GT showed the highest expression level in flowers, about 2.3 times that found in leaves and flower buds, and 19 times that found in the fruit and roots. Anthocyanin showed the highest accumulation level of 130.4 mg/100 g in flower buds, about 3.5, 5.2, 72 and 87 times that found in leaves, flowers, fruits and roots, respectively. We speculated that EsUF3GT was involved in anthocyanin biosynthesis in E. sagittatum. These results lay a foundation for further exploration of the function of EsUF3GT.