葡萄风信子花青素3-O-葡糖基转移酶基因的克隆及其表达分析

摘要

Anthocyanidin 3-O -glucosyltransferase (3GT)is the last key enzyme in the anthocyanin biosynthetic pathway,which can catalyze unstable anthocyanidin into anthocyanin.In this study,we cloned a 3GT gene (designated as Ma3GT from Muscari armeniacum )using the PCR technique.The gene's cDNA was 1377 bp long and encoded an open reading frame of 458 aminoacids.Ma3GT showed 55%~64% similarity with the oth-er 3GTs.Phylogenetic analysis indicated that Ma3GT was classified into monocot subgroups of 3GTs,and had the closest relationship with the 3GTs of Freesia hybrid and Iris hollandica .QRT-PCR analysis detected tran-scripts of Ma3GT in different organs of M .armeniacum .The expression level of this gene was high in the fully opened petals (stage S4 ),very low in the leaves,and almost zero in the roots and bulbs of M .armeniacum . Andit almost had no expression in all the organs of M .aucheri 'White Beauty'and M .armeniacum 'Pink Surprise'.The gene expression was related to the floral developmental stages in M .armeniacum .The transcript level was rarely detectablein the unpigmented buds (stage S1 ),but increased during the pigment accumulation stages and peaked in the fully opened petals (S4 ).The expression had significant differences in three cultivars of different colors.The expression level was high in the petals of M .armeniacum ,and rarely detectable in the pet-als of 'White Beauty'and 'Pink Surprise.'This research will provide informationand theoretical support for the functional study of the Ma3GT gene.%花青素3-O-葡糖基转移酶(3GT)是花青素苷合成最后一步的关键酶,可把不稳定的花青素催化成花青素苷.本研究利用PCR技术从蓝色葡萄风信子'亚美尼亚'(Muscari armeniacum)中克隆到一个3GT基因(Ma3GT),Ma3GT cDNA全长1377 bp,编码458个氨基酸,与其他植物的3GT蛋白序列相似性达55%~64%.进化分析表明,Ma3GT与单子叶植物3GT聚为一类,与小苍兰(Freesia hybrida)、荷兰鸢尾(Iris hollandica)3GT亲缘关系最近.荧光定量PCR分析发现,Ma3GT在'亚美尼亚'花(S4)中高表达,在叶片中微量表达,根和鳞茎中几乎不表达,在'白丽人'及'粉日出'各个组织中均不表达.在'亚美尼亚'中,Ma3GT的转录表达受花发育调控,开花早期(S1)几乎不表达,随着花发育表达量逐渐增加,至完全开放的时期(S4)达到最高峰.此外,Ma3GT在不同品种的花中转录表达不同,在蓝色品种'亚美尼亚'中高表达,而在白色品种'白丽人'和粉色品种'粉日出'中几乎不表达.本研究为进一步研究Ma3GT基因在葡萄风信子花瓣呈色中的功能及其花色分子育种提供基因资源和依据.