葡萄果实MYBA1与UFGT、DFR的作用机制

The Regulations of the MYBA1 in UFGT and DFR from the Grape Berries

【目的】MYBA1转录因子在花色苷生物合成中扮演着重要角色,通过对葡萄果实发育过程中VvMYBA1、VvUFGT、VvDFR的表达和花色苷的积累模式以及VvMYBA1与VvUFGT、VvDFR作用机制的分析,阐明花色苷合成调控机制。【方法】利用实时荧光PCR检测VvMYBA1、VvUFGT、VvDFR在葡萄果实发育过程中的表达模式;采用分光光度计测定葡萄中花色苷积累量的变化规律;用SAS8.0软件分析VvMYBA1、VvUFGT、VvDFR不同时期表达量及花色苷积累量之间的相关性;通过酵母杂交系统检测VvMYBA1转录激活活性及其与VvUFGT、VvDFR间的作用。【结果】实时荧光定量PCR结果显示,VvMYBA1、VvUFGT、VvDFR在葡萄果实发育过程中呈现先上升后下降的趋势,在转色期(花后60—80 d)达到最大值。葡萄果实发育过程中花色苷积累量表现为先上升后趋于稳定,转色期(花后80d)达到最大值。相关性分析结果表明,VvMYBA1表达量与VvUFGT、VvDFR表达量呈显著正相关,花色苷积累量与VvMYBA1、VvUFGT、VvDFR表达量呈显著正相关。酵母杂交系统检测表明,VvMYBA1具有转录激活功能,能够特异结合VvUFGT、VvDFR启动子,与VvUFGT、VvDFR编码的蛋白不具有相互作用。【结论】花色苷含量与VvMYBA1、VvUFGT、VvDFR表达量呈显著正相关,VvMYBA1具有转录激活功能且能特异性结合VvUFGT、VvDFR的启动子,表明VvMYBA1通过激活VvUFGT、VvDFR的启动子来调节其表达,从而调控花色苷的合成积累。

【Objective】MYBA1 transcription factor plays an important role in the biosynthesis of anthocyanins. To further explore the synergistic regulatory mechanism of anthocyanins, we analyzed the mutual mechanism and expression pattern of VvMYBA1, VvUFGT, VvDFR and content of anthocyanins during grape berry development.【Method】The real-time PCR, spectrophotometer and SAS8.0 were used to analyze the expression patterns of VvMYBA1, VvUFGT, VvDFR content of anthocyanins and correlation in different time periods, respectively. The transcriptional activity of VvMYBA1 and the interactions between the VvMYBA1 and VvUFGT, VvDFR were determined by yeast hybrid system. 【Result】The expression pattern analysis showed that the expression of VvMYBA1, VvUFGT and VvDFR was increased until veraison（60-80 d after full bloom） and then declined. The content of anthocyanins was fist increased until veraison（80 d after full bloom） and then stabilization. Correlation analysis showed that the expression of MYBA1 with expression of the DFR, UFGT had positive correlation, and the content of anthocyanins with the expression of MYBA1, DFR, UFGT had positive correlation. Yeast hybrid assay indicated that VvMYBA1 had transcriptional activation functions which could specifically combine promoter of VvUFGT, VvDFR and had no interaction with VvUFGT and VvDFR encoded proteins.【Conclusion】The content of anthocyanins was significantly correlated with expression of VvMYBA1, VvDFR, and VvUFGT. The VvMYBA1 had transcriptional activation functions. All results indicated that VvMYBA1 could regulate the accumulation of anthocyanins in grape berry development by regulating VvUFGT and VvDFR expression combined with VvUFGT and VvDFR promoter specifically.