葡萄‘小白玫瑰’及其突变品种‘小红玫瑰’果皮颜色变异机理分析

‘小红玫瑰’葡萄是源自于‘小白玫瑰’的突变品种,二者都是优良的酿酒葡萄品种,但其果实颜色变异的分子机理尚不清楚。用12对SSR(Simple sequence repeats)荧光标记特征引物对两品种进行分析,结果表明这些位点在二者之间无差别。对色泽变异决定基因Vvmyb A1的基因型进行分析,‘小白玫瑰’仅检测到含有插入逆转座子Gret1(grapevine retrotransposon 1)的VvmybA1a,说明其为VvmybA1a/VvmybA1a纯合体;而‘小红玫瑰’检测到了Vvmyb A1a和残留Gret1 3′-LTR(long terminal repeat)的VvmybA1b,说明其为VvmybA1a/VvmybA1b的杂合体。花色苷合成相关基因的表达分析表明,VvmybA1、UFGT、F3′5′H、CHS、GST和OMT在‘小红玫瑰’及有色对照品种‘黑比诺’中大量表达,而在‘小白玫瑰’和无色对照品种‘白比诺’中几乎不表达。通过HPLC–ESI–MS/MS对花色苷主要成分进行测定,结果表明矢车菊素3–O–葡萄糖苷(CyG)、矢车菊素3,5–O–双葡萄糖苷(Cy2G)、飞燕草素3–O–葡萄糖苷(DpG)、锦葵色素3–O–葡萄糖苷(MvG)、芍药色素3–O–葡萄糖苷(PnG)和矮牵牛色素3–O–葡萄糖苷(PtG)等6种花色苷在有色品种‘小红玫瑰’和‘黑比诺’果皮中的含量均显著高于无色品种,花葵素3–O–葡萄糖苷(Pg G)、花葵素3,5–O–双葡萄糖苷(Pg2G)在有色/无色品种间无显著差异,且含量很低。说明‘小红玫瑰’的着色是由于转录因子基因Vvmyb A1及其调控结构基因的表达引起的,而无功能的VvmybA1a等位基因突变为有功能的VvmybA1b等位基因是其果皮颜色变异的遗传学原因。

Analysis on Molecular Basis of the Color Mutation in 'Muscat Rouge' and 'Muscat Blanc' Grapes

Light-red-skinned'Muscat Rouge'grape is mutation of white-skinned'Muscat Blanc'Both of them are high-quality grapewine cultivars.However,the mechanism of the color mutation in 'Muscat Rouge'has not been elucidated so far.In this study,12 SSR markers were applied to analyze the relationship of these two cultivars firstly.The results revealed that there was not amplification difference between them.The VvmybA1 gene sequence analysis results revealed that'Muscat Blanc'harbored only VvmybA1a at the VvmybA1 locus,both VvmybA1a and VvmybA1b alleles in'Muscat Rouge'.The qRT-PCR results indicated that the higher levels of expression of VvmybA1 gene,3-O-glucosyltransferase (UFGT),flavanone 3',5'-hydroxylase (F3'5'H),chalcone synthase (CHS),O-methyltransferase (OMT),and glutathione-S-transferase (GST) were detected in'Muscat Rouge'and'Pinot Noir'.The elementary composition of the anthocyanin profiles were analyzed using high-performance liquid chromatography and electrospray ionization mass spectrometry (HPLC-ESI-MS/MS),revealing divergent chemical profiles.'Muscat Rouge'and'Pinot Noir'both showed higher abundance of Cyanidin 3-O-glucoside (CyG),Cyanidin 3-O-glucoside-5-O-glucoside (Cy2G),Delphinidin 3-O-glucoside (DpG),Malvidin 3-O-glucoside (MvG),Peonidin 3-O-glucoside (PnG),Petunidin 3-O-glucoside (PtG) than 'Muscat Blanc'and'Pinot Blanc'.These results suggested that the red-skinned'Muscat Rouge'phenotype is the re-mutation of VvmybA1a allele to VvmybA1b gene.