酿酒葡萄原花色素生物合成转录调控研究进展

Transcription and regulation of proanthocyanidin biosynthesis in wine grape:A review

原花色素又称缩合单宁,由黄烷-3-醇和黄烷-3,4-二醇缩合构成,是一类重要的衡量葡萄果实和葡萄酒品质的多酚类物质。文章通过综述葡萄原花色素的组成和检测、生物合成及转录调控机制的进展,发现原花色素主要存在于葡萄果皮和种子中,有利于葡萄抵御生物和非生物胁迫,在葡萄酒酿造过程中,源于果实的原花色素经压榨浸渍后进入葡萄酒中,贡献葡萄酒的苦味和涩味,原花色素与其他色素之间的辅色作用也可加强葡萄酒颜色的稳定性;原花色素的生物合成是苯丙烷—类黄酮代谢路径的一个分支,与黄酮醇和花色苷生物合成共享上游路径,其在葡萄发育早期大量积累;无色花色素还原酶(LAR)和花色素还原酶(ANR)是原花色素生物合成过程的关键酶,葡萄中有2种LAR,分别由VviLAR1和VviLAR2基因编码,均具有时空表达差异性;葡萄原花色素的生物合成主要受到MYB和bHLH家族转录因子的调控,目前已鉴定出8个R2R3-MYB家族转录因子(VviMYBPA1、VviMYBPA2、VviMYBPAR、VviMYB5a、VviMYB5b、VviMYB86、VdMYB14、VviMYBC2-L1)和3个bHLH家族转录因子(VviCA1、VviMYC1、VvibHLH93);当前已鉴定到的转录因子多以VviLAR1和VviANR为靶基因,特异调控VviLAR2基因表达的转录因子亟待挖掘。今后需要关注转录因子对各种生物和非生物胁迫的响应机制、转录和转录后调控对转录因子的修饰方式及转录因子与各种信号和激素之间的互作机理。文章为酿酒葡萄原花色素调控机制的研究提供思路,进而指导我国酿酒葡萄栽培管理实践,助力优质酿酒葡萄品种选育,推动多元化、个性化风格葡萄酒的酿造。

Proanthocyanidin,also known as condensed tannin,is a mixture of flavanol-3-ols and flavan-3,4-diols in complex forms,and is one of the important polyphenolic compounds to measure the quality of grape berries and wines.In this paper,the composition and detection of proanthocyanidins,biosynthesis and transcriptional regulation of proanthocyanidins in grapes were reviewed.Proanthocyanidins,which were mainly existed in grape skins and seeds,could contribute protection to grapes under biotic and abiotic stress.In the process of wine-making,the proanthocyanidins from the fruit were pressed and impregnated into the wine,contributing to the bitterness and astringency of wine,and the copigmentation between them and other pigments could also strengthen the stability of wine color.Proanthocyanidin biosynthesis was a branch of the phenylpropane-flavonoid metabolic pathway,which shared the upstream pathway with flavonols and anthocyanins biosynthesis,and it largely accumulated during early development of grapes.Leucoanthocyanidin reductase(LAR)and anthocyanidin reductase(ANR)were key enzymes in proanthocyanidin biosynthesis.Grape possessed two LAR enzymes,which were encoded by VviLAR1 and VviLAR2 genes respectively,both of them had differences in temporal and spatial expression.The biosynthesis of proanthocyanidin in grapes was mainly regulated by MYB and bHLH family transcription factors.Until now,eight R2R3-MYB family transcription factors(VviMYBPA1,VviMYBPA2,Vvi‐MYBPAR,VviMYB5a,VviMYB5b,VviMYB86,VdMYB14,VviMYBC2-L1)and three bHLH family transcription factors(VviCA1,VviMYC1,VvibHLH93)have been identified.Currently,most of the identified transcription factors utilize VviLAR1 and VviANR as target genes,and the transcription factors that specifically regulated the expression of Vvi‐LAR2 gene needed to be explored.In the future,attention should be paid to the response mechanism of transcription factors to various biotic and abiotic stresses,the modification ways of transcription factors by transcription and posttranscriptional regulation,and the interaction mechanism between these transcription factors and various signals and hormones.This study is expected to provide insights for the study of the regulation mechanism of wine grape proanthocyanidins,and then guide the practice of wine viticulture management in China,help the selection and breeding of high-quality wine grape varieties,and promote the production of diversified and personalized wines.