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类黄酮-3-O-葡萄糖基转移酶(3GT)能催化无色的花色素生成有色的花色苷。本研究采用RT-PCR法从彩色马铃薯中克隆了3GT基因,并对其进行了生物信息学分析和组织表达模式分析。结果显示,3GT基因编码448个氨基酸残基,具有信号肽但无跨膜结构域,还有一定的亲水性,定位于细胞质。同源比对表明3GT与茄子等茄科植物同属一簇,亲缘关系最近,与玉米等单子叶植物亲缘关系较远。3GT蛋白主要的二级结构元件为α-螺旋和无规则卷曲,且只有一个功能结构域,即氨基酸序列中的93~407区段,它与UDP-glucoronosyl、UDP-glucosyl transferase的功能结构域相匹配,因此,3GT属于UDPGT型糖基转移酶超家族的一员。组织特异性表达结果表明:3GT相对表达量和花色苷含量均是块茎高于叶片,它们的变化趋势基本一致,花色苷含量较高的器官,其3GT的相对表达量也较高,说明花色苷的积累与3GT的表达正相关。本研究可为花色苷积累的生化及分子机制研究奠定基础,并为进一步研究该基因在花色苷合成途径中的调控功能提供理论依据。
Flavonoid-3-O-glucosyltransferase (3GT) catalyzes the production of colored anthocyanins by colorless anthocyanidins. In this study, 3GT gene was cloned from potato by RT-PCR and analyzed by bioinformatics and tissue expression patterns. The results showed that the 3GT gene encoding 448 amino acid residues, with signal peptide but no transmembrane domain, but also a certain degree of hydrophilicity, located in the cytoplasm. Homologous alignment indicated that 3GT belongs to the same cluster as Solanaceae such as eggplant, and has the closest genetic relationship with distantly related monocotyledonous plants such as maize. The main secondary structural elements of 3GT protein are α-helix and random coil, and only one functional domain, ie, 93 to 407 in the amino acid sequence, interacts with the functional domains of UDP-glucoronosyl and UDP-glucosyl transferase Therefore, 3GT belongs to the UDPGT type glycosyltransferase superfamily. Tissue-specific expression results showed that the relative expression level of 3GT and anthocyanin content were higher than tuberous, and their trend of change was basically the same. The organs with higher anthocyanin had higher expression of 3GT, indicating that anthocyanins Accumulation is positively correlated with the expression of 3GT. This study laid the foundation for the biochemical and molecular mechanisms of anthocyanin accumulation and provided a theoretical basis for further study on the regulatory function of this gene in anthocyanin synthesis pathway.