Flavonoids are the predominant polyphenolic compounds which are ubiquitously present in plants, responsible for the colour development in different plant parts, thereby playing an important role in plant physiology. In order to understand chemo-diversity and biological functions of flavonoids, it is important to understand flavonoid biosynthetic pathway that involves various structural genes. Three structural genes of flavonoid biosynthetic pathway, chalcone synthase (PgCHS; GenBank accession no: KY498075), flavanone 3-hydroxylase (PgF3H; GenBank accession no: MG012857) and dihydroflavonol 4-reductase (PgDFR; GenBank accession no: MG366127) were isolated and characterized from the wild Punica granatum. Molecular modelling indicated that the secondary structures of PgCHS, PgF3H and PgDFR are mainly α-helix and random coils. HPLC analysis of flavonoids showed its accumulation in different tissues and fruits, thus corroborating well with the expression profile of PgCHS, PgF3H and PgDFR genes. PgF3H and PgDFR genes exhibited high transcripts levels in red fruits while expression of Pg CHS gene was highest in flowers. Further, it is speculated that expression of all these structural genes is independent of each other. This is the first study that provides a comparative expression pattern of flavonoid genes playing a significant role in fruit ripening in wild pomegranate.

中文翻译：

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野生石榴(Punica granatum L.)器官查尔酮合酶、黄烷酮3-羟化酶和二氢黄酮醇4-还原酶基因的鉴定及比较表达分析

黄酮类化合物是植物中普遍存在的主要多酚化合物，负责植物不同部位的颜色发育，从而在植物生理学中发挥重要作用。为了了解类黄酮的化学多样性和生物学功能，了解涉及各种结构基因的类黄酮生物合成途径非常重要。黄酮类生物合成途径的三个结构基因，查耳酮合酶（PgCHS；GenBank登录号：KY498075）、黄烷酮3-羟化酶（PgF3H；GenBank登录号：MG012857）和二氢黄酮醇4-还原酶（PgDFR；GenBank登录号：KY498075）和分离和分离以野生石榴为特征。分子模型表明 PgCHS、PgF3H 和 PgDFR 的二级结构主要是α-螺旋和无规卷曲。黄酮类化合物的 HPLC 分析显示其在不同组织和果实中积累，因此与 PgCHS、PgF3H 和 PgDFR 基因的表达谱很好地证实了。PgF3H 和 PgDFR 基因在红色果实中表现出高转录水平，而 Pg CHS 基因在花中的表达水平最高。此外，推测所有这些结构基因的表达是相互独立的。这是第一项提供类黄酮基因的比较表达模式的研究，该基因在野生石榴果实成熟中起重要作用。据推测，所有这些结构基因的表达是相互独立的。这是第一项提供类黄酮基因的比较表达模式的研究，该基因在野生石榴果实成熟中起重要作用。据推测，所有这些结构基因的表达是相互独立的。这是第一项提供类黄酮基因的比较表达模式的研究，该基因在野生石榴果实成熟中起重要作用。