The diversity on fruit colouration in plants directly depends on the flavonoids that explain the development of different pigmentation patterns. Anthocyanins are the major class of flavonoid pigments that are synthesized through flavonoid biosynthetic pathway. In the present study, two genes: PgUFGT gene and R2R3-PgMYB gene, involved in anthocyanin biosynthesis were analysed in four tissues of wild pomegranate. The structural genes, UDP-glucose: flavonoid-3-O-glucosyl transferase (PgUFGT; GenBank accession number: MK058491) and its myeloblastosis transcription factor (R2R3-PgMYB; GenBank accession number: MK092063) were isolated and their expression pattern were studied. Molecular modelling indicated that the main secondary structures of PgUFGT and R2R3-PgMYB genes are α-helix and random coil. In addition, expression profiling of PgUFGT and R2R3-PgMYB by quantitative-real time PCR indicated a positive correlation between anthocyanin content and their expression in leaves, flowers, green and red fruits of wild pomegranate. Among all the tissues, the red fruit exhibited high transcripts levels of PgUFGT as well as R2R3-PgMYB transcription factor. An extensive homology with UFGTs from other plants was revealed on comparative and bioinformatic analyses. Present study reveals that PgUFGT plays a predominant role in anthocyanin content in wild pomegranate fruits. Further, it is strongly suggested that R2R3-PgMYB transcription factor regulates the anthocyanin biosynthesis in wild pomegranate via expression of PgUFGT gene. This is the first study which provides an insight on expression profile of PgUFGT and R2R3-PgMYB that are involved in colour development and fruit ripening in wild pomegranate.

中文翻译：

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PgUFGT基因和R2R3-PgMYB转录因子在野生石榴（Punica granatum L.）的四个组织中参与类黄酮生物合成的分子表征。

植物果实着色的多样性直接取决于可解释不同色素沉着模式发展的类黄酮。花色苷是通过类黄酮生物合成途径合成的类黄酮颜料的主要类别。在本研究中，在野生石榴的四个组织中分析了涉及花色苷生物合成的两个基因：PgUFGT基因和R2R3-PgMYB基因。分离了结构基因UDP-葡萄糖：类黄酮-3-O-葡萄糖基转移酶（PgUFGT； GenBank登录号：MK058491）及其成纤维细胞病转录因子（R2R3-PgMYB； GenBank登录号：MK092063），并研究了它们的表达模式。分子建模表明，PgUFGT和R2R3-PgMYB基因的主要二级结构是α-螺旋和无规卷曲。此外，实时荧光定量PCR检测PgUFGT和R2R3-PgMYB的表达谱表明，花青素含量与其在野生石榴的叶，花，绿色和红色果实中的表达呈正相关。在所有组织中，红色果实显示出高水平的PgUFGT和R2R3-PgMYB转录因子。通过比较和生物信息学分析揭示了与其他植物的UFGT的广泛同源性。目前的研究表明，PgUFGT在野生石榴果实中的花色苷含量中起主要作用。此外，强烈建议R2R3-PgMYB转录因子通过PgUFGT基因的表达调节野生石榴中的花色苷生物合成。