Functional Characterization of Anthocyanin Biosynthesis-Related <i>Dihydroflavonol 4-reductase</i> (<i>DFR</i>) Genes in Blueberries (<i>Vaccinium corymbosum</i>)

<i>Dihydroflavonol 4-reductase</i> (<i>DFR</i>) genes contribute greatly to anthocyanin biosynthesis in plants. Up to now, however, research on the <i>DFR</i> gene family and the key anthocyanin-related <i>DFR</i> members in blueberries (<i>Vacci...

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Main Authors: Yongyan Zhang, Sijian Guo, Zening Zhang, Ruide Li, Shitao Du, Siyi Hao, Chunzhen Cheng
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/10/1449
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Summary:<i>Dihydroflavonol 4-reductase</i> (<i>DFR</i>) genes contribute greatly to anthocyanin biosynthesis in plants. Up to now, however, research on the <i>DFR</i> gene family and the key anthocyanin-related <i>DFR</i> members in blueberries (<i>Vaccinium corymbosum</i>) has been limited. In this study, we performed a genome-wide identification of the blueberry <i>DFR</i> gene family, identifying 36 <i>VcDFR</i> genes categorized into five subfamilies. Gene expression analysis showed that three Subfamily III members (<i>VcDFR11/29/34</i>) and four Subfamily V members (<i>VcDFR4/7/30/33</i>) are highly expressed in blueberry fruits, particularly at late ripening stages. Transient overexpression analysis in apple fruits verified the contributions of <i>VcDFR11</i> and <i>VcDFR30</i> to anthocyanin biosynthesis, with <i>VcDFR11</i> showing better promoting effects. Blueberry fruit-based transient overexpression further confirmed the promoting effects of <i>VcDFR11</i> on anthocyanin accumulation and the expression of anthocyanin-related structural genes (especially its downstream <i>anthocyanindin synthase</i> (<i>ANS</i>) and <i>UDP-glucose: flavonoid 3-O-glycosyltransferase</i> (<i>UFGT</i>) genes). The <i>VcDFR11</i> promoter contains binding sites for both bHLH and MYB transcription factors (TFs). Consistently, yeast one-hybrid and dual-luciferase assays confirmed that anthocyanin-related VcMYB-1 and VcbHLHs can bind to and activate the <i>VcDFR11</i> promoter. Furthermore, co-overexpressing <i>VcMYB-1</i>/<i>VcbHLHs</i> with <i>VcDFR11</i> led to much higher anthocyanin accumulation than overexpressing <i>VcDFR11</i> alone, indicating that these TFs positively regulate anthocyanin biosynthesis by upregulating <i>VcDFR11</i>. In summary, our study characterized the blueberry <i>DFR</i> gene family and demonstrated the role of <i>VcDFR11</i> in anthocyanin biosynthesis.
ISSN:2223-7747