Flavonoids are phenolic substances and exhibit strong antioxidant properties. The biosynthesis of flavonoids is regulated by various transcription factors (TFs), with MYB TFs playing a key role in controlling essential genes within this pathway. In this study, we identified candidate MYB TFs from our pulp transcriptome database of durian ‘Monthong’ cultivar. MYBs exhibiting upregulation during the ripe stage were considered transcriptional activators, due to their positive correlation with flavonoid gene expression and flavonoid accumulation in ripe durian pulps. One candidate MYB activator, DzMYB1, which was highly expressed at the ripe stage, was selected for functional characterization. Studies involving transient expression of in cv. Micro-Tom fruit demonstrated increased flavonoid content, as analyzed by LC–MS/MS, compared with the control. Moreover, we showed that DzMYB1 controls flavonoid biosynthesis by interacting with the promoters of various flavonoid biosynthetic genes, including chalcone synthase, chalcone isomerase, and flavanone 3-hydroxylase, resulting in their transcriptional activation. Additionally, we found that DzMYB1 functions as a homodimer and binds to a homodimerized DzbHLH1 in the intricate regulation of flavonoid biosynthesis. These findings provide comprehensive insights into the functional roles of MYB protein in the regulation of the flavonoid pathway within durian pulps.

中文翻译：

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榴莲 (Durio zibethinus) 中的一种新型 MYB 转录因子 DzMYB1 可调节果肉中的类黄酮生物合成


黄酮类化合物是酚类物质，具有很强的抗氧化性能。类黄酮的生物合成受到多种转录因子 (TF) 的调节，其中 MYB TF 在控制该途径中的必需基因方面发挥着关键作用。在这项研究中，我们从榴莲“Monthong”品种的果肉转录组数据库中确定了候选 MYB 转录因子。在成熟阶段表现出上调的 MYB 被认为是转录激活剂，因为它们与成熟榴莲果肉中的类黄酮基因表达和类黄酮积累呈正相关。选择一种在成熟阶段高度表达的候选 MYB 激活剂 DzMYB1 进行功能表征。涉及cv中瞬时表达的研究。通过 LC-MS/MS 分析，与对照相比，Micro-Tom 水果的类黄酮含量有所增加。此外，我们发现DzMYB1通过与各种类黄酮生物合成基因的启动子相互作用来控制类黄酮生物合成，这些基因包括查耳酮合酶、查耳酮异构酶和黄烷酮3-羟化酶，导致它们的转录激活。此外，我们发现 DzMYB1 作为同源二聚体发挥作用，并在类黄酮生物合成的复杂调节中与同源二聚体 DzbHLH1 结合。这些发现为 MYB 蛋白在调节榴莲果肉中类黄酮途径中的功能作用提供了全面的见解。