High light triggers flavonoid and polysaccharide synthesis through DoHY5-dependent signaling in Dendrobium officinale
High light triggers flavonoid and polysaccharide synthesis through DoHY5-dependent signaling in Dendrobium officinale
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DOI：
10.1111/tpj.16284
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发表时间：
2023-05-26
期刊：
影响因子：
7.2
通讯作者：
Wang, Hong-Bin
中科院分区：
文献类型：
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作者：
Li, Dongxiao;Ye, Guangying;Wang, Hong-Bin
铁皮石斛可食用，具有药用和观赏功能。多糖和黄酮类化合物，包括花青素，是铁皮石斛的重要成分，在很大程度上决定了营养质量和消费者的吸引力。为了提高铁皮石斛的品质和市场价值，有必要研究调控花色苷和多糖生物合成的分子机制。在这里，我们报道了高光（HL）诱导多糖的积累，特别是甘露糖，以及花青素的积累，导致红色茎。代谢组学和转录组学分析显示，大部分黄酮类化合物的丰度发生了较大变化，HL处理显著激活了黄酮类化合物和多糖的生物合成。有趣的是，DoHY5的表达也被高度诱导。生化分析表明，DoHY5直接结合DoF3H1（参与花青素生物合成）、DoGMPP2和DoPMT28（参与多糖生物合成）启动子，激活它们的表达，从而促进了金莲茎中花青素和多糖的积累。DoHY5沉默降低了黄酮类和多糖相关基因的表达，减少了花青素和多糖的积累，而DoHY5过表达则具有相反的作用。值得注意的是，天然存在的红茎铁皮草同样具有高水平的花青素和多糖积累和生物合成基因表达。我们的研究结果揭示了DoHY5在HL条件下共同调节花青素和多糖的生物合成中的作用，提高了我们对金盏花茎色调节机制和决定营养品质的理解。总的来说，我们的研究结果提出了一种强大而简单的策略，可以显著提高花青素和多糖水平，从而改善铁皮草的营养品质。
Dendrobium officinale is edible and has medicinal and ornamental functions. Polysaccharides and flavonoids, including anthocyanins, are important components of D. officinale that largely determine the nutritional quality and consumer appeal. There is a need to study the molecular mechanisms regulating anthocyanin and polysaccharide biosynthesis to enhance D. officinale quality and its market value. Here, we report that high light (HL) induced the accumulation of polysaccharides, particularly mannose, as well as anthocyanin accumulation, resulting in red stems. Metabolome and transcriptome analyses revealed that most of the flavonoids showed large changes in abundance, and flavonoid and polysaccharide biosynthesis was significantly activated under HL treatment. Interestingly, DoHY5 expression was also highly induced. Biochemical analyses demonstrated that DoHY5 directly binds to the promoters of DoF3H1 (involved in anthocyanin biosynthesis), DoGMPP2, and DoPMT28 (involved in polysaccharide biosynthesis) to activate their expression, thereby promoting anthocyanin and polysaccharide accumulation in D. officinale stems. DoHY5 silencing decreased flavonoid- and polysaccharide-related gene expression and reduced anthocyanin and polysaccharide accumulation, whereas DoHY5 overexpression had the opposite effects. Notably, naturally occurring red-stemmed D. officinale plants similarly have high levels of anthocyanin and polysaccharide accumulation and biosynthesis gene expression. Our results reveal a previously undiscovered role of DoHY5 in co-regulating anthocyanin and polysaccharide biosynthesis under HL conditions, improving our understanding of the mechanisms regulating stem color and determining nutritional quality in D. officinale. Collectively, our results propose a robust and simple strategy for significantly increasing anthocyanin and polysaccharide levels and subsequently improving the nutritional quality of D. officinale.