Anthocyanins (a subclass of flavonoids) and flavonoids are crucial determinants of flower color and substances of pharmacological efficacy, respectively, in chrysanthemum. However, metabolic and transcriptomic profiling regarding flavonoid accumulation has not been performed simultaneously, thus the understanding of mechanisms gained has been limited. We performed HPLC-DAD-ESI-MS (high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization mass spectrometry) and transcriptome analyses using “ARTI-Dark Chocolate” (AD), which is a chrysanthemum mutant cultivar producing dark-purple ray florets, and the parental cultivar “Noble Wine” for metabolic characterization and elucidation of the genetic mechanism determining flavonoid content. Among 26 phenolic compounds identified, three cyanidins and eight other flavonoids were detected only in AD. The total amounts of diverse flavonoids were 8.0 to 10.3 times higher in AD. Transcriptome analysis showed that genes in the flavonoid biosynthetic pathway were not up-regulated in AD at the early flower stage, implying that the transcriptional regulation of the pathway did not cause flavonoid accumulation. However, genes encoding post-translational regulation-related proteins, especially F-box genes in the mutated gene, were enriched among down-regulated genes in AD. From the combination of metabolic and transcriptomic data, we suggest that the suppression of post-translational regulation is a possible mechanism for flavonoid accumulation in AD. These results will contribute to research on the regulation and manipulation of flavonoid biosynthesis in chrysanthemum.

中文翻译：

---

菊花（Chrysanthemum × morifolium (Ramat.) Hemsl.）暗紫色舌状花突变品种中多种黄酮含量大幅增加并伴随F-Box基因下调

花青素（类黄酮的一个亚类）和类黄酮分别是菊花中花色和药理功效的重要决定因素。然而，有关类黄酮积累的代谢和转录组学分析尚未同时进行，因此对所获得机制的理解受到限制。我们使用“ARTI-Dark Chocolate”（AD）（一种产生深紫色的菊花突变品种）进行了 HPLC-DAD-ESI-MS（高效液相色谱结合光电二极管阵列检测和电喷雾电离质谱）和转录组分析。射线小花和亲本品种“Noble Wine”，用于代谢表征和阐明决定类黄酮含量的遗传机制。在鉴定的 26 种酚类化合物中，仅在 AD 中检测到了 3 种矢车菊素和其他 8 种黄酮类化合物。AD 中各种黄酮类化合物的总量增加了 8.0 至 10.3 倍。转录组分析表明，类黄酮生物合成途径中的基因在AD早期花期并未上调，这意味着该途径的转录调控不会导致类黄酮积累。然而，编码翻译后调节相关蛋白的基因，尤其是突变基因中的F-box基因，在AD的下调基因中富集。结合代谢和转录组数据，我们认为翻译后调节的抑制是 AD 中类黄酮积累的可能机制。这些结果将有助于菊花类黄酮生物合成调控和操纵的研究。