Chrysanthemum morifolium is one of the most economically important and popular floricultural crops in the family Asteraceae. Chrysanthemum flowers vary considerably in terms of colors and shapes. However, the molecular mechanism controlling the development of chrysanthemum floral colors and shapes remains an enigma. We analyzed a cut-flower chrysanthemum variety that produces normal capitula composed of ray florets with normally developed pistils and purple corollas and mutant capitula comprising ray florets with green corollas and vegetative buds instead of pistils. We conducted a whole-transcriptome analysis of the differentially expressed genes (DEGs) in the mutant and normal capitula using third-generation and second-generation sequencing techniques. We identified the DEGs between the mutant and normal capitula to reveal important regulators underlying the differential development. Many transcription factors and genes related to the photoperiod and GA pathways, floral organ identity, and the anthocyanin biosynthesis pathway were differentially expressed between the normal and mutant capitula. A qualitative analysis of the pigments in the florets of normal and mutant capitula indicated anthocyanins were synthesized and accumulated in the florets of normal capitula, but not in the florets of mutant capitula. These results provide clues regarding the molecular basis of the replacement of Chrysanthemum morifolium ray florets with normally developed pistils and purple corollas with mutant ray florets with green corollas and vegetative buds. Additionally, the study findings will help to elucidate the molecular mechanisms underlying floral organ development and contribute to the development of techniques for studying the regulation of flower shape and color, which may enhance chrysanthemum breeding. The whole-transcriptome analysis of DEGs in mutant and normal C. morifolium capitula described herein indicates the anthocyanin deficiency of the mutant capitula may be related to the mutation that replaces ray floret pistils with vegetative buds. Moreover, pistils may be required for the anthocyanin biosynthesis in the corollas of chrysanthemum ray florets.

中文翻译：

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菊花突变体和正常头状花序差异表达基因的全转录组分析

菊花是菊科中经济上最重要和最受欢迎的花卉作物之一。菊花的颜色和形状差异很大。然而，控制菊花颜色和形状发展的分子机制仍然是一个谜。我们分析了一种切花菊花品种，该品种产生由具有正常发育的雌蕊和紫色花冠的射线小花组成的正常头状花序和由带有绿色花冠和营养芽而不是雌蕊的射线状小花组成的突变头状花序。我们使用第三代和第二代测序技术对突变体和正常头状体中的差异表达基因 (DEG) 进行了全转录组分析。我们确定了突变体和正常头状体之间的 DEG，以揭示差异发育背后的重要调节因子。许多与光周期和 GA 途径、花器官特性和花青素生物合成途径相关的转录因子和基因在正常和突变头状花序之间差异表达。对正常和突变头状花序小花色素的定性分析表明，花色苷在正常头状花序小花中合成和积累，而在突变头状花序小花中没有。这些结果提供了关于用正常发育的雌蕊和紫色花冠用带有绿色花冠和营养芽的突变体菊花取代菊花射线小花的分子基础。此外，研究结果将有助于阐明花器官发育的分子机制，并有助于开发研究花形和颜色调控的技术，从而促进菊花育种。本文所述的突变体和正常C. morifolium capitula中DEG的全转录组分析表明，突变体头状体的花青素缺乏可能与用营养芽取代射线小花雌蕊的突变有关。此外，在菊花的花冠中，花青素的生物合成可能需要雌蕊。本文所述的突变体和正常C. morifolium capitula中DEG的全转录组分析表明，突变体头状体的花青素缺乏可能与用营养芽取代射线小花雌蕊的突变有关。此外，在菊花的花冠中，花青素的生物合成可能需要雌蕊。本文所述的突变体和正常C. morifolium capitula中DEG的全转录组分析表明，突变体头状体的花青素缺乏可能与用营养芽取代射线小花雌蕊的突变有关。此外，在菊花的花冠中，花青素的生物合成可能需要雌蕊。