Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, College of ornamental horticulture and landscape architecture, Beijing Forestry University, Beijing, 100083, China.
Plant Mol Biol. 2019 Apr;99(6):587-601. doi: 10.1007/s11103-019-00838-6. Epub 2019 Feb 14.
The CmTFL1c gene of Chrysanthemum morifolium inhibits flowering, regulates inflorescence architecture and floral development. The timing of flowering is an important ornamental trait of chrysanthemum. The gene TERMINAL FLOWER1 (TFL1) has been shown to be involved in the regulation of meristem fate and flowering time regulation. Here, a TFL1 gene named as CmTFL1c, was cloned from Chrysanthemum morifolium and further characterized. The open reading frame of CmTFL1c comprises 522 bp, which encodes a polypeptide of 173 amino acids. Phylogenetic analysis revealed that CmTFL1c belongs to the CEN/TFL1 clade. CmTFL1c protein localizes to the nucleus as well as to plasma membrane, which suggests that CmTFL1c may be a transcription factor. The CmTFL1c gene was most highly expressed in vegetative stems, and weakly expressed in leaves and flower buds; both shoot apices and stems had sensitivity to photoperiod. Overexpression of CmTFL1c in wild Arabidopsis and tfl1-13 mutant led to late flowering and altered architecture, including increased secondary branching, and abnormal inflorescences and flowers. The CmTFL1c gene negatively regulated flowering by inhibiting the up-regulation of the AtFT, AtLFY and AtAP1. The biological function of CmTFL1c was further characterized in C. morifolium via Agrobacterium-mediated transformation, which showed that CmTFL1c not only delayed flowering and promoted axillary bud formation, but also played an important role in inflorescence formation of chrysanthemum. These results showed that the CmTFL1c affects flowering time and regulates inflorescence architecture.
菊花CmTFL1c 基因抑制开花，调控花序结构和花发育。开花时间是菊花的一个重要观赏性状。TERMINAL FLOWER1（TFL1）基因已被证明参与分生组织命运和开花时间调控。本研究从菊花中克隆了一个 TFL1 基因，命名为 CmTFL1c，并对其进行了进一步的鉴定。CmTFL1c 的开放阅读框包含 522bp，编码 173 个氨基酸的多肽。系统进化分析表明，CmTFL1c 属于 CEN/TFL1 分支。CmTFL1c 蛋白定位于细胞核和质膜，提示 CmTFL1c 可能是一个转录因子。CmTFL1c 基因在营养茎中表达量最高，在叶片和花蕾中表达量较弱；茎尖和茎都对光周期敏感。在野生型拟南芥和 tfl1-13 突变体中过表达 CmTFL1c 导致开花时间延迟和结构改变，包括增加二级分枝，花序和花朵异常。CmTFL1c 基因通过抑制 AtFT、AtLFY 和 AtAP1 的上调负调控开花。通过农杆菌介导的转化进一步研究了 CmTFL1c 在菊花中的生物学功能，结果表明 CmTFL1c 不仅延迟开花和促进腋芽形成，而且在菊花花序形成中也起着重要作用。这些结果表明，CmTFL1c 影响开花时间并调控花序结构。
