Shi Yufeng, Lu Taoran, Lai Sanyan, Li Song, Zhang Ling, Liu Rong, Ouyang Lin, Zhao Xinxin, Jiang Yuqin, Yan Zhen, Zhang Ju, Miao Baohe
Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, China.
Chengdu National Agricultural Science and Technology Center, Chengdu, China.
Front Plant Sci. 2024 Dec 17;15:1477278. doi: 10.3389/fpls.2024.1477278. eCollection 2024.
Roses () are a famous flower with high ornamental and economic value. But the petals of roses are usually pink and purple, which restricted its application in garden settings. Flavonols and anthocyanins are crucial secondary metabolites related to flower pigmentation in plants. While MYB transcription factors involved in the biosynthesis pathway of anthocyanins have been identified in roses, the functional characterization of the MYB transcription factor regulating flavonol synthesis in remains unexplored. In this study, we isolated and characterized the R2R3-MYB transcription factors RrMYB12 and RrMYB111 involved in regulation of the flavonol biosynthetic pathway from . The bioinformatics analysis indicated that both the RrMYB12 and RrMYB111 belong to the R2R3-MYB subgroup 7 family. qRT-PCR analysis showed that and were expressed at low levels in roots and flowers. And transactivation activity assay indicated that RrMYB12 and RrMYB111 were transcriptional activators. The overexpression of and in tobacco resulted in an elevation of flavonol levels and a reduction in anthocyanin levels in flowers due to the upregulation of structural genes involved in flavonol synthesis, while the biosynthesis genes for the anthocyanin pathway were significantly downregulated. The transient reporter assay demonstrated that RrMYB12 exhibited strong activation of the promoters of and in leaves following transient transformation. Furthermore, it was observed that RrMYBs displayed binding specificity to the promoter region of .The functional characterization of the flavonol synthesis regulatory factors RrMYB12 and RrMYB111 offers a deeper understanding of the regulatory mechanism governing flavonol biosynthesis in roses, while also presenting an effective tool for genetic manipulation aimed at creating new varieties.
玫瑰是一种具有很高观赏和经济价值的著名花卉。但玫瑰花瓣通常为粉色和紫色，这限制了其在园林景观中的应用。黄酮醇和花青素是植物中与花色形成相关的关键次生代谢产物。虽然在玫瑰中已鉴定出参与花青素生物合成途径的MYB转录因子，但调控玫瑰中黄酮醇合成的MYB转录因子的功能特性仍未被探索。在本研究中，我们从玫瑰中分离并鉴定了参与黄酮醇生物合成途径调控的R2R3-MYB转录因子RrMYB12和RrMYB111。生物信息学分析表明，RrMYB12和RrMYB111均属于R2R3-MYB亚组7家族。qRT-PCR分析表明，RrMYB12和RrMYB111在根和花中表达水平较低。反式激活活性分析表明，RrMYB12和RrMYB111是转录激活因子。RrMYB12和RrMYB111在烟草中的过表达导致花中黄酮醇水平升高和花青素水平降低，这是由于黄酮醇合成相关结构基因的上调，而花青素途径的生物合成基因则显著下调。瞬时报告基因分析表明，瞬时转化后，RrMYB12在玫瑰叶片中对FLS和DFR的启动子表现出强烈的激活作用。此外，观察到RrMYBs对FLS的启动子区域具有结合特异性。黄酮醇合成调控因子RrMYB12和RrMYB111的功能特性为深入了解玫瑰中黄酮醇生物合成的调控机制提供了帮助，同时也为旨在培育新品种的基因操作提供了一种有效工具。
