目的 旨在鉴定神农架民间药用植物神农香菊Chrysanthemum indicum var. aromaticum的R2R3-MYB基因家族成员（命名为CiaMYB），解析其基因进化特征及响应UV-B胁迫的表达特征模式，探讨其调控黄酮类化合物合成的分子机制。方法 基于神农香菊全基因组序列，通过生物信息学分析全面鉴定CiaMYB家族成员，系统分析其蛋白理化性质、染色体定位、基因结构、共线性关系及顺式作用元件组成；结合转录组测序与相关性分析，筛选参与黄酮类化合物生物合成的CiaMYB基因；利用实时荧光定量PCR（quantitative reverse transcription polymerase chain reaction，qRT-PCR）验证关键基因表达模式，并解析蛋白功能定位。结果 共鉴定出140个CiaMYB基因，其编码蛋白为206～868个氨基酸组成的亲水性蛋白，不均匀分布于9条染色体中。启动子区富集光响应、脱落酸（abscisic acid，ABA）和茉莉酸甲酯（methyl jasmonate，MeJA）信号通路相关顺式作用元件。UV-B辐照显著诱导CiaMYB基因差异表达和叶片总黄酮积累，其中CiaMYB040和CiaMYB066与拟南芥黄酮醇合成关键的S7亚家族高度同源，且表达量与总黄酮含量呈极强正相关，提示其在黄酮合成途径中发挥关键转录调控作用。亚细胞定位证实CiaMYB040和CiaMYB066蛋白定位于细胞核。结论 首次系统揭示神农香菊R2R3-MYB家族成员的进化特征，初步筛选了响应UV-B胁迫参与调控黄酮类物质合成的CiaMYB基因，为解析植物高海拔抗逆适应的分子机制，菊科植物黄酮代谢调控及抗逆遗传改良提供了重要的候选基因资源。

Objective To identify members of the R2R3-MYB gene family (named CiaMYB) in Chrysanthemum indicum var. aromaticum, a folk medicinal plant from Shennongjia, analyze their genetic evolutionary characteristics and expression patterns in response to UV-B stress, and explore the molecular mechanisms by which they regulate flavonoid synthesis. Methods Based on the whole-genome sequence of C. indicum var. aromaticum, bioinformatics analyses were performed to comprehensively identify CiaMYB members, and systematic analyses were conducted on their protein physicochemical properties, chromosomal localization, gene structure, collinearity relationships, and composition of cis-acting elements. Combined with transcriptome sequencing and correlation analysis, CiaMYB genes involved in flavonoid biosynthesis were screened. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the expression patterns of key genes, and the functional localization of the proteins was analyzed. Results A total of 140 CiaMYB genes were identified, encoding hydrophilic proteins consisting of 206—868 amino acids, which are unevenly distributed on nine chromosomes. The promoter regions are enriched with cis-acting elements related to light response, abscisic acid (ABA) and methyl jasmonate (MeJA) signaling pathways. UV-B irradiation significantly induces differential expression of CiaMYB genes and accumulation of total flavonoids in leaves. Among them, CiaMYB040 and CiaMYB066 are highly homologous to the S7 subfamily, which is critical for flavonol synthesis in Arabidopsis thaliana, and their expression levels show a strong positive correlation with total flavonoid content, suggesting that they play a key transcriptional regulatory role in the flavonoid synthesis pathway. Subcellular localization confirmed that CiaMYB040 and CiaMYB066 proteins are localized in the nucleus. Conclusion This study is the first to systematically reveal the evolutionary characteristics of R2R3-MYB family members in C. indicum var. aromaticum, and preliminarily screen CiaMYB genes that respond to UV-B stress and are involved in regulating flavonoid synthesis. It provides important candidate gene resources for elucidating the molecular mechanism of plant high-altitude stress adaptation, as well as for flavonoid metabolism regulation and stress-resistant genetic improvement in Asteraceae plants.

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国家自然科学基金项目（32270231）；湖北中医药大学重大项目（2023ZDXM006）