The haplotype‐resolved genome of diploid Chrysanthemum indicum unveils new acacetin synthases genes and their evolutionary history

作者：Zhuangwei Hou, S.L. Yang, Weijun He, Tingting Lu, Xunmeng Feng, Lanlan Zang, Wenhui Bai, Xueqing Chen, Bao Nie, Cheng Li, Min Wei, Liangju Ma, Zhengzhou Han, Qingjun Zou, Wei Li, Li Wang · 发表于：The Plant Journal · 年份：2024 · DOI：10.1111/tpj.16854 · 被引用次数：13 · 研究领域：Plant biochemistry and biosynthesis、Genomics and Phylogenetic Studies、Plant Gene Expression Analysis

Acacetin, a flavonoid compound, possesses a wide range of pharmacological effects, including antimicrobial, immune regulation, and anticancer effects. Some key steps in its biosynthetic pathway were largely unknown in flowering plants. Here, we present the first haplotype-resolved genome of Chrysanthemum indicum, whose dried flowers contain abundant flavonoids and have been utilized as traditional Chinese medicine. Various phylogenetic analyses revealed almost equal proportion of three tree topologies among three Chrysanthemum species (C. indicum, C. nankingense, and C. lavandulifolium), indicating that frequent gene flow among Chrysanthemum species or incomplete lineage sorting due to rapid speciation might contribute to conflict topologies. The expanded gene families in C. indicum were associated with oxidative functions. Through comprehensive candidate gene screening, we identified five flavonoid O-methyltransferase (FOMT) candidates, which were highly expressed in flowers and whose expressional levels were significantly correlated with the content of acacetin. Further experiments validated two FOMTs (CI02A009970 and CI03A006662) were capable of catalyzing the conversion of apigenin into acacetin, and these two genes are possibly responsible acacetin accumulation in disc florets and young leaves, respectively. Furthermore, combined analyses of ancestral chromosome reconstruction and phylogenetic trees revealed the distinct evolutionary fates of the two validated FOMT genes...