The chromosome-level wintersweet (Chimonanthus praecox) genome provides insights into floral scent biosynthesis and flowering in winter
The chromosome-level wintersweet (Chimonanthus praecox) genome provides insights into floral scent biosynthesis and flowering in winter
复制标题
DOI：
10.1186/s13059-020-02088-y
复制
发表时间：
2020-08-10
期刊：
影响因子：
12.3
通讯作者：
Chen, Longqing
中科院分区：
文献类型：
--
作者：
Shang, Junzhong;Tian, Jingpu;Chen, Longqing
蜡梅（Chimonanthuspraecox）是一种重要的观赏植物，具有独特的芳香气味和冬季开花特性，是其有性繁殖成功的关键。然而，这些特征背后的分子机制在这个物种中很大程度上是未知的。此外，蜡梅也是木兰科植物的典型代表种，其相对于真双子叶植物和单子叶植物的系统发育位置尚未得到最终解决。结果完成了蜡梅染色体水平的基因组组装，总大小为695.36 Mb，并绘制了蜡梅基因组组装草图。对17个代表性被子植物基因组的系统发育分析表明，木兰科植物和真双子叶植物是单子叶植物的姐妹植物。全基因组重复签名揭示了蜡梅基因组进化史上的两个主要重复事件，一个是由Laurales共享的古老事件，另一个是由Calycantaceae共享的最近事件。全基因组重复和串联重复事件对萜烯和苯类/苯丙素（主要花香挥发物）生物合成相关基因的拷贝数有显著影响，这可能有助于特征香气的形成。综合细胞学、基因组学和转录组学数据，揭示了蜡梅春季开花转变、花器官特化、低温诱导花芽分化、冬季开花早、耐寒性强等生物学特性。结论这些发现为蜡梅的进化历史以及木兰科植物、单子叶植物和真双子叶植物之间的关系提供了见解;花香生物合成的分子基础;和冬季开花，并强调多组学数据在破译蜡梅重要观赏性状方面的实用性。
Background Wintersweet (Chimonanthus praecox), an important ornamental plant, has evolved unique fragrant aroma and winter-flowering properties, which are critical for its successful sexual reproduction. However, the molecular mechanisms underlying these traits are largely unknown in this species. In addition, wintersweet is also a typical representative species of the magnoliids, where the phylogenetic position of which relative to eudicots and monocots has not been conclusively resolved. Results Here, we present a chromosome-level wintersweet genome assembly with a total size of 695.36 Mb and a draft genome assembly ofCalycanthus chinensis. Phylogenetic analyses of 17 representative angiosperm genomes suggest that Magnoliids and eudicots are sister to monocots. Whole-genome duplication signatures reveal two major duplication events in the evolutionary history of the wintersweet genome, with an ancient one shared by Laurales, and a more recent one shared by the Calycantaceae. Whole-genome duplication and tandem duplication events have significant impacts on copy numbers of genes related to terpene and benzenoid/phenylpropanoid (the main floral scent volatiles) biosynthesis, which may contribute to the characteristic aroma formation. An integrative analysis combining cytology with genomic and transcriptomic data reveals biological characteristics of wintersweet, such as floral transition in spring, floral organ specification, low temperature-mediated floral bud break, early blooming in winter, and strong cold tolerance. Conclusions These findings provide insights into the evolutionary history of wintersweet and the relationships among the Magnoliids, monocots, and eudicots; the molecular basis underlying floral scent biosynthesis; and winter flowering, and highlight the utility of multi-omics data in deciphering important ornamental traits in wintersweet.