Li Yongfu, Li Xuan, Sylvester Steven Paul, Zhang Min, Wang Xianrong, Duan Yifan
Co-Innovation Center for Sustainable Forestry in Southern China College of Biology and the Environment International Cultivar Registration Center for Osmanthus Nanjing Forestry University Nanjing China.
Department of Botany and Biodiversity Research Centre University of British Columbia Vancouver British Columbia Canada.
Ecol Evol. 2022 Apr 1;12(4):e8777. doi: 10.1002/ece3.8777. eCollection 2022 Apr.
Species of are economically important ornamental trees, yet information regarding their plastid genomes (plastomes) have rarely been reported, thus hindering taxonomic and evolutionary studies of this small but enigmatic genus. Here, we performed comparative genomics and evolutionary analyses on plastomes of 16 of the 28 currently accepted species, with 11 plastomes newly sequenced. Phylogenetic studies identified four main lineages within the genus that are here designated the: "Caucasian " (corresponding to . ), "" (corresponding to . sect. ), ". + ," and "Core : (corresponding to . sect. + . sect. ). Molecular clock analysis suggested that split from its sister clade c. 15.83 Ma. The estimated crown ages of the lineages were the following: genus at 12.66 Ma; "" clade at 5.85 Ma; ". + " at 4.89 Ma; and "Core : clade at 6.2 Ma. Ancestral state reconstructions and trait mapping showed that ancestors of were spring flowering and originated at lower elevations. Phylogenetic principal component analysis clearly distinguished spring-flowering species from autumn-flowering species, suggesting that flowering time differentiation is related to the difference in ecological niches. Nucleotide substitution rates of 80 common genes showed slow evolutionary pace and low nucleotide variations, all genes being subjected to purifying selection.
[该属的物种]是具有重要经济价值的观赏树木，然而关于其质体基因组（质体基因组）的信息却鲜有报道，这阻碍了对这个虽小却神秘的属的分类学和进化研究。在此，我们对目前已确认的28个物种中的16个物种的质体基因组进行了比较基因组学和进化分析，其中11个质体基因组是新测序的。系统发育研究在该属内确定了四个主要分支，在此将其命名为：“高加索[该属物种]”（对应于[具体物种1]）、“[分支名称1]”（对应于[具体物种2]组）、“[物种3] + [物种4]”以及“核心[该属物种]”（对应于[具体物种5]组 + [具体物种6]组）。分子钟分析表明，[该属物种]与其姐妹分支在约1583万年前分化。各分支的估计冠龄如下：[该属物种]属为1266万年前；“[分支名称1]”分支为585万年前；“[物种3] + [物种4]”为489万年前；“核心[该属物种]”分支为620万年前。祖先状态重建和性状映射表明，[该属物种]的祖先为春季开花，起源于较低海拔地区。系统发育主成分分析清楚地将春季开花物种与秋季开花物种区分开来，表明开花时间的分化与生态位差异有关。80个常见基因的核苷酸替换率显示出缓慢的进化速度和低核苷酸变异，所有基因都受到纯化选择。
