State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
China National Botanical Garden, Beijing 100093, China.
Ann Bot. 2023 May 15;131(5):867-883. doi: 10.1093/aob/mcad051.
Artemisia is a mega-diverse genus consisting of ~400 species. Despite its medicinal importance and ecological significance, a well-resolved phylogeny for global Artemisia, a natural generic delimitation and infrageneric taxonomy remain missing, owing to the obstructions from limited taxon sampling and insufficient information on DNA markers. Its morphological characters, such as capitulum, life form and leaf, show marked variations and are widely used in its infrageneric taxonomy. However, their evolution within Artemisia is poorly understood. Here, we aimed to reconstruct a well-resolved phylogeny for global Artemisia via a phylogenomic approach, to infer the evolutionary patterns of its key morphological characters and to update its circumscription and infrageneric taxonomy.
We sampled 228 species (258 samples) of Artemisia and its allies from both fresh and herbarium collections, covering all the subgenera and its main geographical areas, and conducted a phylogenomic analysis based on nuclear single nucleotide polymorphisms (SNPs) obtained from genome skimming data. Based on the phylogenetic framework, we inferred the possible evolutionary patterns of six key morphological characters widely used in its previous taxonomy.
The genus Kaschgaria was revealed to be nested in Artemisia with strong support. A well-resolved phylogeny of Artemisia consisting of eight highly supported clades was recovered, two of which were identified for the first time. Most of the previously recognized subgenera were not supported as monophyletic. Evolutionary inferences based on the six morphological characters showed that different states of these characters originated independently more than once.
The circumscription of Artemisia is enlarged to include the genus Kaschgaria. The morphological characters traditionally used for the infrageneric taxonomy of Artemisia do not match the new phylogenetic tree. They experienced a more complex evolutionary history than previously thought. We propose a revised infrageneric taxonomy of the newly circumscribed Artemisia, with eight recognized subgenera to accommodate the new results.
蒿属是一个拥有约 400 个物种的大型多样化属。尽管它具有重要的药用价值和生态意义，但由于受到有限的分类群采样和 DNA 标记信息不足的阻碍，全球蒿属的系统发育关系、自然分类群界限和种下分类学仍未得到解决。其形态特征，如头状花序、生活型和叶，表现出明显的变异，并广泛应用于种下分类学。然而，它们在蒿属内的进化情况还了解甚少。在此，我们旨在通过系统基因组学方法重建一个全球蒿属的系统发育关系，推断其关键形态特征的进化模式，并更新其分类群界限和种下分类学。
我们从新鲜和标本采集的材料中采样了 228 种（258 个样本）的蒿属及其近缘植物，涵盖了所有的亚属及其主要地理区域，并基于从基因组刮削数据中获得的核单核苷酸多态性（SNPs）进行了系统基因组学分析。基于系统发育框架，我们推断了在之前的分类学中广泛使用的六个关键形态特征的可能进化模式。
明确了哈萨克蒿属嵌套于蒿属中，具有强烈的支持。重建了一个由八个高度支持的分支组成的蒿属系统发育关系，其中两个分支是首次被识别。大多数以前被认可的亚属都不被支持为单系。基于六个形态特征的进化推断表明，这些特征的不同状态不止一次独立起源。
扩大了蒿属的范围，包括哈萨克蒿属。传统上用于蒿属种下分类学的形态特征与新的系统发育树不匹配。它们的进化历史比以前认为的更为复杂。我们提出了一个修订后的新分类群的蒿属下分类学，其中包括 8 个被认可的亚属，以适应新的结果。
