Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Sciences, Shandong Normal University, Ji'nan 250014, Shandong, China.
Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588, USA; Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA.
Mol Phylogenet Evol. 2022 Sep;174:107544. doi: 10.1016/j.ympev.2022.107544. Epub 2022 Jun 8.
Koenigia, a genus proposed by Linnaeus, has a contentious taxonomic history. In particular, relationships among species and the circumscription of the genus relative to Aconogonon remain uncertain. To explore phylogenetic relationships of Koenigia with other members of tribe Persicarieae and to establish the timing of major evolutionary diversification events, genome skimming of organellar sequences was used to assemble plastomes and mitochondrial genes from 15 individuals representing 13 species. Most Persicarieae plastomes exhibit a conserved structure and content relative to other flowering plants. However, Koenigia delicatula has lost functional copies of all ndh genes and the intron from atpF. In addition, the rpl32 gene was relocated in the K. delicatula plastome, which likely occurred via overlapping inversions or differential expansion and contraction of the inverted repeat. The highly supported but conflicting relationships between plastome and mitochondrial trees and among gene trees complicates the circumscription of Koenigia, which could be caused by rapid diversification within a short period. Moreover, the plastome and mitochondrial trees revealed correlated variation in substitution rates among Persicarieae species, suggesting a shared underlying mechanism promoting evolutionary rate variation in both organellar genomes. The divergence of dwarf K. delicatula from other Koenigia species may be associated with the well-known Eocene Thermal Maximum 2 or Early Eocene Climatic Optimum event, while diversification of the core-Koenigia clade associates with the Mid-Miocene Climatic Optimum and the uplift of Qinghai-Tibetan Plateau and adjacent areas.
林奈提出的 Koenigia 属具有争议的分类历史。特别是，物种之间的关系以及属相对于 Aconogonon 的范围仍然不确定。为了探索 Koenigia 与 Persicarieae 族其他成员的系统发育关系，并确定主要进化多样化事件的时间，使用细胞器序列的基因组掠过技术从代表 13 个物种的 15 个个体中组装了质体和线粒体基因。大多数 Persicarieae 质体相对于其他开花植物表现出保守的结构和内容。然而，Koenigia delicatula 失去了所有 ndh 基因和 atpF 内含子的功能副本。此外，rpl32 基因在 K. delicatula 质体中重新定位，这可能是通过重叠的倒位或倒位重复的差异扩展和收缩发生的。质体和线粒体树以及基因树之间高度支持但相互矛盾的关系使 Koenigia 的范围复杂化，这可能是由于在短时间内快速多样化造成的。此外，质体和线粒体树揭示了 Persicarieae 物种之间替代率的相关变化，这表明在两个细胞器基因组中存在促进进化率变化的共享潜在机制。矮生 K. delicatula 与其他 Koenigia 物种的分化可能与众所周知的始新世热最大值 2 或早始新世气候最佳事件有关，而核心-Koenigia 分支的多样化与中始新世气候最佳事件以及青藏高原及其毗邻地区的隆起有关。
