Lagou Loudmila Jelinscaia, Kadereit Gudrun, Morales-Briones Diego F
Princess Therese von Bayern chair of Systematics, Biodiversity and Evolution of Plants, Ludwig-Maximilians-Universität München, Menzinger Str. 67, Munich 80638, Germany.
Botanical Garden Munich and Botanical State Collection Munich, Bavarian Natural History Collections, Menzinger Str. 65-67, Munich 80638, Germany.
Ann Bot. 2024 Dec 31;134(7):1229-1250. doi: 10.1093/aob/mcae161.
Cypripedium is the most widespread and morphologically diverse genus of slipper orchids. Despite several published phylogenies, the topology and monophyly of its infrageneric taxa remained uncertain. Here, we aimed to reconstruct a robust section-level phylogeny of Cypripedium and explore its evolutionary history using target capture data for the first time.
We used the orchid-specific bait set Orchidaceae963 in combination with transcriptomic data to reconstruct the phylogeny of Cypripedium based on 913 nuclear loci, covering all 13 sections. Subsequently, we investigated discordance among nuclear and chloroplast trees, estimated divergence times and ancestral ranges, searched for anomaly zones, polytomies and diversification rate shifts, and identified potential gene (genome) duplication and hybridization events.
All sections were recovered as monophyletic, contrary to the two subsections within sect. Cypripedium. The two subclades within this section did not correspond to its subsections but matched the geographical distribution of their species. Additionally, we discovered high levels of discordance in the short backbone branches of the genus and within sect. Cypripedium, which can be attributed to hybridization events detected based on phylogenetic network analyses, and incomplete lineage sorting caused by rapid radiation. Our biogeographical analysis suggested a Neotropical origin of the genus during the Oligocene (30 Ma), with a lineage of potentially hybrid origin spreading to the Old World in the Early Miocene (22 Ma). The rapid radiation at the backbone probably occurred in Southeast Asia around the Middle Miocene Climatic Transition (~15-13 Ma), followed by several independent dispersals back to the New World. Moreover, the glacial cycles of the Pliocene-Quaternary may have contributed to further speciation and reticulate evolution within Cypripedium.
Our study provides novel insights into the evolutionary history of Cypripedium based on high-throughput molecular data, shedding light on the dynamics of its distribution and diversity patterns from its origin to the present.
杓兰属是拖鞋兰中分布最广泛且形态最多样化的属。尽管已有多篇关于其系统发育的研究发表，但其属下类群的拓扑结构和单系性仍不明确。在此，我们旨在首次利用靶标捕获数据重建一个可靠的杓兰属组级系统发育，并探索其进化历史。
我们使用兰花特异性诱饵集Orchidaceae963结合转录组数据，基于913个核基因座重建杓兰属的系统发育，涵盖了所有13个组。随后，我们研究了核基因树和叶绿体基因树之间的不一致性，估计了分歧时间和祖先分布范围，寻找异常区域、多歧分支和多样化速率变化，并识别潜在的基因（基因组）重复和杂交事件。
所有组均被恢复为单系类群，这与杓兰组内的两个亚组情况相反。该组内的两个亚分支并不对应其亚组，而是与其物种的地理分布相匹配。此外，我们在该属的短主干分支以及杓兰组内发现了高度的不一致性，这可归因于基于系统发育网络分析检测到的杂交事件，以及快速辐射导致的不完全谱系分选。我们的生物地理分析表明，该属在渐新世（约3000万年前）起源于新热带地区，一个可能具有杂交起源的谱系在中新世早期（约2200万年前）扩散到旧世界。主干分支的快速辐射可能发生在中新世中期气候转变（约1500 - 1300万年前）前后的东南亚地区，随后有几次独立扩散回到新世界。此外，上新世 - 更新世的冰川周期可能促成了杓兰属内进一步的物种形成和网状进化。
我们的研究基于高通量分子数据为杓兰属的进化历史提供了新的见解，揭示了其从起源到现在的分布动态和多样性模式。
