Journal of Systematics and Evolution

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  • 收稿日期:2023-12-15 接受日期:2024-03-19 出版日期:2024-04-08 发布日期:2024-04-08

A study on the distribution, origin, and taxonomy of Populus pseudoglauca and P. wuana

Jia-Xuan Mi1†, Jin-Liang Huang1†, Yu-Jie Shi1,4, Fei-Fei Tian1, JingLi1, Fan-Yu Meng1, Fang He1, Yu Zhong1,2, Han-Bo Yang1,2, Fan Zhang3, Liang-Hua Chen1,2, Xue-Qin Wan1,2*   

  1. 1. College of Forestry, Sichuan Agricultural University, Chengdu 611130, China;
    2. Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, Chengdu 611130, China;
    3. College of Landscape Architecture, Sichuan Agricultural University, Chengdu 611130, China;
    4. Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China
    These authors contributed equally to this work.
    *Author for correspondence.
  • Received:2023-12-15 Accepted:2024-03-19 Online:2024-04-08 Published:2024-04-08

Abstract: Taxonomy of Populus is a challenging task, especially in regions with complex topography, such as the Qinghai-Tibet Plateau because of the effect of hybridization, incomplete lineage sorting, phenotypic plasticity, and convergence. In the Flora of China, P. pseudoglanca and P. wuana are classified into sect. Leucoides and sect. Tacamahaca, respectively, but their taxonomy remains unclear. By conducting a systematic investigation for all taxa of Populus on the plateau, we found 31 taxa from the two sections. Through identification based on morphology and habitats, we confirmed that the “P. pseudoglanca” recorded in the Flora of Sichuan is not true P. pseudoglanca, while P. pseudoglanca and P. wuana recorded in the Flora of China may refer to the same species. By performing whole-genome re-sequencing of 150 individuals from the 31 taxa, we derived 2.28 million SNPs. Further genetic and phylogenetic analyses demonstrated that the genetic structure of P. wuana is extremely consistent with P. pseudoglanca, and they all originate through the natural hybridization between P. ciliata in sect. Leucoides and P. curviserrata in sect. Tacamahaca. Our results suggested that P. wuana should be merged with P. pseudoglanca taxonomically. This study not only clarifies the taxonomic confusions related to P. pseudoglanca and P. wuana but also provides a new framework based on the integration of morphology, distribution, habitat, and genome to solve complex taxonomic problems.

Key words: hybrid species, phylogeny, Populus, taxonomy, the Qinghai-Tibet Plateau