J Syst Evol

• Research Article •    

Dense infraspecific sampling reveals cryptic differentiation in the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae)

Zhi-Fang Liu1,2,3,4, Shi-Fang Zhang4,5, Alex D. Twyford6,7*, Xiu-Qin Ci4, Lang Li4, Xiao-Yan Zhang4,8, Jian-Lin Hu4,9, Jia-Chuan Tan10, Guang-Da Tang11, Sheng-Yuan Qin5,12, Ling Hu13, Xin Ding14, Hong-Hu Meng4, Li-Na Dong15, Ting Huang11, Hui Ma16, Jian-Hua Xiao17, Chao-Nan Cai18, John G. Conran19, Qi Wang1,2,3*, Peter M. Hollingsworth7*, and Jie Li4*   

  1. 1 Institute of Leisure Agriculture, Shandong Academy of Agricultural Sciences, Jinan 250100, China;
    2 Key Laboratory of East China Urban Agriculture, Ministry of Agriculture and Rural Affairs, Jinan 250100, China;
    3 Shandong Engineering Research Center of Ecological Horticultural Plant Breeding, Jinan 250100, China;
    4 Plant Phylogenetics and Conservation Group, Center for Integrative Conservation & Yunnan Key Laboratory for Conservation of Tropical Rainforests and Asian Elephants, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China;
    5 University of Chinese Academy of Sciences, Beijing 100049, China;
    6 Institute of Ecology and Evolution, Ashworth Laboratories, The University of Edinburgh, Edinburgh EH9 3JR, United Kingdom;
    7 Genetics and Conservation Section, Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK;
    8 College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China;
    9 School of Life Sciences, Yunnan Normal University, Kunming 650092, China;
    10 Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China;
    11 South China Limestone Plants Research Center, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510640, China;
    12 Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
    13 Institute of International Rivers and Eco-security, Yunnan University, Kunming 650500, China;
    14 School of Landscape Architecture, Guangdong Eco-engineering Polytechnic, Guangzhou 510520, China;
    15 Guangxi Institute of Botany, Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guilin 541006, China;
    16 College of Life Science and Technology, Longdong University, Qingyang 745000, China;
    17 Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, Jiaying University, Meizhou 514015, China;
    18 School of Advanced Study, Taizhou University, Taizhou 318000, China;
    19 Environment Institute, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
    *Author for correspondence. Jie Li. E-mail:jieli@xtbg.ac.cn;Peter M. Hollingsworth. E-mail:PHollingsworth@rbge.org.uk;Alex D. Twyford. E-mail:alex.twyford@ed.ac.uk;Qi Wang. E-mail:wangqijj-2005@163.com
  • Received:2023-10-02 Accepted:2024-01-17 Online:2024-03-31

Abstract: Species delimitation remains a challenge worldwide, especially in highly diverse tropical and subtropical regions. Here, we use an integrative approach that combines morphology, phylogenomics, and species distribution modeling (SDM) to clarify the cryptic differentiation within the enigmatic hemiparasitic love vine Cassytha filiformis (Lauraceae) in China and adjacent regions. We generated complete plastid genomes and nuclear ribosomal sequences for diverse samples from across the species range and compared results with previously published plastid data, recovering two well-supported monophyletic clades. Further, the analysis revealed significant differences in two morphological characters and SDM, indicating distinct environmental factors influencing their distributions. Fossil-calibrated analyses to estimate the origins and diversification patterns for the cryptic species gave divergence age estimates corresponding to the Oligo-Miocene; a period of new ecological opportunities associated with the prevailing East Asian monsoon. Multivariate analyses support the conclusion that southern China and adjacent regions have a different, previously unknown, cryptic lineage of C. filiformis. Our study highlights the importance of using multivariate approach to characterize plant species, as well as the significant role that past climatic changes have played in driving speciation in parasitic plants in tropical and subtropical zones.

Key words: Cassytha, morphology, parasitic angiosperms, phylogeny, species delimitation