Speciation and conservation genetic assessment of two endangered cycad species  

作　　者：Xiu-Yan Feng Yi-Qing Gong Khang Sinh Nguyen Hiep Tien Nguyen Yong-Bo Liu Jian Liu Xun Gong 

机构地区：[1]CAS Key Laboratory for Plant Diversity and Biogeography of East Asia,Kunming Institute of Botany,Chinese Academy of Sciences,Kunming,650201 China [2]Key Laboratory of Economic Plants and Biotechnology,Kunming Institute of Botany,Chinese Academy of Sciences,Kunming,650201 China [3]Key Laboratory of Southern Subtropical Plant Diversity,Fairy Lake Botanical Garden,Shenzhen&Chinese Academy of Sciences,Shenzhen,518004 China [4]Institute of Ecology and Biological Resources,Vietnam Academy of Science and Technology,Hanoi,100000 Vietnam [5]Graduate University of Science and Technology,Vietnam Academy of Science and Technology,Hanoi,100000 Vietnam [6]enter for Plant Conservation(CPC),Vietnam Union of Science and Technology Associations,Hanoi,100000 Vietnam [7]State Environmental Protection Key Laboratory of Regional Eco-process and Function Assessment,Chinese Research Academy of Environmental Sciences,Beijing,100012 China

出　　处：《Journal of Systematics and Evolution》2024年第4期739-757,共19页植物分类学报（英文版）

基　　金：supported by the Biodiversity Survey,Observation and Assessment of the Ministry of Ecology and Environment,China(2019HJ2096001006);the National Natural Science Foundation of China(31800191).

摘　　要：Understanding the driving forces of speciation is a central question in evolutionary biology.Cycas bifida(Dyer)K.D.Hill and Cycas micholitzii Dyer are two morphologically similar Cycas(Cycadaceae)species with deeply pectinate megasporophylls and dichotomously divided leaflets.Geographically,they are isolated by the Red River Fault Zone(RRFZ),which acts as a biogeographical barrier for many Cycas species.In this study,we investigated the divergence,genetic diversity,genetic structure,and demographic history of C.bifida and C.micholitzii to uncover the speciation mechanisms for the two endangered species.Results revealed high historical gene flow but low contemporary gene flow between the two species,with a deep divergence occurring in the Late Miocene.The long-term geographical isolation and ecological niche differentiation were identified as important factors in driving the divergence of the two species,supported by significant isolation by distance testing,barrier analysis,and niche consistency detection.Geographical isolation by the RRFZ played a pivotal role in facilitating their divergence by constraining gene flow.Conservation genetic analyses indicated high genetic diversity within both species,coupled with disparate responses to Pleistocene climate fluctuations:C.micholitzii experienced population expansion,while C.bifida displayed a mild bottleneck effect.To ensure the protection and long-term sustainability of two threatened species,relevant conservation guidelines were proposed based on the assessment of their genetic diversity and structure.This study furnishes valuable insights into the mechanisms underpinning species divergence and delivers actionable recommendations for cycad conservation.

关 键 词：CONSERVATION Cycas bifida Cycas micholitzii genetic differentiation Red River Fault Zone(RRFZ) 

分 类 号：Q94[生物学—植物学]