基于分子标记的白蜡树属椒叶梣组系统发育及谱系地理格局形成  

Molecular Phylogenetic Analysis of Fraxinus Section Sciadanthus(Oleaceae)and Its Biogeographic Implications

作　　者：韦羿帆 周明芹[1] WEN Jun WEI Yifan;ZHOU Mingqin;WEN Jun(College of Horticulture and Landscape Architecture,Yangtze University,Jingzhou 434023,Hubei;Department of Botany,National Museum of Natural History,Smithsonian Institution,Washington D.C.20013-7012,USA)

机构地区：[1]长江大学园艺园林学院,湖北荆州434023 [2]史密森学会国家自然历史博物馆植物学部,美国华盛顿特区D.C.20013-7012

出　　处：《植物遗传资源学报》2024年第5期844-855,共12页Journal of Plant Genetic Resources

基　　金：国家自然科学基金(31200528)。

摘　　要：木犀科白蜡树属椒叶梣组(Fraxinus sect. Sciadanthus)由自然分布于中国中部的对节白蜡(Fraxinus hupehensis S.Z.Qu,C.B.Shang&P.L.Su)、喜马拉雅西部的椒叶梣(Fraxinusxanthoxyloides(G.Don)DC.)和非洲北部的Fraxinus dimorpha 3个物种组成,呈现出特殊的间断分布模式,目前该组的起源和演化过程尚不清楚。利用ITS、psbA-trnH、rpl32-trnL和matK 4个标记对白蜡树属42个物种间的系统发育关系进行分析,结果表明:(1)利用ITS序列构建的贝叶斯系统树支持Wallander的分类方法,即属内再分成6个组,对节白蜡、椒叶梣和F. dimorpha都属于椒叶梣组,且该组与欧梣组(sect. Fraxinus)的亲缘关系最近,形成姐妹组;(2)椒叶梣可能是F. dimorpha与欧亚种的杂交后代;(3)BEAST分化时间图显示,白蜡树属最早起源于42.05 Ma,椒叶梣组最早分化于21.86 Ma,对节白蜡最早分化于11.87 Ma。青藏高原的快速隆起可能是导致椒叶组物种间断分布的重要原因,对节白蜡和椒叶梣可能是其影响下的孑遗植物。Fraxinus section Sciadanthus is known with three species:Fraxinus hupehensis from Central China,F.xanthoxyloides from Western Himalaya,and F.dimorpha from North Africa.These species exhibit an unusual biogeographic disjunction across Central China,Western Himalaya and North Africa,whereas their origin and evolutionary remain unclear.The phylogenetic relationships of this section was investigated using nuclear ribosomal ITS and chloroplast genes psbA-trnH,rpl32-trnL and matK.The Bayesian system tree constructed by ITS sequences supports the classification system proposed by Wallander,in which the species of Fraxinus were classified into six sections.F.hupehensis,F.xanthoxyloides and F.dimorpha were all resided to section Sciadanthus and formed a sister group with section Fraxinus.We found that F.xanthoxyloides may have originated from hybridization between F.dimorpha and a Eurasian species.The divergence time suggested that Fraxinus first differentiated at 42.05 Ma,section Sciadanthus initially diverged at 21.86 Ma,and F.hupehensis diverged at 11.87 Ma.The uplifts of the Tibetan Plateau in the Tertiary may be the driving force and main reason causing the disjunctive distribution in section Sciadanthus.F.hupehensis and F.xanthoxyloides are proposed to be relict plants conferred by this process.

关 键 词：白蜡树属 椒叶梣组 对节白蜡 谱系地理学 华中—西喜马拉雅—北非间断分布 

分 类 号：S792.41[农业科学—林木遗传育种]