基于5.8SrDNA/ITS序列的几种内蒙古棘豆属植物分子系统学研究

Molecular Phylogeny of Several Species of Oxytropis DC. Based on 5.8SrDNA/ITS Sequence

提取小花棘豆(Oxytropis.glabra DC.)、小叶小花棘豆(O.glabravar.tenuis)、刺叶柄棘豆(O.aciphyllaLedeb.)、砂珍棘豆(O.racemusaTurcz.)、多叶棘豆(O.verticillaris(L.)J.N)、黄毛棘豆(O.ochranthaTurcz.)基因组DNA,扩增其5.8SrDNA/ITS序列并测序,将所测序列与GenBank中疏毛棘豆(O.pilosa)和长白棘豆(O.anertii)5.8SrDNA/ITS序列进行同源性比对,利用MEGA4.0软件采用Neighbor-joining法构建系统发育树,旨在为棘豆属下种间及种下分类研究提供分子依据。结果表明:多叶棘豆、砂珍棘豆和黄毛棘豆构成姐妹群,并在部分地理种群上混杂,认为将三者归入真棘豆亚属Subgen.Euoxytropis轮叶棘豆组Sect.Baicalia Stell.ex Bunge更合理。小叶小花棘豆与小花棘豆亲缘关系很近,支持将其视为变种的观点。刺叶柄棘豆的不同地理种群形成两大分支,对其在亚属水平上的分类还需进一步商榷。研究赞同棘豆属植物为单系起源,认为种内不同地理种群间的亲缘关系在一定程度上受到了植被类型和生境的影响。

Genomic DNAs of Oxytropis glabra,O.glabra var.tenuis,O.aciphylla,O.racemosa,O.verticillaris and O.ochrantha were extracted,then the 5.8SrDNA/ITS sequences were amplified and sequenced.Homologous of the sequences were compared with that of O.pilosa and O.anertii submitted to GenBank.The phylogenetic tree was constructed by NJ methods in MEGA 4.0 software,the purpose of the research was to provide molecular evidences for taxonomy of interspecies and intraspecies of Oxytropis DC.The results showed that O.verticillaris,O.ochrantha and O.racemosa were sister groups and some geographical populations of them were mixed.Therefore,it was reasonable to put the three species into Subgen.Euoxytropis Sect.Baicalia Stell.ex Bunge.O.glabra var.tenuis had a close relationship with O.glabra,which supported the opinion of treating O.glabra var.tenuis as a variant of O.glabra.Different populations of O.aciphylla were divided into two major branches,and the subject position of O.aciphylla at subgenus level needs further investigation.The results also supported that Oxytropis DC.was a monophyletic group.It was indicated that the relationship among different geographic populations within species were influenced by vegetation type and habitat to some extent.