栝楼属基于核糖体ITS序列的系统发育分析

Phylogenetic Analysis of Trichosanthes Based on the nrDNA ITS Region

栝楼属(Trichosanthes)是葫芦科(Cucurbitaceae)中一个种类较多、药用价值较大的属。本文基于ITS序列分析了栝楼属16个种的系统发育关系。聚类分析表明:在组的划分上,具有分类争议的截叶组(sect.Truncata)与大苞组(sect.Involucraria)形成一大支,处于一亚分枝位置,不支持独立成组。在属内分类地位上,在核酸水平不支持贵州栝楼(T.guizhouensis)为一独立种,结合形态特征建议并入双边栝楼(T.rosthornii)。大方油栝楼(T.dafan-gensis)与小苞组(sect.Trichosanthes)成为姊妹群,处于一个向叶苞组(sect.Foliobracteola)过渡位置,结合其形态特征,建议作为小苞组(sect.Trichosanthes)成员。

Trichosanthes is one of the larger genu in Cucurbitaceae,and most of them have medicinal values.In this paper,phylogenetic relationships of 16 species were inferred using nrDNA ITS sequences.The main implications of the phylogenetic trees analyses include： There was an evidence regarding sect.Truncata,which had traditional classification dispute,was not recognized as separate entity,but nested within sect.Involucraria,formed a subsect group.According to phylogenetic analyses the level of nucleotides of ITS sequence,and combining with morphological characteristics of T.guizhouensis,we suggested it should be incorporated into T.rosthorni.sect.Trichosanthes.belong to an independent species but also be in sect.Foliobracteola.In addition,T.dafangensis,an endemic species of Guizhou province,our result showed that it was a sister clade in sect.Trichosanthes,and was in a transition position to sect.Foliobracteola group,combining with its morphology analyses,it should be as a member of sect Trichosanthes.