Phylogeny of Cuscuta subgenus Cuscuta (Convolvulaceae) based on nrDNA ITS and chloroplast trnL intron sequences
Phylogeny of Cuscuta subgenus Cuscuta (Convolvulaceae) based on nrDNA ITS and chloroplast trnL intron sequences
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DOI：
10.1600/036364407783390872
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发表时间：
2007-10-01
影响因子：
1
通讯作者：
Martin, Maria P.
中科院分区：
文献类型：
--
作者：
Garcia, Miguel A.;Martin, Maria P.
在寄生的菟丝子属中，根据花柱和柱头的特征可分为3个亚属。菟丝子属（Cuscuta）是旧大陆种类最多的一个亚属，约有25种。我们提出了第一个系统发育研究的亚属使用核ITS rDNA和叶绿体trnL内含子序列。获得了该亚属几乎所有物种的序列，并对几个分类学上特别困难或地理分布广泛的个体进行了取样。最大简约和贝叶斯分析进行评估的单系的部分以前接受的Yuncker的专著，并调查物种之间的系统发育关系。该亚属的单系性不能用我们的采样进行测试，但使用三个种的亚属Monogyna作为外群，南非部分Pachystigma是姐妹的亚属菟丝子的其余物种。组Epistigma加C. capitata在所有分析中都被解析为单系。独特的C. babylonica在ITS树上是该分支的姐妹，但在trnL树上没有解析。首次在此鉴定的菟丝子组内有两个单系类群，其中一个类群包括热带非洲分布的种，另一个类群包括热带非洲分布的种。europaea，C. approximata和C.另一只手拿着香蕉。影响该亚属许多种分类困难的因素包括缺乏形态特征、相似性以及近缘种与非近缘种之间的基因流动。网状事件或种内重组的证据，获得了两个多系的个体内的ITS序列和冲突的拓扑结构的核和质体树。
Within the parasitic genus Cuscuta, three subgenera have been recognized based on characters of the styles and stigmas. Cuscuta subgenus Cuscuta, with free styles and conical to elongated stigmas, is the most diversified in the Old World with about 25 species. We present the first phylogenetic study of the subgenus using nuclear ITS rDNA and chloroplast trnL intron sequences. Sequences of almost all species of the subgenus were obtained and several individuals of particular taxonomic difficulty or wide geographical distribution were sampled. Both maximum parsimony and Bayesian analyses were performed to evaluate the monophyly of the sections previously accepted in Yuncker's monograph and to investigate phylogenetic relationships between the species. The monophyly of the subgenus could not be tested with our sampling but using three species of subgenus Monogyna as outgroup, the South African section Pachystigma was sister to the remaining species of subgenus Cuscuta. Section Epistigma plus C. capitata are resolved as monophyletic in all analyses. The distinctive C. babylonica was sister to that clade on the ITS trees but it was not resolved on the trnL trees. Two monophyletic groups within section Cuscuta, first identified here, included the species of tropical African distribution in one case and C. europaea, C. approximata, and C. balansae in the other. Factors influencing the taxonomic difficulty of many species in the subgenus include lack of morphological characters, parallelism and gene flow between closely and not so closely related species. Evidence of reticulation events or within species recombination were obtained by both polyphyletic intra-individual ITS sequences and conflicting topologies of the nuclear and plastid trees.