基于GenBank 数据对红柴胡nrDNA序列ITS2片段的分析

Analysis on nrDNA ITS2 Sequences of Bupleurum scorzonerifolium Willd. Based on GenBank Data

[目的]了解红柴胡nrDNA序列ITS2片段特征,为中药柴胡的分子鉴定提供科学依据。[方法]从GenBank中获取已公布红柴胡ITS全长序列38条和ITS2序列3条,利用MEGA6.0进行多序列比对,分析ITS2片段碱基成分、变异位点、信息位点,计算遗传距离,并用邻接法(NJ)构建系统聚类树。[结果]ITS2片段长度为224～230 bp,共发现14个简约信息位点,最大遗传距离0.124,系统树可明显分为4组,85.37%的聚为一组。[结论]ITS2在红柴胡居群中比较保守,可作为DNA barcoding鉴定的片段使用。

[Objective]Sequence character of nrDNA ITS2 fragment in Bupleurum scorzonerifolium Willd.was analyzed to provide scientific evidence in identification of traditional Chinese medicinal herb chaihu.[Method]Forty-one sequences including thirty-eight full length ITS and three ITS2 fragments were downloaded from GenBank.Nucleotide composition,variable sites,parsimony informative sites were analyzed after alignment in MEGA6.0.Meanwhile,the genetic distances were computed using Kimura-2-parameter (K2P) model and phylogenetic tree was constructed using the neighbor-joining (NJ) method.[Result]The length of ITS2 varied from 224 bp to 230 bp including 14 parsimony informative sites,and the maximum K2P distance was 0.124.Four clades were grouped in NJ tree among which 85.37% sequences clustered in clade Ⅳ.[Conclusion]ITS2 is an ideal sequence in chaihu identification for its conservatism among B.scorzonerifolium populations.