五味子与南五味子药材的DNA条形码鉴定

目的:利用内转录间隔区2(ITS2)序列对五味子及南五味子药材进行DNA条形码鉴定。方法:对五味子和南五味子样品的ITS2序列进行聚合酶链式反应(PCR)扩增和测序。从Gen Bank中下载了五味子属10个近缘种和2个外类群的ITS2序列。利用Codon Code Aligner软件拼接,采用MEGA 5.10计算相关数据,基于K2P模型构建聚类树(NJ树),应用Blast法进行鉴定分析。获取所测样品序列的ITS2二级结构信息,分析各样品间ITS2序列二级结构的差异。结果:五味子、南五味子样品序列长度分别为231,225~227 bp,Blast鉴定五味子药材原植物为五味子Schisandra chinensis,南五味子药材原植物为华中五味子S.sphenanthera。五味子与南五味子药材的种间K2P遗传距离(0.010 4~0.015 7)远大于五味子种内K2P遗传距离(0~0.002 5)和南五味子种内K2P遗传距离(0~0.005 1)。在NJ树模型中,五味子样品被独聚为1支,南五味子样品被独聚为1支,皆表现出单系性,Bootstrap支持率较高,可与五味子属近缘种区分开。结论:以ITS2序列为标准的DNA条形码能够有效地鉴定五味子和南五味子药材。

DNA Barcoding Identification of Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus by ITS2 Sequences

Objective: To identify Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus by ITS2 sequences. Method: ITS2 sequences of Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus were amplificated by polymerase chain reaction(PCR) and bidirectionally sequenced.ITS2 sequences of related 10Schisandra species and 2 out-group specie samples were downloaded from GenBank.CodonCode Aligner was used for sequence splicing and MEGA 5.10 was utilized for related data calculating.Then neighbour-joining tree(NJ tree) was built based on K2P model,and Blast method was used to identify specie of samples in this study.Differences between ITS2 secondary structures which were prodicted using ITS2 web server were analysed. Result: Lengths of sequences of Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus were 231,225-227 bp.Blast identification of samples were Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus. K2P genetic distance between two species(0.0104-0.0157) was greater than intraspecific genetic variation.In NJ tree,Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus were clustered into a single branch respectively,which showed monophyletic,and could be distinguished between other species of S. with a high Bootstrap approval rate. Conclusion: DNA barcoding based on ITS2 sequence is a powerful and efficient tool for identification of Schisandrae Chinensis Fructus and Schisandrae Sphenantherae Fructus.