基于DNA条形码的岭南特色药材广东海桐皮、木棉花与其混淆品的分子鉴定

目的：本研究主要应用第二内转录间隔区（ITS2）序列作为DNA条形码进行分析，建立对岭南中药广东海桐皮、木棉花与其混淆品的快速鉴定法。方法：收集广东海桐皮等9个物种样本，提取样本基因组DNA，扩增ITS2 基因片段，对其产物进行双向测序。所得序列采用CodonCode Aligner进行拼接。利用MEGA 6.06软件进行种间变异及遗传距离分析，并构建系统进化树。结果：9个物种的ITS2序列长度范围为224-237bp，物种的种内遗传距离（0.000-0.017）明显小于种间遗传距离（0.045-0.820），NJ和ML聚类树显示，各物种样本独聚一支，表现出单系性。结论：ITS2序列能够有效鉴别植物海桐皮、木棉花与其混淆品，为其基原植物鉴定提供依据，为保证用药真实及其临床疗效提供分子鉴定方法。

Molecular Identification of Erythrina variegate Linn.,Bombax malabaricum and Their Adulterants Using DNA Barcode

A molecular identification method taken ITS2 as DNA barcode was adopted to distinguish E.variegate,B.malabaricum from their adulterants.Samples from nine species were gleaned.The ITS2 regions were amplified with bi-directional sequencing.Along with some downloaded ones from the GenBank database,all sequences were assembled by CodonCode Aligner and analyzed by MEGA 6.06.The Kimura 2-Parameter(K2P)distances were computed and phylogenetic tree was built using the neighbor-joining(NJ)and maximum likelihood(ML)trees.As a result,it was found that the lengths of ITS2 sequence of the nine species varied from 224 to 237bp.The intraspectific distance(0.000-0.017)was significantly shorter than the interspecific distance(0.045-0.820).The results of NJ tree and ML tree presented that all the nine species were separately and obviously clustered to one branch,a monophyletic clade.In conclusion,the ITS2 sequence can be treated as an ideal DNA barcode for the molecular identification of E.variegate,B.malabaricum and their adulterants,providing a reference for clinical application.