基于ITS2序列鉴定中药材金沸草、旋覆花及其近缘混伪品

Identification of Inulae Herba, Inulae Flos and Their Closely Related Species Based on ITS2 Sequence

目的:应用ITS2序列鉴定中药材金沸草、旋覆花及其近缘种混伪品,以确保药材质量,保障临床安全用药。方法:通过对金沸草、旋覆花等药材的3个基原物种条叶旋覆花、旋覆花和欧亚旋覆花及其同属近缘物种进行DNA提取、PCR扩增ITS2序列并双向测序,用CodonCode Aligner对测序峰图进行拼接后,用MEGA5.0软件进行相关数据分析,并构建NJ系统聚类树以直观反映鉴定结果。结果:各基原物种ITS2序列变异位点稳定,其种内平均K2P距离均远小于各自药材以及同属近缘混伪品的种间平均K2P距离;基于ITS2序列的NJ树可以将金沸草和旋覆花药材与同属其它近缘混伪品明显区分开。结论:ITS2序列可准确鉴别中药材金沸草和旋覆花及其同属近缘混伪品。

This study aimed to identify Inulae Herba, Inulae Flos and their closely related species using the ITS2 bar- code, and secure the quality and clinical curative effect of these medicinal materials. DNA was extracted from Inula linariifolia, I. japonica, I. britanica, which are the original species of Inulae Herba and Inulae Flos, together with their closely related species. The ITS2 sequence was amplified by PCR and sequenced bidirectionally. Sequence assembly and generation of consensus sequence were conducted by the CodonCode Aligner. The genetic distances were comput- ed using MEGA 5.0 in accordance with the Kimura-2-parameter （K2P） model, and the phylogenetic tree constructed by the neighbor-joining （N J） method. The results showed that the ITS2 sequences of the various species have stable variable sites. The intraspecific genetic distances among lnulae Herba and Inulae Flos were obviously lower than the interspecific genetic distance among the above two medicinal materials and its adulterants. The NJ tree based on ITS2 sequences can clearly differ from Inulae Herba, Inulae Flos and their closely related species. It is concluded that ITS2 sequence can be used as DNA barcode to identify Inulae Herba, Inulae Flos and their closely related species.