基于DNA条形码技术的中药小蓟基原植物的分子鉴定

目的:对中药小蓟的基原植物进行分子鉴定,以确保药材质量及其临床疗效。方法:以核基因ITS2片段及叶绿体基因片段psbA-trnH作为DNA条形码,对研究材料进行PCR扩增并双向测序,所得序列经CodonCode Aligner拼接后,用软件MEGA4.0进行相关数据分析,并构建NJ(邻接)树。结果:所研究的刺儿菜复合体样本的ITS2序列间存在明显差异,psbA-trnH序列间也存在稳定差异,基于ITS2序列及psbA-trnH序列构建的邻接(NJ)树可以看出大刺儿菜与小刺儿菜不同样本均能聚为独立一支,表明中药小蓟的基原植物刺儿菜复合体确为两个独立的物种。结论:ITS2和psbA-trnH序列作为DNA条形码可以有效地区分和鉴别物种,在中药原植物物种分类与中药鉴定方面具有广阔的应用前景。

Molecular Identification of Original Plant of Cirsii Herba Based on DNA Barcoding Technology

Objective：This study aimed to identify the original plant of Cirsii Herba by DNA barcoding technology in order to guarantee the quality ＂and clinical curative effect of this medical material. Methods ： In this study, the second inter- nal transcribed spacer （ITS2） and chloroplast gene fragments psbA - trnH were applied and sequenced. Sequence assem- bly and consensus sequence generation were performed by using the CodonCode Aligner. Phylogenetic study was per- formed by using software MEGA 4.0 in accordance with the Kimura 2 - parameter （K2P） model. And the phylogenetic tree was constructed using the neighbor-joining methods. Results ：The original plant of Cirsii Herba can be identified by the sequences difference of the ITS2 and psbA - trnH sequences. The phylogenetic tree based on ITS2 sequences and psbA - trnH sequences can also distinguish the original plant of Cirsii Herba. This shows that the original plant of Cirsii Herba comes from two independent species. Conclusion ： ITS2 and psbA - trnH barcode sequences can serve as valuable markers for identifying and distinguishing species. Hence, the application of ITS2 and psbA - trnH as DNA barcodes used in the i- dentification and plant taxonomy of traditional Chinese medicine has a wide prospect.