板蓝根与南板蓝根及其混淆品的ITS2条形码鉴定

Identification of Isatis tinctoria,Baphicacanthus cusia and Thier Adulterants with ITS2 Barcode

目的:利用ITS2条形码鉴定区分中药板蓝根与南板蓝根及其混淆品蓼蓝和大青。方法:提取4种中药基原植物基因组DNA扩增ITS2序列,隐马尔科夫模型HMMer进行序列注释,Clustal W法进行序列比对,K2P模型计算种内和种间遗传距离,邻接法构建进化树。结果:遗传距离分析显示,4个物种的最大种内遗传距离为0.034,最小种间遗传距离为0.347,最大种内遗传距离大于最小种间遗传距离。同时4个物种可以在进化树上明显区分开来。结论:ITS2序列可以用于板蓝根与南板蓝根及其混淆品蓼蓝和大青的分子鉴定,相较于传统鉴定方法,该方法更加高效与准确。

Objective：To identify lsatis tinctoria, Baphicacanthus cusia and their adulterants such as Polygonum tinctorium and Clerodendrum cyrtophyllum. Methods： Genomic DNA was extracted from the original plants of the four traditional Chinese medicines. Then the sequences internal transcribed spacer 2 （ITS2） were amplified with different DNA templates. Sequence annnotaion was finished with Hidden Markov model（HMMer）. The annotated sequences were then aligned with ClustalW method. Genetic distances within interspecies and intraspecies were calculated with K2P model. Results ： The analysis showed that the largest genetic distance of in- terspecies was 0. 034, while the smallest genetic distance of intraspecies was 0. 347, so that the largest interspecies genetic distance was larger than the smallest intraspecies genetic distance. What＇s more, the four species could be distinguishable in the phylogenetic tree constructed with Neighbor-joining method. Conclusion：ITS2 could be used in identification of Isatis tinctoria,Baphicacanthus cusia,Polygonum tinctorium and Clerodendrum cyrtophyllum. DNA barcoding has advantages compared to traditional identification methods.