大黄与易混伪品土大黄、虎杖原植物的ITS2序列鉴定

Identification of original plants of Radix et Rhizoma Rhei from its adulterants Rhizoma et Radix Polygoni Cuspidati and Radix Rumicis Obtusifolii by ITS

目的分析大黄与其易混伪品原植物的rDNA上的ITS2序列信息,探索鉴定大黄及其混伪品的新方法。方法提取DNA模板后对其ITS2区进行PCR扩增、测序;拼接序列;计算种内种间K2P距离,最后基于K2P距离建立NJ树。结果大黄与其混伪品的最小种间K2P距离(38.6%)大于最大种内K2P距离(8.0%),NJ树中大黄三个基原的不同来源样品聚为一支。结论因此ITS2序列可以作为鉴定大黄与易混伪品土大黄、虎杖的候选条形码序列,DNA条形码技术在中药鉴定中具有极大的前景。

Objective The ITS2 sequence of rDNA was utilized as a novel technique to discriminate three original plants of Radix et Rhizoma Rhei from its adulterants. Methods DNA was extracted from each sample as template, of which the ITS2 region was amplified in a PCR and then sequenced. Sequences were assembled. Inter-and intra-specific K2P distances were calculated, based on which NJ tree was performed. Results The K2P distance of the minimum inter-specific 38.6% was higher than that of the maximum intra-specific 8.0%. The different samples of three original plants of Radix et Rhizoma Rhei were clustered into one elade. Conclusion The ITS2 fragment could be used as a candidate bareode for identifying original plants of Radix et Rhizoma Rhei from its adulterants Rhizoma et Radix Polygoni Cuspidati and Radix Rumicis Obtusifolii, and DNA barcoding has a wide prospect in authenticating Traditional Chinese Medicine.