目的：评价DNA条形码候选序列对景天属药用植物及其混伪品的鉴别能力，探索景天属药用植物鉴定的新方法。方法：使用ITS2、rbcL、matK和psbA-trnH序列的通用引物对景天属药用植物进行PCR扩增和测序，通过比较各序列的扩增效率、种内和种间变异的显著性，以及Barcoding gap，采取BLAST 1和Nearest Distance 方法评价不同序列的鉴定能力。结果: ITS2序列在采集的景天属几种药用植物中扩增成功率为100%，其种内种间变异差异、Barcoding Gap较psbA-trnH、rbcL序列具有更明显的优势，而且纳入网上48个样品33个种的数据后鉴定成功率仍达到100%。结论：ITS2序列能够准确鉴定景天属药用植物，并将其与常见混伪品区别开，ITS2可推荐为景天属首选的DNA条形码序列。

This study aimed to test and evaluate different DNA barcoding sequences and develop a new method for identification of the medicinal plants in genus Sedum. Using universal primers, three chloroplast sequences, psbA-trnH, rbcL, matK and nuclear ribosomal DNA ITS2, were amplified and sequenced. PCR amplification and sequencing efficiency, intra- and inter-specific divergence, barcoding gap and identification efficiency were used to evaluate different loci. The ITS2 of all samples of Sedum studied was amplified and sequenced. Analysis of the intra- and inter-specific divergence and barcoding gap showed that ITS2 was superior to other loci. 48 samples of 32 species of Sedum were identified by ITS2. Taken together, medicinal plants in genus Sedum can be identified correctly using ITS2 sequence, which may be a potential DNA barcode for identifying other medicinal plants.

科技部国际科技合作项目（2007DFA30990）：中药材DNA条形码鉴定研究，负责人：陈士林；卫生部卫生行业科研专项（200802043）：药用植物DNA barcoding（条形码）鉴定研究，负责人：陈士林。