Identification of Traditional She Medicine Shi-Liang Tea Species and Closely Related Species Using the ITS2 Barcode

Abstract

Traditional She medicine is part of China’s cultural heritage and has become remarkably popular worldwide. The Shi-Liang tea is made from the processed leaves of Chimonanthus salicifolius S. Y. Hu and Chimonanthus zhejiangensis M. C. Liu. To ensure the safety and efficacy of Shi-Liang tea, we used DNA barcoding based on the internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA to distinguish the original plant sources of Shi-Liang tea from closely related species. All 71 ITS2 sequences were aligned by Clustal-W, and genetic distances were computed using MEGA 6.0 according to the Kimura 2-parameter model. The results indicated that the sequence lengths of ITS2 regions of the original plants of Shi-Liang tea and closely related species ranged from 256 bp to 260 bp. Interspecific genetic distances ranged from 0 to 0.078. The neighbor-joining (NJ) tree showed that the original plants of Shi-Liang tea species can be easily differentiated from closely related species. Distinct molecular differences were found between the secondary structures of ITS2 sequences from Shi-Liang tea and closely related species. The results in the present investigation suggested that the ITS2 could be an effective DNA marker to identify the original plants of Shi-Liang tea and their closely related species. These DNA barcodes can greatly benefit the supervision of the commercial circulation of She medicine.