[Identification of Tibetan medicine "Dida" of Gentianaceae using DNA barcoding]

The ITS2 barcode was used toidentify Tibetan medicine "Dida", and tosecure its quality and safety in medication. A total of 13 species, 151 experimental samples for the study from the Tibetan Plateau, including Gentianaceae Swertia, Halenia, Gentianopsis, Comastoma, Lomatogonium ITS2 sequences were amplified, and purified PCR products were sequenced. Sequence assembly and consensus sequence generation were performed using the CodonCode Aligner V3.7.1. The Kimura 2-Parameter (K2P) distances were calculated using MEGA 6.0. The neighbor-joining (NJ) phylogenetic trees were constructed. There are 31 haplotypes among 231 bp after alignment of all ITS2 sequence haplotypes, and the average G±C content of 61.40%. The NJ tree strongly supported that every species clustered into their own clade and high identification success rate, except that Swertia bifolia and Swertia wolfangiana could not be distinguished from each other based on the sequence divergences. DNA barcoding could be used as a fast and accurate identification method to distinguish Tibetan medicine "Dida" to ensure its safe use.