[DNA barcoding identification of endangered medicinal plants of Orchidaceae]

In this study, DNA barcoding was used to validate the traditional morphological classification of medicinal plants of Orchidaceae. The 163 samples of 135 species belong to 49 genera which have been confirmed by morphological identification were collected. Candidate sequences, including matK, psbA-trnH and ITS2 sequences, were amplified, bidirectionally sequenced, and assembled. All the sequences were blasted to GenBank database at NCBI, then analyzed using Neighbor-joining tree method by MEGA 7.0. The results showed that the DNAs of 163 samples were successfully extracted. The amplification efficiency of matK, psbA-trnH and ITS2 sequences were 100%, 100% and 98.77%, respectively. The 487 sequences were obtained, 345 sequences of which have matched corresponding sequences in the GenBank database and 142 sequences were new sequences. The topology of NJ tree which were constructed with the matK sequences was better than the trees of psbA-trnH and ITS2 sequences. In conclusion, the matK, psbA-trnH and ITS2 sequences were complementary and suitable for identification of medicinal plants of Orchidaceae. DNA barcoding can be used as an auxiliary means for identification of medicinal plants of Orchidaceae.