DNA barcoding identification of medicinal Dendrobium based on ITS and ITS2 sequences
Objective To explore the feasibility of using internal transcribed spacer(ITS)and internal transcribed spacer 2(ITS2)fragments as DNA barcodes to identify 41 species of medicinal Dendrobium in China.Methods By PCR amplification sequencing combined with GenBank public sequence screening,433 ITS and 410 ITS2 sequences from 41 medicinal Dendrobium species nuclear genes were obtained.The intra-and inter-species genetic distances were estimated based on Kimura-2-parameter(K2P)model.The phylogenetic trees were constructed by neighbor joining(NJ)method.The secondary structures of ITS2 were also predicted and analyzed.Results The results of genetic distances calculation and NJ tree analysis revealed that ITS and ITS2 as DNA barcodes could effectively distinguish 30 and 31 tested medicinal Dendrobium species,with the species identification rates of 73.2％and 75.6％,respectively.The combination of phylogenetic tree construction and ITS2 sequence secondary structure analysis could increase the species identification rate of medicinal Dendrobium to 87.8％.Conclusion The identification rate of ITS2 as a DNA barcode for medicinal Dendrobium species tested in this study is better than that of ITS.Moreover,the success rate of species identification was found to be significantly affected by the number of species sampled.Our results not only enriched the DNA barcode database of Dendrobium plants in China,but also provided scientific basis and technical support for ensuring the germplasm resources and medicinal safety of medical Dendrobium.
万方数据
维普
