Molecular identification of Tibetan medicinal plants based on ITS2 sequence / 中草药

ABSTRACT

Objective: The barcoded ITS2 DNA sequence was used to identify 44 Tibetan medicinal plants. Methods: Genomic DNA of Tibetan medicinal plants were extracted with high salt and low pH method. The PCR technique was performed to obtain the ITS2. A total of 145 ITS2 sequences was obtained belonging to 24 families, 39 genera, and 44 species. Some homologous sequences were also selected according to sequence alignment from Genbank database. The ITS2 sequences were aligned using Bioedit and the intraspecific and interspecific Kimura 2-parameter genetic distance was calculated using MEGA, and the neighbor-joining (NJ) phylogenetic trees were constructed to analyze phylogenetic relationship. Results: ITS2 regions have significant intra-and inter-specific difference, phylogenetic analysis based on ITS2 regions concurred with the result of morphological classification, and it could also determine the phylogenetic relationship between species. In addition, the secondary structure of the ITS2 sequence of Tibetan medicinal plants is different, providing another method for species identification. Conclusion: ITS2 can be used as a very effective single-locus barcode in the identification and phylogenetic study of Tibetan medicinal plants. The barcoding technique provides a scientific baseline for the utilization of resources and conservation of Tibetan medicinal plants.