Molecular identification of Tougucao and its adulterants based on ITS2 sequence
10.7501/j.issn.0253-2670.2019.23.026
- Author:
Li-Jie MA
1
Author Information
1. School of Pharmacy, Nanjing University of Chinese Medicine
- Publication Type:Journal Article
- Keywords:
Adulterants;
DNA barcode;
ITS2;
Species identification;
Tougucao
- From:
Chinese Traditional and Herbal Drugs
2019;50(23):5830-5837
- CountryChina
- Language:Chinese
-
Abstract:
Objective: ITS2 barcoding was used to discriminate Tougucao and its adulterants in order to provide a new method for the identification of Tougucao. Methods: The total genomic DNAs were extracted from 35 samples of Tougucao and its adulterants. The ITS2 sequences of these samples were amplified and bidirectional sequenced by PCR. The obtained sequences were submitted to the GenBank and the ITS2 sequences of 42 samples belonging to 13 species were downloaded from the GenBank. Genetic distance, neighbor joining (NJ) phylogenetic tree and secondary structures of ITS2 sequences were analyzed by using MEGA 7.0. Results: The maximum intraspecific genetic distance (K2P distance) was much smaller than the minimum interspecific genetic distance between Tougucao and its adulterants. The NJ tree showed that Tougucao and its adulterants could be distinguished obviously, which showed high monophyly. Comparing the secondary structure of ITS2 among Tougucao and its adulterants, it was found that there were significant differences in the number, size, position of loop, and the angle of helix exsertion. Conclusion: As a DNA barcode, ITS2 sequences can stably and accurately distinguish Tougucao from its adulterants and it can also provide a new technique to ensure the clinical safety in utilization of Chinese materia medica.
