Stability and accuracy of the identification of Notopterygii Rhizoma et Radix using the ITS/ITS2 barcodes / 药学学报

ABSTRACT

In this study, Notopterygii Rhizoma et Radix was used to verify the stability and accuracy of DNA barcodes in identification of Chinese materia medica for the first time. All genomic DNAs from thirty one samples were extracted. The ITS (internal transcribed spacer) regions were amplified and sequenced bi-directionally. Obtained sequences were assembled using the CodonCode Aligner. And the sequences of the ITS regions were aligned through Clustal-W and the genetic distances were computed using MEGA 5.0 in accordance with the kimura 2-parameter (K2P) model. The neighbor-joining (NJ) phylogenetic trees were constructed. The ITS2 regions were obtained by using the hidden Markov model (HMM)-based annotation methods from the ITS sequences. Results indicated that the lengths of ITS regions of Notopterygii Rhizoma et Radix were 603-604 bp, while the lengths of ITS2 regions were 228 bp. The haplotypes of ITS/ITS2 regions of Notopterygii Rhizoma et Radix were the same as those of the original plant leaves. The intra-specific genetic distances were smaller than inter-specific ones in ITS/ITS2 regions of Notopterygium incisum and N. franchetii. The NJ trees showed that N. incisum, N. franchetii and its adulterants can be easily differentiated according to their monophyly. Therefore, ITS/ITS2 regions as DNA barcodes can stably and accurately distinguish Notopterygii Rhizoma et Radix from its adulterants and could provide a new technique to ensure clinical safety in utilization of traditional Chinese medicines.