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

Xin TY, Yao H, Luo K, Xiang L, Ma XC, Han JP, Lin YL, Song JY, Chen SL.

Abstract

BACKGROUND:

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

METHODOLOGY/PRINCIPAL FINDINGS:

In this study, 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 ofITS/ITS2 regions of Notopterygii Rhizoma et Radix were the same as those of the originalplant 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.

CONCLUSIONS:

Therefore, ITS/ITS2regions 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.

PMID:23162910 [PubMed - indexed for MEDLINE]