Identification of Meconopsis species by a DNA barcode sequence: The nuclear internal transcribed spacer (ITS) region of ribosomal deoxyribonucleic acid (DNA)

Abstract

Deoxyribonucleic acid (DNA) barcoding is a novel technology that uses a standard DNA sequence to facilitate species identification. Species identification is necessary for the authentication of traditional plant based medicines. Although a consensus has not been agreed regarding which DNA sequences can be used as the best plant barcode, the internal transcribed spacer (ITS) region of nuclear ribosomal DNA has been tested and applied extensively in recent years. In this study, we used the ITS region to test its possibility to serve as barcodes for Meconopsis species which are widely used in traditional Tibetan medicines that are used throughout the Himalayas. We sequenced 14 accessions representing four Meconopsis species. The result shows ITS sequences were found to be unique for each species, with the interspecies percentages of nucleotide differences averaging 5.1% and ranging from 0.2 to 9.6%. In contrast, the intraspecies percentages of nucleotide differences among the Meconopsis species studied ranged from 0 to 1.9%. Our results indicate that the ITS region can be used as a barcode to distinguish Meconopsis species.

Key words: DNA barcoding, species identification, Meconopsis, ITS region.