Testing candidate plant barcode regions in the Dendrobium species

Abstract

There are 74 species and 2 varieties of Dendrobium found in China and more than half of them are used as Herba Dendrobii in China and other Asian countries. Because of its high market demand, Herba Dendrobii has a relatively high market price compared to other medicinal plants. Moreover, medicinal Dendrobium is listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). This has led to substantial adulterations with other Dendrobium species or other orchid species. Dendrobium is difficult to identify and is an ideal model group to test DNA barcoding technique [1]. In our previous study, the candidate DNA barcoding sequence, psbA-trnH intergenic spacer region, could be used as a barcode to distinguish various Dendrobium species and to differentiate Dendrobium species from other adulterating species [2]. In this study, more samples were used to test the utility of six coding (matK, rpoC1, rpoB, rbcL, accD, ycf5) and two non-coding (atpF-atpH, psbK-psbI) chloroplast markers as potential plant barcoding regions. The results showed that six of the regions we tested were slightly variant across species (rpoB, rpoC1, accD, rbcL, ycf5, atpF-atpH), and psbK-psbI had significant variation and show promise for barcoding in Dendrobium species.