Evaluation of seven DNA barcodes for differentiating closely related medicinal Gentiana species and their adulterants

Abstract

BackgroundSpecies identification of living organisms by standard DNA sequences has been well-accepted. Consortium for the Barcode of Life (CBOL) recommends chloroplast regions rbcL and matK as the DNA barcodes for the land plants. This study aims to evaluate the feasibility and limitations of rbcL, matK, and 5 other commonly used regions as the DNA barcodes for the medicinal Gentiana and their adulterants, Gentiana. rhodantha and Podophyllum hexandrum.MethodsThe species differentiation power of rbcL, matK, nuclear internal transcribed spacer (ITS) and 5S rRNA intergenic spacer, and chloroplast trnH-psbA, trnL-F and rpl36-rps8 intergenic spacers were tested in different medicinal Gentiana, including Gentiana scabra, Gentiana triflora, Gentiana manshurica and Gentiana rigescens, from common adulterants such as Gentiana rhodantha and Podophyllum hexandrum (a toxic herb producing podophyllotoxin).ResultsAll seven tested loci could be used to differentiate medicinal Gentiana species from their adulterants, and to distinguish Guanlongdan from Jianlongdan. In terms of general differentiation powers, rbcL and matK had no significant advantages over the other five loci. Only the 5S rRNA and trnL-F intergenic spacers were able to discriminate the closely related species G. triflora, G. scabra and G. manshurica.ConclusionThe DNA barcodes rbcL and matK are useful in differentiation of closely related medicinal species of Gentiana, but had no significant advantages over the other five tested loci.

Testing DNA barcodes in closely related species of Curcuma (Zingiberaceae) from Myanmar and China

“…However, PCR and sequencing success rate of matK in the present study were high, that is 85.4% amplification success rate using three primers. The trnL-F region showed a high PCR success rate (88.6% %) with only one pair primer and had the longest DNA sequence among the tested loci, which corresponded well with the results of studies carried out on other groups of plants (Chen et al 2013b;Wong et al 2013). The ITS2 region had the lowest sequencing success in this study (76.1%).…”

The Use of DNA Barcoding on Recently Diverged Species in the Genus Gentiana (Gentianaceae) in China

“…However, other highly variable regions are required to successfully identify all species. In a recent Gentiana barcoding study, 5S rRNA and trnL-F were successfully used as barcodes to differentiate five medicinal Gentiana species and their adulterants [ 55 ]. However, using 5S rRNA requires cloning the amplified PCR product rather than direct sequencing, which limits its value as a barcode.…”

Emergence of Plastidial Intergenic Spacers as Suitable DNA Barcodes for Arid Medicinal Plant <i>Rhazya stricta</i>

“…It was proposed that an ideal DNA barcode (i) can be easily amplified and sequenced, (ii) does not exceed 1 kb in size, and (iii) has higher interspecific than intraspecific variation [54]. We selected six barcoding loci to examine with these criteria in mind.…”