Assessment Of Candidate DNA Barcodes For Medicinal Plants From Cucurbitaceae Family And Sedum Genus

Objective:To test and evaluate the ability for several hotspot DNA barcode sequences to identify the species in Cucurbitaceae family and Sedum genus.Methods:Using universal primers, three chloroplast sequences, psbA-trnH, rbcL, matK and a nuclear ribosomal DNA ITS2 were amplified and sequenced. PCR amplification and sequencing efficiency, intra- and inter-specific divergence, barcoding gap and identification efficiency (with BLAST 1 and nearest Distance method) were used to evaluate these loci.Results:The rate of successful identification using ITS2 region was 88.5% at the species level for 182 plant samples of the Cucurbitaceae belonging to 90 species from 33 distinct genera. The rate of successful identification using psbA-trnH region was 73.1 %, but it can discriminate some species which can't be successfully discriminated by ITS2 region. The ITS2 of all samples of Sedum studied can be amplified and sequenced. Analysis of the intra- and. inter-specific divergence and barcoding gap showed ITS2 were superior to other loci.48 samples of 32 species of Sedum can be correctly identified by ITS2.Conclusion:It was proposed that the ITS2 and psbA-trnH senquence combination was promising for identifying the Cucurbitaceae species. Medicinal plants in genus Sedum can be identified correctly using ITS2 sequence which would be a potential DNA barcode for identifying other medicinal plants.