Identification Of 76 Varieties Of Chinese Herbal Medicine In The Lingnan Area By DNA Barcoding Technique

ObjectiveThis study aimed to screen out suitable DNA barcodes for identifying medicinal plants in Lamiaceae family, Liliaceae family, Rutaceae family, Rosaceae family, Asteraceae family and Zingiberaceae family by comparing and evaluating the ability of several international and hotspot candidate sequences of DNA barcodes.MethodsChosing some Chinese medicinal herbs on MedicineKing Mountain in Guangzhou University of Traditional Chinese Medicine as experimental materials, the genomic DNAs of 76 kinds of plants in the Lamiaceae family, Liliaceae family, Rutaceae family, Rosaceae family and Asteraceae family were, extracted by Plant Genomic DNA Kit, then nuclear ITS2 and the chloroplast sequences, psbA-trnH, rbcL and matK of the plants were amplified using the universal primers and sequenced bidirectionally. To test the candidate DNA barcodes’utility for species authentication, we evaluated the identification efficiency of these loci by measuring a series indexes including PCR amplification and sequencing efficiency, intra-and inter-specific genetic divergence and phylogenetic tree.ResultsAs for 60 plant samples belonging to 20 species in Lamiaceae family, the rate of successful amplification and sequencing using ITS2, psbA-trnH, rbcL and matK sequence was all 100%. ITS2 ranked first in the aspect of variable sites (69.3%). According to the phylogenetic tree, the rate of successful identification based on ITS2, psbA-trnH, rbcL and matK was 70%,55%,45% and 75% respectively.As for 45 plant samples belonging to 16 species in Liliaceae family, the rate of successful amplification and sequencing using ITS2, psbA-trnH, rbcL and matK sequence was all 100%. ITS2 ranked first in the aspect of variable sites (89.1%). According to the phylogenetic tree, the rate of successful identification based on ITS2, psbA-trnH, rbcL and matK was 87.5%,62.5%,68.8% and 68.8% respectively.As for 32 plant samples belonging to 16 species in Rutaceae family, the rate of successful amplification and sequencing using ITS2, psbA-trnH, rbcL and matK sequence was all 100%. PsbA-trnH ranked first in the aspect of variable sites (64.7%). According to the phylogenetic tree, the rate of successful identification based on ITS2, psbA-trnH, rbcL and matK was 81.3%,81.3%,68.8% and 75% respectively.As for 28 plant samples belonging to 11 species in Rosaceae family, the rate of successful amplification and sequencing using ITS2, psbA-trnH, rbcL and matK sequence was all 100%. MatK ranked first in the aspect of variable sites (59.5%). According to the phylogenetic tree, the rate of successful identification based on ITS2, psbA-trnH, rbcL and matK was 100%,81.8%,63.6% and 81.8% respectively.As for 39 plant samples belonging to 13 species in Asteraceae family, the rate of successful amplification and sequencing using ITS2, psbA-trnH, rbcL and matK sequence was all 100%. ITS2 ranked first in the aspect of variable sites (71.7%). According to the phylogenetic tree, the rate of successful identification based on ITS2, psbA-trnH, rbcL and matK was 100%,84.6%,76.9% and 69.2% respectively.ConclusionConsidering all the experimental materials, the four candidate DNA barcodes failed to discriminate all the chosen plant samples in Lamiaceae family, Liliaceae family and Rutaceae family and combining the barcodes might be a way out in the following research. ITS2 performed best in all the candidate loci and it succeeded in the authentication of all the species from Rosaceae and Asteraceae. Therefore, we propose that ITS2 is a promising candidate barcode for the Rosaceae and Asteraceae family.