Study On DNA Barcoding In Coptis (Ranunculaceae)Based On Population Genetics

Objective:Study on DNA barcoding in Coptis (Ranunculaceae) based on population genetics with the purpose to:verify the discriminating feasibility of DNA barcoding used in identification of medicinal Coptis Salisb plants, and then to explore the possibilities of discriminating feasibility of DNA barcoding used in identification of some medicinal plants and their related species,especially for cultivated medicinal plants;strucuture the genetic evolution relationship among the species of Coptis Salisb; extrapolate the origin of cultivated species of Coptis deltoideaC. Y. Cheng et Hsiao and Coptis chinensis Franch.Methods:There are6species and1varietas in Coptis Salisb plants in our country. In this study, samples collected from mainland China,230samples representing4species and1varietas of Coptis SalisbiCoptis omeiensis(Chen) C. Y.Cheng、Coptis deltoidea C.Y.Cheng et Hsiao、Coptis teeta Wall、Coptis chinensis Franch and Coptis chinensis var. brevisepala]. After DNA extraction, One nuclear and three chloroplast DNA regions (ITS and rbcL、matK、trnH-psbA) for4species and1varietas of Coptis Salisb was amplified and sequenced. After monoclonal, sequence the ITS region for some samples appeared heterozygosis. The multiple sequence alignment was completed by ContigExpress and BioEdit v.7software. Mean values of genetic distance between and within species were calculated by MEGA4software base on the Kimura2-parameter model, these results were used to compare the inter-specific divergence and intra-specific variation. Haplotypes were summed up by the DnaSP software from the sequence matrix of four DNA regions’sequences. Haplotypes’evolutionary trees were builtby the Network4.6.0.0. software.Results:The results suggest that only Coptis teeta Wall is distinguished from4species and1varietas of Coptis Salisb by one nuclear and three chloroplast DNA regions (ITS and rbcL、matK、trnH-psbA). The discriminating power of three chloroplast DNA regions (rbcL、matK、trnH-psbA) at the species level are all20%, and the discriminating power of one nuclear region (ITS) is20%-40%. Four regions are not suitable for identification of medicinal Coptis Salisb plants at the species level. The numbers of haplotype were summed up by the DnaSP software from the sequence matrix of four DNA regions’sequences (rbcL、matK、 trnH-psbA and ITS) are6,12,19and11. Representative sequences were submitted to GenBank and given accession numbers. After haplotypes’evolutionary trees were built by the Network4.6.0.0. software, the results showed:each3species and1varietas of medicinal Coptis Salisb plants is not reciprocally monophyletic to all others, except Coptis teeta Wall. Mean values of genetic distance between and within species change obviously following the vary of sampling volume. After analysised monoclonal data, Nuclear genes’ITS region appeared high diversification in the cultivated population of Coptis Salisb, and the species with more same genotypes.Conclusion:①In recent years,the research of Study on DNA barcoding in Coptis with insufficient individuals from the same species sampled have gotten some results, the results gotten without reliability to show the reciprocal monophyly.To verify the discriminating feasibility of DNA barcoding used in identification of medicinal Coptis Salisb plants, the research shoud based on population genetics. After analysised data of genetic evolution relationship, verify the reciprocal monophyly, an then distinguish species.②After analysised haplotypes’evolutionary trees’data, Coptis omeiensis(Chen) C. Y. Cheng、Coptis deltoidea C.Y.Cheng et Hsiao、Copt is chinensis Franch and Copt is chinensis var. brevisepala with same genotypes, each3species and1varietas of medicinal Coptis Salisb plants is not reciprocally monophyletic to all others, except Coptis teeta Wall. After analysised monoclonal data, Nuclear genes’ITS region appeared high diversification in the cultivated population of Coptis Salisb, and the species with more same genotypes. The results show that germplasm hybrid and concerted evolution incompletely.③After analysised haplotypes’evolutionary trees’data, Coptis omeiensis(Chen) C. Y. Cheng、Coptis deltoidea C.Y.Cheng et Hsiao and Coptis chinensis Franch share same genotypes, Coptis chinensis Franch and Coptis chinensis var. brevisepala share same genotypes. On this account, Coptis omeiens is (Chen) C.Y.Cheng and Coptis chinensis Franch were extrapolated as the origin of Coptis deltoidea C. Y. Cheng et Hsiao, Coptis chinensis var. brevisepala were extrapolated as the origin of Coptis chinensis Franch.