基于DNA条形码的甘草属植物的分子鉴别

目的:评价不同DNA条形码序列对甘草属的鉴定能力。方法:应用5条常用DNA条形码序列ITS、ITS2、psbA-trnH、matK与rbcL对甘草属进行PCR扩增与序列测序,结合在GenBank数据库下载的序列数据,通过分析各序列种内与种间变异与遗传距离,构建系统发育树,并基于相似性搜索算法和最近距离法计算各序列鉴定成功率,以分析比较各序列对甘草属的鉴定效率。结果:matk序列因扩增与测序成功率均较低,没有加入后续的数据分析。各个序列的鉴定成功率由高到低的顺序为psbA-trnH、ITS、ITS2、rbcL。ITS和ITS2序列种间最小变异均大于种内最大变异,且种内变异最小。Barcoding gap检验结果显示,ITS、ITS2的重叠区较小。NJ树结果显示,只有psbA-trnH序列能把甘草属不同物种分开。结论:利用DNA条形码序列可准确鉴别甘草属植物,psbA-trnH和ITS组合序列可作为鉴定甘草属植物的较优序列组合。本研究为甘草属植物的分子鉴别提供科学依据。

Molecular Identification in Genus of Glycyrrhiza Based on DNA Barcoding

Objective:To evaluate the identification ability of different DNA barcodes for the genus of Glycyrrhiza.Methods:Five DNA barcodes of ITS,ITS2,psbA-trnH,matK and rbcL were amplified and sequenced,coupled with the sequences downloaded from the GenBank database to analyze the genus of Glycyrrhiza in term of the variation of inter-and intra-species,barcoding gap,and identification efficiency which is evaluated by Nearest distance and BLAST1 methods.The neighbor joining tree(NJ tree)for each barcode were constructed.Results:The order of success rate of identification of each sequence from high to low was as following psbA-trnH,ITS,ITS2,rbcL.The minimum inter-specific distance of ITS and ITS2 sequences was greater than the maximum intra-specific distance,and the minimum intra-specific distance.Barcoding gap test results showed that the overlap area between ITS and ITS2 was the least.The results of NJ tree showed that only psbA-trnH sequence could distinguish different Glycyrrhiza.Conclusion:DNA barcoding could identify the plants of Glycyrrhiza accurately.The psbA-trnH and ITS sequence could be used as an ideal combination for identification of Glycyrrhiza.This study should provide scientific basis for molecular identification on the genus of Glycyrrhiza.