姜科砂仁属植物DNA条形码序列的筛选

砂仁属（Amomum）隶属于姜科,全属约150种,我国有39种。该属多种植物可作药物或香料,但目前砂仁属的分类还不清楚,准确鉴定物种有很大难度。本研究利用DNA barcoding技术,对砂仁属50种121个个体的matK、rbcL-a、trnH-psbA序列及其不同组合进行比较,用Taxon DNA计算种间、种内bar-coding gap,运用相似法的BLASTn计算条码的正确鉴定率,筛选适合砂仁属的条码片段。结果显示：所有条码的barcoding gap均不存在;matK的正确鉴定率高于trnH-psbA和rbcL-a,联合片段的条码正确鉴定率高于单片段条码,三个片段联合条码的正确鉴定率最高。因此,推荐matK＋rbcL-a＋trnH-psbA作为砂仁属物种鉴定的候选条码。

Screening Potential DNA Barcode Regions in Amomum (Zingiberaceae)

Amomum contains 150 species,and 39 of them are found in China.Many Amomum species are used in traditional Chinese medicines and favorite food condiment.The intrageneric classification of this genus is largely unclear,and the accurate identification of species is difficult.DNA barcoding is a technique to identify species using standardized DNA region.The COI sequence has been successfully used to identify animal species.Unfortunately,there are no universally accepted barcode systems for plants.This study compared the each three candidate plastid regions（matK,rbcL-a,trnH-psbA）and the combined data（matK＋rbcL-a,matK＋trnH-psbA,rbcL-a＋trnH-psbA,matK＋rbcL-a＋trnH-psbA）among 121 accessions representing 50 species of the genus.In order to screen out the suitable barcode for identifying the species of Amomum,Taxon DNA was used to estimate the barcoding gap between interspecific and intraspecific distances,and BLASTn was used to calculate the rate of correct identification.The results indicated that there was no DNA barcode gap in three loci.The correct identification of matK was higher than that of trnH-psbA or rbcL-a,the combined data has higher correct identification than that of single one,and the three-locus combined data showed the greatest level of species discrimination.To sum up,matK＋rbcL-a＋trnH-psbA can be considered as a potential barcode for identifying the species of Amomum.