稗属植物DNA条形码研究

DNA Barcodes Study of Echinochloa

为评估DNA条形码在稗属植物鉴定中的有效性,选取核DNA条形码序列ITS和ETS及叶绿体DNA条形码序列psbA、trnL-F和matK作为候选序列进行了分析。本研究对无芒稗、稗、长芒稗和细叶旱稗4种稗属植物的不同DNA条形码序列进行了扩增、测序,并分析了不同候选条形码序列的特征。结果显示,matK序列变异位点占比最高(3.6%),ETS序列最低(1.7%);psbA序列种间变异最大,matK序列种内变异最大;邻接树分析显示,条形码序列ITS、ETS、psbA、trnL-F和matK均可以区分出长芒稗,支持率均大于80%;此外,ITS序列将无芒稗和稗聚于同一支,可以区分出细叶旱稗。因此,建议ITS作为鉴别稗属植物潜在的DNA条形码序列。

To evaluate the effectiveness of DNA barcodes in the identification of the genus Echinochloa,two candidate DNA barcodes from nuclear genome(ITS,ETS)and three candidate DNA barcodes from chloroplast genome(psbA,trnL-F,matK)were analyzed.The study amplified and sequenced the five candidate DNA barcodes from four Echinochloa species(E.crus-galli var.mitis,E.crus-galli var.crus-galli,E.caudate and E.crus-galli var.praticola),and analyzed the characteristics of each DNA barcode.The results show that matK has the highest proportion of variable sites(3.6%),and ETS has the lowest(1.7%);psbA has the largest interspecific distance,while matK has the largest intraspecific distance.The neighbor-joining(NJ)tree shows that all five candidate DNA barcodes have the ability to identify E.caudata,and their support rates are all higher than 80%.Furthermore,ITS could distinguish E.crus-galli var.praticola from E.crus-galli var.mitis and E.crus-galli var.crus-galli species.Therefore,it is recommended to use ITS as the potential DNA barcode for identifying Echinochloa.