麦田杂草节节麦与圆柱山羊草的DNA条形码鉴定

DNA barcoding identification of Aegilops tauschii and Ae.cylindrica in wheat fields

麦田恶性杂草节节麦Aegilops tauschii Coss.和圆柱山羊草Aegilops cylindrica Host.均为我国检疫性有害生物,二者形态极其相似,导致生产中难以采取针对性的防控措施。为快速、准确地进行区分鉴定,本研究利用DNA条形码技术,对采自河北、河南、山东等9省的52份样品进行了鉴定。针对4个DNA条形码序列区段rbcL、matK、trnH-psbA和ITS2,测序并计算种内、种间的双参数遗传距离,采用邻接法构建系统发育树。结果表明,matK扩增测序结果不理想;rbcL序列无差异;ITS2序列种内遗传距离0.0007,种间遗传距离0.0096;trnH-psbA序列存在15个差异位点,种内遗传距离0,种间平均遗传距离0.0051,NJ树支持率为96.0%,能明显区分二者。特异性检测中,节节麦和圆柱山羊草均存在特异性碱基,进一步证明trnH-psbA为最优鉴定序列。本研究为快速、准确鉴定这2种检疫性杂草提供了新的分子检测技术。

Aegilops tauschii Coss.and Ae.cylindrica Host.,both malignant weeds in wheat fields,are considered quarantine pests in China.The morphological similarity between Ae.cylindrica and Ae.tauschii complicates targeted weed management in agricultural production.To address this,this study utilized DNA barcoding technology to differentiate and identify these weeds.A total of 52 samples from 9 provinces,including Hebei,Henan,and Shandong,were analyzed.Four DNA barcode sequences(rbc L,mat K,trn H-psb A,and ITS2)were sequenced.Intraspecific and interspecific genetic distances were calculated,and a phylogenetic tree was constructed using the neighbor-joining method.The results showed that among the four DNA barcodes,mat K sequencing was unsatisfactory.The rbc L sequences of the two species were identical.The intraspecific genetic distance of ITS2 was 0.0007,while its interspecific genetic distance was 0.0096.The trn H-psb A sequence accurately identified Ae.tauschii and Ae.cylindrica,showing 15 different interspecific loci with a genetic distance of 0.0051,and no intraspecific differences.The neighbor-joining tree had a frequency of 96.0%.In specificity testing,both Ae.tauschii and Ae.cylindrica exhibited specific bases,confirming trn H-psb A as the optimal identification sequence.This study provides a novel molecular approach for the rapid and accurate identification of these two quarantine weeds.