基于ITS2序列的三棱及其混伪品的分子鉴定

摘 要 目的：通过分析三棱及其混伪品的ITS2条形码序列,探索鉴定三棱及其混伪品的新方法。方法: 采集三棱及其混伪品共5个物种8个样本,并从Genbank网上下载三棱及其混伪品共6个物种23条ITS2序列,用MEGA5.0软件计算上述ITS2序列的种间、种内遗传距离,并构建系统发育树。结果: 三棱种内最大K2P距离为0.038,与混伪品种间最小K2P距离为0.697。由所构建的系统发育树可以看出,正品三棱的不同样品聚在一支,并能很好地与混伪品区分开。结论:ITS2条形码序列能够成功鉴定三棱与其混伪品,为三棱及其混伪品的鉴别提供了新的方法。     

市售覆盆子药材DNA条形码鉴定研究

目的基于ITS2条形码序列检测市场销售覆盆子药材,为保证覆盆子药材使用的正确性和安全性提供一种新的鉴定手段。方法获取掌叶覆盆子及其5种常见同属易混种ITS2序列,以及GenBank上下载的共计48条序列。使用Gene Tool软件分析ITS2序列长度,GC含量和变异位点等情况,利用Clustal X和MEGA 7.0软件计算遗传距离和构建邻接系统发育聚类树。同时随机检测24份市售覆盆子药材,利用中药材DNA条形码鉴定系统和构建邻接系统发育聚类树确定物种,鉴别真伪。结果掌叶覆盆子基原植物可与其同属易混种进行明显区分;市售药材中正品22份,伪品1份,混合物1份。结论基于ITS2序列的DNA条形码技术能够成功鉴定市场销售的掌叶覆盆子及其混伪品。     

基于高通量测序技术的9种铁线莲属药材混合粉末分子鉴定

目的 建立基于高通量测序技术的9种铁线莲属混合粉末分子鉴定方法。方法 采用高通量测序技术,对9种铁线莲属药材混合粉末样品中的总DNA经提取,对ITS2片段进行PCR扩增,利用IlluminaMiSeq平台对DNA片段进行双端测序,最后采用 FLASH、QIIME、GraPhlAn及 MEGA 7.0 软件对序列进行整理并聚类分析,鉴定混合粉末中的物种。结果 混合粉末样品中得到高质量的ITS2序列共496条,铁线莲属物种含有序列72条,比对出棉团铁线莲、女萎铁线莲、短尾铁线莲、灌木铁线莲、单叶铁线莲、黄花铁线莲、粗齿铁线莲等7个物种,未能比对出东北铁线莲和芹叶铁线莲。结论 以ITS2 作为条形码,采用高通量测序技术,可以鉴定出铁线莲属药材混合样品中的 7个物种,为混合药材的鉴定提供依据。     

基于DNA条形码ITS2序列对阿魏属药用植物的鉴别研究

目的:建立一种快速、准确和标准化的中药材阿魏属植物DNA条形码鉴别方法。方法:提取新疆阿魏(Ferula sinkiangensis K.M.Shen)和阜康阿魏(Ferula fukanensis K.M.Shen)基因组DNA,扩增ITS2序列并测序;运用分析相似性搜索法,下载Gen Bank数据库中阿魏属植物13个物种26个样本基因ITS2序列并进行比对分析,计算种间种内遗传距离并构建系统进化树进行聚类分析。结果:通过计算,15个物种遗传距离分布范围为0.009~0.230,平均遗传距离为0.018;聚类分析结果显示DNA条形码ITS2序列能够将阿魏属32种植物聚为不同的类。结论:建立的阿魏药材DNA条形码ITS2序列鉴别方法可准确、快速地鉴别出阿魏属药材的正品和混淆品。     

基于DNA条形码序列分析的5种菖蒲属药用植物鉴定

目的构建菖蒲属药用植物的鉴别方法。方法采用DNA条形码序列技术,对5种菖蒲属药用植物的4条候选DNA条形码序列(ITS2、rbc L、mat K、psb A-trn H)进行PCR扩增和测序,比较各序列的扩增和测序效率,对比分析种内、种间的遗传变异、分析barcoding Gap并构建聚类分析树。结果 4条候选DNA条形码序列PCR扩增和测序效率均为100%,ITS2序列对菖蒲属药用植物的鉴定成功率最高。结论基于ITS2序列的DNA条形码技术可以鉴定菖蒲属药用植物。     

ITS2+psbA-trnH复合序列鉴定徐长卿、白薇和白前

目的：建立以ITS2+psbA-trnH复合序列鉴定徐长卿、白薇和白前及其同属近缘混伪品的DNA条形码鉴定方法。方法：搜集徐长卿、白薇、白前及其近源混伪品,采用改良的CTAB法提取DNA,通过实验分别获得ITS2和psbA-trnH序列,将同一样本的ITS2序列与psbA-trnH序列整合得到43条ITS2+psbA-trnH复合序列,从GenBank数据库中下载来源于同一样本的ITS2序列与psbA-trnH序列整合得到14条ITS2+psbA-trnH 网上复合序列,用MEGA 6.05软件分析徐长卿、白薇、白前及其近源混伪品的复合序列变异位点,计算种内、种间的K2P距离,并构建NJ系统聚类树。结果：徐长卿、白薇和白前药材ITS2+psbA-trnH复合序列比对后产生17个变异位点;徐长卿、白薇和白前基源物种种内最大K2P距离均小于其与混伪品的种间最小K2P距离;系统NJ树能准确将徐长卿白薇和白前及其近缘混伪品。结论：该研究建立了应用ITS2+psbA-trnH复合序列鉴定徐长卿、白薇、白前及其近缘混伪品的DNA条形码鉴定方法。     

基于ITS序列分析技术鉴定川牛膝与常见伪品麻牛膝

目的:比较川牛膝与其常见伪品麻牛膝之间的ITS序列差异及规律。为川牛膝与麻牛膝的DNA条形码鉴别提供适合的分子标记。方法:收集川牛膝及麻牛膝成品药材并提取纯化其基因组DNA,经PCR扩增得到ITS序列(包括ITS1、5.8S nrDNA、ITS2)并进行T-A克隆后测序,分析两者序列差异。结果:PCR扩增获得两者ITS序列,经多序列对比分析得出川牛膝与伪品麻牛膝的ITS序列存在明显差异。结论:ITS序列分析可以用作鉴定川牛膝与麻牛膝药材。     

基于matK和ITS2及二级结构对药材香薷及其混伪品的鉴别研究

目的 快速、准确鉴别药材香薷及其混伪品，保障香薷的药材质量和用药安全。方法 收集石香薷、江香薷和香薷植物材料分别进行matK和ITS2序列的扩增与测序，测序结果经Codon Code Aligner软件校对，同时从GenBank下载石香薷、江香斋及其易混品种海州香薷、香薷、密花香薷、牛至等物种的matK和ITS序列。其中，ITS序列经隐马尔可夫模型去除两端的5.8S和28S序列，共得到16个物种的ITS2序列50条；经Clustal软件校对共获得9个物种的matK序列28条。通过Mega7.0软件分析matK和ITS2序列，计算所有物种种内和种间遗传距离，构建邻接法(neighbor joining，NJ)聚类树，通过ITS2 Database预测ITS2二级结构，采用4Sale软件比对二级结构，通过ProfDistS软件构建基于联合ITS2一级序列及其二级结构的剖面邻接(profile neighbor-joining，PNJ)系统发育树。结果 基于matK和ITS2序列的遗传距离均表明香薷正品与其各种混伪品之间存在明显barcoding gap。NJ和PNJ进化树的拓扑关系一致，可以区分药材香薷及其混伪品。香薷的ITS2二级结构与其各混伪品具有显著差异。结论 建议matK和ITS2序列均可以作为鉴别香薷与其混伪品的DNA条形码，ITS2二级结构信息的加入可丰富鉴定结果，为香薷药材的准确鉴别、香薷属与石荠苎属植物的科学分类提供参考。     

泉州“过饥草”类植物的种类调查与ITS2序列分析

目的 采集与鉴定泉州民间一类保胃药用植物“过饥草”(闽南语KèKi Chháu),并选用内转录间隔区2(Internal Transcribed Spacer 2,ITS2)序列作为条形码进行分析。方法 采集泉州区域内“过饥草”类植物样本,经传统形态学鉴定后,提取基因组DNA,测序各样本的ITS和ITS2区域。根据ITS2序列计算各样本间的遗传距离,构建邻接法系统进化树,并预测ITS2序列的二级结构,比较各个ITS2序列二级结构的差异。结果 获取了全部样本的ITS2序列,并将14株采集样本分属于8种植物。而基于ITS2序列的系统进化分析、二级结构比对分析与其形态学鉴定结果一致,可明显区分“过饥草”类植物的物种差异。结论 共梳理出8种“过饥草”类药用植物的物种信息,且ITS2序列可作为鉴别该类民间药用植物的有效条形码。     

重楼属药用植物DNA条形码鉴定研究

为评价DNA条形码候选序列对重楼属药用植物的鉴定作用, 探讨重楼属药用植物鉴定新方法, 本研究对重楼属11个物种17份样品的psbA-trnH、rpoB、rpoC1、rbcL、matK和核ITS2序列进行PCR扩增和测序, 比较各序列扩增和测序效率、种内和种间变异, 进行barcoding gap分析, 采用BLAST1和Nearest Distance方法评价不同序列的鉴定能力。结果显示, ITS2序列在所研究的重楼属药用植物中的扩增和测序效率均为100%, 其种内种间变异、barcoding gap与其他DNA条形码候选序列相比具有明显的优势, ITS2序列在重楼属中的鉴定成功率达到100%, 而生物条形码协会 (CBOL) 植物工作组推荐的matK和rbcL序列的鉴定成功率分别为52.9% 和5.9%, 二者联合鉴定能力没有提高, 对于ITS2序列扩大至29个物种67份样品依然具有100%的鉴定成功率。实验结果表明, ITS2序列能够准确鉴定重楼属药用植物, 可以作为潜在的药用植物通用条形码序列。     

基于ITS序列鉴别特色民族药材土牛膝及其混伪品的研究

目的:利用DNA条形码对特色民族药材土牛膝(粗毛牛膝、野生牛膝和柳叶牛膝)及其混伪品进行分子鉴定.方法:利用DNA条形码方法,分别对土牛膝及其混伪品的ITS和MatK基因片段进行扩增并双向测序,使用Codon?Code?Aligner软件对扩增序列进行拼接,用MEGA软件对数据比对分析,并基于K2P模型进行遗传距离分析...     

Identification of cortex herbs using the DNA barcode nrITS2

To discriminate the cortex herbs of Chinese Pharmacopoeia, the second internal transcribed spacer (ITS2) of ribosomal DNA of 51 samples belonging to 19 kinds of cortex herbs were analyzed in this paper. Sequence assembly was performed using the CodonCode Aligner. Phylogenetic study was performed using the molecular evolutionary genetics analysis (MEGA) 4.0 software in accordance with the Kimura 2-Parameter (K2P) model. Phylogenetic tree was constructed using the neighbor-joining (NJ) method. We found that the ITS2 sequences of the studied samples ranged from 207 to 256 bp in length and easy to be amplified. The intraspecific genetic distance of the cortex herbs was between 0 and 0.073, which was lower than their interspecific genetic distance (mean, 0.868; minimum, 0.101). In the cluster dendrogram, all the studied medicinal materials with several samples, were monophyletic. It is concluded that ITS2 barcode is suitable for the identification of cortex herbs of Chinese Pharmacopoeia, and it will play an important role in the field of identification of traditional Chinese medicine (TCM).     

Assessing product adulteration of Eurycoma longifolia (Tongkat Ali) herbal medicinal product using DNA barcoding and HPLC analysis

Context: Eurycoma longifolia Jack (Simaroubaceae) commonly known as Tongkat Ali is one of the most important plants in Malaysia. The plant extracts (particularly roots) are widely used for the treatment of cough and fever besides having antimalarial, antidiabetic, anticancer and aphrodisiac activities.

Objectives: This study assesses the extent of adulteration of E. longifolia herbal medicinal products (HMPs) using DNA barcoding validated by HPLC analysis.

Materials and methods: Chloroplastic rbcL and nuclear ITS2 barcode regions were used in the present study. The sequences generated from E. longifolia HMPs were compared to sequences in the GenBank using MEGABLAST to verify their taxonomic identity. These results were verified by neighbor-joining tree analysis in which branches of unknown specimen are compared to the reference sequences established from this study and other retrieved from the GenBank. The HMPs were also analysed using HPLC analysis for the presence of eurycomanone bioactive marker.

Results: Identification using DNA barcoding revealed that 37% of the tested HMPs were authentic while 27% were adulterated with the ITS2 barcode region proven to be the ideal marker. The validation of the authenticity using HPLC analysis showed a situation in which a species which was identified as authentic was found not to contain the expected chemical compound.

Discussion and conclusions: DNA barcoding should be used as the first screening step for testing of HMPs raw materials. However, integration of DNA barcoding with HPLC analysis will help to provide detailed knowledge about the safety and efficacy of the HMPs.     

DNA barcode and identification of the varieties and provenances of Taiwan’s domestic and imported made teas using ribosomal internal transcribed spacer 2 sequences

The major aim of made tea identification is to identify the variety and provenance of the tea plant. The present experiment used 113 tea plants [Camellia sinensis (L.) O. Kuntze] housed at the Tea Research and Extension Substation, from which 113 internal transcribed spacer 2 (ITS2) fragments, 104 trnL intron, and 98 trnL-trnF intergenic sequence region DNA sequences were successfully sequenced. The similarity of the ITS2 nucleotide sequences between tea plants housed at the Tea Research and Extension Substation was 0.379–0.994. In this polymerase chain reaction-amplified noncoding region, no varieties possessed identical sequences. Compared with the trnL intron and trnL-trnF intergenic sequence fragments of chloroplast cpDNA, the proportion of ITS2 nucleotide sequence variation was large and is more suitable for establishing a DNA barcode database to identify tea plant varieties. After establishing the database, 30 imported teas and 35 domestic made teas were used in this model system to explore the feasibility of using ITS2 sequences to identify the varieties and provenances of made teas. A phylogenetic tree was constructed using ITS2 sequences with the unweighted pair group method with arithmetic mean, which indicated that the same variety of tea plant is likely to be successfully categorized into one cluster, but contamination from other tea plants was also detected. This result provides molecular evidence that the similarity between important tea varieties in Taiwan remains high. We suggest a direct, wide collection of made tea and original samples of tea plants to establish an ITS2 sequence molecular barcode identification database to identify the varieties and provenances of tea plants. The DNA barcode comparison method can satisfy the need for a rapid, low-cost, frontline differentiation of the large amount of made teas from Taiwan and abroad, and can provide molecular evidence of their varieties and provenances.     

DNA barcode and identification of the varieties and provenances of Taiwan's domestic and imported made teas using ribosomal internal transcribed spacer 2 sequences

The major aim of made tea identification is to identify the variety and provenance of the tea plant. The present experiment used 113 tea plants [Camellia sinensis (L.) O. Kuntze] housed at the Tea Research and Extension Substation, from which 113 internal transcribed spacer 2 (ITS2) fragments, 104 trnL intron, and 98 trnL-trnF intergenic sequence region DNA sequences were successfully sequenced. The similarity of the ITS2 nucleotide sequences between tea plants housed at the Tea Research and Extension Substation was 0.379–0.994. In this polymerase chain reaction-amplified noncoding region, no varieties possessed identical sequences. Compared with the trnL intron and trnL-trnF intergenic sequence fragments of chloroplast cpDNA, the proportion of ITS2 nucleotide sequence variation was large and is more suitable for establishing a DNA barcode database to identify tea plant varieties. After establishing the database, 30 imported teas and 35 domestic made teas were used in this model system to explore the feasibility of using ITS2 sequences to identify the varieties and provenances of made teas. A phylogenetic tree was constructed using ITS2 sequences with the unweighted pair group method with arithmetic mean, which indicated that the same variety of tea plant is likely to be successfully categorized into one cluster, but contamination from other tea plants was also detected. This result provides molecular evidence that the similarity between important tea varieties in Taiwan remains high. We suggest a direct, wide collection of made tea and original samples of tea plants to establish an ITS2 sequence molecular barcode identification database to identify the varieties and provenances of tea plants. The DNA barcode comparison method can satisfy the need for a rapid, low-cost, frontline differentiation of the large amount of made teas from Taiwan and abroad, and can provide molecular evidence of their varieties and provenances.     

艾叶及其常见混伪品的分子鉴定

目的：对艾叶及其几种常见混伪品进行分子鉴定。方法：通过聚合酶链式反应（PCR）法直接测序,对艾及其8种混伪品进行核糖体DNA内转录间隔区片段2（ITS2）扩增并双向测序,所得序列经CodonCodeAligner拼接后,用系统发育软件MEGA4．0进行相关数据分析,同时利用邻接（NJ）法构建系统聚类树。结果：艾叶基原植物艾ITS2序列长度为225bp,种内平均Kimura．双参数（K2P）遗传距离（0．000）小于其与混伪品的种间平均K2P遗传距离（0．022）;由所构建的系统聚类树图可以看出,艾具有单系性,同时又与其他混伪品明显分开。结论：ITS2序列作为DNA条形码可以方便快捷地鉴别中药材艾叶及其混伪品,可为其质量评价及临床安全用药提供重要的分子鉴别依据。