紫苏属药用植物的rDNA ITS区SNP分子标记与位点特异性PCR鉴别

目的分析单种属——紫苏属各变种间rDNA ITS区的序列以及存在的单核苷酸多态性(SNP)现象，设计出位点特异性PCR引物，用于紫苏属各变种间的分子标记鉴别。方法对紫苏属各变种多个体的rDNA ITS区全序列进行了准确测定，运用Clustral X 1.8，MEGA 3.0进行排序并进行SNP分析，从而设计出鉴别各变种的等位基因位点特异性PCR鉴别引物。结果紫苏属各变种(紫苏、白苏、鸡冠苏和耳齿紫苏等)的rDNA ITS区全序列共有615～618 bp的长度，ITS1为233～235 bp，5.8S为179 bp，ITS2为203～204 bp，GC含量为61.5%～61.9%。从rDNA ITS区碱基变异的整体情况来看，紫苏属各变种间不仅在非编码的转录间隔区ITS1和ITS2内存在非编码区单核苷酸多态性(ncSNP)，而且在保守的5.8S编码区内也存在3个位点的单核苷酸多态性，即编码区SNP(cSNP)，所有的SNP均只具2等位多态性。5.8S区cSNP的出现与产生该变异的变种出现的显著形态差异关联。本文还利用这些SNP位点设计出了鉴别紫苏属各变种的位点特异性PCR引物，无需测序即可对紫苏属的原植物及“苏子”、“苏叶”等药材进行有效准确的分子鉴别。结论紫苏属药用植物rDNA ITS区存在的SNP可用作紫苏属各变种鉴别的分子标记。     

曲茎石斛及其近似种鉴别的形态和DNA分子证据

目的　探讨曲茎石斛(南阳居群)与同属近似种:细茎石斛(南阳居群)、霍山石斛(霍山居群)、铁皮石斛(天台居群)药材鉴别的形态及DNA分子证据。方法　对曲茎石斛(南阳居群)及其近似种的药材进行了外部形态和rDNA ITS序列比较。结果　曲茎石斛及其近似种药材的外部形态虽无明显区别,但在rDNA ITS序列上却存在着显著而稳定的差异。曲茎石斛(南阳居群)与铁皮石斛(天台居群)的rDNA ITS序列的差异最小,绝对遗传距离为7;但与细茎石斛(南阳居群)及霍山石斛(霍山居群)rDNA ITS区的差异较大,绝对遗传距离分别为40和42。在rDNA ITS区域中,作者共挑选了7个碱基位点用作鉴别曲茎石斛(南阳居群)及其近似种的DNA证据。结论　根据药材的形态特征及rDNA ITS区碱基序列差异,可准确鉴别曲茎石斛及其近似种药材。     

覆盆子及其近缘混淆品的PCR-RFLP鉴别研究

目的 建立一种覆盆子特异性的分子鉴别方法。方法 通过对覆盆子及其混淆品的ITS序列进行测序分析，根据差异位点设计限制性内切酶，采用聚合酶链反应-限制性片段长度多态性方法（polymerase chain reaction restriction fragment length polymorphism，PCR-RFLP）进行鉴别，建立并优化PCR鉴别方法，并对其稳定性和适用性进行考察与验证。结果 设计的引物可实现对覆盆子及其混淆品序列的扩增，扩增产物为800 bp大小的条带，通过对限制性内切酶MboI进行酶切后的片段长度进行分析，仅覆盆子的序列可被酶切形成2个片段，而混淆品的序列不能被切开，从而特异性鉴别是否为覆盆子。结论 本实验建立的PCR-RFLP方法可用于鉴别覆盆子。     

枫斗类石斛rDNA ITS区的全序列数据库及其序列分析鉴别

目的建立枫斗类石斛的rDNA ITS区碱基全序列数据库,利用该数据库对枫斗类石斛待检种进行准确鉴别。方法对枫斗类石斛的rDNA ITS区进行了PCR扩增、测序,运用CLUSTRAL,MEGA等软件以及枫斗类石斛rDNA ITS区全序列数据库对待检种rDNA ITS区进行序列分析鉴别。结果建立了21种枫斗类石斛的rDNA ITS区全序列数据库, 枫斗类石斛在该区的种间差异显著而稳定,转换和颠换总数为11～122,变异位点数为341,信息位点数为195。与外类群植物云南石仙桃间的差异较大,转换和颠换总数为131～161。枫斗类石斛居群间的差异较小,转换和颠换总数为0～6。结论利用枫斗类石斛的全序列数据库及遗传分析软件,通过对待检种rDNA ITS区进行序列测定,可以成功鉴别属于数据库中枫斗类石斛的待检种。     

基于rDNA ITS序列SNP位点的特异性聚合酶链反应引物鉴别青椒和花椒

目的设计专用于花椒与青椒鉴别的特异性聚合酶链反应(PCR)引物,建立花椒与青椒的分子鉴别方法。方法本研究提取花椒与青椒样品的DNA,并利用rDNA ITS(核糖体DNA内部转录间隔区)序列通用型引物分别对样品进行PCR扩增,PCR产物经双向测序、比对,寻找单核苷酸多态性(SNP)特异性位点,并分别针对花椒与青椒的SNP位点设计出花椒与青椒的特异性PCR引物,用于花椒与青椒的特异性PCR引物鉴别。结果所设计的特异性引物为花椒和青椒的鉴别提供了分子鉴定的依据,可以快速、准确地检测出花椒和青椒。结论本文所设计的特异性PCR引物能有效地鉴别出花椒与青椒,该方法具有准确、高效、灵敏、简便等特点,具有较好的市场应用前景。     

球花石斛的位点特异性PCR鉴别研究

为建立球花石斛的DNA分子标记鉴别方法，本文根据测定及GenBank上登录的109种共计164个石斛样本的rDNA ITS序列，设计了特异性鉴别引物QH-JB1 和QH-JB2，并对球花石斛进行了位点特异性PCR鉴别研究。结果表明，当复性条件为63.5 ℃，1 min时，只有球花石斛的模板DNA能被扩增出约300 bp的阳性扩增带，而其他种石斛均为阴性。证明用本法鉴别球花石斛简便、省时，也适用于干燥球花石斛药材的鉴别，具有广泛的应用前景。     

冬虫夏草与其他品系虫草及其混伪品的18S rRNA基因测序鉴别研究

目的从分子水平鉴别冬虫夏草与其他品系虫草及其混淆品虫草。方法从冬虫夏草与其他品系虫草及其混淆品虫草中提取DNA;采用核糖体基因(rDNA)测序,设计18S基因特异性引物进行扩增,扩增产物经纯化后,直接测序法进行测序。结果测序得到各样品18S序列,冬虫夏草与西藏白草、西藏黑草、无头草、默勒草的18S序列相似度为100%;与亚香棒的18S序列相似度为91.37%;与北虫草的18S序列相似度为91.74%。结论 18S序列可有效地鉴别冬虫夏草及其混淆品北虫草和亚香棒虫草。     

基因测序技术在中药质量研究中的应用（Ⅰ）——山东郓城猴头半夏基原的DNA测序鉴别

目的：分析半夏Pinellia ternata(Thunb.)Breit.及其伪品虎常南星Pinellia pedatisecta Schott的核基因组序列,为半夏正品基原鉴别提供分子依据。方法：采用PCR直接测序技术测定半夏及其伪品的18S rRNA基因核苷酸序列并作序列变异和选择性内切酶谱（PCR－SR）分析。结果：半夏和伪品的18S rRNA序列长度均为1805bp,根据排序比较,半夏原植物与商品药材间的序列完全相同,虎掌南星亦如此。而半夏与其伪品虎掌南星间则存在序列差异（有4个变异位点）。在半夏18S rRNA序列中有一个限制性内切酶Ase Ⅰ识别位点,通过PCR－SR图谱显示800bp和900bp2个酶切片断,而虎掌南星则无此位点,PCR－SR图谱显示1个未消化的1800bp片断。结论：通过核基因组序列和PCR－SR图谱差异DNA测序技术可成为半夏正品基原鉴别准确而有效的分子方法。     

曲茎石斛及其近似种鉴别的形态和DNA分子证据

目的　探讨曲茎石斛 (南阳居群 )与同属近似种 :细茎石斛 (南阳居群 )、霍山石斛 (霍山居群 )、铁皮石斛(天台居群 )药材鉴别的形态及DNA分子证据。方法　对曲茎石斛 (南阳居群 )及其近似种的药材进行了外部形态和rDNAITS序列比较。结果　曲茎石斛及其近似种药材的外部形态虽无明显区别 ,但在rDNAITS序列上却存在着显著而稳定的差异。曲茎石斛 (南阳居群 )与铁皮石斛 (天台居群 )的rDNAITS序列的差异最小 ,绝对遗传距离为 7;但与细茎石斛 (南阳居群 )及霍山石斛 (霍山居群 )rDNAITS区的差异较大 ,绝对遗传距离分别为 4 0和 4 2。在rDNAITS区域中 ,作者共挑选了 7个碱基位点用作鉴别曲茎石斛 (南阳居群 )及其近似种的DNA证据。结论　根据药材的形态特征及rDNAITS区碱基序列差异 ,可准确鉴别曲茎石斛及其近似种药材。     

不同产地蒺藜核糖体DNA内转录间隔区序列分析

目的通过测定核糖体DNA内转录间隔区(Ribosomal DNA internal transcribed spacer,rDNA-ITS)基因序列,确定不同产地的蒺藜在种质遗传上是否存在差异。方法利用PCR产物直接测序,测定不同产地蒺藜的rDNA-ITS基因序列。结果测得ITS碱基序列742 bp,其中ITS1全部序列267 bp,5.8 S全部序列167bp,ITS2全部序列209 bp。6个产地的蒺藜样品的ITS的碱基序列完全相同。结论不同地区的蒺藜在种质上没有发生变异。     

Authentication of stems of Dendrobium officinale by rDNA ITS region sequences

The rDNA ITS regions of five Dendrobium species were sequenced. Each Dendrobium species was found to have a unique sequence in the ITS region, so that they could be easily distinguished at the DNA level. The aligned 644 bp of the ITS region includes 235 bp ITS1, 163 bp 5.8S, and 246 bp ITS2. One hundred and eighty-nine sites are variable. The sequences of D. officinale could be easily distinguished from the other four adulterant species according to the sequence variation at 11 sites, 7 in ITS1, 1 in 5.8S, and 3 in ITS2. These could be used as molecular characters to distinguish the stems of D. officinale from the adulterants.     

基于ITS2序列鉴别维吾尔药材薰衣草及其混伪品

建立了基于ITS2序列鉴别维吾尔药材薰衣草及其混伪品(全叶青兰和夏枯草)的方法。对维吾尔药材薰衣草及其混伪品的ITS2序列进行PCR扩增和双向测序,使用CodonCode Aligner软件对测序峰图进行序列拼接,用MEGA 6.0软件对拼接后的序列进行多重比对。并计算种内、种间遗传距离,构建NJ系统聚类树,预测其ITS2二级结构。结果表明,经PCR扩增测序后,18份维吾尔药材薰衣草药材ITS2序列比对无差异,序列长度均为235 bp,GC含量为67.23%~69.36%;9份全叶青兰药材序列长度均为218 bp,GC含量为66.21%~69.51%;9份夏枯草药材序列长度均为234 bp,GC含量为66.24%~67.09%。并且维吾尔药材薰衣草的种内遗传距离明显小于种间遗传距离。ITS2序列可作为鉴定维吾尔药材薰衣草及其混伪品的DNA条形码,为维吾尔药材薰衣草的用药安全提供有效的科学技术手段。     

Molecular authentication of the traditional Tibetan medicinal plant Swertia mussotii

Swertia mussotii is an important species in Tibetan folk medicine. However, it is quite expensive and frequently adulterated, so reliable methods for authentication of putative specimens and preparations of the species are needed to protect consumers and to support conservation measures. We show here that the chloroplast (cp) DNA RPL16 intron has limited utility for differentiating S. mussotii from closely related species, since the cpDNA RPL16 sequences are identical in S. mussotii and two other species of Swertia. However, the rDNA internal transcribed spacer (ITS) sequences differ significantly between S. mussotii and all of 13 tested potential adulterants. Thus, the ITS region provides a robust molecular marker for differentiating the medicinal S. mussotii from related adulterants. Therefore, a pair of allele-specific diagnostic primers based on the divergent ITS region was designed to distinguish S. mussotii from the other species. Authentication by allele-specific diagnostic PCR using these primers is convenient, effective and both simpler and less time-consuming than sequencing the ITS region.     

Differentiation of medicinal Codonopsis species from adulterants by polymerase chain reaction-restriction fragment length polymorphism

DNA sequence analysis of rDNA internal transcribed spacer (ITS) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were exploited for their applications in differentiating medicinal species Codonopsis pilosula, C. tangshen, C. modesta, and C. nervosa var. macrantha, from two related adulterants Campanumoea javania and Platycodon grandiflorus. The data demonstrated that the rDNA ITSI and ITSII sequences of the four Codonopsis are highly homologous but not identical, and are significantly different from those of the two adulterants. The sequence difference allows effective and reliable differentiation of Codonopsis from the adulterants by PCR-RFLP.     

Authentication of an endangered herb <Emphasis Type="Italic">Changium smyrnioides</Emphasis> from different producing areas based on rDNA ITS sequences and allele-specific PCR

The rDNA ITS region of 18 samples of Changium smyrnioides from 7 areas and of 2 samples of Chuanminshen violaceum were sequenced and analyzed. The amplified ITS region of the samples, including a partial sequence of ITS1 and complete sequences of 5.8S and ITS2, had a total length of 555 bp. After complete alignment, there were 49 variable sites, of which 45 were informative, when gaps were treated as missing data. Samples of C. smyrnioides from different locations could be identified exactly based on the variable sites. The maximum parsimony (MP) and neighbor joining (NJ) tree constructed from the ITS sequences based on Kumar’s two-parameter model showed that the genetic distances of the C. smyrnioides samples from different locations were not always related to their geographical distances. A specific primer set for Allele-specific PCR authentication of C. violaceum from Jurong of Jiangsu was designed based on the SNP in the ITS sequence alignment. C. violaceum from the major genuine producing area in Jurong of Jiangsu could be identified exactly and quickly by Allele-specific PCR.     

Molecular authentication of the traditional Chinese medicinal plant Euphorbia pekinensis

The ITS regions of Euphorbia pekinensis and six other Euphorbia species used as adulterants of E. pekinensis were sequenced to differentiate them. The sequences are identical among the individuals in the seven species studies. Diversity in DNA sequences among various species was found ranging from 8.3% to 43.8% in ITS1 and 7.6% to 36.6% in ITS2 region. Furthermore, based on the divergent ITS regions, species-specific primers, JDJp 1 and JDJp 2, were designed in the polymorphic regions of E. pekinensis to distinguish it from adulterants. These ITS-derived primers amplified a 281-bp-specific DNA fragment from E. pekinensis. No amplified product was observed using DNA of six adulterants.     

中国不同地区蛇床的rDNA ITS序列分析

目的：探讨不同分布区的蛇床Cnidium monnieri的ITS序列变异与其地理分布和化学成分的相关性。方法：设计2对引物,Pf+Pb及P5.8S ITS1+P5.8S ITS2,PCR扩增产物纯化后用银染法或ABI 310测序。结果：得到核糖体DNA中的ITS及5.8S rDNA完全序列,18S和26S rDNA部分序列,共约700 bp。5个地点样品的ITS-1及ITS-2的序列大小分别为210～217 bp和219～224 bp。ITS-1碱基序列的遗传距离0.00～1.93%,ITS-2碱基序列的遗传距离0.46～2.34%,ITS-1较为保守。以NJ法根据ITS-2序列数据重建系统发生树。哈尔滨样品聚为一组,衡水与德州样品和郑州与高淳样品各自聚为一组。结论：ITS-2序列的变异与中国产蛇床的纬度分布相关,而其与蛇床化学型的关系尚需作进一步研究。