蓼属头状蓼组rDNA-ITS的序列扩增及分析

以贵州境内蓼属头状蓼组6种(含1变种)植物为材料,对其rDNA的内转录间隔区(ITS)序列进行PCR扩增,得到6种植物的ITS序列,分别为:赤胫散2个居群(Polygonum runcinatum var.sinense,GenBank登录号FJ606887、FJ648802),平卧蓼(P.strindbergii,GenBank登录号FJ648803 ),尼泊尔蓼(P.nepalense,GenBank登录号FJ648804),羽叶蓼(P.runcinatum,GenBank登录号FJ648805),火炭母(P.chinense,GenBank登录号FJ648806)和头花蓼(P.capitatum,GenBank登录号FJ648807).其中赤胫散与平卧蓼的ITS序列为首次报道.序列分析结果表明,蓼属头状蓼组6种植物ITS序列总长度为661～666 bp,ITS1区序列长度为243～246 bp,5.8 S rDNA区序列长度165 bp,ITS2区序列长度253～258 bp,6种植物的差异主要集中在ITS1和ITS2区.聚类分析显示,6种头状蓼组植物具有共同起源,结果支持赤胫散从羽叶蓼变种上升为独立物种.     

两栖蓼的分子系统学研究

两栖蓼是一种水陆两栖植物,植株在不同生态环境下外部形态差异较大,同时两栖蓼的系统位置存在争议,被归入春蓼组(sect.Persicaria)或提升为两栖蓼组(sect.Amphibium)。该文选取两栖蓼及春蓼组植物12种,以及刺蓼组、头状蓼组、神血宁组、拳参组、萹蓄组和外类群掌叶大黄共23种植物进行研究。植物总DNA的提取采用改进的CTAB法,所测序列以及从Genbank数据库下载的序列,以掌叶大黄为外类群,采用最大简约法和贝叶斯法对核糖体ITS序列和叶绿体trn L-F序列进行了系统发育分析。ITS序列对位排列的长度为735 bp,包括489个可变位点,272个位点是信息位点。简约法得到9个简约树,步长为1 084,CI指数为0.680,RI指数为0.614。trn L-F序列对位排列的长度为1 121 bp,包括427个可变位点,239个位点是信息位点。简约法寻找到9个简约树,步长为551(CI=0.911,RI=0.910)。贝叶斯法和简约法得到的树基本一致。分子序列分析结果显示,trn L-F序列树类似于ITS序列树。ITS序列构建的发育树上,两栖蓼与刺蓼组植物、春蓼组其他植物形成3个并列的分支;在trn L-F序列树上,两栖蓼则与其他春蓼组植物形成两个并列的分支。由此可见,两栖蓼与春蓼组其他植物的亲缘关系较远,成一独立的分支。两个分子证据支持将两栖蓼提升为两栖蓼组的处理意见。此外,两栖蓼的花粉具散沟,与典型的春蓼组的具散孔花粉不一致。再加上两栖蓼水陆两栖的特性,因此支持把两栖蓼提升为两栖蓼组的观点。两栖蓼组的界定为多年生草本,水陆两栖,根状茎横生,生于水中茎漂浮,叶长圆形或椭圆形,生于陆地茎直立,叶披针形或长圆状披针形,托叶鞘为筒状、薄膜质,总状花序穗状,瘦果近圆形,花粉具散沟。     

基于trnL-F序列探讨杠板归Polygonum perfoliatum的系统位置

杠板归（Polygonum perfoliatum L．）的系统位置一直存在争议,文中以塔黄为外类群,采用最大简约法对杠板归及其近缘类群的trnL-F序列进行了系统发育分析,结果表明：（1）杠板归和刺蓼为姊妹群,自展分析的支持率为99％,分子证据支持杠板归归人刺蓼组,而没有必要单立组或属。（2）刺蓼组、春蓼组和头状蓼组植物聚在一起,自展支持率为100％,说明它们之间有很近的亲缘关系。     

基于ITS序列探讨金线草的系统学位置

金线草的系统位置一直存在争议,该试验以Triplaris weigeltiana为外类群,采用最大简约法对金线草及其近缘类群的ITS序列进行了系统发育分析.结果表明:(1)金线草和蓼属的春蓼组、刺蓼组形成三个并列的分支,因此,金线草没有必要独立成属,分子证据支持金线草成立为组;(2)金线草和春蓼组、刺蓼组植物聚在一起,...     

对翼蓼(蓼科)属级位置的重新探讨

通过对翼蓼Pteroxygonum giraldii Damm. &; Diels及相关属(蓼属Polygonum、何首乌属Fallopia、虎杖属Reynoutria、荞麦属Fagopyrum和金线草属Antenoron)的形态观察、果实解剖学观察、花被片脉序观察、花粉形态、核型分析, 以及ITS序列的分析确定了翼蓼和荞麦F. esculentum Moench较远的亲缘关系。其中我们发现翼蓼果实基部有三个角状物明显不同于其他属果实的形态特征。翼蓼外果皮明显加厚, 并有零星散布的波状内腔, 而荞麦的外果皮很薄, 细胞不等径, 中果皮极厚。以上证据证明了翼蓼与荞麦属亲缘关系较远。在观察荞麦属和翼蓼的花被片脉络时发现了两种不同的脉序类型, 符合将荞麦属分为两个组的划分。翼蓼花被片脉序为三出状, 支持将翼蓼归为Persicarieae族。对翼蓼及荞麦属植物的花粉进行比较后, 发现荞麦属植物的花粉网孔有明显的内凹穿孔而翼蓼却没有, 结果表明二者亲缘关系较远。通过对nrDNA ITS区域序列分析得出翼蓼及相关属为一个单系类群, 含有两个稳定的分支: 第一个分支由蓼属(萹蓄组sect. Avicularia)、何首乌属、虎杖属的植物组成, 第二个分支由蓼属(刺蓼组sect. Echinocaulon、蓼组sect. Polygonum、分叉蓼组sect. Aconogonon、拳参组sect. Bistorta、翼蓼和荞麦属植物组成。同时第二个分支又分成了两个亚分支, 蓼属(刺蓼组、蓼组、分叉蓼组、拳参组)和翼蓼属Pteroxygonum植物属于第一个亚支而荞麦属植物属于第二个亚支。结果支持翼蓼不属于荞麦属的范畴。实验结果显示翼蓼是个单型属, 属于Persicarieae族。     

基于核糖体DNA内转录间隔区ITS序列的广义蓼属及近缘属分子系统学研究(英文)

通过对广义蓼属及近缘属共32个代表种内转录间隔区ITS序列的分子系统学分析,尝试研究备受争议的广义蓼属及近缘属的物种族、属、组级的划分问题,结果显示,广义蓼属在系统发育树上并不能形成一个单系类群,这些物种共聚为3大支,分别对应春蓼族、蓼族及荞麦族,其中荞麦属与翅果蓼属形成了一支独立于春蓼族及蓼族之外的类群。在春蓼族中,冰岛蓼属与分叉蓼组形成一个单系类群。     

基于核糖体DNA内转录间隔区ITS序列的广义蓼属及近缘属分子系统学研究

通过对广义蓼属及近缘属共32个代表种内转录间隔区ITS序列的分子系统学分析,尝试研究备受争议的广义蓼属及近缘属的物种族、属、组级的划分问题,结果显示,广义蓼属在系统发育树上并不能形成一个单系类群,这些物种共聚为3大支,分别对应春蓼族、蓼族及荞麦族,其中荞麦属与翅果蓼属形成了一支独立于春蓼族及蓼族之外的类群。在春蓼族中,冰岛蓼属与分叉蓼组形成一个单系类群。     

基于叶绿体trnL-F,rbcL序列和核核糖体ITS序列探讨蓼属（蓼科）头状蓼组的系统发育

选用叶绿体基因trnL-F,rbc-L序列和核核糖体ITS序列对蓼属头状蓼组的分类和系统发育进行了分析。以药用大黄为外类群,用最大简约法对3个片段的单独和联合矩阵分别构建系统发育树。结果表明,头状蓼组是一个较自然的类群,与春蓼组、刺蓼组和金线草属的亲缘关系较近;支持头状蓼组作为一组放在春蓼属,细茎蓼和蓝药蓼从头状蓼组转移至冰岛蓼属;不支持将刺蓼组并入头状蓼组;对于小叶蓼的系统学位置有待于进一步研究。     

中国冰岛蓼属植物花粉形态的研究

采用光学显微镜和扫描电镜对国产冰岛蓼属Koenigia L. 9种植物的花粉形态进行了观察。结果表明：花粉均为球形;直径为17.0-32.5 μm（包括刺长）;萌发孔有7(-8)赤道环沟、散沟、散孔;外壁纹饰均为刺状。根据萌发孔类型和外壁纹饰,将该属花粉划分为3种类型,即细冰岛蓼型（Delicatulum-type）、大连线冰岛蓼型（Forrestii-type）及冰岛蓼型（Koenigia-type）。细冰岛蓼型花粉的主要特征是具7(-8)赤道环沟,覆盖层无穿孔,外壁纹饰为显著的长刺状,此种类型的植物有细冰岛蓼K. delicatula （Meisn.） Hara。大连线冰岛蓼型花粉的主要特征是具12散沟,覆盖层无穿孔,外壁纹饰为显著的长刺状,此种类型的植物有大连线冰岛蓼K. forrestii (Diels) Měsíek & Soják 及连线冰岛蓼K. nummularifolia (Meisn.) Měsíek & Soják。冰岛蓼型花粉的主要特征是具15,20(-30)散孔,覆盖层无穿孔,外壁纹饰为显著的长刺状,此种类型的植物有冰岛蓼K. islandica L.、蓝蕊冰岛蓼K. cyanandra (Diels) Měsíek & Soják、线茎冰岛蓼K. nepalensis D. Don、柔毛蓼K. pilosa Maxim.、陕甘蓼K. hubertii (Lingelsh.) Měsíek & Soják及青藏蓼K. fertilis Maxim.。结果表明冰岛蓼属的花粉形态具有重要的分类学意义,研究结果支持Koenigia的属的地位,大铜钱叶蓼Polygonum forrestii Diels和铜钱叶蓼P. nummularifolium Meisn.应从蓼属分叉蓼组Polygonum L. sect. Aconogonon Meisn.中移入冰岛蓼属中,细冰岛蓼、蓝蕊冰岛蓼、青藏蓼、陕甘蓼、线茎冰岛蓼和柔毛蓼应从蓼属头状蓼组Polygonum L. sect. Cephalophilon Meisn.中移入冰岛蓼属中。     

基于trnL-F序列推测冰岛蓼属的系统发育

冰岛蓼属的界定一直存在争议,本实验以塔黄为外类群,采用最大简约法对冰岛蓼属及其近缘类群的trnL-F序列进行了系统发育分析,结果表明:(1) 冰岛蓼(Koenigia islandica)和大铜钱叶蓼(Polygonum forrestii)为姊妹群,自展分析的支持率为100%,因此,大铜钱叶蓼应归于冰岛蓼属;(2) 冰岛蓼和分叉蓼组植物聚在一起,自展支持率为99%,说明它们之间有很近的亲缘关系.     

山姜属中药草豆蔻和益智nrDNA ITS区序列的测定

中药草豆蔻、益智的原植物分别为山姜属草豆蔻（Ａｌｐｉｎｉａ ｈａｉｎａｎｅｎｓｉｓ Ｋ．Ｓｃｈｕｍ．）与益智（Ａ．ｏｘｙｐｈｙｌａ Ｍｉｑ．）。本文采用ＰＣＲ直接测序法,首次测定了它们的核糖体ＤＮＡ ＩＴＳ区序列。结果显示,两者序列长度（ＩＴＳ１＋ＩＴＳ２）分别为４０３ｂｐ与４０４ｂｐ,序列间具有２７个变异位点（包括５．８Ｓ编码区）。本研究为山姜属中药材的ＤＮＡ分子鉴定提供了必要的序列资料。     

不同产区太子参的rDNA ITS区序列的比较

使用1对引物18SPl和26SP2对采自14个产区的太子参[Pseudostellaria heterophylla(Miq．)Pax ex Pax et Hoffm．]进行ITS基因的PCR扩增和测序。序列分析结果表明,14个产区太子参的ITSl片段长度为219—222bp,ITS2片段长度为235～236bp,5．8S片段长度为155—157bp.除江苏宜兴,江苏句容马梗,江苏南京老鹰山和江苏溧阳等4个产区的ITS序列碱基完全一致外,其他10个产区的ITS序列则有不同的变异,碱基变异数目(包括5．8S编码区)为1—17个。使用UPGMA法重建系统发生树,从分子生物学角度说明了它们的变异程度,为利用ITS区序列的差异鉴别不同产区的太子参提供了依据。     

中药乌头及其近缘种的rDNA—ITS序列分析

运用PCR扩增产物直接测序的方法对云南、安徽的乌头及其近缘种植物的ITS区碱基序列测定。表明核糖体DNA中ITS区的完整序列（包括ITS1,ITS2和5．8s）,4种乌头属植物的ITS1序列长度为249bp,云南鸟头和安徽乌头及黄山鸟头ITS2序列长度为189bp,赣皖乌头ITS2序列长度为217bp。运用Mega2软件进行系统分析得到系统进化树。ITS序列特征是乌头鉴别的有效分子标记。     

国产“水山姜”的分类学研究—来自核糖体DNA ITS区序列的证据

用直接测序法对国产黑果山姜Alpinia nigra(Gaertn.)Burtt以及“水山姜Alpinia aquatica (Koen.)Rose”。的核糖体DNA中的内转录间隔区（ITS）序列进行了测定,结果显示两者序列完全一致;ITS1长度为178bp,ITS2长度为232bp,5.8S编码区长度为164bp,GC含量为56.9%,形态学特征结合DNA分子证据,认为《中国植物志》记载的水山姜实为黑果山姜。     

Nucleotide sequence of the 17S–25S spacer region from rice rDNA

Summary The nucleotide sequence of a spacer region between rice 17S and 25S rRNA genes (rDNAs) has been determined. The coding regions for the mature 17S, 5.8S and 25S rRNAs were identified by sequencing terminal regions of these rRNAs. The first internal transcribed spacer (ITS1), between 17S and 5.8S rDNAs, is 194–195 bp long. The second internal transcribed spacer (ITS2), between 5.8S and 25S rDNAs, is 233 bp long. Both spacers are very rich in G+C, 72.7% for ITS1 and 77.3% for ITS2. The 5.8S rDNA is 163–164 bp long and similar in primary and secondary structures to other eukaryotic 5.8S rDNAs. The 5.8S rDNA is capable of interacting with the 5′ terminal region of 25S rDNA.     

帘蛤科贝类rDNA内转录间隔区序列的研究

根据18SrDNA、5．8SrDNA和28SrDNA保守序列设计引物,应用聚合酶链式反应（PCR）扩增了文蛤（Meretrix meretrix L．）、青蛤（Cyclina sinensis G）、硬壳蛤（Mercenaria mercenaria L．）和江户布目蛤（Protothaca jedoensis L．）4种帘蛤科贝类的第一内转录间隔区（ITS1）和第二内转录间隔区（ITS2）序列,并进行了测序。结果表明,文蛤、青蛤、硬壳蛤和江户布目蛤的ITS1扩增产物大小分别为978bp、663bp、757bp和942bp,GC含量分别为61．55％、60．78％、62．48％和64．86％～64．97％,其中ITS1序列长度分别为900bp、585bp、679bp和864bp,是迄今已报道双壳贝类中变化范围最大的,GC含量分别为61．67％、61．03％、63．03％和65．51％～65．62％,江户布目蛤种内ITS1序列有个体差异;ITS2扩增产物大小分别为644bp、618～620bp、593bp和513～514bp,GC含量分别为61．18％、61．29％～61．81％、62．73％和61．48％61．60％,其中ITS2序列长度分别为412bp、386～388bp、361bp和281～282bp,GC含量分别为65．29％、65．21％～66．06％、67．87％和67．38％～67．62％,青蛤和江户布目蛤种内ITS2序列有个体差异。4种蛤ITS1和ITS2序列种间差异很大,有明显的长度多态性,ITS2种间序列相似度73．0％～89．1％,与ITS1的种间序列相似度48．7％～81．5％相比略高。此外,在4种蛤ITS1和ITS2序列中各发现2个与rRNA加工有关的保守区。通过对ITS1和ITS2序列的组装获得了4种蛤5．8SrRNA基因完整序列,序列长度都是157bp,GC含量57．96％～58．60％,4种蛤5．8SrRNA基因相对保守,种间序列差异度0-6．0％,共有10个变异位点,其中转换4处,颠换6处,硬壳蛤和江户布目蛤5．8SrRNA基因序列完全相同。以ITS2序列（包含5．8SrRNA和28SrRNA基因部分序列）为标记,调用北极蛤科的Arctica islandica相应序列数据作外群,构建了帘蛤科贝类的系统发育树,其拓扑结构显示江户布目蛤与硬壳蛤亲缘关系最近,青蛤与其他3物种的亲缘关系最远。     

A phylogenetic study ofPolygonum sect.Tovara (Polygonaceae) based on ITS sequences of nuclear ribosomal DNA

Polygonum sect.Tovara comprises three morphologically very similar species;P. virginianum,P. filiforme, andP. neofiliforme. Sequences of internal transcribed spacers (ITSs) of nuclear ribosomal DNA of these were determined to examine phylogenetic relationships and the levels of differentiation among them. The size of ITS 1 was 241 bp inP. filiforme andP. neofiliforme, and 242 bp inP. virginianum. The size of ITS 2 was 243 bp, and that of the 5.8S rRNA coding region was 163 bp. The ITS sequences clearly separate North AmericanP. virginianum from the eastern Asian species. Nucleotide divergence between them ranges from 3.3% to 3.8% for ITS 1 and from 9.3% to 10.7% for ITS 2. The molecular data also revealed that two eastern Asian species are closely related but should be treated as distinct species.     

Comparative study on DNA sequences of ribosomal DNA and cytochrome c oxidase subunit 1 of mitochondrial DNA among five species of gnathostomes

The nucleotide sequences of partial 18S, complete internal transcribed spacer region 1 (ITS1), complete 5.8S, complete ITS2 and partial 28S of ribosomal DNA (rDNA) and cytochrome c oxidase subunit 1 of mitochondrial DNA (MCOI) from five species of gnathostomes (G. spinigerum, G. doloresi, G. nipponicum, G. hispidum and G. binucleatum with the former four species being distributed in Japan and Asia) that cause human gnathostomiasis were compared by direct polymerase chain reaction cycle-sequencing. The nucleotide sequences of each region of the18S (613 bp), 5.8S (158 bp) and 28S (598 bp) rDNA from the five species were almost identical. The ITS1 region was different in length for the five species. The nucleotide sequences of each region of ITS2 and partial MCO1 regions were different among the five species. Therefore, these two regions can be used as genetic markers for identification of worms.     

Length Variation of the Nuclear Ribosomal DNA Internal Transcribed Spacer in the Genus Abies,with Reference to Its Systematic Utility in Pinaceae

The internal transcribed spacer (1TS) region (1TS1, ITS2 and 5.8S rDNA) of the nuclear ribosomal DNA (nrDNA) was amplified via PCR in 28 taxa of Abies Mill. The amplified fragments showed length polymorphism among species, with species from Central America and two species from North America having a length of approximately 2 500 base pairs (bp) and the remaining taxa having a length of approximately 1 700 bp based on 100 bp and 1 kb ladder standard markers. The complete sequencing of ITS of Abies bracteata showed that the shorter type is 1 697 bp (1TS1 is 1 296 bp, 5.8S + 1TS2 is 401 bp). For the longer one, the partial rrs1 and complete 5.8S + ITS2 sequencing revealed that thelength of 5.8S + ITS2 is the same as that of the shorter type. The length difference of ITS in Abies is mainly due to the length difference in the ITS1 region, a result similar to the previous findings in other genera of Pinaceae. Variation in ITS length seems well correlated with morphological and geographic characters in Abies, suggesting that the length variation may be a phylogenetically informative character within the genus, long ITS was also found in other genera of Pinaceae in the previous studies. The long length of ITS in the family makes the sequencing of the region and subsequent alignment of sequences among species or genera more difficult than in taxa with short ITS, such as angiosperms. Although the length variation of ITS in the genus Abies is significant, the homogenous of ITS sequence between the longer one and the shorter one is obvious if the insertion in the longer ITS is ignored.     

A Conserved Motif in the 5.8S Ribosomal RNA (rRNA) Gene is a Useful Diagnostic Marker for Plant Internal Transcribed Spacer (ITS) Sequences

The nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) region has become an important nuclear locus for molecular systematic investigations of angiosperms at the intergenic and interspecific levels. Universal PCR primers are positioned on the conserved rRNA genes (18S, 5.8S, 26S) to amplify the entire ITS spacer region. Recent reports of fungal and algal contaminants, first described as plant ITS sequences, stress the need for diagnostic markers specific for the angiosperm ITS region. This report describes a conserved 14 base pair (bp) motif in the 5.8S rRNA gene that can be used to differentiate between flowering plants, bryophytes, and several orders of algae and fungi, including common plant pathogenic and non-pathogenic fungi. A variant of the motif (found in fungi and algae) contains a convenient EcoRI restriction site that has several applications for eliminating problematic contaminants from plant ITS preparations.