基于ITS序列探讨杜鹃属的亚属和组间系统关系

首次报道了 15种杜鹃属 (Rhododendron)植物、1种杜香属 (Ledum)植物和Cassiopefastigiata的内转录间隔区(ITS) (包括 5 .8S)序列。加上从GenBank下载的 13种杜鹃属植物和Bajiariaracemosa的ITS序列 ,以C .fastigiata和B .racemosa为外类群 ,用最大简约法对杜鹃属的亚属和组间的系统关系进行了分析。结果表明 :1)杜鹃属是一个单系类群 ,叶状苞亚属为杜鹃属的基部类群 ;2 )杜香属确应归并到杜鹃属中 ,且与有鳞杜鹃亚属有较近的亲缘关系 ;3)有鳞杜鹃亚属和杜香构成一个单系分支 ,该分支是其余无鳞杜鹃花的姐妹群 ;4 )由无鳞杜鹃花组成的一个分支的内部支持率较低 ,其中常绿杜鹃亚属和映山红亚属均为内部支持率很高的单系类群 ,而羊踯躅亚属和马银花亚属均为多系类群 ;5 )在马银花亚属中 ,长蕊杜鹃组和马银花组均分别得到强烈支持 ,马银花组与异蕊杜鹃亚属可能构成姐妹群关系 ,异蕊杜鹃亚属和马银花组组成的一个分支可能与映山红亚属构成姐妹群关系。     

基于ITS序列分析探讨杜鹃属映山红亚属的组间关系

以叶状苞亚属的叶状苞杜鹃为外类群,以杜鹃属映山红亚属（subg.Tsutsusi)2组12种杜鹃和羊踯躅亚属（subg.Pentanthera）3种4种杜鹃的ITS区（包括5.8S rDNA)的序列了系统学分析。3个亚属的ITS区序长度范围为642－645bp。排序后ITS区的序列长度为653个位点,gap做缺失处理时,变异位点和信息位点分别占6．58％和3．68％。运用PAUP4．0软件分析,获得15个最简树,步长为75,一致性指数（CI）和维持性指数（RI）值分别为0．9333和0．9515,利用15个最简约树获取严格一致树,结果表明：1）映山红亚属为一单系类群,其内部支持率为81％;2）不支持将R.ashiroi独立成假映山红组,也不支持将R.tashiroi并入映山红组,而支持将R.tashiroi并入轮生叶组中的观点;3）支持将R.tsusiophyllum并入映山红组中的观点;4）大字杜鹃的系统位置还需进一步的研究。     

用ITS序列研究杨属各组之间的系统发育关系

杨树是重要的工业用材树种。我国杨树遗传资源丰富 ,分布范围广泛 ,不少种为我国特有。开展杨属系统发育和分子进化研究 ,对丰富的杨树遗传资源保存和利用有着重大意义。杨属 (Ｐｏｐｕｌｕｓ)全世界约 10 0余种 ,属下通常分 5个组[1] 。胡志昂等[2 ] 对杨属不同组间的过氧化物酶同工酶进行了研究 ;李宽钰等[3] 利用ＲＡＰＤ标记技术对白杨组、青杨组、黑杨组 2 0个种作了遗传分析。但是在杨属系统分类上还存在着许多混乱 ,同物异名、同名异物现象相当普遍。本文以杨属 5个派主要代表种为材料 ,用ＰＣＲ产物直接测序法测定杨树ＩＴＳ序列 ,…     

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.     

基于ITS序列探讨山茶属金花茶组的系统发育关系

测定了分布于我国的 2 2个山茶属金花茶组的种或变种的nrDNAITS区序列 ,它们的序列长度在 476～ 496之间。GC含量都超过了 70 % ,应用Kimura2 模型计算了序列间的分化程度 ,构建了最大简约树、邻接树和最大似然树 ,分析结果表明 :( 1 )淡黄金花茶、毛籽金花茶、陇瑞金花茶、弄岗金花茶、大样金花茶和凹脉金花茶的关系较近 ;( 2 )小瓣金花茶、小花金花茶、薄叶金花茶、多瓣金花茶、夏石金花茶和龙州金花茶的关系较近。ITS区序列分析结果与AFLP分析结果相近     

基于ITS序列探讨忍冬属的系统发育关系

以七子花(Heptacodium miconioides)为外类群,运用MEGA软件对20种忍冬属植物进行系统发育分析,采用邻接法(NJ)和最大简约法(MP)构建系统发育树,从分子系统学角度探讨忍冬属下的亲缘关系.结果表明:(1)在NJ和MP系统树中,没有形成系统树的基部分支,忍冬亚属(Subg.Chamaecerasus)和轮花亚属(Subg.Lonicera)没有形成姐妹群关系.(2)在各系统树中,囊管组内的各种没有聚为一支,故认为对囊管组的划分应进一步探讨.(3)忍冬属ITS区(ITS1+ITS2)的信息位点达到11.0%,信息位点比较丰富,证明ITS序列可以为解决忍冬属植物的系统发育问题提供较强的证据.     

香港红山茶个体内ITS多态性及物种鉴定的应用

核糖体DNA的内转录间隔区(ITS)一直被作为一种重要的分子标记,却很难用于山茶物种中。通过对1个疑似香港红山茶(Camellia hongkongensis)的样本进行ITS区域的扩增、克隆和测序,从中获得74种不同序列。研究结果表明,其ITS区域具有高度的多态性,其中76%的序列为假基因。系统发育分析显示,超过半数的假基因源自同一祖先。这些假基因在经历多次基因重复后分化成至少5个谱系,且每个谱系中的序列非常相似,这表明一些假基因不但未被剔除,反而通过快速复制事件幸存下来。由于山茶物种个体内ITS的高度多态,使用这个区域区分山茶物种可能导致错误。然而,通过比较香港红山茶中的1个种间特异性r DNA假基因,确定该样本属于香港红山茶。     

基于形态特征和ITS序列对7个鹅膏菌属菌株的分类鉴定

以采自浙江省丽水地区的7个鹅膏菌属菌株作为研究材料,在基于形态特征进行初步鉴定的基础上,对7种鹅膏菌的rDNAITS区段进行克隆测序和序列特征比较分析。进一步对ITS序列进行核酸序列数据库GenBank同源性检索比对,将从GenBank检索获得的9个最相似物种的ITS序列连同7种鹅膏菌的ITS序列一起作系统发育分析。结果表明:基于ITS序列对f6、f9和f493个菌株的分子鉴定支持了基于形态特征的鉴定结果,对f5的分子鉴定不支持形态鉴定的结果,f8为鹅膏菌属内某种,f66为鹅膏菌属内某种,并与Amanitafulva,A.atrofusca,A.orientifulva3种鹅膏菌的亲缘关系较近,f7与另外6种鹅膏菌的亲缘关系相差甚远。研究结果提示基于分子水平上的ITS序列分析不能单方面作为大型真菌分类鉴定的可靠依据,可以作为基于传统形态学分类鉴定的辅助参考依据。     

基于ITS序列探讨珍珠菜属过路黄组的系统关系

测定了紫脉过路黄、临时救和过路黄的nrDNA ITS序列,并分析了珍珠菜属过路黄组17个物种的遗传距离及亲缘关系。结果表明,过路黄组植物的ITS序列长度在620～628间,一致性高达90.59%,种间遗传距离为0.002～0.199。系统发育树表明:(1)紫脉过路黄、临时救和小茄亲缘关系较近;(2)大叶过路黄、落地梅和过路黄亲缘关系较近;(3)山萝过路黄、贯叶过路黄、管茎过路黄、叶头过路黄、峨眉过路黄及三角叶过路黄亲缘关系较近。ITS序列分析结果为组内植物的鉴定、分类及系统进化提供了新的参考。     

杂交稻亲本核糖体DNA的ITS序列比较

以典型粳稻(O．sativa ssp．japonicn)秋光作为外类群,典型籼稻(O．sativa ssp．indica)南京11号作为对照,对两优培9、培两优288、汕优63三个籼型组合的6个亲本的核糖体基因(nrDNA)内转录间隔区(ITS)的全序列进行了比较分析,结果表明：供试材料的ITS序列有较丰富的遗传差异,以ITS序列信息构建的系统树能反映出品种间的亲缘关系,3个组合亲本间遗传距离以超级稻两优培九的亲本9311与培矮64S遗传距离最远．     

基于ITS序列探讨杜鹃花属马银花组的系统发育

以杜鹃花属叶状苞亚属Rhododendron　subg. Therorhodion (Maxim.) Gray 的叶状苞杜鹃R. redowskianum Maxim.为外类群,使用PAUP4.0b8软件对马银花亚属sub g. Azaleastrum Planch.的马银花组sect. Azaleastrum (Planch.) Maxim. 7种1 变种和长蕊杜鹃组sect. Choniastrum Planch. 2种及2个相关的单型亚属（异蕊杜鹃 亚属subg. Mumeazalea Max     

Phylogenetic analysis of eastern Asian and eastern North American disjunct Lespedeza (Fabaceae) inferred from nuclear ribosomal ITS and plastid region sequences

Lespedeza (tribe Desmodieae, Fabaceae) follows a disjunct distribution in eastern Asia and eastern North America. Phylogenetic relationships among its species and related taxa were inferred from nuclear ribosomal internal transcribed spacer (ITS) and plastid sequences (trnH‐psbA, psbK‐psbI, trnK‐matK and rpoC1). We examined 35 species of Lespedeza, two of Kummerowia and one of Campylotropis, the sole constituents of the Lespedeza group. An analysis of these data revealed that the genus Campylotropis is sister to the other two genera. However, we were unable to resolve the relationships between Kummerowia and Lespedeza in the strict consensus trees of parsimony analyses based on plastid and combined DNA data. In the genus Lespedeza, the Old World subgenus Macrolespedeza is monophyletic, whereas the transcontinental subgenus Lespedeza is paraphyletic. Monophyly of eastern Asian species and of North American species is strongly supported. Although inconsistent with the traditional classification, this phylogenetic finding is consistent with seedling morphology. Three subgroups recognized in subgenus Macrolespedeza were unresolved in our phylogenetic trees. An incongruence length difference (ILD) test indicated that the two partitions (nuclear ITS and plastid sequences) were significantly incongruent, perhaps because of hybridization between species in Lespedeza. Most of the primary clades of tribe Desmodieae are Asian, implying that the relatively few New World ones, such as those in Lespedeza, are more recently derived from Asia. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 221–235.     

Morphological and molecular evidence of natural hybridization between two distantly related Rhododendron species from the Sino-Himalaya

Rhododendron (Ericaceae) is a large woody genus in which hybridization may play an important role in evolution and speciation, particularly in the Sino-Himalayan region, where many interfertile species often occur sympatrically. Natural hybridization between Rhododendron delavayi Franch. (=  R. arboreum ssp. delavayi ) and Rhododendron decorum Franch., which belong to different subsections of subgenus Hymenanthes, was investigated. Material of R. delavayi and R. decorum and their putative hybrids was collected from the wild. On the basis of morphology, chloroplast DNA, nuclear ribosomal DNA, and AFLP profiles, hybrids and parental species were identified. Hybridization occurred in both directions, but was asymmetrical, with R. delavayi as the major maternal parent in the hybrid zone. Most of the hybrids possessed intermediate phenotypes, and amongst the 15 hybrids detected were six F1s, two F2s, one first-generation backcross to R. delavayi , and two first-generation backcrosses to R. decorum . This indicates that, if Rhododendron underwent rapid radiation in this region, it did so in spite of permeable species barriers.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 119–129.     

Phylogenetic origin of Beckmannia （Poaceae） inferred from molecular evidence

The phylogenetic origin of Beckmannia remains unknown. The genus has been placed within the Chlorideae, Aveneae （Agrostideae）, Poeae, or treated as an isolate lineage, Beckmanniinae. In the present study, we used nuclear internal transcribed spacer （ITS） and chloroplast trnL-F sequences to examine the phylogenetic relationship between Beckmannia and those genera that have assumed to be related. On the basis of the results of our studies, the following conclusions could be drawn： （i） Beckmannia and Alopecurus are sister groups with high support; and （ii） Beckmannia and Alopecurus are nested in the Poeae clade with high support. The results of our analysis suggest that Beckmannia should be placed in Poeae.     

Phylogenetic analysis of the genus Hexachlamys (Myrtaceae) based on plastid and nuclear DNA sequences and their taxonomic implications

Myrtaceae are one of the most species‐rich families of flowering plants in the Neotropics. They include several complex genera and species; Hexachlamys is one of the complex genera. It has not been recognized as a distinct genus and has been included in Eugenia, based on morphological grounds. Therefore, molecular systematic studies may be useful to understand and to help to solve these relationships. Here, we performed a molecular phylogenetic analysis using plastid and nuclear data in order to check the inclusion of Hexachlamys in Eugenia. Plastid (accD, rpoB, rpoC1, trnH‐psbA) and nuclear (ITS2) sequence data were analysed using Bayesian and maximum parsimony methods. The trees constructed using ITS2 and trnH‐psbA were the best able to resolve the relationships between species and genera, revealing the non‐monophyly of Hexachlamys. The molecular phylogenetic analyses were in agreement with previous morphological revisions that have included Hexachlamys in Eugenia. These results reinforce the importance of uniting knowledge and strategies to understand better issues of delimitation of genera and species in groups of plants with taxonomic problems. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 532–543.     

Phylogeny of the Neotropical Alibertia group (Rubiaceae), with emphasis on the genus Alibertia, inferred from ITS and 5S ribosomal DNA sequences

Phylogenetic relationships of 38 species of the Alibertia group (Rubiaceae) and two outgroup species were investigated using the nuclear ribosomal 5S nontranscribed spacer (5S-NTS) and the internal transcribed spacers (ITS). Analysis of the data sets separately and in combination resulted in several well-supported and congruent groupings. However, the three analyses yielded different results as to the branching order of the basal clades. With the exception of Alibertia hispida, the species in the genus Alibertia appear in one weakly to moderately supported clade. This clade is in turn composed of two strongly supported subclades. One comprises several Alibertia species, including the type (A. edulis), three Borojoa species, and Randia tessmannii. The other subclade consists of Alibertia species only. This division is also generally supported morphologically by fruit size, corolla size, number of corolla lobes, and pollen aperture (porate vs. colporate). The sister group to the Alibertia clade comprises Duroia with Amaioua species internested. The close relationship of Ibetralia and Kutchubaea is corroborated. In addition, Alibertia hispida is a member of this strongly supported clade. Likewise, the two "Genipa" species are supported as a monophyletic group in 100% of the bootstrap replicates. It is concluded that the 5S spacer is superior to the commonly used ITS region in terms of resolution and robustness among closely related taxa.     

中国柽柳属和水柏枝属的分子系统学研究

对中国柽柳科 3属 2 1种植物的核糖体DNA中的内转录间隔区 (ITS)序列及 5 8SrRNA基因的 3′端序列进行测定。结果表明 ,ITS - 1片段的长度范围在 2 5 4bp～ 2 6 9bp之间 ,ITS - 2片段的长度范围在 2 2 5bp～ 2 5 3bp之间。以Reaumuriasongarica作为功能性外类群 ,运用PAUP软件分析仅得到一个最简约树。简约树步长为 4 6 6步 ,一致性指数CI =0 85 84 ,保持性指数RI=0 86 2 2。系统发育分析表明 :秀丽水柏枝不应从水柏枝属中分出。另外 ,研究分析为目前分类上存有争议的白花柽柳、短毛柽柳及甘蒙柽柳的划分提供了分子生物学证据