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Cassiope fastigiata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Bajiaria racemosa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.     

大白口蘑分离菌株的DNA鉴定

以松口蘑Tricholoma matsutake子实体为外类群,对大白口蘑T.giganteum野生子实体及其组织分离菌丝进行ITS序列测序,通过DNAStar软件进行比较分析。结果表明大白口蘑ITS序列长度为589bp,松口蘑ITS序列长度为601bp,ITS1和ITS2呈现不同程度的种间多态性;ITS序列测定证实了大白口蘑野生子实体及其组织分离菌丝的同质性,并且ITS区序列在大白口蘑种内不同菌株间的变异程度很小,表明使用通用引物ITS4和ITS5,通过PCR扩增测序即可用于大白口蘑的种质鉴定。     

大白口蘑分离菌株的DNA鉴定

以松口蘑Tricholoma matsutake子实体为外类群,对大白口蘑T. giganteum 野生子实体及其组织分离菌丝进行ITS序列测序,通过DNAStar软件进行比较分析。结果表明大白口蘑ITS序列长度为589bp,松口蘑ITS序列长度为601bp,ITS1和ITS2呈现不同程度的种间多态性;ITS序列测定证实了大白口蘑野生子实体及其组织分离菌丝的同质性,并且ITS区序列在大白口蘑种内不同菌株间的变异程度很小,表明使用通用引物ITS4和ITS5,通过PCR扩增测序即可用于大白口蘑的种质鉴定。     

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.     

MOLECULAR SYSTEMATICS OF ECTOCARPUS AND KUCKUCKIA (ECTOCARPALES, PHAEOPHYCEAE) INFERRED FROM PHYLOGENETIC ANALYSIS OF NUCLEAR- AND PIASTTD-ENCODED DNA SEQUENCES

The phylogeny of Ectocarpus and Kuckuckia strains representing widely separated populations from both hemispheres was inferred from sequence analysis of the internal transcribed spacers of the nuclear ribosomal DNA (ITS 1—5.8S-ITS 2) and the spacer region in the plastid-encoded ribulose- bis -phosphate-carboxylase (RUBISCO) cistron (partial rbc L-spacer-partial rbc S ). Both sequences resulted in matching phylogenies, with the RUBISCO spacer region being most informative at the level of genera and species and the internal transcribed spacer sequences at the level of species and populations. Three major clades were formed by strains previously described by morphology and physiology as Kuckuckia, E. fasciculatus, and E. siliculosus, confirming the validity of these taxa . Ectocarpus and Kuckuckia are regarded as sibling taxa with respect to the outgroup species Feldmannia simplex, Hincksia mitchelliae, and Pilayella littoralis. The clade formed by sexual E. siliculosus strains and most asexual Ectocarpus strains was subdivided into several clades that are consistent with geographical races within E. siliculosus. The inferred phylogeny of Ectocarpus corresponds generally with results from cross-fertilization experiments, morphology, and lipid analysis. A hypothesis on the origin and dispersal of E. siliculosus suggests several natural dispersal events during periods of global cooling as well as recent and possibly anthropogenic dispersal events .     

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.     

Phylogeny and Biogeography of Thuja L. （Cupressaceae）, an Eastern Asian and North American Disjunct Genus

In order to develop better insights into biogeographic patterns of eastern Asian and North American disjunct plant genera, sequences of nuclear ribosomal DNA internal transcribed spacer (nr DNAITS) region were used to estimate interspecific relationships of Thuja L. (Cupressaceae) and infer its biogeography based on the phylogeny. According to the phylogenetic analysis, two clades were recognized. The first clade included Thuja plicata D. Don (western North America) and T. koraiensis Nakai (northeastern Asia), and the second one contained T. occidentalis (Gord.) Cart. (Japan). The ancestral area of Thuja was inferred to be eastern Asia, and two dispersal events were responsible for the modern distribution of Thuja in North America. Both the North Atlantic land bridge and Bering land bridge were possible routes for the migration of ancestral populations to North America.     

维吾尔药材红豆杉植物基原研究

从分子学角度探明维吾尔药材红豆杉的植物基原,为维吾尔药材标准化与维吾尔药产业化提供科学依据。采用试剂盒法提取红豆杉属植物及药材基因组DNA,PCR扩增ITS2片段,双向测序,应用Mega 6.0软件分析序列,计算种内及种间遗传距离,构建NJ鉴别树。红豆杉属植物ITS2序列长度为229~231bp,GC含量为59.13%~60.26%;西藏红豆杉与红豆杉及南方红豆杉种内种间K2P距离为0,与东北红豆杉、命叶红豆杉及曼地亚红豆杉种间K2P距离分别为0.012、0.013、0.015。NJ树结果表明,西藏红豆杉与红豆杉及南方红豆杉无法区分,与东北红豆杉、命叶红豆杉可区分;曼地亚红豆杉与其母本东北红豆杉聚在一起,无法区分。根据ITS2序列鉴定结果,西藏红豆杉与红豆杉、南方红豆杉可作为药材的同一基原,东北红豆杉可与曼地亚红豆杉作为同一基原,为维吾尔药材的真伪鉴别及质量标准提升提供基原鉴定依据。