链格孢属真菌的分子复核鉴定及系统发育研究

为了验证中国林业微生物保藏管理中心库藏链格孢属(Alternaria Nees)菌种资源分类地位的准确性,探索一种链格孢属真菌的快速复核鉴定方法,本研究采用ITS序列分析、NCBI blast以及系统发育分析等方法,对中国林业微生物保藏管理中心库藏链格孢属的36个种及未定种的375个菌株进行分子复核鉴定以及系统发育关系研究。结果表明：本研究的375个菌株中,有21个菌株的分类地位不准确,其中有9株菌的ITS序列与链格孢属菌种的同源性在92%~96%之间,另外12株菌的ITS序列与链格孢属菌种的同源性在60%~85%之间。基于ITS序列构建的NJ树显示,29个小孢子种的37个生物型形成了一个稳定的分支,而6个大孢子种与外群Ulocladium sp.聚在一个分支。本研究中,ITS序列分析可以用来区分和鉴定形态差别明显的大孢子种,但无法区分亲缘关系较近的29个小孢子种。     

杨属ITS序列的分子进化特点分析

本文通过对杨属5组代表种并以柳属中旱柳的ITS序列作为参照,用成对比较的方法对杨属21个植物样品的ITS序列比较发现,杨属ITS序列的碱基替换情况是转换数大于颠换数,ITS-1序列中碱基发生转换和颠换的数目基本相似,而ITS-2序列中碱基发生转换的数目远远大于颠换。用朱克斯和坎托一参数模型和木村二参数模型对杨属ITS序列的替换率计算,无论是ITS-1还是ITS-2序列都没有达到数理统计上的明显差异。但由于ITS-2序列碱基的变化转换大大高于颠换,所以二参数模型计算所得结果大于一参数模型;采用相对速率测验法,对杨属各组分子进化相对速率进行了检测,结果分析得知,杨属5组的ITS序列分子进化速率有差异。杨属各组的ITS-1序列比较说明,大叶杨组、青杨组、黑杨组的进化速率都小于白杨组,而胡杨组则是进化速率最快的,大叶杨组的进化速率小于青杨组、胡杨组和黑杨组,黑杨组和胡杨组大于青杨组;ITS-2序列比较发现白杨组是进化速率最慢,其次是大叶杨组、青杨组,而黑杨组则稍大于胡杨组;总ITS序列比较是大叶杨组和黑杨组相对较慢,胡杨组最快;但就总的碱基替换分析,除了黑杨组和大叶杨组在ITS-1区间及青杨组、胡杨组和白杨组在ITS-2区间进化速率有显著差异外,其余组间都无显著的差异,尤其是在整个ITS序列区段碱基替换的差异都无显著差异。     

基于核糖体DNA的ITS序列和叶绿体trnT-trnL及trnL-trnF基因间区的菊花起源与中国菊属植物分子系统学研究

Several sequences were applied to resolve phylogenetic relationships within Dendranthema and clarify the origin garden chrysanthemums including sequences of nrDNA ITS,trnT-trnL and trnL-trnF intergenic spacer regions in cpDNA.The relationships among the species are so close that the three sequences could only provide limited information. Form the evidence presented,we suggest that:①D.lavandulifolium might be the chloroplast donor of D.vestitum(HN)with the resembling morphology and the same trnT/L IGS sequence.②D.vestitum,a putative ancestor,may be not the chloroplast donor of garden chrysanthemums.D.lavandulifolium migth be the chloroplast donor of the type population of D.indicum(HN)or the direct.chloroplast donor of the ancient garden chryanthemum cultivar.③D.zawaskii might be not the ancestor of garden chrysanthemums.     

基于5.8SrDNA/ITS序列的几种内蒙古棘豆属植物分子系统学研究

提取小花棘豆(Oxytropis.glabra DC.)、小叶小花棘豆(O.glabra var.tenuis)、刺叶柄棘豆(O.aciphylla Ledeb.)、砂珍棘豆(O.racemusa Turcz.)、多叶棘豆(O.verticillaris (L.)J.N)、黄毛棘豆(O.ochrantha Turcz.)基因组DNA,扩增其5.8SrDNA/ITS序列并测序,将所测序列与GenBank中疏毛棘豆(O.pilosa)和长白棘豆(O.anertii)5.8SrDNA/ITS序列进行同源性比对,利用MEGA4.0软件采用Neighbor-joining法构建系统发育树,旨在为棘豆属下种间及种下分类研究提供分子依据.结果表明:多叶棘豆、砂珍棘豆和黄毛棘豆构成姐妹群,并在部分地理种群上混杂,认为将三者归入真棘豆亚属Subgen.Euoxytropis轮叶棘豆组Sect.Baicalia Stell.ex Bunge更合理.小叶小花棘豆与小花棘豆亲缘关系很近,支持将其视为变种的观点.刺叶柄棘豆的不同地理种群形成两大分支,对其在亚属水平上的分类还需进一步商榷.研究赞同棘豆属植物为单系起源,认为种内不同地理种群间的亲缘关系在一定程度上受到了植被类型和生境的影响.     

Modal parameters identification for short data sequences based on stratified sampling and optimism complex Morlet wavelet

A novel modal parameter identification method based on stratified sampling and optimism complex Morlet wavelet is proposed for short data sequences. Stratified sampling is applied to divide the structure response signal into different layers which called sub samples with different thresholds, and then free decrement response signal of each layer is extracted by random decrement technique. The optimism complex Morlet wavelet transform is applied to identify modal parameter of each layer, and the weight of the layer is also determined based on the sample standard deviation. The modal parameter of the structure can be obtained by weighted calculation.The engineering application shows that the proposed method has the ability to identify modal parameter accurately, decouple low frequency intensive modal composition and restrain high frequency fake modal effectively.     

Genetic diversity within cultivated teas based on nucleotide sequence comparison of ribosomal RNA maturase in chloroplast DNA

The wild tuber-bearing Solanumspecies represent a genetic pool of enormous diversity, embracing high variability for many agronomic traits. S. kurtzianum (ktz), S. chacoense(chc) and S. ruiz-lealii (rzl) are wild diploid self-incompatible relatives of the common potato, Solanum tuberosumssp. tuberosum, with resistance to adverse biotic and abiotic factors. Pollen-pistil/style compatibility relations and seed set in intra- and interspecific crosses among ktz, chc and rzl were investigated. Pre- and post-zygotic hybridization barriers were detected in the three species, with variable incidence because the percentage of genotypic combinations that produced seeds was15–30% and 7–28% in intra and interspecific crosses, respectively. In pollen-pistil/style incompatible combinations, either pollen grains did not germinate or pollen tube growth was arrested at different sites of the style, but mainly in its upper third. Unilateral incompatibility was detected in both intra-and interspecific crosses, as well as bilateral incompatibility in certain combinations. The incompatibility relations observed could be explained by a genetic model with dominant genes in pistils that interact with corresponding dominant genes in pollen, that are independent of the S-locus. The complex arrangement of compatibility relationships found could not be directly related to taxonomic hypothesis or geographic distribution. These results suggest that divergence between the three species has occurred recently, and that internal barriers of reproductive isolation have not been an important factor in their evolution. This revised version was published online in July 2006 with corrections to the Cover Date.     

山东省番茄灰霉病菌种类与遗传多样性研究

利用单孢分离的方法从山东省11个地区的番茄病害标本上分离获得66个灰霉病菌菌株,通过形态学观察和5.8S rDNA-ITS序列分析,该66个菌株均为灰葡萄孢菌(Botrytis cinerea)。通过序列比对,该66个菌株的ITS序列属于两种类型,并且两种ITS序列只有单碱基差异。利用ISSR（inter-simple sequence repeats）标记技术对66个菌株进行遗传多样性分析,结果获得24个ISSR分子标记,其中58.33%的片段具有多态性,该结果表明菌株种群间遗传多样性不丰富。UPGMA聚类分析将66个菌株划分成4个遗传聚类群,遗传聚类群的菌株组成表明遗传群组的划分与菌株的种类和地理来源存在一定的相关性。     

基于ITS和trnL-F序列的具有优良性状蕉类资源的遗传结构分析

为了构建广西具有优良性状的蕉类遗传结构,本研究收集了广西7个不同地理来源的5大种类具有优良性状的蕉类资源,利用PCR技术将这些蕉类资源细胞核DNA的ITS序列及叶绿体DNA的trnL-F序列进行扩增和测序,并对测序所获得的序列进行STRUCTURE分类、PCoA排序、AMOVA分析、群体遗传分化(F_ST指数)及基于NJ树和UPGMA树的聚类分析,进一步研究蕉类资源遗传变异分布和遗传变异水平。STRUCTURE结果显示:当K=2时,Delta K出现了最高的峰值,即将个体分为2个类别最合适,大蕉中的多数和野蕉中的少数可归为第一类,所有粉蕉、鸡蕉、香蕉和大多数的野蕉归为第二类。PCoA排序图显示粉蕉虽然个体数量较多,但是遗传多样性较低,而大蕉和野蕉具有较高的多样性。AMOVA分析表明遗传变异主要存在于群体内的个体间,方差占总和的63.088%,品种间的遗传变异大于品种内群体间的遗传变异,方差分别占总和的27.676%和9.236%。遗传分化非常大(F_ST>0.25)且P<0.05的群体绝大多数在不同蕉类型之间。NJ树和UPGMA树同样显示不同蕉类型之间的群体遗传距离较远。以上结果表明野蕉存在的历史最久,积累了大量的遗传变异;在人工杂交育种时,不同蕉之间的交配可能产生更多的具有遗传多样性的后代;具有育种潜力性状的粉蕉分布在遗传关系非常近的一个群体内,今后的资源收集时应该更加注重对某个粉蕉群体的详尽调查以发现更多的可利用性状。研究结果有助于对广西具有优良性状的蕉类资源的蕴藏状况和遗传潜力进行评估,为进一步的育种学应用奠定基础。     

基于细胞学和DNA序列的苎麻与其野生近缘类群系统关系研究

为了了解苎麻与野生近缘种的系统学关系,更有效利用野生苎麻资源,通过细胞学观察和分子标记证据,对中国苎麻与其24个野生近缘类群进行了系统学分析。细胞学结果表明,苎麻间期核形态属于田中分类体系的前染色体型,而其野生近缘种分别属于前染色体型和分散型;苎麻和23个野生近缘物种(其中15个类群的染色体数目为首次报道)中,19个为二倍体(2n=28),而大叶苎麻组3个类群为三倍体(2n=42),1个为四倍体(2n=56),1个为五倍体(2n=70)。ITS序列和trnL-F序列分析表明,苎麻属可分成A(含A₁和A₂亚分支)、B(含B₁和B₂亚分支)和C 3个基本分支。根据分析结果本文提出苎麻属的两条演化路线: (1)前染色体型进化路线A₁→A₂,即腋球苎麻组→苎麻组;(2)分散型进化路线B→C,即腋球苎麻组→帚序苎麻组→序叶苎麻组→大叶苎麻组。     

基于ITS 2序列的15种淫羊藿属药用植物分类鉴定研究

为探讨内转录间隔区2(ITS2)序列及其二级结构在15种淫羊藿属(Epimedium)中的鉴定效率。利用试剂盒提取叶片总DNA,对ITS2序列进行PCR扩展与测序,计算K2P遗传距离,构建系统发育树,预测其二级结构。结果表明,ITS2序列在15种淫羊藿属植物中的通用性好,扩增成功率与测序成功率均为100%。从K2P种间和种内遗传距离看,ITS2在淫羊藿属中的种间变异较小,部分种类种内遗传距离大于种间遗传距离,鉴定成功率约为60%。采用比对法(Blast)分析,ITS2鉴定效率为75%。由ITS2系统进化树可知,淫羊藿属与鬼臼属各为一支,易于分开。除薄叶淫羊藿、竹山淫羊藿、巫山淫羊藿外,其余种类均能较好的进行聚类;除粗毛淫羊藿、保靖淫羊藿外其余均不能与NCBI下载到的序列进行较好聚类。研究表明,15种淫羊藿属植物ITS2序列在ML系统进化树中具较好的鉴别能力,但淫羊藿属各样本种内与种间遗传较为混乱,遗传距离复杂,ITS2二级结构形态结构亦较为相似,将各种间进行区分存在一定难度,不适合单独作为该属条形码使用。