Diversity of the ectomycorrhiza community at a uranium mining heap

Ectomycorrhiza (EM) community structure was analyzed at one bare heap site (BHS), one heap site with organic cover (HS-OH) and one reference site (RS) in the former uranium mining area near Ronneburg (Thuringia, Germany). Twenty-three EM morphotypes were distinguished, and 14 of them were additionally characterized by polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) and internal transcribed spacer (ITS) sequence analysis. Colonization of birch by the different morphotypes was quantified, and the EM diversity at the different sites was investigated. Compared to RS, total EM colonization was reduced by 6% (P=0.851) at HS-OH and by 58% (P<0.001) at BHS. Likewise, EM diversity was reduced by 16% (P=0.229) at HS-OH and 52% (P<0.001) at BHS. The Sørensen similarity between EM samples from RS was nearly independent from the sampling date, whereas at HS-OH and especially BHS, the Sørensen similarity decreased with increasing time between the samplings. All EM fungal species dominating at the two heap sites were also present at RS. Thus, fungi with high tolerance against uranium and other stress factors at the heap sites (e.g. heavy metals, nutrient limitation, drought) were selected among all EM fungi of the area. Highly adapted fungi with a distribution restricted to the contaminated soils were not detected.Electronic Supplementary Material Supplementary material is available for this article at .     

Phylogenetic relationships in the North African genus <Emphasis Type="Italic">Hedysarum</Emphasis> as inferred from ITS sequences of nuclear ribosomal DNA

Sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA were analysed to precise their length (637–643 bp) and resolve phylogenetic relationships among eight Mediterranean species of the genus Hedysarum (Fabaceae). The infra-specific variability levels of the ITS sequences of spontaneous population of H. coronarium proved a lack of polymorphism both in the length and in the sequences examined in this species. Hence, a consensus ITS sequence characterising each Hedysarum species has been investigated for analysis of inter-specific polymorphisms. The level of variation of ITS sequence was high enough to make the ITS1 and ITS2 a useful tool for phylogenetic reconstruction. However, ITS2 seems to be relatively more polymorphic and more informative than ITS1 regarding length or GC percent. The phylogenic relationships in the genus Hedysarum based on ITS1 and ITS2 sequences taken independently or together, are discussed in the context of current work in molecular biosystematics. Results exhibited the distinctiveness of the two H. spinosissimum subspecies (i.e. H. spinosissimum ssp. capitatum and H. spinosissimum ssp. spinosissimum). In addition, the great similarity of the ITS sequences between H. coronarium (the only cultivated species of the genus) and H. carnosum suggests the usefulness of the latter in selection programmes to improve pastoral production in semi-arid areas.     

FISH技术在大白菜初级三体额外染色体鉴定中的应用

植物三体是非常重要的遗传材料,在基因、连锁群和分子标记的染色体定位及染色体工程育种等研究中有着十分重要的作用(程祝宽等,2000),但采用传统的核型分析方法     

一株抗铜根瘤菌的分离鉴定及其16S rDNA序列分析

为了发挥微生物和植物在重金属矿尾区铜污染土壤的共同修复作用,本研究从陕西省凤县矿尾区天蓝苜蓿根瘤中筛选分离到一株抗重金属铜的菌株,定名为CCNWSX0020.该菌株在YMA琼脂平板上抗铜浓度为3.0mmol/L,TY液体培养基中抗铜浓度为1.4 mmo1/L,因此,它是研究根瘤菌抗铜机制的良好菌株.该菌株经生理生化分析...     

黄杨属植物ITS序列分子进化特点分析

黄杨属植物种类多,分类较为混乱,特别是中国特有种珍珠黄杨的分类地位和系统进化存有争议,鉴于此,本文选取黄杨属5种植物和珍稀濒危植物珍珠黄杨的5个居群,对其rDNA ITS序列分析,结合GenBank中报道的黄杨属其它9个种,以板凳果属顶花板凳果的ITS序列为参照,用成对比较的方法对黄杨属18种植物的ITS序列比较发现,...     

Phylogenetic Relationships of Sorghum and Related Species Inferred from Sequence Analysis of the nrDNA ITS Region

Analysis of phylogenetic and evolution in six species of Sorghum was based on internal transcribed spacer （ITS） sequences in nuclear ribosomal DNA. Results showed that the length of the ITS regions among the six species ranged from 588 to 589 bp and the contents of G＋C in ITS （ITS1 ＋5.8S＋ITS2） regions ranged from 60.27 to 61.05%; the length of ITS1 ranged from 207 to 208 bp and the contents of G ＋ C in the ITS 1 regions ranged from 53.91 to 61.54%. The length of the 5.8S rDNA and ITS2 regions in the six species was 164 and 217 bp respectively, and the contents of G ＋ C ranged from 56.10 to 58.54% in the 5.8S rDNA region and 66.36 to 67,28% in the ITS2 region. Among regions of ITS, ITS1, ITS2, and 5.8S, the best sequence for genetic relationship analysis in the six species was the ITS region. On the basis of the Jaccard coefficient and phylogentic tree, S. sp. was more related to S, propinguum than to other species. This was consistent with the fact that S. sp. is derived from S. propinguum. From the phylogenetic tree based on ITS1, S. halepense, silk sorghum and S. sudanense, are identical in the ITS 1 sequence, whereas the phylogenetic tree based one shows that S. sudanense has a closer genetic association with S. almum rather than with S. halepense and silk sorghum.     

有齿食道口线虫ITS及5.8S DNA片段的PCR扩增、克隆及序列分析

 运用PCR方法以保守引物NC5及NC2扩增了从广东阳江地区猪体分离的食道口线虫rDNA 的内转录间隔区（ITS）及5.8S序列。将PCR扩增出的片段纯化后克隆至pGEM-T Easy载体，用PCR技术及酶切鉴定阳性菌落，对阳性菌落质粒DNA进行测序。结果表明，扩增的片段大小为828 bp，包含部分的18S、28S及全部的ITS-1（362 bp）、5.8S(153 bp)及ITS-2（217 bp）序列。序列比较表明，该食道口线虫为有齿食道口线虫。本研究在国际上首次报道了中国猪有齿食道口线虫的ITS及5.8S序列，为食道口线虫的分子生物学的进一步研究奠定了基础。     

桑属ITS,TrnL-F,rps16序列分析及12个特殊桑资源评鉴

 【目的】分析桑属ITS,TrnL-F,rps16序列,探讨系统学价值,建立系统进化树,并对12个特殊桑资源进行评鉴,为开发利用提供理论依据。【方法】用67份桑资源,经DNA提取、PCR扩增、测序,测序结果用软件拼接、比对、除去非序列碱基,计算长度、G+C%含量、变异位点、信息位点、以构树、柘树为外类群,MP分析,根据分析结果,结合桑资源研究积累,对12个特殊桑资源进行评鉴。【结果】桑ITS(包括5.8S)基本序列576 bp ,变异范围576-590 bp,G+C% 59.55-62.25,40个信息位点;TrnL-F（包括tRNA-Leu内含子）基本序列923 bp , 变异范围920-924 bp, G+C%33.69-34.13,23个信息位点;rps16内含子基本序列929 bp ,变异范围923-929 bp,G+C%32.51-32.72,17个信息位点。最适碱基进化模型分别为(GTR+G),(GTR),(GTR+G),可能的分支概率,混合卡方概率值分别为0.000001 ,0.027175,0.000222, 三片段合并最适进化模型(GTR+G),基于模型,MP分析, 2538个位点,80个信息位点。分支图首先将黑桑M. nigra分出,其它桑种分成两支,第一支桑(mulberry),包括长穗桑、瑞穗桑、蒙桑、鬼桑、鸡桑、山桑、白桑、广东桑,第二支乔木桑(arbor),包括华桑、奶桑、川桑。12个特殊桑资源,神农华桑♀（优质木材桑）分在第二支,乔木特性,其它11个特殊桑资源分在第一支,具桑(mulberry)特性。【结论】桑属TrnL-F;rps16序列信息位点有限,单独研究桑属系统学,价值不大,与ITS序列合并,能增加分支图的信息位点,使分支图更具客观性,更近于似然。基于ITS,TrnL-F;rps16序列MP分支图,新疆黑桑为最原始类型,乌克兰等栽培种是进化类型。桑属可根据分支的亲缘关系,结合桑资源研究积累,评鉴特殊桑资源。     

辽宁营口地区锦鸡儿与树锦鸡儿根瘤菌遗传多样性研究

对锦鸡儿与树锦鸡儿根瘤菌进行研究,以了解其系统发育地位及遗传多样性。通过分离、纯化、回接结瘤测定共获得了31株待测菌,并采用16S rDNA PCR RFLP及BOX-PCR等方法对这些菌进行了研究。结果表明,31株待测菌的系统发育地位全部源于中间根瘤菌属（Mesorhizobium spp.）,并产生5种不同的rDNA图谱组合。BOX-PCR研究中,待测菌株呈现出较高的多样性,在80%相似性水平上,将待测菌归于17个不同的类型当中。