不同球孢白僵菌菌株DNA的RAPD分析

采用RAPD技术分析了16个球孢白僵菌菌株的遗传分化。由160个随机引物中筛选出27个引物对各菌株进行了PCR扩增。结果表明从16个 孢白僵菌菌株中共获301个RAPD标记,其中多态性标记288个,占95．7％,表明菌株间具有较丰富的遗传多态性,聚类分析把16个球孢白僵菌菌株分为三大类型（1）Blh,,Bgd和Bpy;(3)By7,F-263,RECBb01,B12和B13;（3）B7,B11,Bxs,B6,By2,Bpc和Bzs。菌株DNA多态性与采集地之间有一定的相关性,但与寄主来源,孢子形态和对松墨天牛幼虫的毒力间未表现出明显的相关性。     

云南省玉米大斑病菌的RAPD分析

 应用7条随机引物对采自云南省不同玉米产区的玉米大斑菌81个菌株的DNA进行了RAPD分析.结果表明,这些菌株共产生60条谱带,其中43条为多态性带,占71.7%.利用UPGMA法对DNA扩增图谱进行聚类分析,以遗传距离0.50为阈值,81个菌株可分为5个遗传群体,表明云南省玉米大斑病菌中具有丰富的种内遗传多样性.然而,这种分子标记所划分的群体与菌株来源地及致病类型间没有直接关系.     

利用RAPD研究星天牛地理种群间亲缘关系

利用随机扩增的多态性DNA(RAPD)方法对分布在我国甘肃、宁夏、内蒙、河北、西安、青岛、福建、江苏等16个地区,美国纽约、芝加哥、新泽西3个地区和韩国2个地区的光肩星天牛及其近缘种星天牛共23个地理种群进行了研究.实验筛选出17个多态性引物产生了219个多态性位点,RAPD聚类分析表明,美国和中国的光肩星天牛种群之间存在显著差异,遗传关系较远.     

油松遗传多样性研究的ISSR—PCR体系优化与初步应用

以油松基因组DNA为模板,对影响ISSR-PCR的主要因素进行研究,建立了适宜于油松的ISSR-PCR优化体系及扩增程序;并采用lSSR标记对山西灵空山和陕西洛南2个油松种群的遗传多样性进行了分析,同时将此结果与使用RAPD标记的研究结果进行了对比.结果表明,在20μL反应体系中,模板DNA、Mg2+、dNTPs、Taq DNA聚合酶和引物5种主要成分的最适浓度分别为40 ng、2.5 mmol·L-1、0.20 mmol·L-1、1 U和0.5 μmol·L-1.扩增程序为:94℃预变性5 min;94℃变性30s,最适温度(54～56℃)退火45s,72℃延伸2min.共计35个循环;循环结束后72℃延伸7min,4℃保存.山西灵空山和陕西洛南2个油松种群的Nei's遗传多样性分别为0.3520和0.3514,前者的遗传多样性显著高于后者(P<0.001).使用ISSR标记与RAPD标记所获结果基本一致,但是lSSR标记优于RAPD标记.     

大蒜种质资源遗传多样性的分子标记研究

本研究利用RAPD和ISSR两种分子标记技术,对中国10个不同地区的大蒜品种进行了种质资源遗传多样性研究.从30个RAPD引物当中,筛选出11个具有多态性的引物,共扩增出多态性带224条,多态性条带比率为41.18%,从12个ISSR引物中筛选出5个具多态性的ISSR引物,共扩增出多态性带121条,多态性条带比率为50.21%.对RAPD和ISSR两种标记分别运用Nei指数法,计算出10个大蒜品种的平均遗传距离为0.28和0.32.根据这两种标记的结果,采用UPGMA进行聚类分析,得到与生物学分类地位基本一致的结果.结果表明,在实验稳定性上,ISSR优于RAPD,且ISSR比RAPD能检测到更多的遗传变异,RAPD和ISSR两种标记可用于大蒜种质遗传多样性的研究.     

中国特有极度濒危植物猪血木的保护遗传学研究

应用RAPD标记分析了广东阳春八甲镇猪血木Euryodendron excelsumH.T.Chang种群全部14个个体的遗传变异和进化关系.23个引物共检测到156个位点,其中多态位点95个,多态位点比率60.90%.根据所得数据求出的观察等位基因数为1.609 0、有效等位基因数为1.347 1、Nei基因多样性为0.199 3、Shannon多样性指数为0.153 4.猪血木还保留有比较丰富的遗传多样性.对Jaccard相似性系数用UPGMA法进行聚类分析表明,猪血木个体明显地分为2个亚群,其中2号个体同其他成员的遗传关系疏远.RAPD谱带表型的主成分分析(PCA)支持聚类分析结果.根据这些结果讨论了种群的管理和保护策略.     

几种中国栽培灵芝品种的RAPD及rDNA分子标记鉴定

以常见几种中国栽培灵芝菌株为研究材料,运用RAPD、18SrDNA和ITS 3种分子标记来分析各灵芝菌株之间的亲缘关系,同时比较3种分析结果,探索适于灵芝属研究的技术方法。RAPD分析结果表明,6种菌株在相似性系数为0.584的水平上聚为3类:Ganodermaluidun、GanodermaluidumHG、Ganodermasinenses和Ganodermaatrum为一类;Xuezhi和Coriolusversicolor各单归为一类。ITS分析结果显示,灵芝菌株间相似性较低(43.8%～88.0%),其中Ganodermasinenses和Xuezhi的相似性为43.8%,在较低相似性水平上,Ganodermaluidun和Ganodermasinenses归为一类,Coriolusversicolor和Xuezhi各单归为一类,这与RAPD分析结果一致,也与传统分类结果基本一致。18SrDNA分子标记显示的结果与前两种分析结果有很大差异,说明18SrDNA分子标记并不适合灵芝属的分类研究。     

利用RAPD标记对中国石竹属植物亲缘关系的研究

利用RAPD标记研究了中国石竹属10个种和10个栽培品种亲缘关系。39个随机标记共获得242个多态位点，聚类分析结果表明可分为野生种和栽培品种2大类群，两类群的Nei(1978)遗传距离为0．4698。野生种可分为生长于湿润草甸和生长于干燥山地两类群，遗传距离为0．2428。     

大蒜种质资源遗传多样性的分子标记研究

本研究利用RAPD和ISSR两种分子标记技术．对中国10个不同地区的大蒜品种进行了种质资源遗传多样性研究．从30个RAPD引物当中．筛选出11个具有多态性的引物．共扩增出多态性带224条．多态性条带比率为41．18％．从12个ISSR引物中筛选出5个具多态性的ISSR引物．共扩增出多态性带121条．多态性条带比率为50．21％．对RAPD和ISSR两种标记分别运用Nei指数法．计算出10个大蒜品种的平均遗传距离为0．28和0．32．根据这两种标记的结果．采用UPGMA进行聚类分析，得到与生物学分类地位基本一致的结果．结果表明，在实验稳定性上．ISSR优于RAPD．且ISSR比RAPD能检测到更多的遗传变异．RAPD和ISSR两种标记可用于大蒜种质遗传多样性的研究．     

何首乌野生种质资源的RAPD指纹图谱构建

采用RAPD分子标记技术对广西何首乌野生种质资源进行遗传多样性分析。结果表明:40对随机引物用于PCR扩增,共得到295条扩增DNA片段,175个多态性片段,多态性达到59.3%,其中田林种源与西林种源之间的遗传变异最小,西林种源和灌阳种源之间遗传变异最大;根据RAPD标记划分10个何首乌野生种源得到5个品种群,这5个类型与地理分布有一定关系,地理位置较近的材料能聚在一起。分子标记可用于何首乌种质资源的分类、真伪鉴定及良种选育。     

Genetic relationships among Chinese and American isolates of Phytophthora sojae assessed by RAPD markers

The genetic diversity of three geographic populations of Phytophthora sojae from China and the United States was determined using random amplified polymorphic DNA （RAPD）. The purpose was to explore genetic relationships among Chinese and American isolates of the organism. 21 random primers were selected among 200 random primers screened. A total of 223 reproducible RAPD fragments were scored among 111 individuals, of which 199 （89.23%） were polymorphic. Analysis of genetic variation showed that there existed higher genetic variation in the United States population in comparison to the Chinese populations. Nei＇s genetic identity and principal component analysis indicated that the populations of Fujian and United States are closer to each other than to Heilongjiang populations. Shannon-Wiener diversity index revealed that the United States populations have a higher genetic di- versity than that of Chinese populations. These data are in support of the hypothesis that P. sojae in the United States might not have been introduced from China.     

松枯梢病菌的培养性状和致病力变异及其相互关系

对从我国１３个省（市）１６种松树和其它２种针叶树上收集的松枯梢病菌５５个菌株在６种基质上进行性状培养的研究表明,我国松枯梢病菌在培养性状上存在明显的类群分化,模糊聚类分析将５５个菌株２分为三个类群。采用人工接种方法测定供试菌株对５种实生苗的致病力。结果显示,该病菌的致病力在各菌株、不同松种或不同接种方法间均差异显。供试菌株的致病力分化状况与其在培养性状上所表现出的差异存在明显的相关性。     

松材线虫和拟松材线虫种间及种内遗传相关性的RAPD分析

运用RAPD技术对来自日本、韩国、美国、加拿大和中国大陆6省及台湾地区的松材线虫和拟松材线虫16个虫株的基因组DNA进行随机扩增,聚类分析结果显示,松材线虫和拟松材线虫明显分为两大类。在松材线虫群体中,又可分为3个亚组:中国大陆虫株与日本虫株为一亚组,加拿大虫株为一亚组,中国台湾虫株与美国虫株为一亚组。拟松材线虫群体亦可分为两亚组:一为日本、中国台湾和中国江苏虫株,二为韩国和中国湖南虫株。     

松枯梢病菌群体分化研究进展

松枯梢病菌是一种分布广泛、为害严重的世界性病原真菌。该菌从发现至今至少出现了２２个其他的同义名,Ｓｐｈａｅｒｏｐｓｉｓ ｓａｐｉｎｅａ现已得到世界各国的广泛认同。南非和美国等对松枯梢病菌群体分化的研究结果表明,该病菌的不同分离系在培养性状和致病力等方面存在差异。美国将该病菌的美国分离系分为Ａ型和Ｂ型两个类群,而南非认为根据这些差异尚不能将瑞分离系划分两类。新西兰、法国和中国等对此亦作了初步研究。     

Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin.     

COVID-19和SARS病毒领域中美合作研究模式研究基于文献计量

为研究中美两国在传染性病毒领域COVID-19和SARS的合作研究范式,以中美两国在该领域的合作发文为研究对象,分别对两个病毒领域的学科领域、发文机构和资助情况进行可视化分析。研究结果表明：合作学科模式,整体呈现出阶段性集中的研究范式;在合作机构模式上,中美两国的主要参与机构属性不同;在合作资助模式上,中美两国资助投入力度较为均衡,同时受到国际层面的广泛关注。     

RAPD analysis of genetic variability among Stylosanthes guianenesis accessions of resistant and susceptible to the stylo anthracnose

Stylosanthes guianenesis Sw. is an important tropical forage legume grown and utilized in the tropics and the subtropics of South China. Anthracnose, caused by Colletotrichum gloeosporioides (Penz.) Sacc., is a major constraint to the extensive use of Stylosanthes. Forty-five accessions of S. guianensis were assessed with RAPD for genetic diversity and for resistance to anthracnose. RAPD analysis was performed using twenty primers screened from 200 arbitrary oligonucleotides, and a 71.5% level of polymorphism was found. The dendrogram obtained with unweighted pair group method of averages (UPGMA) based on the RAPD data showed genetic similarity from 50% to 94% among all stylo accessions, and fourteen clusters were defined at 66.5% genetic similarity. Two strains of C. gloeosporioides from stylo in China were used for anthracnose resistance screening. All plant accessions showed variation in the reaction to two strains and the correlation of resistance had a value of 0.904. Multiple correspondence analysis displayed a random distribution of the resistance or susceptibility response with respect to the genetic diversity measured by RAPD analysis except one group. Mean distance was also calculated to determine the diversity within clusters. From our results, the RAPD analysis is an effective and efficient technique of providing quantitative estimates of genetic similarity among stylo accessions.     

Characterization and molecular marker screening of a rice bacteria-resistant gene Xa-min(t)

To test the resistant spectrum of the Xa-min(t) gene introgressed from Oryza minuta, thirty-four isolates of different bacterial blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo), from 11 countries were used to inoculate the Xa-min(t) introgression line 78-15. Four rice cultivars, IR24, C64 (IRBB21), Nipponbare and Zhonghua 11 were used as controls. The results showed that the Xa-min(t) gene was broad-spectrum and highly resistant to diverse Xoo isolates. The methods of bulk segregant analysis (BSA), randomly amplified polymorphic DNA (RAPD) and sequence characterized amplified regions (SCAR) were used to analyze F2 individuals of the hybrid IR24×78-15 and molecular genetic markers linked to Xa-min(t) gene were identified. A total of 800 arbitrary decamer oligonucleotide primers were used for RAPD analysis. Two RAPD markers, BE05300 and BE061400, produced by primers BE05 and BE06 respectively, were closely linked to the Xa-min(t) gene. Based on the sequences of these two markers, sequence specific primers were designed and used to screen all F2 plants. One RAPD marker, BE05300, was converted into a stable SCAR marker (ScBE05300). Linkage analysis was carried out using markers ScBE05300 and BE061400 on 948 and 719 F2 individuals of the hybrid IR24×78-15. Our results indicate that the genetic distances from Xa-min(t) to ScBE05300 and BE061400 are 2.2 cM and 3.7 cM respectively on the same side. This study may facilitate the construction of the fine physical map of the Xa-min(t) gene.     

国内外稀土行业环境规制对比及启示

 梳理了中国、美国、澳大利亚等主要稀土生产国稀土环境规制的发展历程，从放射性污染物的安全管理、矿区土地复垦管理、大气污染排放管理和稀土环境税费制度4个方面，对各国环境规制的特点进行了对比和分析，研究发现：（1）从2012年开始针对中国稀土产业的环境法规体系逐渐形成，这些法规有效遏制了中国稀土环境污染蔓延和恶化的态势，但也对稀土供应产生了一定影响；（2）美国、澳大利亚等国稀土环境规制的起步较早，为稀土企业的生产设置了很高的环境“门槛”，迫使稀土企业及相关下游产业进行国际转移，也成为其恢复稀土生产的重要障碍；（3）为降低环境规制带来的高昂生产成本，美国、澳大利亚等国依托国际贸易在全球范围内建立了产能转移、管制规避和渠道转移3种环境污染转移渠道，驱使马来西亚等国承担了巨大的环境成本。因此，应立足国际视角，吸取西方国家在稀土环境管理上的经验和教训，推动建立本国稀土环境治理措施及全球稀土环境治理体系，以减少本国稀土行业环境污染并促成全球稀土产业链的合理布局。     

榛子种质资源遗传多样性的RAPD分析

利用RAPD分子标记技术，对来自欧洲、美国和我国北方的共48份榛子品种或品系（包括4个种及种间杂种）的遗传多样性进行了分析．从150条随机引物中筛选出24条引物，共扩增出142条清晰可重复的带，其中多态性带130条，比例为91．5％．聚类分析将48份榛子种质分为5组：欧榛、平榛各自列为1组；杂交榛分成2个组；另外一组包括滇榛和藏榛2份种质．研究结果对榛子的种间亲缘关系进行了验证，且为同种不同品种的亲缘关系提供了更为详细的信息．