蓖麻品种遗传多样性与亲缘关系的SRAP分析

利用SRAP技术对81份蓖麻品种材料亲缘关系进行了分析,实验选用20对SRAP引物组合,在81份蓖麻材料中共扩增出263条带,多态性条带计214条,多态性条带比率（PPB）为81.37%,遗传相似系数变幅范围在0.32558～0.92973,显示了蓖麻品种的遗传多样性较丰富。从分子聚类结果分析表明,在相异系数0.43为阈值时,可将81份蓖麻材料分为4个类群L1-1、L1-2、L1-3和L1-4;若在相异系数0.287为阈值时,又可将L1-4大类群分为两个亚类群L2-1和L2-2。从聚类图得知,聚在同一亚类群的蓖麻品种大多数所处的地域相近或者是由同一育种单位所选育,其类内的品种基因型遗传相似系数较高,类间的品种遗传差异相对较大,该分子聚类树状图可为蓖麻栽培种种质资源遗传多样性与亲缘关系在育种的利用上提供科学依据。     

番茄ILs果实性状的主成分分析与聚类分析

利用以栽培番茄Lycopersicon esculentum(加工番茄M82)为背景创建的L.pennellii LA716渐渗系群体(ILs,introgression lines),对7个番茄果实主要性状进行了主成分和聚类分析。结果表明,7个果实性状可简化为3个主成分,分别为果实质量因子、果形因子和品质因子,累计贡献率85.435%。利用欧式距离,类平均法可将77份渐渗系分为3大类群,第Ⅰ类群包括70个渐渗系材料,在D=17.53的水平又可将第Ⅰ类群分为2个亚群,果实性状较好的材料主要集中在这个类群中;第Ⅱ类群包括1个材料,说明此材料的独特性;第Ⅲ类群包括6个材料。     

苦瓜种质遗传多样性的SRAP标记分析

从144对SRAP引物中筛选出61对多态性强、重复性好的SRAP引物,对43份苦瓜种质DNA进行了扩增,共得到2078条谱带,其中多态性谱带863条,平均每对引物扩增得到14.15条多态性谱带,多态性位点百分率为42.11%。用UPM-GA方法进行聚类分析,供试苦瓜种质的遗传相似系数为0.50～0.95,在阈值0.65处(L1)可将苦瓜分为2个类群,第Ⅰ类群为野生种,第Ⅱ类群为半栽培种和栽培种;在阈值0.80处(L2)将第Ⅱ类群分为5个亚类群,L2的划分反映了苦瓜种质间的遗传多样性与果实性状、来源或地理分布有较高相关性;在阈值0.83处,第Ⅱ类群1亚类群又分为4类,大致分为滑身苦瓜(粗棱无瘤)、大顶苦瓜(棱细大圆瘤、倒锥形)、棱细圆瘤苦瓜以及尖刺瘤或凸瘤苦瓜,分类结果与苦瓜的刺瘤有无、棱条粗细、瘤的形状和瓜色等密切相关,初步认为刺瘤苦瓜为较原始类型。     

香蕉EST-SSRs标记的开发与应用

从NCBI搜索的2 282条香蕉EST中, 发掘出含有SSR的EST序列110条, 共有122个SSR位点, 检出率为5.3%。SSR位点可分为37种重复单元, 平均长度为20 bp, 其中二、三核苷酸重复单元的SSR占主导地位, 分别占总SSR的33.1%和47.6%。GA和GAA是二、三核苷酸中的优势重复类型, 分别占二、三核苷酸重复类型的75.7%和36.0%; 其他重复类型所占比例均不足10%, 而四核苷酸重复类型最少, 为4.0%。设计的63对EST-SSRs引物中, 有41对EST-SSRs引物对巴西蕉基因组DNA能扩增出产物, 占总引物数的65.1%。应用进一步筛选出的重复性好、多态性高的19对引物对49个香蕉品种(系)进行PCR扩增。每对引物扩增的多态性带数目为4~12个, 平均7.58个; 引物多态信息量变化范围为0.3572~0.8744, 平均0.7324。在相似系数为0.63的水平可将49个品种聚为2个类群：一类为含B基因组香蕉品种; 另一类为不含B基因组的香蕉品种, 表明EST-SSR引物可以应用于香蕉品种资源分类的研究。     

SSR标记在毛木耳种质资源遗传多样性研究中的应用

本研究利用基于毛木耳全基因组开发的SSR标记对27份毛木耳菌株（野生14株、栽培13株）的遗传多样性进行分析。首先随机选取3个菌株（2个野生菌株、1个栽培菌株）的DNA为模板,从144对SSR引物中筛选出扩增条带清晰、稳定性强、多态性丰富的引物24对。24对SSR引物共检测到116个多态性SSR片段,每对引物的多态性片段有3-7个,引物平均检测效率为4.83个,Shannon’s遗传多样性指数范围是0.866-1.885,多态性位点比率100%。供试菌株遗传相似系数范围是0.618-0.971,说明毛木耳种质资源具有丰富的遗传多样性。野生菌株与栽培菌株间平均遗传相似系数分别为0.746、0.779,说明毛木耳野生菌株遗传多样性更为丰富。经聚类分析,在遗传相似系数为0.680时,可将供试菌株分为无色（白色）类群Ⅰ和有色（浅黄色到红褐色）类群Ⅱ。遗传相似系数为0.704时,可将供试菌株中栽培菌株和野生菌株明显区分（14株野生菌株均在类群Ⅱ-2中,13株栽培菌株分别在类群Ⅰ和Ⅱ-1中）。本研究表明基于全基因组的SSR标记能从分子水平上揭示各菌株间的遗传差异,丰富毛木耳遗传多样性的研究手段,并为进一步进行毛木耳的品种选育、遗传学研究等提供有力手段。     

香蕉炭疽菌菌株亲缘关系的RAPD分析

应用筛选的8个Operon随机引物对供试菌株的DNA进行扩增,所产生的RAPD图谱揭示了长时期蕉炭疽菌具有丰富的种内遗传多样性,UPGMA聚类分析的结果表明：26个香蕉炭疽菌被分为两个与地理来源相关的RAPD聚类群,它们分别由广东菌株和海南菌株为主组成,在两个香蕉菌群的外侧,两个胶胞炭疽菌菌株聚为一个小的外群,这些结果表明香蕉炭疽菌存在有与地域相关的种下类群分化。     

分离自杭子梢等3个宿主的根瘤菌的表型分析*

对86株分离自杭子梢、决明和菜豆的根瘤菌及20株已知参比菌进行了数值分类和全细胞蛋白SDS-PAGE的表型分析。在数值分类聚类中,所有供试菌在68％的相似性水平上分为两群。群I为快生和中侵生根瘤菌,群Ⅱ为慢生根瘤菌。群I在85％的相似性水平上又可分为3个亚群,群Ⅱ在76％的相似性水平上分为3个亚群。蛋白电泳结果表明,群I在68％的相似性水平上,分为4个亚群,其中亚群1和亚群2相当于数值分类中的亚群1,亚群3和亚群4与数值分类中的亚群2和亚群3相对应;群Ⅱ在59％的相似性水平上分为3个亚群,分别与数值分类中的亚群3、亚群1和亚群2大致对应。这说明两种方法在分类上得到的结果比较接近。正在通过进一步的实验确定两种方法一致的未与已知菌株聚在一起的亚群的分类地位。研究结果还表明,三种宿主的根瘤菌存在着多样性。     

青岛市19个樱花品种的RAPD分析

采用改良的CTAB法提取19个樱花品种的基因组DNA.利用RAPD技术对19个樱花品种进行亲缘关系鉴定和品种分类研究.从60条10 bp随机引物中筛选出32条扩增效果较好的引物进行扩增,共扩增出533条带,其中多态性带为406条,多态率达76.17%.根据扩增结果进行UPGMA聚类分析,聚类结果将19个品种分为2大类群,第1类群主要为杂交樱系;第2类群为日本晚樱系,根据樱花的重瓣性、枝姿和花色又可分为不同的亚类群、类和亚类.结果表明应用RAPD技术对樱花分子水平的分类结果与传统分类学的结果基本一致,进一步证明种源、重瓣性、枝姿和花色都可作为樱花品种分类的重要指标.     

苦瓜种质遗传多样性的SRAP标记

从144对SRAP引物中筛选出61对多态性强、重复性好的SRAP引物,对43份苦瓜种质DNA进行了扩增,共得到2078条谱带,其中多态性谱带863条,平均每对引物扩增得到14.15条多态性谱带、多态性位点百分率为 42.11%。用UPMGA方法进行聚类分析,供试苦瓜种质的遗传相似系数为0.50～0.95,在阈值0.65 处( L1)可将苦瓜分为2个类群,第Ⅰ类群为野生种,第Ⅱ类群为半栽培种和栽培品种;在阈值0.80 处( L2)将第Ⅱ类群分为5个亚类群,L2 的划分反映了苦瓜种质间的遗传多样性与果实性状、来源或地理分布有较高相关性。在阈值0.83处,第Ⅱ1亚类群又分为4组,大致分为滑身苦瓜(粗棱无瘤)、大顶苦瓜（棱细大圆瘤、倒锥形）、棱细圆瘤苦瓜以及尖刺瘤或凸瘤苦瓜,分类结果与苦瓜的刺瘤有无、棱条粗细、瘤的大小和瓜色等密切相关,初步认为刺瘤苦瓜为较原始类型。     

新麦草种质的SSR遗传多样性及群体结构分析

利用38对SSR引物对来源于不同国家与地区的171份野生和栽培新麦草单株种质进行遗传多样性和群体结构分析。研究结果显示,有效引物在新麦草单株材料间共获得308个位点,多态性位点275个,多态性百分率为89.29%,供试新麦草材料的遗传相似性系数介于0.537～0.899之间,平均为0.742。群体结构分析、主成分分析与NJ聚类法均将供试材料分为3个类群,且类群间的材料相互渗透形成混合类群,分类结果与遗传相似性系数分析表明171份新麦草单株种质分布较集中;3种分类方法对新麦草材料3个不同类群的划分结果基本一致,但混合类群的划分存在差异,每个类群的新麦草单株材料来源背景不同,未表现出明确的地域性规律。     

香蕉33个品种的RAPD研究

利用RAPD技术对香蕉（Musa nana Lour.)33个品种的遗传变异进行了研究,从249个随机引物中筛选出18个有效引物,用它们共扩增出192条DNA带,其中183条为多态性带,占95．31％,平均每个引物扩增的DNA带数为10．67条,利用18个有效引物扩增的192条DNA带对香蕉33个品种间的亲缘关系进行UPGMA聚类分析,计算出33个品种间的平均遗传距离为0．3412。在此基础上建立了香蕉33个品种的DNA分子系统树状图。该系统将香蕉33个品种划归A,B,C和D4个群,其中A群20个品种,B群5个品种,C群2个品种,D群6个品种;A群又可以分为3个亚群。对香蕉遗传多样性分子基础进行了探讨。     

Analysis of the sugar-binding specificity of mannose-binding-type Jacalin-related lectins by frontal affinity chromatography--an approach to functional classification

The Jacalin-related lectin (JRL) family comprises galactose-binding-type (gJRLs) and mannose-binding-type (mJRLs) lectins. Although the documented occurrence of gJRLs is confined to the family Moraceae, mJRLs are widespread in the plant kingdom. A detailed comparison of sugar-binding specificity was made by frontal affinity chromatography to corroborate the structure-function relationships of the extended mJRL subfamily. Eight mJRLs covering a broad taxonomic range were used: Artocarpin from Artocarpus integrifolia (jackfruit, Moraceae), BanLec from Musa acuminata (banana, Musaceae), Calsepa from Calystegia sepium (hedge bindweed, Convolvulaceae), CCA from Castanea crenata (Japanese chestnut, Fagaceae), Conarva from Convolvulus arvensis (bindweed, Convolvulaceae), CRLL from Cycas revoluta (King Sago palm tree, Cycadaceae), Heltuba from Helianthus tuberosus (Jerusalem artichoke, Asteraceae) and MornigaM from Morus nigra (black mulberry, Moraceae). The result using 103 pyridylaminated glycans clearly divided the mJRLs into two major groups, each of which was further divided into two subgroups based on the preference for high-mannose-type N-glycans. This criterion also applied to the binding preference for complex-type N-glycans. Notably, the result of cluster analysis of the amino acid sequences clearly corresponded to the above specificity classification. Thus, marked correlation between the sugar-binding specificity of mJRLs and their phylogeny should shed light on the functional significance of JRLs.     

Biological and Molecular Characterization of Taiwanese Isolates of Cucumber mosaic virus Associated with Banana Mosaic Disease

Banana mosaic disease (BMD) caused by Cucumber mosaic virus (CMV) has become an important threat to the banana industry. We collected and characterized 10 CMV isolates associated with BMD in Taiwan and compared their biological characteristics and coat protein sequences. The isolates fell into four pathotypes on the basis of the symptoms they induce on banana, Nicotiana glutinosa and Vigna unguiculata (cowpea). Double-stranded RNA analysis revealed that the different pathotypes are not related to the presence of CMV satellite RNA. Phylogenetic analysis of worldwide CMV coat protein sequences revealed that among the currently known CMV subgroups IA, IB and II, subgroup IB is phylogenetically unresolved. Our CMV isolates form a new subgroup, IT, within subgroup I. In addition, we resolved another new CMV subgroup, IS, within subgroup I. The analysis also revealed that isolates within different subgroups can infect the banana.     

Genetic relationships among a collection of Musa germplasm by fluorescent-labeled SRAP

Edible banana and plantains of the Musa genus are important staple food crops cultivated in humid tropical and subtropical climatic zones. These crops are important for subsistence farming in rural communities and also to generate significant employment and income. In an effort to increase the genetic variability of available cultivars, indexed accessions have been introduced into a regional collection in southeastern Mexico, through the Banana Bioversity International Program. The aim of this study was to use the fluorescently labeled sequence-related amplified polymorphism (SRAP) molecular marker system to characterize the genetic variability within 71 accessions of the existing collection and resolved uncertainties for the better management of the collection, as a preliminary step to establishing a breeding program. These accessions, which included wild species and cultivars of different subgroups, were consistently identified and separated by SRAP markers. A total of 330 polymorphic bands were detected using 12 primer combinations. The average number of polymorphic bands per primer pair was 27.5. The genetic similarity between accessions ranged between 0.44 and 0.97, as estimated using Jaccard's coefficient. Moreover, SRAP marker system probed to be useful to identify closely related accessions in the genus Musa and facilitated the recognition of duplicates to be eliminated and clarified uncertainties or mislabeled banana accessions introduced to the collection.     

浙江省薄皮甜瓜地方品种的表型遗传多样性

利用表型性状探讨了浙江省沿海地区27份薄皮甜瓜地方品种资源的遗传多样性。结果表明48个质量性状遗传多样性指数在0.17–1.98之间;33个数量性状的变异系数在4.56%–83.50%,表明其丰富的遗传多样性。形态学聚类分析表明,在相似系数0.30处可以将27个资源分成两大类,这与按生育期长短分类结果完全一致;亚类的划分与果实形状、种子形状、叶片颜色、果皮颜色、覆纹颜色等质量性状具有一定的相关性,但其划分依据相对独立。本研究结果进一步丰富了甜瓜的评价体系,并为今后优异基因资源的挖掘与利用提供重要依据。     

甘蔗近缘种滇蔗茅(Erianthus rockii)表型性状遗传多样性研究

选用6个数量性状和23个质量性状对滇蔗茅野生资源的表型变异、多样性及聚类关系进行分析。结果表明,数量性状变异系数在12.72%~22.38%之间,最大的是田间锤度,为22.38%,其次是茎径,为22.27%,最小的是叶长,为12.72%;质量性状的曝光后节间颜色多样性丰富,茎形、芽形、生长裂缝、节间形状、花序形状等5个性状均表现一致;聚类分析表明51份滇蔗茅无性系材料可分为4大类群和5个亚类群。遗传多样性和聚类分析为资源杂交利用和优异基因挖掘提供参考。     

红麻微卫星DNA标记指纹图谱的构建

DNA指纹图谱对新品种选育、种质资源保存和管理具有重要的意义。然而,利用SSR标记构建红麻DNA指纹图谱的研究仍十分有限。在本研究中,利用课题组开发并筛选出的131对SSR引物,分析不同来源的96份红麻种质资源,包括红麻品种审定的区试对照品种福红952。结果表明,131对引物共扩增出375条带,平均每对引物扩增出2.6条带。以遗传相似系数0.614为切割线时,可以分为2个类群,52个为类群P1,44个为类群P2;以遗传相似系数0.710做切割线,可分为5个亚群。利用这131对引物标记所得的数据成功绘制了一份85个品种独特的指纹图谱,其中福红952可被HcEMS238引物特异识别。其他11份因存在遗传相似性高的现象,未被识别。上述结果为红麻品种的真实性鉴定及遗传多样性分析提供依据。     

甘蔗近缘种滇蔗茅(Erianthus rockii)表型性状遗传多样性研究

为有效评价和利用蔗茅种质资源,挖掘其优良性状,以滇、黔、川考察收集的29份蔗茅为材料,选取5个数量性状为指标,对其多样性指数、变异系数、数量性状之间的相关性、数量性状与经纬度、海拔的相关性进行研究。分析结果表明：(1)共采集到25份高海拔种质资源,其中海拔超过2800米有4份,进一步丰富了甘蔗野生种质资源库;(2)蔗茅种质资源数量性状的Shannon-Wiener多样性指数均较高,株高多样性指数最高(1.441),锤度多样性指数最低(1.291);数量性状遗传变异较丰富,各性状变异系数范围为21%～38%,变异系数最大的为株高(38%),最小的为叶长(21%);(3)蔗茅种质资源性状差异显著,叶长、叶宽、株高、茎径存在较大相关性,而与锤度不相关;叶宽与经度呈正相关,与纬度、海拔呈负相关。(4)聚类分析结果表明,蔗茅种质资源可分为四大类群,其中Ⅱ类群(EF-27)具有良好的数量性状和锤度品质潜力,可推荐作为甘蔗育种杂交利用首选材料。     

Analysis of genetic diversity and relationships in East African banana germplasm

The genetic diversity and phylogenetic relationships of 29 East African highland banana (Musa spp.) cultivars and two outgroup taxa, M. acuminata Calcutta 4 and Agbagba were surveyed by RAPD analysis. A genetic similarity matrix was established based on the presence or absence of polymorphic amplified fragments. Phylogenetic relationships were determined by UPGMA cluster analysis. RAPDs showed that the highland bananas are closely related with a narrow genetic base. Nevertheless, there were sufficient RAPD polymorphisms that were collectively useful in distinguishing the cultivars. The dendrogram was divisible into a major cluster composed of all the AAA highland banana cultivars and Agbagba (AAB) and a minor cluster consisting of Kisubi (AB), Kamaramasenge (AB) and Calcutta 4 (AA). Several subgroups are recognized within the major cluster. RAPD data did not separate beer and cooking banana cultivars. Our study showed that RAPD markers can readily dissect genetic differences between the closely related highland bananas and provide a basis for the selection of parents for improvement of this germplasm. Received: 28 June 2000 / Accepted: 1 August 2000