不同产地连翘EST-SSR标记遗传多样性研究

以采自连翘主产区河南和山西12个产地的77份连翘种质资源为试材,采用EST-SSR分子标记技术分析其遗传多样性,以期探索不同产地连翘的遗传相似性以及其关键影响因素。结果表明:从60对引物中筛选出14对扩增条带清晰,稳定性好的多态性EST-SSR引物,14对引物在77份样品中共扩增出370条带,多态性条带368条,多态位点百分率为99.46%,12个产地的遗传距离范围是0.020 3~0.092 2,平均遗传距离为0.055 8。根据遗传相似系数对12个产地进行聚类分析,在0.935处把12个居群聚为5类;同时对77份样品进行聚类分析,在0.72处把77份样品聚为5类,个体聚类结果与产地聚类结果相似。聚类结果分析表明,连翘的遗传相似性与地理距离没有显著的相关性,主要与生长环境以及海拔等因素有关。试验结果揭示了不同产地连翘遗传相似度的关键因素,为连翘亲缘关系的鉴定、连翘资源的保护与开发奠定了基础。     

甜叶菊重要农艺性状关联分析

为挖掘与甜叶菊重要农艺性状显著相关标记,利用相关标记辅助甜叶菊育种。本研究对93份甜叶菊种质材料11个重要农艺性状描述性统计,并利用58对EST-SSR引物对其扩增,群体遗传结构分析,基于以上分析采用Tassel 5.0的GLM (generalized linear model)模型进行EST-SSR标记与甜叶菊11个重要农艺性状的关联分析。分析检测到10个标记与6个农艺性状极显著相关,各标记对表型变异的解释率范围为0.071 6～0.189 3,部分标记与2～3个农艺性状极显著关联。     

核果类果树EST SSR标记研究进展

介绍了EST SSR分子标记的原理和特点,并且对EST SSR技术在核果类果树分析资源、构建遗传图谱、挖掘基因、比较作图等方面的研究进展进行综述。     

小麦EST-SSR标记的开发和遗传作图

【目的】利用小麦EST序列数据库开发EST-SSR标记。【方法】对GenBank/dbEST注册的普通小麦EST序列(2006.4.18—2007.2.4)进行SSR查找,采用Primer5.0软件设计EST-SSR引物,选用3个小麦品种进行有效性检测,利用RIL群体和Mapmaker/Exp3.0软件进行遗传作图。【结果】在265362条普通小麦EST序列中,共发现6314个SSR,占整个EST数据库的2.38%。其中二核苷酸、三核苷酸重复序列最多,分别为2237(35.43%)和2084(33.01%)个。二核苷酸重复中,以GA/CT和AG/TC出现频率最高、分别占SSR总数的17.85%和10.37%,其次是CA/GT(4.07%)和AC/TG(2.53%);三核苷酸重复中,CAA/GTT(3.93%)、CGG/GCC(3.83%)、CGC/GCG(3.36%)、GGC/CCG(3.14%)、CTT/GAA(2.53%)、TGC/ACG(2.27%)以较高的频率出现。根据筛选得到的微卫星序列共设计了596个EST-SSR引物对,选择其中95分以上的194个合成。PCR检测表明,165个引物对(85%)可以扩增出稳定清晰的带型;在RIL群体中检测到21个EST-SSR引物26个位点有多态性,将其中的23个位点整合到已有的小麦遗传图谱上。【结论】开发了165个小麦EST-SSR新标记,EST序列是小麦SSR标记的重要来源。     

EST-SSR标记的发展和在植物遗传研究中的应用

SSR标记已经成为植物遗传育种中应用的主要的分子标记之一,然而,SSR引物的开发源于基因组文库,即花费大又效率低。随着大量表达序列标签(ESTs)的出现,对于许多植物而言,利用ESTs数据库开发SSR引物是一项高效、低花费的选择。目前,EST-SSR标记在一些植物中的利用已有报道,笔者就EST-SSR标记的发展和在植物遗传中应用的研究进展进行回顾和评述。     

Characterization of dinucleotide and trinucleotide EST-derived microsatellites in the wheat genome

Over the past decade microsatellites or simple sequence repeats (SSRs) have attracted a considerable amount of attention from researchers. The aim of the present paper was to analyse expressed sequence tag-derived SSR (EST-SSR) marker variability in wheat and to investigate the relationships between the number and type of repeat units and the level of microsatellite polymorphism. Two hundred and forty-one new EST-SSR markers available in a public database () were characterized in eight durum wheat cultivars (Svevo, Ciccio, Primadur, Duilio, Meridiano, Claudio, Latino, Messapia), two accessions of Triticum turgidum var. dicoccoides (MG4343, MG29896), one accession of T. turgidum var. dicoccum (MG5323) and in the common wheat cv. Chinese Spring. Of these, 201 primer pairs (83.4%) amplified PCR products successfully, while the remaining 40 (16.6%) failed to amplify any product. Of the EST-SSRs analysed, 45.2% of the primer pairs amplified one or two PCR products. Multiple discrete PCR products were observed among both di- and trinucleotide EST-SSR markers (31.2 and 40.5%, respectively). Markers based on dinucleotide microsatellites were more polymorphic than those based on trinucleotide SSRs in the 12 wheat genotypes tested (68.9 and 52.7%, respectively). An average of 2.5 alleles for dinucleotide and 2.0 alleles for trinucleotide SSRs was observed. The data reported in the present work indicate the presence of a significant relationship between motif sequence types and polymorphism. The primer set based on the AG repeat motif showed the lowest percentage of polymorphism (55.0%), while the primer set based on the AC repeat motif showed t he highest percentage (85.0%). Among trinucleotide SSRs, the AGG microsatellite markers showed the highest percentage of polymorphism (70.0%), and the ACG motif the lowest value (25.0%). The characterization of these new EST-SSR markers and the results of our studyon the effect of repeat number and type of motifs could have important applications in the genetic analysis of agronomically important traits, quantitative trait locus discovery and marker-assisted selection.     

大豆基因组SSR和EST-SSR在黄芪中的通用性分析

分子标记的种间通用性可降低其开发成本,提高利用效率,促进遗传研究较薄弱物种的分子遗传学研究。为开发黄芪SSR分子标记,本研究利用大豆的66对基因组SSR(G-SSR)和43对EST-SSR引物在黄芪基因组中进行通用性分析,并选出其中条带清晰易辨的23对引物对6种不同来源的黄芪进行遗传分析。结果表明:大豆G-SSR、EST-SSR引物在黄芪中的通用性比例分别为31.82%、76.74%,多态性引物分别占18.18%、53.49%,大豆EST-SSR在黄芪的通用性高于基因组SSR,且通用的大豆SSR标记可以用于不同来源黄芪的遗传多样性分析。本研究发掘的多态性SSR引物可以有效用于黄芪的分子遗传多样性研究。     

日本落叶松EST-SSR标记开发及二代优树遗传多样性分析

利用SSR标记研究选自第1代育种试验林、拟纳入二代育种群体的264株日本落叶松二代优树的遗传变异情况。利用1620条落叶松EST序列进行EST-SSR标记的开发,共发现58条序列中含有67个SSR位点,占全部EST序列的3.58%。获得7个多态性EST-SSR标记,其中5个在朝鲜落叶松、长白落叶松、兴安落叶松和华北落叶松中均可扩增出预期目标片段,且具有多态性,表明这些标记在落叶松属内的通用性良好。利用6个EST-SSR标记和4个gSSR标记对日本落叶松二代优树群体开展遗传多样性分析,每个位点的平均等位基因数为4.6个,有效等位基因平均数为3.1个。群体观察和期望杂合度均值分别为0.5902和0.5702;Nei's基因多样度和Shannon多样性指数分别为0.5691和1.0966;全部单株间遗传相似系数0.1725～0.9667。说明该二代优树群体的遗传多样性较高,具有构建二代育种群体的潜力。     

Identification of SSR loci in <Emphasis Type="Italic">Betula luminifera</Emphasis> using birch EST data

Expressed sequence tags(ESTs) are generated from single-pass sequencing of randomly picked cDNA clones and can be used for development of simple sequence repeat(SSR) markers or microsatellites.However,EST databases have been developed for only a small number of species.This paper provides a case study of the utility of freely available birch EST resources for the development of markers necessary for the genetic analysis of Betula luminifera.Based on birch EST data,primers for 80 EST-SSR candidate loci were ...     

Development of EST-SSR in foxtail millet (<Emphasis Type="Italic">Setaria italica</Emphasis>)

The development of EST-SSR in foxtail millet (Setaria italica) for polymorphism and transferability study was reported here. From 1213 EST sequences, 30 SSRs were obtained and primers were designed for 26 SSRs. Among them, four pairs of SSR primers amplified polymorphic products in 12 foxtail millet cultivars and one accession of Setaria viridis, a wild relative of foxtail millet, with 10 alleles detected for the four loci and 2.5 alleles per locus. In addition, ten SSR markers could be transferred to other nine Gramineae species. The putative functions of 11 ESTs containing polymorphic and transferable SSRs were also identified.