Amplified fragment length polymorphism as a tool for molecular characterization of almond germplasm: genetic diversity among cultivated genotypes and related wild species of almond,and its relationships with agronomic traits

Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient method for producing DNA fingerprints and molecular characterization. Our objectives were to: estimate genetic similarities (GS), marker indices, and polymorphic information contents (PICs) for AFLP markers in almond cultivars; assess the genetic diversity of almond cultivars and wild species, using GS estimated from AFLP fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression and cultivar improvement. The genetic diversity of 45 almond cultivars from Iran, Europe, and America, were studied assaying 19 primer combinations. In addition, several agronomic traits were evaluated, including flowering and maturity times, self-incompatibility, and kernel and fruit properties. Out of the 813 polymerase chain reaction fragments that were scored, 781 (96.23%) were polymorphic. GS ranged from 0.5 to 0.96, marker indices ranged from 51.37 to 78.79, and PICs ranged from 0.56 to 0.86. Results allowed the unique molecular identification of all assayed genotypes. However, the correlation between genetic similarity clustering as based on AFLP and clustering for agronomic traits was low. Cluster analysis based on AFLP data clearly differentiated the genotypes and wild species according to their origin and pedigree, whereas, cluster analysis based on agronomic data differentiated according the pomological characterization. Our results showed the great genetic diversity of the almond cultivars and their interest for almond breeding.     

Persistence over time,overlapping distribution and molecular indications of interspecific hybridization in wild potato populations of Northwest Argentina

Solanum gourlayi and Solanum spegazzinii, wild potatoes endemic to Argentina, possess desirable traits for breeding. In periodical regenerations of accessions, variability was detected for morphology and breeding barriers. The persistence of these populations in nature was evaluated after more than 20 years. Both species were observed in all visited sites, along with other wild and cultivated potatoes. Chromosome numbers coincided with the originally reported, except for one population of Solanum gourlayi, with diploid and tetraploid cytotypes. The accompanying flora and environmental conditions revealed important alterations as the result of road construction, excessive stocking rates and overgrazing. Principal coordinate and cluster analyses and an AMOVA using AFLP data of three original accessions and the corresponding new accessions revealed high molecular variability and extensive overlapping. Plant grouping of accessions occurred at a distance of 0.58 for S. gourlayi, 0.62 for S. spegazzinii and 0.67 for both species. The role of natural hybridization and sexual polyploidization in the evolution of sympatric populations of wild potatoes is discussed.

基于AFLP遗传多样性和叶片内含物的银杏特异种质资源分析

本研究以南京林业大学银杏种质资源库中新收集30份特异种质资源为材料,通过对AFLP遗传关系和叶片黄酮总量和3个主要单体(槲皮素,山奈酚,异鼠李素)及可溶性糖含量分析,探究各特异种质资源间遗传联系。研究表明各种质资源间存在不同程度的遗传差异,不同种质资源黄酮总量和单体组成比例均具有较大差异,筛选出具有较高特异性的种质资源C16。以黄酮单体和可溶性糖含量进行系统聚类,与UPGMA聚类结果不能完全吻合,说明UPGMA聚类分析结果和叶片内含物含量聚类具有一定的差别。通过结合AFLP分子标记技术和生理特征探究特异种质资源遗传多样性,发掘银杏种质遗传变异,可以为选育银杏特异种质资源提供思路,后续种质资源筛选与鉴定提供依据。     

棉花分子遗传图谱构建和纤维品质性状QTL分析

以陆地棉(Gossypium hirsutum L.)中棉所8号和海岛棉(Gossypium barbadense L.) Pima90-53组配衍生的214个单株的F₂群体为材料,构建了包含110个SSR标记和65个AFLP标记的遗传连锁图谱。该图谱共包括42个连锁群,连锁群长度为4.5~147.3 cM,包括2~22个分子标记,标记间平均距离为11.6 cM,总长为2 030 cM,约占棉花全基因组的40.6%。应用复合区间作图法分析该组合的F₂单株和F_2:3家系纤维品质性状,共得到25个纤维品质数量性状基因座(QTL),其中5个与纤维长度相关s,分布在Chr.21、Chr.15、LG2和LG12上,可解释表型变异的10.2%~35.8%;4个与整齐度相关,分布在Chr.21、LG9、LG18和LG12上,可解释表型变异的12.6%~36.6%;7个与马克隆值相关,分布在Chr.9、LG1、LG9、LG20和LG12上,可解释表型变异的11.5%~26.1%;7个与断裂比强度相关,分布在Chr.21、Chr12、Chr.8、LG1、LG4和LG10上,可解释表型变异的16.5%~52.8%;2个与伸长率相关,分布在Chr.9和Chr.21上,可解释表型变异的18.1%和27.1%。LG9、LG12和Chr.21上存在QTL聚集区。     

黄瓜远缘群体分子遗传连锁图谱的构建和分析

以野生黄瓜品种和普通栽培黄瓜品种作亲本获得的142个F2群体为材料,采用AFLP,SRAP,SSR等分子标记进行遗传分析,构建了包含10个连锁群,有159个标记组成的黄瓜遗传连锁图谱,其中包括112个AFLP标记,39个SRAP标记和8个SSR标记。该遗传图谱覆盖基因组长度743.11 cM,平均图距4.67 cM。     

甘蔗SSR和AFLP分子遗传连锁图谱构建

采用甘蔗商业品种Co419与野生种割手密Y75/1/2杂交,获得269个单株,组成F1群体,用F102/356与商业品种ROC25回交获得266个单株,组成BC1群体。利用筛选的多态性条带丰富的36对SSR引物和12对AFLP引物,对两个群体进行PCR扩增和分子遗传连锁分析,构建甘蔗分子遗传连锁图谱。用F1群体获得630个分离标记,经χ2检测,298个标记为单双剂量标记,占总标记数的47%;用BC1群体获得571个分离标记,有264个标记为单双剂量标记,占总标记数的46%;4个亲本获得单双剂量标记的数量依次为Co41902/356Y75/1/2ROC25。在LOD≥5.0,相邻标记遗传距离≤40cM的条件下,F1群体有134个单双剂量标记被纳入55个连锁群,其中39个连锁群归属8个同源组,16个未列入,总遗传距离为1458.3cM,标记间平均图距为10.9cM;BC1群体有133个单双剂量标记被纳入47个连锁群,其中34个连锁群归属于8个同源组,13个连锁群未列入,总遗传距离为1059.6cM,标记间平均图距为8.0cM。从4个亲本单双剂量标记进入的连锁群数来看,Co419最多,归入34个连锁群,其次为Y75/1/2,归入20个连锁群,第3为02/356和ROC25,归入19个连锁群。研究结果表明,从单双剂量标记比例、形成连锁群数量、总遗传距离来看,F1群体构图质量要优于BC1群体。     

利用SRAP、ISSR、SSR标记绘制黄麻基因源分子指纹图谱

以国内外引进保存的231份黄麻种质资源为材料,分别采用SRAP、ISSR、SSR分子标记和编程DNA指纹图谱分析软件,绘制黄麻遗传资源基因组DNA指纹图谱。结果表明,通过筛选出的35对SRAP引物对231份黄麻品种进行标记分析,获得96份黄麻品种DNA指纹图谱;11个ISSR多态性引物对96份材料进行DNA标记分析,获得45份黄麻品种DNA指纹图谱;49对SSR多态性引物对48份黄麻品种进行DNA标记分析,获得13份黄麻品种DNA指纹图谱,累计完成了154份黄麻品种基因组DNA分子指纹图谱绘制。每一个被识别的品种都具有其独特的分子"身份证"。其他77份地方品种因与部分品种遗传相似性过高,未能被识别,表明黄麻地方品种存在较为严重的同种异名现象。     

Establishment and characterization of Brassica juncea–Orychophragmus violaceus additions, substitutions and introgressions

Intergeneric hybridizations between cultivated Brassica species and Orychophragmus violaceus have been shown to be an efficient approach to produce Brassica aneuploids. Herein B. juncea–O. violaceus additions, substitutions and introgressions were obtained among progenies of partial hybrids after B. juncea (2n = 36) was pollinated by O. violaceus (2n = 24) and they expressed some traits from O. violaceus or novel for two parents. The single O. violaceus chromosome which was added to or substituted into the B. juncea chromosome complement was distinguishable most easily in pollen mother cells at anaphase I (AI) from its darker staining and more condensed form. The one pair of the O. violaceus chromosome in the substitutions paired and segregated regularly with others from B. juncea, and the single one formed one bivalent with one B. juncea chromosome and showed normal segregation and was more darkly stained in some AI group. Stable introgressions with 2n = 36 gave amplified fragment-length polymorphism (AFLP) profiles mainly similar to those of the female B. juncea parent, but fragments specific for O. violaceus could be found in every plants together with those deleted in B. juncea and novel bands for two parents. The mechanisms behind these unusual results are discussed.     

黄淮海地区大豆品种苗期根系性状的遗传变异及与耐逆境胁迫的关系

从83份黄淮海地区代表性大豆地方品种和育成品种(系)中按根系类型选取32份,用以研究苗期根系性状的遗传特点、与地上部性状的相关以及与逆境胁迫的关系。大豆苗期一级侧根数、主根长、根干质量、总根长和根体积等性状,在品种间、各苗龄间均存在显著遗传变异;根系性状与整株干质量呈高度相关;根干质量、根总长和根体积的相对值与耐旱平均隶属函数值,一级侧根数、主根长、总根长、根体积、根干质量的相对值与耐铝毒平均隶属函数值呈极显著相关,且根系性状的相对值在品种间存在显著变异,可用做耐逆性选择的根系指标。     

Molecular characterization of novel resynthesized rapeseed (Brassica napus) lines and analysis of their genetic diversity in comparison with spring rapeseed cultivars*

Resynthesized (RS) rapeseed generated from interspecific hybridization between suitable forms of Brassica rapa L. (syn. campestris; genome AA, 2n = 20) and B. oleracea L. (CC, 2n = 18) represents a potentially important resource to expand genetic diversity in the narrow gene pool of oilseed rape (B. napus L., AACC, 2n = 38). In this study 165 RS rapeseed lines originating from crosses between an Indian Yellow Sarson (B. rapa ssp. trilocularis) and five different cauliflower (B. oleracea convar. botrytis) cultivars were studied using amplified fragment length polymorphism (AFLP) markers and their genetic diversity was compared in relationship to an assortment of 40 diverse spring oilseed and fodder rape varieties. Using three AFLP primer combinations, a total of 467 polymorphic bands were scored. Cluster analysis allowed differentiation among the different RS lines, which, as expected, were genetically highly divergent from the cultivars. The genetic diversity of the material is discussed in relation to its morphological variability with a view to the implementation of RS lines in oilseed rape breeding.     

基于SSR标记的80份烟草种质指纹图谱的构建及遗传多样性分析

利用均匀分布于烟草24个连锁群上的48个SSR标记对80份烟草材料进行分析。结果显示,48个SSR标记共扩增出211个等位基因,平均每个标记4.396个,Shannon′s信息指数I为1.034,多态信息含量值为0.229~0.905,观测杂合度（H_o）、期望杂合度（H_e）和Nei′s多样性指数（H）平均值分别为0.320、0.572、0.431。聚类结果表明,在遗传距离为0.68时可以将80份烟草种质分为2个类群。5个烟草居群间的遗传一致度在0.643~0.765范围内,遗传距离分布在0.268~0.442。筛选4对核心引物构建了不同烟草种质资源的数字指纹图谱, 可将这80份烟草种质资源全部区分开。本研究在分子水平上为筛选优质烟草种质资源、挖掘重要基因以及拓宽烟草育种遗传基础等工作提供科学依据。     

华北平原冬小麦根系生长规律及其与氮肥磷肥和水分的关系

通过田间试验，采用大口径根钻取样研究了华北平原冬小麦根系生长的基本规律及其氮，磷肥和根系生长的影响。结果表明，冬小麦根系生长分布规律是冬前较快，越冬不停，拔节至抽穗最，快抽穗后生长减缓并达到最大；根长和根重的增长遵循Ｌｏｇｉｓｔｉｃ模型。空间分布规律是：冬小麦根系随土层深度的分布，无论是根长还是根重都是由上至下逐渐减少，遵循指数递减模型。施用氮肥和磷肥能显著促进冬小麦根系的生长。水分污缺限制冬小麦     

高锌胁迫下不同大白菜品种生长、Zn吸收及根系分泌物的研究

采用液培试验研究了高锌胁迫下不同品种大白菜生长、Zn吸收及Zn富集品种与一般品种根分泌物特点。结果表明,Zn胁迫显著抑制了6个品种大白菜生长。0.5<根系耐性指数(RTI)<1.0。随锌水平的增加大白菜地上部干重、RTI明显下降。大白菜地上部Zn含量、根系Zn含量均随锌胁迫的增加而增加。植株吸收的Zn主要积累在大白菜根部。供试锌水平下,以丰园高抗1号的地上部、根系Zn含量明显高于其它5个品种,最大值为251.1、273.6 mg/kg (40mg/L Zn), 以丰抗80地上部、根系Zn含量最低。培养介质pH随锌水平增加先升高,然后下降。大白菜2个品种根系分泌物中检测到草酸、酒石酸、苹果酸3种低分子量有机酸,主要氨基酸包括丝氨酸、异亮氨酸、缬氨酸、赖氨酸（含量大于1.0μg/10 g干土）。锌胁迫降低了大白菜根系分泌的低分子量有机酸、氨基酸总量。Zn富集品种丰园高抗1号根系分泌的低分子量有机酸,加Zn与否都高于一般品种攻关2号。2个品种根分泌物中低分子有机酸和氨基酸含量与种类不同,尤其是低分子有机酸含量与种类不同是大白菜品种之间Zn吸收差异的重要原因     

对大豆耐萎蔫材料PO471938根系和地上部的性状鉴定、QTL定位

PI471938是从美国引进的大豆耐萎蔫抗旱种质资源。为更好了解和利用该材料,分别在灌水和干旱胁迫条件下比较PI471938与普通大豆品种Dare、丰收黄根系及地上部性状的差异,并配制杂交组合,构建分离群体,利用主基因-多基因混合遗传模型分析杂交后代根系性状的遗传规律。结果表明,在正常灌水和干旱处理条件下,PI471938的根干重、根体积、主根长均显著高于Dare和丰收黄(P<0.01),说明根系发达是PI471938耐萎蔫的重要原因。供试亲本和各世代材料的株高、地上部干重均与根干重及根体积显著正相关,可作为对根系性状进行间接选择的指标。在Dare×PI471938杂交组合的F₂代,不论在灌水还是干旱条件下,根干重均以微效多基因控制为主,主基因遗传率较低;根体积在灌水条件下表现多基因遗传,而在干旱条件下则由2对加性-显性-上位性主基因+加性-显性多基因控制,主基因遗传率为54.63%。在干旱条件下,丰收黄 × PI471938组合的根干重、根体积均以多基因控制为主。以在干旱条件下种植的Dare×PI471938组合的F₂代群体为材料,采用SSR标记对大豆根系及地上部性状进行QTL定位,检测到位于3个不同连锁群的5个主效QTL,表型贡献率在16.07%~38.44%之间。     

Genetic diversity of a global collection of maize genetic resources in relation to their subspecies assignments,geographic origin,and drought tolerance

The genetic diversity among an international collection of 40 maize accessions has been evaluated using DNA ISSR fingerprinting. Among the 180 ISSR markers scored by 15 primers, 161 markers (89.59%) were polymorphic and 19 were unique in 16 accessions. A cluster tree based on the average distance coefficients and the Dice similarity indices divided the accessions into three major groups, each including clusters of accessions assigned to their subspecies. However, a low level of genetic differentiation among the accessions was demonstrated by the STRUCTURE analysis of ISSR data in agreement with the low gene flow (Nm) value among the accessions. A scatter diagram of the principal component analysis (PCA) based on ISSR data analysis revealed that the accessions were differentiated into three groups comparable to those produced by the cluster analysis, in which some accessions of the same subspecies showed a close similarity to each other. A scatter diagram of the principal coordinate analysis (PCoA) based on the drought tolerance indices (DTIs) showed that nine genetically similar accessions share drought tolerance characteristics; these include four of subsp. indurata, three of subsp. everata, and two of subsp. indentata. An abundance of unique ISSR alleles found in the 16 accessions, including the nine drought-tolerant accessions, represents rich untapped genetic resources and these accessions may be exploited in the future breeding of maize commercial lines.     

玉米ZmGS5基因克隆、分子特性分析及对拟南芥的遗传转化

高产是玉米育种的重要目标,籽粒大小是决定籽粒产量的重要因子。基于水稻中控制籽粒大小的OsGS5基因编码序列,利用同源克隆方法,获得了玉米ZmGS5基因,其cDNA全长为1 695bp,开放阅读框1 491bp,编码496个氨基酸,含有Peptidase-S10结构域、1个信号肽和1个丝氨酸羧肽酶（serine carboxypeptidases,SCP）类蛋白所特有的催化活性中心,这些都与SCP家族结构特点相符,也与OsGS5相关研究结果相同;磷酸化位点分析结果表明,ZmGS5含有丝氨酸、苏氨酸和酪氨酸等蛋白激酶识别位点。qRT-PCR分析显示ZmGS5在雄穗和叶片中的表达量较高,而在胚及胚乳中的表达量相对较低。除此之外,采用农杆菌介导法,建立了拟南芥的遗传转化体系,得到纯合转基因株系,T₃代转基因拟南芥种子千粒重为0.0169g,较野生型千粒重（0.0139g）高。     

应用RAPD标记进行茶树优异种质遗传多态性、亲缘关系分析与分子鉴别

采用RAPD分子标记技术,对茶树优异种质资源的遗传多态性、亲缘关系和分子鉴别进行了研究。结果表明,20个引物在15份优异资源中得到1050个RAPD位点,平均52．5个位点／引物,70个位点／资源。在所获得的137条可重现谱带中,8条是单态的,129条是多态的,多态性程度达94．2％;引物的多态性相对频度为0．24～0．83,总平均为0．47;遗传距离在0．16～0．62之间,平均为0．37,这可能与我国是茶树的原产地和起源中心有密切关系。RAPD数据的类平均法聚类结果显示,15份资源可划分为3个类群,从相似性系数讨论了资源间的亲缘关系。应用12个引物产生的20个特异标记的存在和11个特异的缺失,可以鉴别所有15份优异茶树种质资源。RAPD可以作为茶树优异种质资源遗传多态性、系统演化和分子鉴别研究的有效手段之一。     

甘蔗CIPK23基因克隆及对低钾、干旱、盐胁迫的响应

本研究采用RT-PCR技术从低钾胁迫的甘蔗根系中克隆得到一个长度为1 749 bp的与CBL互作的丝氨酸/苏氨酸蛋白激酶基因,命名为Ss CIPK23(Gen Bank登录号为KM981737),包含1 350 bp的开放阅读框(ORF),可编码一个449氨基酸残基的多肽。Ss CIPK23具有CIPK基因家族典型的蛋白激酶结构域和NAF调控结构域。进化树分析显示Ss CIPK23与其他作物的CIPK23关系较近,具有较高的保守性。q PCR分析结果表明,在低钾、干旱和盐胁迫下,Ss CIPK23的表达都发生改变。在低钾胁迫24 h后Ss CIPK23相对表达量开始上升,而且随着胁迫时间的延长,相对表达量持续增加;而在干旱和盐胁迫下,相对表达量最高出现在48 h,随后表达量开始下降,暗示了该基因在低钾、干旱和盐胁迫下发挥重要的调控作用,可为深入研究Ss CIPK23基因功能奠定坚实的基础。     

甜菜耐盐性形态学、生理生化特性及分子水平研究进展

盐胁迫被认为是主要的非生物胁迫之一,对作物生长发育有着重要影响。甜菜具有一定的耐盐性,明确甜菜耐盐机理并加以利用,进而培育出耐盐性较强的甜菜新品种对高效利用盐渍化土壤具有重要意义。从盐胁迫对甜菜的形态学特征、生理生化特性及分子水平3个方面阐述了甜菜耐盐的研究进展,同时对当前耐盐研究存在的问题和今后可以进行的研究方向进行了探讨。