Development of diversity array technology (DArT) markers for assessment of population structure and diversity in Aegilops tauschii

Aegilops tauschii Coss. is the D-genome donor to hexaploid bread wheat (Triticum aestivum) and is the most promising wild species as a genetic resource for wheat breeding. To study the population structure and diversity of 81 Ae. tauschii accessions collected from various regions of its geographical distribution, the genomic representation of these lines were used to develop a diversity array technology (DArT) marker array. This Ae. tauschii array and a previously developed DArT wheat array were used to scan the genomes of the 81 accessions. Out of 7500 markers (5500 wheat and 2000 Ae. tauschii), 4449 were polymorphic (3776 wheat and 673 Ae. tauschii). Phylogenetic and population structure studies revealed that the accessions could be divided into three groups. The two Ae. tauschii subspecies could also be separately clustered, suggesting that the current taxonomy might be valid. DArT markers are effective to detect very small polymorphisms. The information obtained about Ae. tauschii in the current study could be useful for wheat breeding. In addition, the new DArT array from this Ae. tauschii population is expected to be an effective tool for hexaploid wheat studies.     

山羊草谷胱甘肽S-转移酶基因家族鉴定及表达分析

谷胱甘肽S-转移酶是一种多功能蛋白酶,在植物体内参与干旱、盐、低温、重金属等多种非生物胁迫的调节;山羊草是普通小麦D染色体组的供体物种,深入挖掘山羊草中GST基因,对进一步分析六倍体小麦GST基因的功能具有重要意义。本研究利用信息生物学手段,在山羊草中共发现114条GST基因序列,分属于6个亚族;基因复制分析发现共4对基因发生了基因复制,且均为纯化选择;采用荧光定量PCR对部分GST基因在非生物胁迫下的表达分析发现,8个GST基因在响应干旱和盐胁迫时,主要在根部显著上调表达,3个GST基因在响应低温胁迫时,在根和叶中均显著上调表达,说明山羊草中的GST基因在应答非生物胁迫时,在不同组织中的表达存在着差异。     

顶芒和无芒山羊草育种价值及细胞学标记

为了评价顶芒山羊草和无芒山羊草在小麦育种中的利用价值,本研究利用人工接种和近红外二极管阵列分析仪分别对圆锥小麦-顶芒山羊草双二倍体和中国春-无芒山羊草双二倍体的抗病性及籽粒品质进行了鉴/测定。结果表明,二者均近免疫小麦条锈病和白粉病,且其籽粒蛋白和湿面筋含量均极显著高于对照小麦,因此,这2个种质值得向小麦进行回交转育。为了建立可用于鉴定小麦背景中2种山羊草的细胞遗传标记辅助鉴定相应回交群体,利用寡聚核苷酸原位杂交(FISH)方法对2份双二倍体进行分析。结果发现,探针(GAA)8可有效鉴定小麦背景中的顶芒山羊草染色体;探针Oligop Sc119.2-1、Oligo-p Ta-535-1和(GAA)8结合使用可有效鉴定小麦背景中的无芒山羊草染色体。本研究首次建立的2种山羊草细胞遗传学标记可用于相应杂种后代的筛选与鉴定工作,为辅助选育含有2种山羊草优异基因的小麦新种质奠定了基础。     

内生放线菌ts-6对灰葡萄孢菌的拮抗作用及其防病效果

近年来的研究表明,植物体组织内普遍存在各类内生菌,这些内生菌有的可提高植物对不良环境的抗逆性,有的可抑制或延缓植物病原菌的侵染危害,而且它们定植于植物体内,不易受到外界环境的影响,比传统生防菌的防病效果更稳定和持久。     

偏凸山羊草的核型和C-带研究

通过对偏凸山羊草的核型和C-带分析研究表明,偏凸山羊草的D染色体组与节节麦的D染色体组很相似,其可能来自于节节麦;M^V染色体组臂比较大,有2对普通小麦所没有的近端着丝粒染色体,且所显C-带带型与普通小麦的染色体组有明显区别。     

Multivariate analysis of genetic variation in Aegilops tauschii from the world germplasm collection

A study of Aegilops tauschii subspecies constitution was undertaken. The data on allozyme and morphologic variation among 308 plants from 154 accessions were used for multivariate analysis. ACPH1 and (glume width)/(rachis segment width) ratio were found to be reliable criteria to distinguish between sspp. tauschii and strangulata.     

Granule‐bound starch synthase (GBSS) diversity of ancient wheat and related species

Granule‐bound starch synthase of ancient wheat and related species was examined by sodium dodecyl sulphate polyacrylamide gel. A total of 13 different alleles were revealed in a collection of three accessions of diploid wheat, six accessions of tetraploid wheat, 49 accessions of spelt wheat, nine accessions of Sitopsis and two accessions of Aegilops tauschii. A new allele named Wx‐A1a′ appeared in four spelt wheat accessions. The tetraploid wheat accessions evaluated did not show any polymorphism; nevertheless the tetraploid accessions of Sitopsis section revealed three novel alleles. The novel allele Wx‐D^dn1g was found in two accessions of A. ventricosa and the Wx‐D^dcm1h and Wx‐D^dcm1i in two accessions of A. crassa. A novel allele named Wx‐A^u1g was found in Triticum urartu, which is different from the also new Wx‐A^m1h allele of T. monococcum. The diploid‐related species accessions revealed two novel alleles named Wx‐B^sl1h and Wx‐B^s1g found, respectively, in A. longissima and A. speltoides. The amylose content was measured for the different alleles found in all evaluated species and no significant effects of the allele composition on the amylose content were detected.     

Association analysis of grain traits with SSR markers between Aegilops tauschii and hexaploid wheat(Triticum aestivum L.)

Seven important grain traits, including grain length(GL), grain width(GW), grain perimeter(GP), grain area(GA), grain length/width ratio(GLW), roundness(GR), and thousand-grain weight(TGW), were analyzed using a set of 139 simple sequence repeat(SSR) markers in 130 hexaploid wheat varieties and 193 Aegilops tauschii accessions worldwide. In total, 1 612 alleles in Ae. tauschii and 1 360 alleles in hexaploid wheat(Triticum aestivum L.) were detected throughout the D genome. 197 marker-trait associations in Ae. tauschii were identified with 58 different SSR loci in 3 environments, and the average phenotypic variation value(R2) ranged from 0.68 to 15.12%. In contrast, 208 marker-trait associations were identified in wheat with 66 different SSR markers in 4 environments and the average phenotypic R2 ranged from 0.90 to 19.92%. Further analysis indicated that there are 6 common SSR loci present in both Ae. tauschii and hexaploid wheat, which are significantly associated with the 5 investigated grain traits(i.e., GA, GP, GR, GL, and TGW) and in total, 16 alleles derived from the 6 aforementioned SSR loci were shared by Ae. tauschii and hexaploid wheat. These preliminary data suggest the existence of common alleles may explain the evolutionary process and the selection between Ae. tauschii and hexaploid wheat. Furthermore, the genetic differentiation of grain shape and thousand-grain weight were observed in the evolutionary developmental process from Ae. tauschii to hexaploid wheat.     

粗山羊草JAZ基因家族的全基因组鉴定与分析

为了挖掘可用于小麦茉莉酸调控通路及其穗部或花器官发育研究的候选基因,基于已发布的粗山羊草全基因组数据,利用生物信息学分析方法鉴定了粗山羊草JAZ基因家族,并从染色体分布、基因及蛋白结构、启动子顺式作用元件、系统进化关系和基因表达模式等方面对该基因家族的特征进行了比较分析。结果表明,本研究共鉴定到9个粗山羊JAZ基因,命名为AetJAZ1-AetJAZ9。染色体定位结果显示,9个粗山羊草JAZ基因分别定位在2D、5D、6D和7D染色体上,其中在7D染色体上分布最多。进化分析表明,粗山羊草JAZ蛋白与短柄草JAZ蛋白亲缘关系最近,且9个粗山羊草JAZ蛋白被分别聚类到了S5、S12、S13、S16和S20五个亚族中,其中S20亚族有五个粗山羊草JAZ蛋白。启动子分析表明,9个粗山羊草JAZ基因启动子顺式作用元件种类和数量存在差异,推测其各自的功能也存在差异。表达谱分析表明,粗山羊草JAZ基因在粗山羊草不同组织间存在不同的表达特性,且不存在组成型表达基因,其中,AetJAZ1和AetJAZ2表现出明显的组织特异性,分别只在穗部、雌蕊和雄蕊中特异表达。     

普通小麦与粗山羊草正反杂交研究

【目的】研究普通小麦与粗山羊草杂交后的成胚率、成苗率及F1代的田间表现,为提高小麦的杂交成功率提供参考。【方法】以小麦矮败不育系(RH/CS)、中国春、辽春10号3个春性小麦及济南17和济麦20 2个冬性小麦为供试小麦材料,Y122、Y212、Y215为3个粗山羊草材料,先以小麦为母本,粗山羊草为父本构建正交组合,并在去雄后1~5d连续授粉,分析授粉次数对授粉率的影响,再以粗山羊草为母本,普通小麦为父本构建反交组合,分析各组合下胚、胚乳的形成情况;对正交组合进行幼胚拯救后,统计各组合的成胚率和成苗率;并将幼苗移至大田中,观察F1代的田间表现。【结果】小麦反交组合的授粉率(70.32%)远高于正交组合(8.51%),但正交和反交组合均未能形成种子,需要幼胚拯救才能获得后代;重复授粉可以提高授粉率;正交时春麦或者冬麦做母本对胚的形成和成苗率没有影响;胚培养最佳时间为13~18d;组培苗移入大田后成活率极低,仅为5.20%;杂交F1代成活单株有效分蘖数平均为263个。【结论】普通小麦×粗山羊草杂交后授粉2~3次,并于13~18d进行胚培养,可以提高杂交成功率。