利用组织培养和辐射诱变创造高频率小麦与簇毛麦染色体易位

利用荧光原位杂交证明普通小麦与硬粒小麦－簇毛麦双二倍体杂种培养细胞和再生植株中能够发生属间染色体易位,易位染色体不仅有臂间易位,还有小片段易位,表明通过杂种组织培养是创造属间易位的一个可行的方法,辐射处理能够大幅度促进杂种愈伤组织细胞中的染色体数目和结构变异,特别是易位频率达到７．４％。观察还表明,培养时间对杂种愈伤组织细胞中染色体数目和结构变异都有较大影响,培养细胞的染色体 异在培养的初期阶段就     

小麦背景中簇毛麦6V染色体的遗传稳定性及其在配子中的传递

小麦－簇毛麦６Ｖ二体附加系,６Ａ（６Ｖ）二体代换系,６Ａ＾Ｌ．６Ｖ＾ｓ二体易位系在细胞学上是基本稳定的６Ｖ,６Ａ＾Ｌ．６Ｖ＾ｓ染色体能够通过配子稳定地传递给后代,在杂合状态下,带有６Ｖ的配子传递率普遍显著下降,在单体附加系（２１”Ｗ＋６Ｖ）中,６Ｖ通过雌配子的传递率（１１．３％）高于通过雄配子的传递率（５．９％）,在单体代换系（２０”Ｗ＋６Ａ－６Ｖ）中,６Ｖ通过雌配子的传递率（１０．４％）低于通过     

小麦-簇毛麦易位系的抗条锈性遗传分析

本文对7个小麦-簇毛麦易住系种质V9128-1、V9128-3、V9129-1、V3、V4、V5、V12的抗条锈性进行遗传研究。用小麦条锈菌对供试材料苗期接种鉴定表明,7个易位系的抗病谱存在着明显的差异,据基因推导原理和系谱分析,可初步推测这7个易位系所包含的抗条锈基因不尽相同。进而对两个抗病谱较宽的易住系的抗条锈性进行了遗传分析。结果表明：小麦．簇毛麦易位系V9128-1对条锈菌CY30的抗条锈性由一对显性基因控制,小麦-簇毛麦易位系V3对条锈菌CY31的抗条锈基因由一显一隐2对基因控制。揭示了小麦．簇毛麦易位系抗条锈性为寡基因控制,为尽快利用这些宝贵抗病基因,培育小麦抗锈品种提供了科学依据。     

从小麦-簇毛麦易位系TAC文库中筛选Hv-SITPK基因

本实验室已经通过基因芯片技术筛选到一个白粉菌诱导后上调表达的抗病相关基因Hv-S／TPK,并获得了它的全长cDNA序列。利用Hv-S／TPK的特异引物筛选小麦．簇毛麦6VS／6AL易位系基因组可转化人工染色体（Transformation-competent artificial chromsome,TAC）文库,获得了阳性TAC单克隆,并进一步获得了含有Hv-S／TPK cDNA序列的5160bp（GenBank Accession No．EU153366）的亚克隆。对亚克隆的序列分析结果表明,Hv-S/TPK基因在起始密码子和终止密码子之间有3个内含子和4个外显子,4个外显子序列与簇毛麦上已得到的Hv-S／TPK的cDNA序列100％同源。对起始密码子上游序列分析结果表明,该基因的调控序列中,含有W-Box、OCS-element等与抗病相关的元件。以TAC克隆为探针与小麦．簇毛麦6VS／6AL易位系有丝分裂中期染色体进行荧光原位杂交（Fluorescence in situ hybridization,FISH）,结果表明含有Hv-S／TPK基因的TAC克隆来自于簇毛麦。     

从小麦-簇毛麦易位系TAC文库中筛选Hv-S/TPK基因

本实验室已经通过基因芯片技术筛选到一个白粉菌诱导后上调表达的抗病相关基因Hv-S/TPK, 并获得了它的全长cDNA序列。利用Hv-S/TPK的特异引物筛选小麦-簇毛麦6VS/6AL易位系基因组可转化人工染色体(Transformation-competent artificial chromsome, TAC)文库, 获得了阳性TAC单克隆, 并进一步获得了含有Hv-S/TPK cDNA序列的5160 bp(GenBank Accession No. EU153366)的亚克隆。对亚克隆的序列分析结果表明, Hv-S/TPK基因在起始密码子和终止密码子之间有3个内含子和4个外显子, 4个外显子序列与簇毛麦上已得到的Hv-S/TPK的cDNA序列100%同源。对起始密码子上游序列分析结果表明, 该基因的调控序列中, 含有W-Box、OCS-element等与抗病相关的元件。以TAC克隆为探针与小麦-簇毛麦6VS/6AL易位系有丝分裂中期染色体进行荧光原位杂交(Fluorescence in situ hybridization, FISH), 结果表明含有Hv-S/TPK基因的TAC克隆来自于簇毛麦。     

筛选利用小麦微卫星标记追踪簇毛麦各条染色体

选用定位于普通小麦7个部分同源群上的276对微卫星引物对普通小麦中同春和簇毛麦的基因组DNA进行扩增分析,有148对引物可在两个物种间检测到多态性。利用上述显示多态性的引物进一步对7个中国春-簇毛麦二体附加系进行扩增分析,筛选出分别可用来追踪簇毛麦1V至7V染色体的引物wmc49（1BS）、wmc25（2BS）、gdm36（3DS）、gdml45（4AL）、wmc233（5DS）、wmc256（6AL）和gwm344（7BL）。此外还发现6DS上的微卫星引物gwm469可以用来追踪簇毛麦的2V染色体;2DS上的微卫星引物gdm107可用来追踪簇毛麦的6V染色体。进一步用涉及不同簇毛麦和小麦背景的小麦一簇毛麦染色体附加系、代换系和易位系进行扩增分析,这些微卫星标记也可用来鉴定簇毛麦的各条染色体。因此,这然簇毛麦染色体特异的微卫星标记可用来追踪普通小麦背景中的簇毛麦染色体。     

由簇毛麦V染色体引起的小麦-簇毛麦染色体代换系、易位系中线粒体蛋白质组的变化(简报)

线粒体是需氧生物中的一种半自主性细胞器.在能量代谢中,它起了一个关键的作用,柠檬酸循环、电子传递和氧化磷酸化过程均在线粒体内完成.线粒体具有高度的生物化学和遗传上的独立性.含有DNA和核糖核蛋白体.负责合成生物体内2%-5%的蛋白质[1].线粒体DNA具有自身复制能力,控制着众多的遗传性状.在植物中广泛存在的细胞质雄性不育则被认为是由线粒体基因组控制的性状[2].     

小麦-簇毛麦易位系的抗条锈性遗传分析

本文对7个小麦-簇毛麦易位系种质V9128-1、V9128-3、V9129-1、V3、V4、V5、V12的抗条锈性进行遗传研究.用小麦条锈菌对供试材料苗期接种鉴定表明, 7个易位系的抗病谱存在着明显的差异,据基因推导原理和系谱分析,可初步推测这7个易位系所包含的抗条锈基因不尽相同.进而对两个抗病谱较宽的易位系的抗条锈性进行了遗传分析.结果表明小麦-簇毛麦易位系V9128-1对条锈菌CY30的抗条锈性由一对显性基因控制,小麦-簇毛麦易位系V3对条锈菌CY31的抗条锈基因由一显一隐2对基因控制.揭示了小麦-簇毛麦易位系抗条锈性为寡基因控制,为尽快利用这些宝贵抗病基因,培育小麦抗锈品种提供了科学依据.     

小麦-簇毛麦易位系 6VS/6AL中6VS的遗传传递及其所携Pm21基因的遗传稳定性分析

以簇毛麦(Haynaldiavillosa(L.)Schur)物种专化重复序列探针pHv62及小麦(TriticumaestivumL.)第六部分同源群短臂专化RFLP探针Psr113对扬94_138(“扬麦158”的改良品系)与易位系92R149配制的F2群体进行分析,观察到易位系中的6V短臂在杂交后代中的传递率为69.5%,接近75%的理论值。对来自同一个F1的另外147株F2群体以6个白粉菌菌株进行苗期抗病性测定,检测结果表明6VS上所携Pm21基因在向“扬麦158”小麦基因型转移时,按显性单基因遗传,并能很好地表达。     

Identification and physical mapping of three Haynaldia villosa chromosome-6V deletion lines

Three deletion lines (del6V?2S-1, del6V? 2L-1, and del6V?2L-2) of Haynaldia villosa chromosome 6V added to wheat were identified by C-banding and characterized by RFLP analyses. The breakpoints were located at fraction lengths (FL) 0.58 in del6V?2S-1 in the short arm, and FL 0.66 in del6V?2L-1 and FL 0.64 in del6V?2L-2 in the long arm. Thirty-one Triticeae homoeologous group-6 DNA probes were used to map RFLP loci in the deletion lines and the wheat-H. villosa disomic substitution (DS) line 6V?2(6A). Nine probes failed to detect polymorphism between Chinese Spring and DS6V?2(6A). Ten of sixteen polymorphic short-arm loci were not detected in del6V?2S-1. Thus, the loci are located in the deleted distal chromosome region. Six RFLP markers were mapped in the proximal 58% of 6VS. Of 20 DNA markers specific for 6VL, six mapped in the distal 36% of the long arm, and nine mapped in the proximal 64% of 6VL. The breakpoint of the short arm of 6V?2 occurs between Xpsr106 and Xcdo270, and that of the long arm between Xpsr915 and Xmwg934. The powdery mildew resistance gene Pm21 is located on the short arm of chromosome 6V?2. Pm21 is present in del6V?2S-1, and can be further mapped in the proximal 58% of 6V?2S.     

Asymmetric somatic hybridization between Triticum aestivum L. and Haynaldia villosa Schur

Suspension cell-derived protoplasts of wheat, inactivated with different concentrations (0-2.5mol/L) of IOA, were fused by PEG method with the Haynaldia villosa protoplasts which originated from the calli 4-5d after subculture and were irradiated with 60Co-γ ray. Cell colonies, calli or regenerated plants were obtained from different combinations of fusion. The calli and plants were verified to be hybrids by chromosome counting, isozyme analysis and morphological inspection.     

Comparative study of symmetric and asymmetric somatic hybridization between common wheat and Haynaldia villosa

Symmetric and asymmetric protoplast fusion between long term cell suspension-derived protoplasts of Triticum aestivum (cv. Jinan 177) and protoplasts of Haynaldia villosa prepared from one-year-old embryogeneric calli was performed by PEG method. In asymmetric fusion, donor calli were treated with gamma ray at a dose of 40, 60, 80 Gy (1.3 Gy/min) respectively and then used to isolate protoplasts. Results of morphological, cytological, biochemical (isozyme) and 5S rDNA spacer sequence analysis revealed that we obtained somatic hybrid lines at high frequency from both symmetric and asymmetric fusion. Hybrid plants were recovered from symmetric and low dose γ-fusion combinations. GISH (genomic in situ hybridization) analysis proved exactly the existence of both parental chromosomes and the common occurrence of several kinds of translocation between them in the hybrid clones regenerated from symmetric and asymmetric fusion. And the elimination of donor DNA in hybrid clones regenerated from asymmetric fusion     

Standard karyotype of Triticum umbellulatum and the characterization of derived chromosome addition and translocation lines in common wheat

A standard karyotype and a generalized idiogram of Triticum umbellulatum (syn. Aegilops umbellulata, 2n = 2x = 14) was established based on C-banding analysis of ten accessions of different geographic origin and individual T. umbellulatum chromosomes in T. aestivum — T. umbellulatum chromosome addition lines. Monosomic (MA) and disomic (DA) T. aestivum — T. umbellulatum chromosome addition lines (DA1U = B, DA2U = D, MA4U = F, DA5U = C, DA6U = A, DA7U = E = G) and telosomic addition lines (DA1US, DA1UL, DA2US, DA2UL, DA4UL, MA5US, (+ iso 5US), DA5UL, DA7US, DA7UL) were analyzed. Line H was established as a disomic addition line for the translocated wheat — T. umbellulatum chromosome T2DS·4US. Radiation-induced wheat — T. umbellulatum translocation lines resistant to leaf rust (Lr9) were identified as T40 = T6BL·6BS-6UL, T41 = T4BL·4BS-6UL, T44 = T2DS·2DL-6UL, T47 = Transfer = T6BS·6BL-6UL and T52 = T7BL·7BS-6UL. Breakpoints and sizes of the transferred T. umbellulatum segments in these translocations were determined by in situ hybridization analysis using total genomic T. umbellulatum DNA as a probeContribution no. 94-349-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506-5502, USA     

The relationship between vernalization requirement and frost tolerance in substitution lines of wheat

Two sets of wheat (Triticum aestivum L.) substitution lines for the homoeologous group 5 chromosomes, 5A, 5B and 5D, carrying vernalization genes (Vrn-A1, Vrn-B1, Vrn-D1) were used to study the relationship between vernalization requirement and winter survival, with respect to the induction and maintenance of frost tolerance. Substitution lines carrying dominant Vrn loci substituted from the spring cultivars Zlatka (5A), Chinese Spring (5D) and the alternative cultivar eská Pesívka (5B) into three different winter wheat backgrounds, Vala, Koútka and Zdar, showed lower winter survival by 20, 36, and 41 % for substitutions of 5B, 5A and 5D, respectively, compared to the original winter cultivars. Reciprocal substitution lines between two winter cultivars Mironovskaya 808 and Bezostaya 1 carrying different recessive alleles, vrn-A1, vrn-B1, vrn-D1, did not exhibit a modified induction of frost tolerance, but the duration of good frost tolerance, as well as the ability to survive the whole winter, was changed. In accordance with the model suggesting that genes for vernalization act as a master switch regulating the duration of frost tolerance, substitutions of homoeologous group 5 chromosomes induced, at first, frost tolerance at a level equal to the parental cultivar, and then, relative to the different extent of saturation of vernalization requirement, they gradually lost both frost tolerance and their ability to re-induce significant frost tolerance with a drop in temperature following warm periods in the winter.     

Chromosome translocations in wild populations of tetraploid emmer wheat in Israel and Turkey

Translocation frequencies (as compared to the standard chromosome arrangement typified by that in Chinese Spring) in 9 or more genotypes from each of 15 populations of Triticum dicoccoides in Israel were determined. Data also were obtained from 2 genotypes of the southernmost population (Jaba). A single population from Turkey was also investigated. There were 119 genotypes with translocations in the sample of 171 genotypes investigated (70%). The frequency of translocations in different populations varied from 0.27 to 1.00, and all populations had 1 or more genotypes with one or more translocations. Some populations such as Qazrin appeared to be homogeneous for translocations, but most populations were heterogeneous. A sample of 17 genotypes from 12 of the populations were crossed with the Langdon D-genome disomic substitutions to determine the identity of the chromosomes involved in the translocations. There were nine genotypes with translocations and with the exception of a 2A/2B translocation, none of them involved the same chromosomes. The B-genome chromosomes were involved in translocations more frequently than the A-genome chromosomes. Translocation frequencies (TF) of the various populations were correlated with environmental variables, primarily with water availability and humidity, and possibly also with soil type. In general, TF was higher in peripheral populations in the ecologically heterogeneous frontiers of species distribution than in the central populations located in the catchment area of the upper Jordan valley.     

Genetic analysis of anther culture response in wheat using aneuploid,chromosome substitution and translocation lines

Summary Marked effects of genotype on wheat anther culture response have been observed. Genetic factors have been recognised to be one of the major contributors to in vitro responses of cultured wheat tissues. In wheat anther culture, embryo induction, plant regeneration and albina/green ratio have been determined to be heritable traits. Using Chinese Spring (CS) monosomic 1D, single chromosome substitution lines of chromosome 5B or chromosome arm 5BL from Chinese Spring into six varieties, and F₁ hybrids heterozygous for the 1B chromosome structure (1BL-1BS/1BL-1RS), the anther culture response was studied: genes on CS1D chromosome and 5BL chromosome arm increases the embryo frequency; gene(s) involved in regeneration ability are located on the 1RS chromosome arm; a gene increasing albina frequency is located on Chinese Spring 5B chromosome. Our results support the fact that without gametic selection, a differential development occurred from the particular classes of microspores carrying genes for higher regeneration ability. Moreover, in some crosses, a few genes with major effects were involved in determination of anther culture response.     

Cytological and molecular characterization of a chromosome interchange and addition lines in Cadet involving chromosome 5B of wheat and 6Ag of Lophopyrum ponticum

Efforts to transfer wheat curl mite (Eriophyes tulipae Keifer) resistance from Lophopyrum ponticum 10X (Podb.) Love to bread wheat (Triticum aestivum L.) have resulted in the production of a number of cytogenetic stocks, including an addition line of 6Ag, a ditelo addition line, and a wheat-Lophopyrum translocation line. Characterization of these lines with C-banding, in situ hybridization with a Lophopyrum species-specific repetitive DNA probe (pLeUCD2), and Southern blotting with pLeUCD2 and a 5S ribosomal DNA probe (pScT7) confirmed that the distal portion of the short arm of 6Ag was translocated onto the distal portion of 5BS (5BL. 5BS-6AgS). It was also determined that the ditelo addition was an acrocentric chromosome of 6AgS.     

Association between simple sequence repeat-rich chromosome regions and intergenomic translocation breakpoints in natural populations of allopolyploid wild wheats

Background and Aims

Repetitive DNA sequences are thought to be involved in the formation of chromosomal rearrangements. The aim of this study was to analyse the distribution of microsatellite clusters in Aegilops biuncialis and Aegilops geniculata, and its relationship with the intergenomic translocations in these allotetraploid species, wild genetic resources for wheat improvement.

Methods

The chromosomal localization of (ACG)_n and (GAA)_n microsatellite sequences in Ae. biuncialis and Ae. geniculata and in their diploid progenitors Aegilops comosa and Aegilops umbellulata was investigated by sequential in situ hybridization with simple sequence repeat (SSR) probes and repeated DNA probes (pSc119·2, Afa family and pTa71) and by dual-colour genomic in situ hybridization (GISH). Thirty-two Ae. biuncialis and 19 Ae. geniculata accessions were screened by GISH for intergenomic translocations, which were further characterized by fluorescence in situ hybridization and GISH.

Key Results

Single pericentromeric (ACG)_n signals were localized on most U and on some M genome chromosomes, whereas strong pericentromeric and several intercalary and telomeric (GAA)_n sites were observed on the Aegilops chromosomes. Three Ae. biuncialis accessions carried 7U^b–7M^b reciprocal translocations and one had a 7U^b–1M^b rearrangement, while two Ae. geniculata accessions carried 7U^g–1M^g or 5U^g–5M^g translocations. Conspicuous (ACG)_n and/or (GAA)_n clusters were located near the translocation breakpoints in eight of the ten translocated chromosomes analysed, SSR bands and breakpoints being statistically located at the same chromosomal site in six of them.

Conclusions

Intergenomic translocation breakpoints are frequently mapped to SSR-rich chromosomal regions in the allopolyploid species examined, suggesting that microsatellite repeated DNA sequences might facilitate the formation of those chromosomal rearrangements. The (ACG)_n and (GAA)_n SSR motifs serve as additional chromosome markers for the karyotypic analysis of UM genome Aegilops species.