VE161小麦外源染色体的传递特点

VE161小麦包括具有一对长穗偃麦草染色体的雄性不育代换系,可育附加系和杂育系,杂育系由其代换系×附加系产生,其外源染色体（E染色体）具有促进小麦部分同源染色体配对作用。本报道了VE161小麦本身含E染色体配子的传递率为VE161小麦与普通小麦杂交F2,BC1中分离出含E染色体植株的频率,发现VE161小麦本身含E染色体配子的传递率极高,而在F2和BC1代分离群体中保留或消除E染色体都较为容易,这一特点极利于E染色体促进部分同源染色体配对作用在创造易位系上的应用。     

小麦VE161雄性不育异代换系的染色体分析

VE161是一个具有一对长穗偃麦草(Agropyron elongatum)染色体的小麦雄性不育异代换系。由于不能用做父本,采用一般单体分析法确定其被代换的染色体比较困难。因此用一套中国春缺-四体和重双端体对其进行了分析,并以F_1花粉母细胞MI单价体的N-显带技术进行了验证。结果表明,VE161代换系所代换的染色体为7B,该方法对确定雄性不育代换系所代换的染色体是一个简单易行的方法。染色体行为观察说明,该代换系的一对长穗偃麦草染色体可能与小麦的染色体7B没有部分同源关系,除了引起雄性不育以外,有时与小麦染色体分裂不同步而表现落后,并有抑制Ph基因的作用,能强烈促进小麦部分同源染色体的联会配对,致使在中期Ⅰ出现很高频率的各种多价体。     

小麦的外源染色体鉴定

通过染色体原位杂交、RFLP分析和染色体重双端体分析,对在小麦遗传育种研究中具有重要理论和应用价值的VE161小麦不育异代换系及其附加系进行了染色体鉴定.结果表明,VE161小麦代换的或附加的外源染色体为来自长穗偃麦草的4E染色体,被代换的小麦染色体为4B.过去曾鉴定为7B,可能是由于VE161早代染色体易位较多所致.同时发现,VE161小麦在5B,7B和1D所在的3个部分同源群中仍有染色体相互易位存在,为进一步研究VE161小麦促进部分同源染色体配对的机制、不育的机制和应用奠定了基础.     

硬粒小麦 长穗偃麦草2E和4E附加系及E染色体传递

为探讨长穗偃麦草E染色体在硬粒小麦背景中的传递特点,利用染色体特异分子标记、基因组原位杂交(GISH)、非变性荧光原位杂交(ND FISH)等方法,对小偃麦8801(AABBEE)与硬粒小麦(AABB)杂交后代中选育的株系Du_No.2和Du_No.4进行了分析。结果表明：(1)分子标记检测株系Du_No.2及Du_No.4分别能扩增出长穗偃麦草2E、4E染色体特异条带。(2)GISH和ND FISH分析显示,株系Du_No.2和Du_No.4分别附加了1条2E和4E染色体,表明株系Du_No.2 和Du_No.4分别为硬粒小麦 长穗偃麦草2E和4E单体附加系。(3)2个株系的减数分裂过程观察发现,后期Ⅰ、Ⅱ和末期Ⅱ都有E染色体分离异常现象,且株系Du_No.2和 Du_No.4的异常率分别为22.24%和36.18%。(4)2个株系分别与硬粒小麦进行正反杂交的后代PCR分析表明, 2E和4E染色体经雄配子的传递率分别为4.41%和2.17%,而通过雌配子的传递率都为零,表明2E和4E染色体在硬粒小麦背景中能通过雄配子传递,但不通过雌配子的传递。该研究为创建全套硬粒小麦 长穗偃麦草双体附加系及代换系提供基础。     

利用生化及分子标记确定长穗偃麦草（Elytrigia elongatum,EE.2n=14） …

利用限制性片段长度多态性（ＲＦＬＰ）及等电聚焦（ＩＥＦ）技术确定普通小麦中国春－二倍体长穗偃麦草７个异附加系所附加的外源染以体与小麦染色体的部分同源性,共有８个生化标记,１３个ＲＦＬＰ标记在亲本间揭示了多态性,结果表明：长穗偃麦草的１Ｅ,２Ｅ,３Ｅ,４Ｅ,５Ｅ,６Ｅ,７Ｅ７条染色体分别与小麦染色体的１、２、３、４、５、６、７７个部分同源群具有部分同源关系,偃麦草的１Ｅ与７Ｅ、５Ｅ与７Ｅ染色体间可能     

VE161小麦的外源染色体鉴定

通过染色体原位杂交、ＲＦＬＰ分析和染色体重双端体分析,对在小麦遗传育种研究中具有重要理论和应用价值的ＶＥ１６１小麦不育异代换系及其附加系进行了染色体鉴定。结果表明,ＶＥ１６１小麦代换的或附加的外源染色体为来自长穗偃麦草的４Ｅ染色体,被代换的小麦染色体为４Ｂ。过去曾鉴定为７Ｂ,可能是由于ＶＥ１６１早代染色体易位较多所致。同时发现,ＶＥ１６１小麦在５Ｂ,７Ｂ和１Ｄ所在的３个部分同源群中仍有染色体相互易     

小麦和彭梯卡偃麦草杂种及其衍生后代的细胞遗传学研究——Ⅰ.彭梯卡偃麦草及其与普通小麦和硬粒小麦杂种F_1的染色体配对

花粉母细胞中期Ⅰ染色体配对观察发现,长穗偃麦草平均染色体配对构型为:27.65Ⅱ(20—35)+1.15Ⅲ(0—4)+1.22IⅤ(0—4)+0.42Ⅴ(0—2)+0.43Ⅵ(0—2)+0.20Ⅶ(0—1)+0.06Ⅷ(0—1)+0.021Ⅹ(0—1)+0.75Ⅰ(0—5)。大量多价体的出现说明在Th.ponticum中必然存在着染色体组重复。小麦和长穗偃麦草杂种F_1根尖细胞及花粉母细胞染色体醋酸洋红N-带分析发现在Th.ponticum中并无B染色体组存在,并且在杂种F_1花粉母细胞中显带的B组染色体很少参与配对。普通小麦品种Fukuho和“中国春”与Th.ponticum杂种F_1的染色体配对构型分别为:16.40Ⅱ(6—12)+2.78Ⅲ(0—6)+0.55Ⅳ(0—3)+0.25Ⅴ(O—3)+10.87Ⅰ(5—19)和14.73Ⅱ(7—20)+3.12Ⅲ(0—6)+0.67Ⅳ(0—2)+0.63Ⅴ(0—5)+11.19Ⅰ(4—17)。综合两个小麦品种与Th.ponticum杂种染色体配对资料发现20.5%的花粉母细胞中单价体数小于7,表明在Th.ponticum中有与小麦极为相近的染色体组。硬粒小麦品系DR147和该偃麦草杂种F_1花粉母细胞染色体配对构型为:11.92Ⅱ(5—18)+2.14Ⅲ(0—5)+0.54Ⅳ(0—3)+0.41Ⅴ(0—2)+14.93Ⅰ(9—25)。T.aestivum×Th.ponticum F_1由于比T.durum×Th.ponticum F_1多了一个D染色体组,使前者配对染色体数比后者增加了约11条,表明Th.ponticum可能含有与D组非常     

phlb基因诱导小麦ABD染色体组部分同源染色体配对的研究

通过花药培养首次获得了“中国春”phlb突变体单倍体,同时也获得了“中国春”单倍体。对其细胞学观察表明,前者花粉母细胞减数分裂中期Ⅰ每个细胞染色体交叉为5.08个,后者为1.30个。证明了phlb基因在单倍体状态下具有强的诱导ABD染色体组部分同源染色体间的配对作用。     

phKL基因和Ph2基因缺失重组体的创制及其与小麦外源物种杂种的染色体减数分裂观察

以小麦(Triticum aestivum L.)双端体3DL为细胞学标记,用具有phKL基因的小麦地方品种"开县罗汉麦"为受体连续回交,将促进小麦外源部分同源染色体配对的phKL基因和Ph2基因缺失重组在一起获得了重组体phKL+Ph2.这种重组体有正常的育性.与只有phKL基因的小麦材料相比,重组体与外源物种AegilopsvariabilisEig.或黑麦(Secale cereale L.)杂种的部分同源染色体配对水平显著增加,表明Ph2基因的缺失体与phKL基因可能存在加性效应.部分同源染色体配对水平的增加表现在棒状二价体、环状二价体和三价体的数量变多而单价体数量减少.单价体的减少主要是由于棒状二价体的增加所造成的.在小麦外源遗传转移中,运用重组体pHKL +Ph2可能比单纯应用Ph2缺失或phKL基因材料更理想.当与具有ph1b基因的材料比较时发现,重组体phKL+Ph2与 Ae.variabilis(或黑麦)杂种的部分同源染色体配对水平显著降低,这主要是由环状二价体和多价体的减少造成的,但是棒状二价体数量表现增加(与Ae.variabilis杂种)或达到类似水平(与黑麦杂种),这一有趣的发现从表现型上证明了Ph1基因与Ph2或phKL基因在诱导部分同源染色体配对时的遗传作用机制存在差异.     

phKL基因诱导小麦远缘杂种部分同源染色体配对的能力界于Ph1和Ph2基因突变体之间

在普通小麦地方品种自然群体中天然存在促进小麦-外源杂种部分同源染色体配对的基因phKL。本研究比较了phKL基因与人工Ph基因突变系诱导小麦-Aegilops variabilis及小麦-黑麦杂种部分同源染色体配对的作用大小。研究结果表明,诱导小麦- Ae. variabilis(或黑麦)部分同源染色体配对作用的顺序是ph1b > phKL > ph2b > ph2a,即phKL基因的作用介于Ph1与Ph2突变体之间。     

Transfer of small chromosome fragments of Agropyron elongatum to wheat chromosome via asymmetric somatic hybridization

~~Transfer of small chromosome fragments of Agropyron elongatum to wheat chromosome via asymmetric somatic hybridization1 .Dong,Y.C,GenePools of common wheat,Journal of Triticeae CroPs(in Chinese),2000,20(3):78-81. 2 .Wei,Y.M.,Zheng,YL.Zhou,R.H., Detectlon of the rye chro- matin in multisPikelet wheat germplasm 10-A background using fluorescence in situ hybridization(FISH)and RFLP markers,Acta Bot.Sinica(in Chinese),1999,41(7):722-725. 3 .Xiang,E N.,Xia,G M.…     

ph1b基因对簇毛麦遗传物质导入普通小麦的影响

ph1b基因对簇毛麦遗传物质导入普通小麦的影响@陈静$中国科学院成都生物研究所!成都610041ph1b基因;;小麦;;簇毛麦     

Transfer of small chromosome fragments of<Emphasis Type="Italic">Agropyron elongatum</Emphasis> to wheat chromosome via asymmetric somatic hybridization

The chromosome constitution of hybrids and chromatin patterns of Agropyron elongatum (Host)Neviski in F₅ somatic hybrid lines -1–3 and I-1-9 between Triticum aestivum L. and A. elongatum were analyzed. Based on the statistic data of pollen mother cells, F₅ I-1-9 and-1-3 had 20–21 bivalents with a frequency of 84.66% and 85.28%, of which, 89.83% and 89.57% were ring bivalents. The result indicated that both hybrid lines were basically stable in the chromosome constitution and behavior. RAPD analysis showed that the two hybrids contained biparental and integrated DNA. GISH (Genome in situ hybridization) revealed that in the form of small chromosome segments, A. elongatum chromatin was scattered on 4–6 wheat chromosomes near by the region of centromere and telomere in the two hybrid lines. SSR analysis indicated that A. elongatum DNA segments were distributed on the 2A, 5B, 6B and 2D wheat chromosomes in the hybrids, which was in accordance with the GISH results that small-segments intercalated poly-site.     

小麦籽粒抗性淀粉含量的分析

选用3个抗性淀粉含量较高的小麦品种和3个抗性淀粉含量较低的小麦品种按Griffing双列杂交设计配置成15个杂交组合, 以亲本及F₁为材料进行了小麦籽粒抗性淀粉含量的遗传规律分析, 旨在为高抗性淀粉含量且综合性状优良的新型保健小麦新品种(系)的选育提供理论依据。结果表明, 在6个小麦品种中, 安农90202和D68-20抗性淀粉含量的一般配合力较好, 能显著地提高杂种后代籽粒抗性淀粉含量。安农90202×04单28和06-5×D68-20组合的特殊配合力最好, 两者特殊配合力效应值显著地高于其他组合。小麦抗性淀粉含量的遗传符合加性-显性模型, 显性程度为超显性。控制抗性淀粉含量的增效等位基因表现为隐性, 且亲本中抗性淀粉含量的增减效等位基因的分布不平衡, 高抗性淀粉含量的亲本中隐性基因数量多于显性基因数量。实验中安农90202和04单28控制抗性淀粉含量的隐性基因较多,而宁春18和新春5号含有的显性基因数量较多。同时研究发现小麦抗性淀粉含量的狭义遗传力中等, 为36.49%。     

Transfer of Ph I genes promoting homoeologous pairing from Triticum speltoides to common wheat

Diploid-like chromosome pairing in polyploid wheat is controlled by several Ph (pairing homoeologous) genes with major and minor effects. Homoeologous pairing occurs in either the absence of these genes or their inhibition by genes from other species (Ph ^I genes). We transferred Ph ^I genes from Triticum speltoides (syn Aegilops speltoides) to T. aestivum, and on the basis of further analysis it appears that two duplicate and independent Ph ^I genes were transferred. Since Ph ^I genes are epistatic to the Ph genes of wheat, homoeologous pairing between the wheat and alien chromosomes occurs in the F₁ hybrids. Using the Ph ^I gene stock, we could demonstrate homoeologous pairing between the wheat and Haynaldia villosa chromosomes. Since homoeologous pairing occurs in F₁ hybrids and no cytogenetic manipulation is needed, the Ph ^I gene stock may be a versatile tool for effecting rapid and efficient alien genetic transfers to wheat.Contribution no. 93-435-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506-5502, USA     

Three stages of meiotic homologous chromosome pairing in wheat: cognition, alignment and synapsis

 Chromosome painting enabled the study of homologous chromosome behaviour prior to and during meiosis. Total genomic DNA from rye, used as a probe for in situ hybridization, identified the rye chromosome arm in a wheat-rye translocation line (T5AS·5RL) at meiotic prophase and the preceding interphase. Accurate staging of the development of the meiocytes was attained by parallel studies of chromatin morphology, nucleolar behaviour and synaptonemal complex formation in electron microscopy thin sections and silver-stained surface spreads. Three stages of pairing were identified for the large cereal genomes that are organized in a Rabl configuration: first, cognition occurs during the long interphase before leptotene, bringing the homologous chromosome domains into close proximity and possibly starting at the centromere; second, homologous chromosome segments align at late leptotene; and third, zygotene synapsis initiates near the telomere, although it was also observed to occur near the centromere. A pairing model is proposed for wheat, with a genome size of 17000 Mbp, that shows prallels to and notable differences from yeast and mammalian models of meiosis. Received: 25 January 1997 / Revision accepted: 14 July 1997