杀配子染色体在小麦-黑麦异代换系中的作用研究

利用小麦-黑麦异代换系H-13(1R/1D), H-24(5R/5A),H-33(6R/6A)与中国春-杀配子染色体二体异附加系CS-DA2C(来自山羊草Ae. cylindrica),CS-DA3C(来自山羊草Ae. triuncialis)配置杂交组合,对杀配子染色体的作用进行了研究。结果表明,杀配子染色体3C对H-13和H-24都是致死的,即有着完全的杀配子作用,但对H-33的杀配子作用则是不完全的,有着接近正常的结实率,说明不同的小麦-黑麦异代换系遗传背景对杀配子作用有很大影响,可能在品系H-33中存在对2C染色体杀配子作用的抑制基因。在以品系H-33为母本时,2个杀配子附加系F1的自交结实率差异显著,说明在相同的小麦-黑麦异代换系遗传背景下,染色体2C与3C的杀配子作用是不同的,在这2个杀配子染色体上可能带有不同的杀配子基因?这些研究结果为进一步创制小麦-黑麦易位系奠定了基础。     

杀配子染色体的研究进展

来源于山羊草属的杀配子染色体,已被导入普通小麦中,这些外源染色体可以选择性地引起缺少这些染色体的配子不育,并且能够使其自身得以优先传递.杀配子染色体可诱导染色体畸变产生易位、缺失,有利于构建物理图谱.阐述了杀配子染色体研究进展的有关内容.     

普通小麦-簇毛麦易位系T4VS·6AL的选育

在小麦背景中离果山羊草3C染色体具有优先传递的作用.当离果山羊草3C染色体处于单体状态时会导致后代不含有杀配子染色体的配子中产生包括缺失和易位等染色体结构变异.簇毛麦4V染色体携有抗小麦眼斑病和全蚀病基因.为进一步利用簇毛麦4V染色体上的有益基因.利用染色体C-分带和基因组原位杂交分析,从普通小麦-簇毛麦4V染色体二体异附加系(DA4V)与普通小麦农林26-离果山羊草3C染色体二体异附加系(DA3C)杂种后代中选育出小麦-簇毛麦纯合易住系T4VS·6AL.该易位系为杀配子染色体诱发形成的非补偿型易位;易位系T4VS·6AL高抗梭条花叶病.是小麦抗病育种的新种质.     

簇毛麦染色体通过硬粒小麦-簇毛麦双二倍体与普通小麦杂种F1的雌雄配子传递的研究

利用“单株植物C-带技术”,对6x小簇麦与普通小麦的杂种F2和回交BC1 世代的染色体结构进行观察,研究了簇毛麦染色体在杂种后代中的传递行为.结果表明,在大多数杂种组合中,簇毛麦染色体通过雌配子的传递行为是随机的,并显著高于通过雄配子的概率,但在含有小麦亲本‘J-11'的杂种组合中情况不同,簇毛麦染色体在这个杂种组合中通过雌、雄配子的传递率都是随机的.说明簇毛麦染色体的传递受杂种F1中小麦亲本的影响,推测在小麦亲本‘J-11'中可能存在一个影响簇毛麦染色体通过雄配子传递的基因.单个簇毛麦染色体的传递与6x小簇麦作为父本或母本有关.通过雌雄配子传递中,以4V 和7V染色体的传递频率最高,而3V的传递频率最低.本研究结果表明,在用6x小簇麦作为桥梁转移簇毛麦有利基因,创制杂种F1时,最好以普通小麦为父本,并且F3和BC1F2 是关键的选择世代.     

普通小麦-簇毛麦易位系T4VS·6AL的选育

在小麦背景中离果山羊草3C染色体具有优先传递的作用。当离果山羊草3C染色体处于单体状态时会导致后代不含有杀配子染色体的配子中产生包括缺失和易位等染色体结构变异。簇毛麦4V染色体携有抗小麦眼斑病和全蚀病基因。为进一步利用簇毛麦4V染色体上的有益基因,利用染色体C-分带和基因组原位杂交分析,从普通小麦-簇毛麦4V染色体二体异附加系（DA4V）与普通小麦农林26-离果山羊草3C染色体二体异附加系（DA3C）杂种后代中选育出小麦-簇毛麦纯合易位系T4VS·6AL。该易住系为杀配子染色体诱发形成的非补偿型易位;易位系T4VS·6AL高抗梭条花叶病。是小麦抗病育种的新种质。     

外源优先传递染色体（基因）在普通小麦中的遗传及其在育种中的应用

已发现某些小麦近缘种的染色体在转移到小麦的过程中具有优先传递效应，这些染色体的单体添加系和单体代换系产生的配子中，凡具有这些染色体的配子才有效，否则便败育，因此，它们又被称为杀配子染色体。这些外源染色体的优先传递频率因来源而异，可引起部分不育，种子皱瘪和染色体突变。根据这些优先传递染色体的遗传特点，通过由它们引起的染色体缺失进行基因定位，促成某些控制重要性状基因的优先传递，并可能为生产杂种小麦种子     

中国春-柱穗山羊草杀配子染色体2C附加系与小麦-冰草附加系杂交F2的细胞学特性

 【目的】对5个小麦-冰草附加系与中国春-杀配子染色体2C附加系杂交F2的减数分裂进行观察,分析杀配子染色体在小麦-冰草附加系背景下诱导染色体变异的有效性,为获得小麦-冰草染色体易位奠定基础。【方法】杂交F2植株幼穗减数分裂染色体行为观察采用常规细胞学方法,冰草P染色质的检测采用GISH方法。【结果】杂交F2PMC减数分裂中期普遍观察到多个单价体、多价体以及落后染色体和断片,多数组合观察到染色体桥,个别组合出现单价环状染色体。杂交F2减数分裂染色体存在异常现象：平均36.5%的细胞中有多个单价体,15.8%的细胞含有多价体,31.6%和11.7%的细胞中含有染色体断片和桥,四分体时期存在微核、多裂和四分孢子退化现象。F2植株的自交结实率平均为31.47%。对部分F2植株的减数分裂细胞GISH检测表明,P染色体多为单体附加,有2.7%的植株可能产生染色体易位。【结论】较高频率的染色体断裂和部分配子致死是杀配子染色体诱导变异的典型特征,柱穗山羊草2C杀配子染色体在小麦-冰草附加系背景下能够有效诱导染色体产生结构变异,这种诱变作用和频率在不同附加系背景下存在差异。     

小麦易位系的创造研究进展

小麦作为世界上广泛种植的粮食作物之一,其种质资源日益匮乏,创造小麦外源染色体易位系是拓宽小麦遗传基础的有效途径。创造易位系的方法有利用电离辐射、利用杀配子染色体、通过调节Ph基因的作用诱发部分同源染色体交换、通过染色体错分裂、利用组织培养诱导易位。对这几种创造小麦易位系的方法进行了综述,并作出展望,为小麦育种提供基础。     

小麦易位系的创造研究进展

小麦作为世界上广泛种植的粮食作物之一,其种质资源日益匮乏,创造小麦外源染色体易位系是拓宽小麦遗传基础的有效途径。创造易位系的方法有利用电离辐射、利用杀配子染色体、通过调节Ph基因的作用诱发部分同源染色体交换、通过染色体错分裂、利用组织培养诱导易位。对这几种创造小麦易位系的方法进行了综述,并作出展望,为小麦育种提供基础。     

簇毛麦染色体通过硬粒小麦—簇毛麦双二倍体与普通小麦杂种F1的雌雄配子传递的研究

利用“单株植物C－带技术”,对6x小簇麦与普通小麦的杂种F2和回交BC1世代的染色体结构进行观察，研究了簇毛麦染色体在杂种后代中 的传递行为。结果表明，在大多数杂种组合中，簇毛麦染色体通过雌配子的传递行为是随机的，并显著高于通过雄配子的概率，但在含有小麦亲本‘J－11‘的杂种组合中情况不同，簇毛麦染色体在这个杂种组合中通过雌、雄配子的传递率都是随机的。说明簇毛麦染色体的传递受杂种F1中小麦亲本的影响，推测在小麦亲本‘J－11‘中可能存在一个影响簇毛麦染色本通过雄配子传递的基因。单个簇毛麦染色体的传递与6x小簇麦作为父本或母本有关。通过雌雄配子传递中，以4V和7V染色体的传递频率最高，而3V的传递频率最低。本研究结果表明，在用6x小簇麦作为桥梁转移簇毛麦有利基因，创制杂种F1时，最好以普通小麦为父本，并且F3和BC1F2是关键的选择世代。     

利用离果山羊草3C染色体诱导簇毛麦2V染色体结构变异

【目的】簇毛麦是普通小麦的一个近缘物种,它具有许多抗病基因,在小麦育种中起重要作用。抗白粉病基因Pm21已被南京农业大学细胞遗传所成功地转移到小麦背景中,并被广泛地用于小麦育种实践。为了进一步转移和利用定位于簇毛麦2V染色体上的有用基因,如抗眼斑病基因、抗条锈基因和护颖颖脊刚毛基因,为小麦育种创造新种质。【方法】通过普通小麦农林26-离果山羊草3C二体异附加系与小麦-簇毛麦2V（2D）二体代换系杂交,综合运用染色体C-分带、基因组原位杂交、染色体构型分析和分子标记分析。【结果】从杂种F２和F３中鉴定出涉及簇毛麦2V结构变异的异染色体系7份,包括纯合缺失系1份（Del 2VS•2VL-）,易位系4份,其中纯合易位2份（初步推断为T3DS•2VL,T2VS•7DL）、小片段易位1份（T6BS•6BL-2VS）和中间插入易位1份（T2VS•2VL-W-2VL）,等臂染色体1份（2VS•2VS）和单端体1份（Mt2VS）。利用可分别追踪2VS 和2VL的分子标记Xwmc25-120和NAU/STSBCD135-1进行PCR分析,进一步证明这7份异染色体系中涉及簇毛麦2V染色体片段。【结论】涉及2V短臂的单端体Mt2VS,等臂染色体2VS•2VS和易位系T2VS•7DL在护颖颖脊上有簇状分布的刚毛,而涉及2V长臂的易位系T3DS•2VL无刚毛,进一步证实簇毛麦护颖颖脊刚毛基因位于2VS。离果山羊草3C染色体可有效诱发簇毛麦2V染色体结构变异。     

Structural Changes of 2V Chromosome of Haynaldia villosa Induced by Gametocidal Chromosome 3C of Aegilops triuncialis

Haynaldia villosa （2n=2X= 14, VV）, a relative of wheat, plays important roles in wheat improvement mainly owing to its disease resistance. Powdery mildew resistance gene Pm21 has been successfully transferred into wheat by Cytogenetic Institute, Nanjing Agricultural University, China, and is widely used in the current wheat breeding programs. In this research, our objective is to further transfer and utilize the beneficial genes such as eye-spot resistance, yellow rust resistance, and gene of the tufted bristles on the glume ridge （a remarkable morphology） mapped on 2V of Haynaldia villosa. A disomic addition line with gametocidal chromosome 3C ofAegilops triuncialis added in Norin-26 was crossed to the wheat-H, villosa disomic substitution 2V（2D） and the hybrid F1 was then self-crossed. Chromosome C-banding, genomic in situ hybridization （GISH）, and meiotic analysis in combination with molecular markers were applied to detect the chromosome variations derived from hybrids Fz and F3. To date, four translocations including one small segmental translocation T6BS·6BL-2VS, two whole arm translocations （preliminarily designed as T3DS·2VL and T2VS.7DL） and one intercalary translocation T2VS·2VL-W-2VL, one deletion Del. 2VS·2VL-, one monotelosomic Mt2VS, and one isochromosome 2VS·2VS line have been developed and characterized. One wheat SSR marker Xwmc25.120 tagging 2VS and one wheat STS marker NAU/STSBCD135-1 （2BL） tagging 2VL were successfully used to confirm the alien chromosome segments involved in the seven lines. The tufted bristles on the glume ridge appeared in lines T2VS-7DL, Mt2VS, 2VS-2VS as well as the parent DS2V（2D）, whereas in T3DS·2VL, this trait did not appear. The gene controlling the tufted bristles was located on 2VS. Gametocidal chromosome 3C ofAegilops triuncialis could successfully induce chromosome 2V structural changes.     

Structural Changes of 2V Chromosome of Haynaldia villosa Induced by Gametocidal Chromosome 3C of Aegilops triuncialis

Haynaldia villosa (2n =2X = 14, VV), a relative of wheat, plays important roles in wheat improvement mainly owing to its disease resistance. Powdery mildew resistance gene Pm21 has been successfully transferred into wheat by Cytogenetie Institute, Nanjing Agricultural University, China, and is widely used in the current wheat breeding programs. In this research, our objective is to further transfer and utilize the beneficial genes such as eye-spot resistance, yellow rust resistance, and gene of the tufted bristles on the glume ridge (a remarkable morphology) mapped on 2V of Haynaldia villosa. A disomic addition line with gametocidal chromosome 3C ofAegilops triuncialis added in Norin-26 was crossed to the wheat-H, villosa disomic substitution 2V(2D) and the hybrid F1 was then self-crossed. Chromosome C-banding, genomie in situ hybridization (GISH), and meiotic analysis in combination with molecular markers were applied to detect the chromosome variations derived from hybrids F2 and F3. To date, four translocations including one small segmental translocation T6BS.6BL-2VS, two whole arm translocations (preliminarily designed as T3DS·2VL and T2VS·7DL) and one intercalary translocation T2VS·2VL-W-2VL, one deletion Del. 2VS·2VL-, one monotelosomic Mt2VS, and one iso- chromosome 2VS·2VS line have been developed and characterized. One wheat SSR marker Xwmc25-120 tagging 2VS and one wheat STS marker NAU/STSBCD135-1 (2BL) tagging 2VL were successfully used to confirm the alien chromosome segments involved in the seven lines. The tufted bristles on the glume ridge appeared in lines T2VS·7DL, Mt2VS, 2VS·2VS as well as the parent DS2V(2D), whereas in T3DS·2VL, this trait did not appear. The gene controlling the tufted bristles was located on 2VS. Gametocidal chromosome 3C of Aegilops triuncialis could successfully induce chromosome 2V structural changes.     

普通小麦-簇毛麦易位系T6BS·6BL-2VS的选育

[目的]为进一步利用簇毛麦2V染色体上的有益基因,为小麦育种提供新种质。[方法]通过普通小麦-簇毛麦2V(2D)二体代换系(DS2V)与普通小麦农林26-离果山羊草3C染色体二体异附加系(DA3C)杂交,综合运用染色体C-分带、基因组原位杂交和分子标记分析,并结合性状调查。[结果]从杂种后代中选育出小麦-簇毛麦纯合易位系T6BS.6BL-2VS,性状调查发现该易位系植株护颖颖脊上有刚毛。[结论]该易位系为杀配子染色体诱发的小片段易位;簇毛麦护颖颖脊刚毛基因定位于2VS的中部至端部。     

普通小麦-簇毛麦易位系T6BS·6BL-2VS的选育(英文)

[Objective] The aim of experiment was to provide a new germplasm for wheat breeding by further using desirable genes in 2V chromosome of Haynaldia villosa.[Method] Through hybridization between common wheat(Triticum aestivum)-Haynaldia villosa disomic substitution line and common wheat Nonglin26-3C chromosome of Aegilops triuncialis disomic addition line,the analysis methods such as chromosome C-banding,genomic in situ hybridization and molecular marker technique were comprehensively applied and combined characters investigation.[Result] The wheat-Haynaldia villosa translocation line(T6BS·6BL-2VS)was selected from hybrid progenies to conduct characters investigation,which found some bristles on glume ridge of T6BS·6BL-2VS.[Conclusion] The translocation line induced by gametocidal chromosome was a small segment translocation line and the gene of bristle on glume ridge of Haynaldia villosa was located between the middle and the terminal of 2VS.     

Nonrandomness of translocations in man: preferential entry of chromosomes into 13-15-21 translocations

Lymphocytes from 20 individuals with Down's syndrome due to 13-15/21 centric-fusion translocations were studied by autoradiography after continuous late labeling with tritiated thymidine. In no case was chromosome 13 involved; chromosome 14 was involved in 18 cases, and chromosome 15 in two cases. These results are similar to those from 13 previously studied cases and indicate that the entry of chromosomes 13-15 into translocations is nonrandom. This nonrandomness is not a simple function of chromosome size or shape, since chromosomes 13-15 are acrocentrics of similar size.     

Chromosome segregation errors as a cause of DNA damage and structural chromosome aberrations

Various types of chromosomal aberrations, including numerical (aneuploidy) and structural (e.g., translocations, deletions), are commonly found in human tumors and are linked to tumorigenesis. Aneuploidy is a direct consequence of chromosome segregation errors in mitosis, whereas structural aberrations are caused by improperly repaired DNA breaks. Here, we demonstrate that chromosome segregation errors can also result in structural chromosome aberrations. Chromosomes that missegregate are frequently damaged during cytokinesis, triggering a DNA double-strand break response in the respective daughter cells involving ATM, Chk2, and p53. We show that these double-strand breaks can lead to unbalanced translocations in the daughter cells. Our data show that segregation errors can cause translocations and provide insights into the role of whole-chromosome instability in tumorigenesis.