Confirmation of a 1A/1R Wheat-Rye Chromosome Translocation in the Wheat Variety 'Amigo'

Differential chromosome staining by using the Giemsa C- banding technique and test crosses have revealed rye chroma tin in the hexaploid wheat variety ‘Amigo’ which resulted from wheat crosses with the octoploid triticale ‘Gaucho’. The results demonstrated a pair of translocated wheat chromosomes involving the short arm of rye chromosome 1R and the long arm of the homoeologous wheat chromosome 1A (1Aq/1Rp translocation). The localization of the translocation breakpoint is supposed 10 be within the centromeric region.     

Dosage Response of Rye Genes in a Wheat Background

Wheat (Triticum aestivum L.) breeders often utilize alien sources to supply new genetic variation to their breeding programs. However, the alien gene complexes have not always behaved as desired when placed into a wheat background. The introgressed genes of interest may be linked to undesirable genes, expressed at low levels or not at all. The short arm of rye (Secale cereale L.) chromosome one (1RS) contains many valuable genes for wheat improvement. In order to study rye gene response to varying copy number, wheat lines were constructed which contained zero, two or four doses of 1RS. The meiotic behavior of rye chromosome 1R, and wheat/rye translocation chromosomes, 1AL/1RS and 1BL/1RS was studied in the F₁ hybrids between wheat lines carrying 1R or the translocation chromosomes. The IRS arm was transmitted at a very high frequency; 98 % of the F₂ plants had at least one of the chromosomes with a IRS arm. In addition, 44 % of the F₂ plants received at least one copy of the chromosomes from each parent. Analysis of the meiotic behavior of the IRS arm suggested that few euploid wheat gametes were formed. Therefore, most of the pollen must have contained IRS. It is unknown whether the lack of euploid wheat pollen could account for the high transmission frequency of the rye chromosomes. There may have been differential survival of the embryos receiving the rye chromosome as well.     

Further manipulation by centric misdivision of the 1RS.1BL translocation in wheat

Complete chromosomes 1R and 1B were reconstructed in wheat from the centric wheat-rye translocation 1RS.1BL. Three substitutions: 1R(1A), 1R(1B), 1R(1D), and three new centric translocations: 1RS.1AL, 1RS.1BL, 1RS.1DL were produced from the reconstructed chromosome 1R. Each one of these has the same rye chromosome arm 1RS which was present in the original translocation 1RS.1BL of ‘Kavkaz’ wheat. Reconstructed chromosome 1B and a normal chromosome 1R were used to produce a new 1RS.1BL translocation. This translocation has the long arm from the original 1RS.1BL translocation of ‘Kavkaz’, but a different 1RS arm. The third generation centric translocations were mitotically stable and were normally transmitted to progeny. Misdivision frequency of the reconstructed chromosomes 1R did not change relative to normal 1R, whereas the misdivision frequency of the two reconstructed chromosomes 1B tested was significantly higher relative to normal 1B. These experiments demonstrate that repeated cycles of centric breakage and fusion do not impair the function of centromeres in wheat and rye but may change chromosome's susceptibility to misdivision. This revised version was published online in July 2006 with corrections to the Cover Date.     

Identification of Rye Chromosome 1R Translocations and Substitutions in Hexaploid Wheats Using Storage Proteins as Genetic Markers

Grain protein compositions of 106 advanced generation backcross lines from crosses involving ‘Amigo’ (1AL.1RS), ‘Aurora’, ‘Kavkaz’, ‘Skorospelka-35’ and ‘Sunbird’ (all 1BL.1RS) and ‘Gabo’ 1DL.1RS parents and 152 cultivars with unknown pedigree were analysed by one-dimensional SDS-PAGE. Eighty seven backcross lines and 16 cultivars carried one or other of these translocations, 2 cultivars had a 1R (1B) substitution, whereas 5 backcross lines were found to be heterogeneous for the 1BL.1RS translocation. The translocation lines were easily identified by the presence of secalins (Sec-1) controlled by rye chromosome arm IRS and a simultaneous loss of the gliadin (Gli-1) and/or triticin (Tri-1) protein bands controlled by the replaced wheat chromosome arm (1AS, 1BS or 1DS). Certain gliadins, showing no allelic variation among the genotypes analysed, were identified as markers for chromosome arms 1AS (M_r= 34 kd) and IBS (M_r= 42,33 kd). The whole chromosome substitutions 1R (1B) were recognized by scoring for the presence of Sec-1 and HMW secalin bands, Sec-3 (controlled by rye chromosome arm 1RL) and the absence of Gli-B1 and HMW glutenin subunits, Glu-B1 (controlled by wheat chromosome arm 1BL). The results have shown that protein electrophoresis provides a rapid and reliable technique for screening genotypes for these translocations and substitutions in a breeding programme.     

Genetic, agronomic and quality comparisons of two 1AL.1RS. wheat-rye chromosomal translocations

The 1AL.1RS wheat-rye chromosomal translocation originally found in ‘Amigo’ wheat possesses resistance genes for stem rust, powdery mildew and greenbug biotypes B and C, but also has a negative effect on wheat processing quality. Recently, a second 1AL.1RS translocation carrying Gb6, a gene conferring resistance to greenbug biotypes B, C, E, G and I, was identified in the wheat germplasm line ‘GRS1201′. Protein analytical methods, and the DNA polymerase chain reaction were used to identify markers capable of differentiating the 1RS chromosome arms derived from ‘Amigo’ and ‘GRS1201′. The secalin proteins encoded by genes on 1RS chromosome arms differed in ‘Amigo’ and ‘GRS1201′. A 70 kDa secalin was found in the ‘Amigo’1AL.1RS, but did not occur in the ‘GRS1201’1AL.1RS. Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also differentiated the two translocations. When ‘GRS1201’was mated with a non-1RS wheat, no recombinants between 1RS markers were observed. In crosses between 1RS and non-1RS parents, both DNA markers and secalins would be useful as selectable markers for 1RS-derived greenbug resistance. Recombination between 1RS markers did occur when 1RS from ‘Amigo’ and 1RS from ‘GRS1201’were combined, but in such intermatings, the molecular markers described herein could still be used to develop a population enriched in lines carrying Gb6. No differences in grain yield or grain and flour quality characteristics were observed when lines carrying 1RS from ‘Amigo’ were compared with lines with 1RS from ‘GRS1201′. Hence, differences in secalin composition did not result in differential quality effects. When compared with sister lines with 1AL.1AS derived from the wheat cultivar ‘Redland’, lines with ‘GRS1201’had equal grain yield, but produced flours with significantly shorter mix times, weaker doughs, and lower sodium dodecyl sulphate sedimentation volumes.     

小麦-黑麦1RS/1BL新易位系的创制和分子细胞遗传学鉴定

利用普通小麦（Triticum aestivum L．）品种小偃6号与黑麦（Secale cereale L．）品种德国白粒杂交，选育出一批带有黑麦抗病性状的小偃6号类型种质材料。应用连续C-分带-基因组原位杂交（sequent C-banding-GISH）技术对上述材料进行染色体组成分析，筛选出2个小麦-黑麦1RS/1BL纯合易位系BC152-1-1和BC01-89-1。其中，BC152-1-1（2n=42）除含有1对1RS/1BL易位染色体外，未见其他染色体变异；BC01-89-1（2n=43）除含有1对1RS/1BL纯合易位染色体外，还附加1条两端缺失的3R染色体。高分子量麦谷蛋白亚基（HMW-GS）组成分析和品质分析结果表明，BC152-1-1和BC01-89-1不仅含有来自小偃6号的14＋15优质亚基，而且其蛋白质含量、湿面筋含量和SDS沉降值等品质性状都得到显著改良。     

Characterization of three wheat cultivars possessing new 1BL.1RS wheat-rye translocations

The wheat-rye 1BL.1RS translocation chromosomes have been used widely around the world in commercial wheat ( Triticum aestivum L.) production because of the presence of several disease resistance genes and a yield enhancement factor on the rye ( Secale cereale L.) chromosome. However, the recent reports of the loss of complete effectiveness of the disease resistance genes on the most commonly used 1BL.1RS chromosome have highlighted the need to seek and deploy additional sources of disease resistance genes. Three new sibling wheat cultivars, 'CN12', 'CN17' and 'CN18', were developed carrying 1RS arms derived from the rye inbred line L155. Genomic in situ hybridization and C-banding analysis revealed that all the three cultivars contained the rye chromosome 1RS arm fused to the wheat 1BL wheat chromosome arm. The three cultivars displayed high yields and high resistance to local powdery mildew and stripe rust pathotypes. Fluorescence in situ hybridization analysis indicated the different structure of 1BL.1RS chromosome between 'CN18' and the other two cultivars. The present study provides a new 1RS resource for wheat improvement.     

Biochemical, molecular, and cytogenetic technologies for characterizing 1RS in wheat: A review

Chromosome arm 1RS of rye ( Secale cereale L.), when transferred to wheat ( Triticum sp.), significantly influences variety performance, because it carries genes for resistance to disease and insect pathogens. Inserted into wheat, 1RS also promotes haploid production, affects end-product quality, and sometimes affects yield. Therefore, its detection by breeders and geneticists is important. The entire 1RS arm is present in chromosome substitutions and in Robertsonian translocations involving chromosomes 1A, 1B, or 1D of wheat. In recombinant lines, a segment of 1RS has been exchanged with a segment of a group-1 wheat chromosome. Determining the wheat chromosome arm involved in a translocation, the source of rye chromatin, and the amount of 1RS chromatin introduced is necessary for a complete characterization of the introgressed segment. Biochemical, molecular, and cytogenetic technologies are described which enable such a characterization of 1RS in wheat. Examples of using gel electrophoresis, high-performance liquid chromatography, monoclonal antibodies, rye-specific molecular probes, RFLP and PCR assays, chromosome banding, in situ hybridization, and flow cytometry are provided. A comparison of these technologies is made and the advantages and disadvantages of each technology are discussed relative to modern wheat breeding efforts. This revised version was published online in July 2006 with corrections to the Cover Date.     

利用1RS特异标记和染色体原位杂交技术鉴定小麦1BL·1RS易位系

以小麦-黑麦1BL·1RS易位系(Kavkaz、山农030-1)、1AL·1RS易位系(Amigo)、荆州黑麦、八倍体小黑麦劲松49、1R-7R二体异附加系以及普通小麦中国春、辉县红、铭贤169、Chancellor等为材料,对65个黑麦1RS特异标记进行鉴定,从中筛选出8个稳定的标记,即NOR-1、SECA2/SECA3、SCSS30.2、Sec1Gene、Sec1Pro、ω-Sec-P1/P2、ω-Sec-P3/P4和IB-267,可用于检测1AL·1RS易位系或1BL·1RS易位系;另外3个特异标记O-SEC5′-A/O-SEC3′-R、IAG95-1和SCM-9可用于区别1RS来源不同的1AL·1RS和1BL·1RS易位系。利用这11个标记和染色体原位杂交技术对40份山东省近年育成小麦品种(系)进行检测,发现潍麦8号、鲁麦14、济宁13、山农664、山农优麦3号和烟农25为1BL·1RS易位系,而且是1RS的整臂易位系,未检测到1AL·1RS易位系和其他易位类型。     

Genetic diversity of wheat–rye 1BL.1RS translocation lines derived from different wheat and rye sources

Many studies have been conducted to determine the relative effects of the 1BL.1RS translocation on various traits in wheat. The effects of different wheat (Triticum aestivum L.) genetic backgrounds and rye (Secale cereale L.) sources have been addressed as major factors for inconsistent agronomic performance and end-use-quality traits of 1BL.1RS translocation wheats. However, all these studies were accomplished by using 1BL.1RS translocations with impure wheat genetic bases and narrow rye origins. The objective of this study was to test the genetic effects of centric fusion translocations by using primary 1BL.1RS lines derived from various pure wheat lines and rye sources. Twenty-one primary 1BL.1RS translocation lines were created from crosses between two pure wheat lines and three Chinese local rye varieties. These translocation lines and their wheat parents were then evaluated in southwestern China. The results provide direct evidence of the diverse effects of the different wheat parents and rye sources, taking part in 1BL.1RS translocations, on resistance to diseases, agronomic performance, and end-use quality traits. The highest amount of genetic diversity was observed in 1BL.1RS translocations derived from the same wheat lines and diverse rye varieties. The results suggest that the genetic diversity of 1BL.1RS translocation lines may originate from the different wheat genetic backgrounds, from different rye sources, from their interaction, and from the translocation itself. Creation of diverse 1BL.1RS translocations offers ample possibilities to introduce more variation into wheat for improved performance.     

小麦–黑麦易位系T1BL·1RS在小麦品种中的分布及其与小麦赤霉病抗性的关联

黑麦1R染色体短臂(1RS)携带条锈病、叶锈病、秆锈病、白粉病和蚜虫等抗性基因。为了检测1RS上是否携带与赤霉病抗性相关的基因,本研究采用1RS特异标记Xscm9对192个来自不同国家的品种/系构成的小麦自然群体和1个重组自交系(RIL)群体(宁7840与Chokwang杂交的F_7群体,共184个系)进行了分子检测,并在2011 2013年采用单花滴注法于温室中进行赤霉病抗性鉴定。结果发现,自然群体中22个品种携带1RS,携带1RS的株系三季赤霉病平均病小穗率(PSS)均显著低于不携带1RS株系的PSS(P0.01),表明1RS对降低病小穗率有显著作用。分子标记和基因组原位杂交(GISH)检测结果表明,宁7840携带1RS。通过对宁7840/Chokwang衍生的RIL群体进行赤霉病抗性鉴定和基因型分析,发现不论主效赤霉病抗性基因Fhb1(标记Xsts142)存在与否,携带1RS株系的PSS显著低于不携带1RS株系的PSS(P0.01);方差分析表明,宁7840携带的Fhb1与1RS在赤霉病抗扩展性上无显著互作(P0.05)。因此认为,黑麦1RS染色体很可能携带赤霉病扩展抗性相关基因,与Fhb1基因有累加效应。     

Development and identification of wheat–Haynaldia villosa T6DL.6VS chromosome translocation lines conferring resistance to powdery mildew

Three lines conferring resistance to powdery mildew, Pm97033, Pm97034 and Pm97035, were developed from the cross of Triticum durum-Haynaldia villosa amphidiploid TH3 and wheat cv.'Wan7107' via backcrosses, immature embryo and anther culture. Genomic in situ hybridization analysis showed that these lines were disomic translocation lines. Cytogenetic analysis indicated that the F1 plants of crosses between the three translocation lines and 'Wan7107' and crosses between the three translocation lines and substitution line 6V(6D) formed 21 bivalents at meiotic metaphase I. Aneuploid analysis with 'Chinese Spring' double ditelocentric stocks indicated that the translocated chromosomes were related to chromosome 6D. Biochemical and restriction fragment-length polymorphism (RFLP) analyses showed that the translocation lines lacked a specific band of 6VL of H. villosa compared with the substitution and addition lines but possessed specific markers on the short arm of the 6V chromosome of H. villosa. The three translocation lines lacked specific biochemical loci and RFLP markers located on chromosome 6DS. The results confirmed that Pm97033, Pm97034 and Pm97035 were T6DL.6VS translocation lines.     

Genetic mapping of sequence-specific PCR-based markers on the short arm of the 1BL.1RS wheat-rye translocation

Wheat cultivars carrying the 1BL.1RStranslocation were crossed with newly synthesised octoploid triticale lines involving four rye genotypes having ο-secalin banding patterns different from each other and from that of the 1BL.1RS translocation. Homologous recombination was expected between the short arm of the 1R chromosomes of the rye genotypes and the 1RS arm of the 1BL.1RSwheat/rye translocation. Seven sequence-specific PCR-based markers:Xiag95, RMS13, Bmac0213, GPI, Xpsr960, 5Sand SCM9, and ο-secalinproteins were used to detect recombination events in the BC₁F₂ generation. Segregation analysis demonstrated that a barley SSR marker (Bmac0213) locus was present on the 1RS chromosome arm. Of 834plants tested in four different BC₁F₂ populations, 246individuals were found to carry recombined1BL.1RS translocation chromosomes. Genetic linkage analysis was performed on the eight markers in the four different mapping populations. The physical positions of the markers are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chromosomal location of aluminium tolerance genes in rye

Rye is known for its high tolerance of aluminium in the soils in comparison with wheat and other cereals. To localize the major gene/ genes controlling aluminium tolerance on the rye chromosomes, four series of wheat‐rye addition lines, two sets of triticale D(R) substitution lines and several wheat/rye translocation lines were tested in experiments on seedlings grown in nutrient solutions with various concentrations of aluminium. The results indicate that the major locus responsible for Al tolerance in rye is located on the short arm of chromosome 3R. The importance of these results for controlled introgressions into cereals is discussed.     

Die Nutzung der Antherenkulturmethode im Zuchtprozeß von Winterweizen

Anther culture in the breeding process of winter wheat. III. Ability of winter wheat F₁ populations with the two heterozygous 1AL–IAS/1AL–IRS and 1BL–1BS/1BL–IRS chromosome pairs Application of anther culture to four F₁ hybrids between the IBL–IRS (‘Amigo’) and several 1BL–IRS wheat-rye translocation forms yielded 129 green pollen plants in an average embryo induction frequency of 17.6 %. A total of 2632 anthers was inoculated. 25 % and 42 % of the regenerated plants were haploid and spontaneously doubled haploid, and 33 % had abnormal chromosomal structure. After chromosome doubling treatment 87% of all pollen plants set seeds. By means of multiple peroxidases and Giemsa C-banding patterns, the anther culture progeny could be further classified into 16 plants without the short arm of IR-chromosome of rye, 21 IAL–IRS and 50 1BL–IRS translocation lines and into 16 IAL–IRS, IBL–IRS double translocation lines according to the four possible characteristic types of F₂ gametes of the tested F₁ hybrids. Advantages of the haploid technique for the selection of desirable traits and the meaning of the IRS genes in wheat are discussed.     

About the origin of 1RS.1BL wheat-rye chromosome translocations from Germany

In order lo investigate the origin of two of the German 1RS. 1BL wheat-rye translocations used world-wide in breeding, a number of DNA probes were considered which (a) were critical for the short arm of the rye chromosome 1 R and (b) should show a specificity for the gene pool of Petkus rye. The DNA probe CDO580 was revealed as a specific one. (1) It clearly differentiated 1RS.1AL (‘Amigo’). 1RS.lBL (‘Salmon’) and 1RS.1DL (‘Gabo’) from the two German sources. (2) Both translocation wheats deriving from the Weihenstephan (Munich) and from the Salzmünde (Halle/S.) origin showed an identical DNA fragment which was typical for the gene pool of Petkus rye. It is supposed that both German sources have one progenitor in common.     

Die Nutzung der Antherenkulturmethode im Zuchtprozeß von Winterweizen

The use of anther culture in breeding winter wheat. II. Production of new doubled haploid lines of winter wheat with 1AL—1RS-translocation A total of 4472 anhers was cultured from 8 F¹ populations of winter wheat with the 1AL—1RS wheat-rye translocation cultivar ‘Amigo’ as one of the crossing arents. When averaged over all populations a frequency of embruoid formation of 10% and of regeneration efficiency of green plants of 1% were observed. In addition to the 45 green regenerated plants, 93 albinos were obtained. 44% of the green plantlets had 21 chromosome in root tips and 29% were spontaneous diploids. Multiple peroxidases were used a biochemical markers in the subsequent characterization of the homogeneous breeding material. The electrophoretic patterns showed that 16 doubled haploids without rye chromosome segments were produced. In addition the features of dh₀- plants showed, that several of the new 1AL—1RS-translocation lines were awnless.     

生物素标记的重复DNA序列与黑麦染色体的原位杂交

本研究以两个黑麦重复ＤＮＡ序列ｐＳｃ１１９．１和ｐＳｃ１１９．２作探针进行原位杂交，研究其在小麦和黑麦杂色体上的分布及在检测黑麦染色质中的应用。实验结果表明：ｐＳｃ１１９．１分布于所有黑麦染色体的长短臂上，但在小麦染色体上几乎检测不到杂交信号，证明ｐＳｃ１１９．１对黑麦染色体具有专化性。进一步用该探针与小麦品种“Ａｍｉｇｏ”的体细胞染色体进行原位杂交，可明显检测出其中一对含ＩＲＳ的染色体。ｐＳｃ１     

Intergeneric Transfer (Rye to Wheat) of a Gene(s) for Russian Wheat Aphid Resistance

An octoploid triticale was derived from the F, of a Russian wheat aphid-resistant rye, ‘Turkey 77’, and ‘Chinese Spring’ wheat. The alloploid was crossed to common wheat, and to ‘Imperial’ rye/‘Chinese Spring’ disomic addition lines. F₂, progeny from these crosses were tested for Russian wheat aphid resistance and C-banded. A resistance gene(s) was found to be associated with chromosome arm IRS of the ‘Turkey 77’ rye genome. A monotelosomic IRS (‘Turkey 77’) addition plant was then crossed with the wheat cultivar ‘Gamtoos’, which has the 1BL.1RS ‘Veery’ translocation. Unlike the IRS segment in ‘Gamtoos’, the ‘Turkey 77’-derived 1 RS telosome did not express the rust resistance genes Sr31 and Ar26, which could then be used as markers. From the F, a monotelosomic 1 RS addition plant that was also heterozygous for the 1BL. 1 RS translocation was selected and testerossed with an aphid-susceptible common wheat, ‘Inia 66’ Meiotic pairing between the rye arms resulted in the recovery of five euploid Russian-wheat-aphid-resistant plants. One recombinant also retained Sr31 and Lr26 and was selfed to produce translocation homozygotes.     

Basic studies on hybrid wheat breeding using the 1BL-1RS translocation chromosome / Aegilops kotschyi cytoplasm system 1. Development of male sterile and maintainer lines with discovery of a new fertility-restorer

The Aegilops kotschyi cytoplasm and a 1BL-1RS translocation chromosome that consists of the long arm of wheat chromosome 1B and the short arm of rye chromosome 1R were transferred to six spring common wheat cultivars by repeated backcrossing. Resistance to leaf rust race 21B conditioned by the Lr26 gene and a secalin subunit encoded by the Sec-1 gene, both on the 1RS arm, were used as the selection markers of the translocation chromosome. Five of the six cultivars used were converted to complete male steriles, whereas the remaining one, cv. Kitamiharu 48, retained normal fertility, after transfer of both the 1BL-1RS chromosome and Ae. Kotschyi cytoplasm. Conventional gene analysis suggested that Kitamiharu 48 carries an incompletely dominant fertility-restoring gene. The F₁ hybrids between the male steriles and ordinary common wheat cultivars recovered fertility only at a low level, indicating that a single dose of the Rfv1 gene on the 1BS arm of wheat is insufficient for full fertility restoration under spring-sowing condition. Our results are in clear contrast to complete fertility restoration under fall-sowing condition reported by Nonaka et al. (1993). Combination of the 1BL-1RS chromosome / Ae. Kotschyi cytoplasm system with a new fertility-restoring gene discovered in Kitamiharu 48 may provide a breakthrough for spring-type hybrid wheat. This revised version was published online in August 2006 with corrections to the Cover Date.