Distribution of 1AL.1RS and 1BL.1RS wheat-rye translocations in Triticum aestivum using specific PCR

Chromosome arm 1RS of rye (Secale cereale) is a valuable resource for wheat (Triticum aestivum) improvement. 1AL.1RS and 1BL.1RS translocations play an important role in wheat breeding, since wheat carrying these chromosomal translocations has higher tolerance to biotic and abiotic stress. In this study, the presence of 1RS and the distribution of 1AL.1RS and 1BL.1RS wheat-rye translocations were examined in 66 Iranian cultivars and 70 regional foreign accessions of bread wheat, using three rye-specific primers (“RYER3/F3”, “O-SEC5′-A/O-SEC3′-R”, “PAWS5/S6”). Based on “RyeR3/F3”, the presence of 1RS was verified in 15 (23%) Iranian cultivars and in two (3%) foreign accessions. Further, “O-SEC5′-A/O-SEC3′-R” and “PAWS5/S6” were used to distinguish 1AL.1RS and 1BL.1RS translocations. According to results from these primers, 1BL.1RS was identified in 14 (21%) Iranian cultivars and two (3%) foreign accessions. The results confirm that “Sholeh” is the only cultivar (1.5%), among all cultivars and accessions, that carries 1AL.1RS. This study provides a useful tool in marker-assisted selection of materials containing 1RS, and in the creation of new Iranian common wheat cultivars with a larger genetic diversity in wheat breeding programs.     

Conjugation of the 1BL/1RS translocation with qualitative and quantitative traits in the common wheat T.aestivum

The review considers the effect of the rye 1BL/1RS translocation in the common wheat genome on qualitative and quantitative traits: grain quality, resistance to diseases, productivity and adaptivity, parthenogenesis, regeneration in anther culture, frequency of chromosome aberrations and frequency of cross-pollination. Data on special features of transmission of the 1BL/1RS translocation through male and female gametes are presented.     

Characteristics of common wheat cultivars of West Siberia carrying the wheat-rye 1RS.1BL translocation

Using genomic in situ hybidization, among the common wheat cultivars produced in West Siberia (Siberian Research Institute of Agriculture, Omsk) with the involvement of the winter wheat cultivar Kavkaz carrying the wheat-rye 1RS.1BL translocation we identified three cultivars with this translocation: Omskaya 29, Omskaya 37, and Omskaya 38. The protein and crude gluten contents in the grain of these cultivars are equal to or exceed the levels observed in cultivars without the wheat-rye translocation. The common wheat cultivars carrying the wheat-rye translocation were evaluated in terms of resistance of plants reaching wax ripeness to leaf rust and powdery mildew in the natural field conditions. The cultivars Omskaya 37 and Omskaya 38 displayed a high field resistance to leaf rust and were resistant to a variable extent to powdery mildew. The cultivar Omskaya 29 was susceptible to leaf rust and powdery mildew pathogens. Importance of the selection direction and the role of the genetic background in developing common wheat cultivars carrying the wheat-rye translocation is discussed.     

Production of a new wheat line possessing the 1BL.1RS wheat-rye translocation derived from Korean rye cultivar Paldanghomil

The 1BL.1RS translocations between wheat (Triticum aestivum L.) and rye (Secale cereale L.) are widely used in bread wheat breeding programs, but all modern wheat cultivars with the 1BL.1RS have shown genetic vulnerability due to one rye source – a German cultivar, Petkus. We have developed, a new 1BL.1RS wheat-rye translocation line from the backcross of the F₁ hybrid of wheat cv. Olmil and rye cv. Paldanghomil, both cultivars from Korea. The GISH technique was applied to identify the presence of rye chromatin in 467 BC₁F₆ lines selected from 77 BC₁F₅ lines. Only one line, Yw62–11, showed wheat-rye translocated chromosomes, with a somatic chromosome number of 2n=42. C-banding patterns revealed that the translocated chromosome was 1BL.1RS, showing prominent bands in the terminal and sub-terminal regions of the short arm as well as in the centromeric region and terminal region of the long arm. This new 1BL.1RS translocation line formed 21 bivalents like common wheat at meiotic metaphase I, thereby showing complete homology. Received: 28 February 2001 / Accepted: 17 April 2001     

Effect of genome, induction medium and temperature pretreatment on green plant production in durum ( Triticum turgidum var. durum ) x bread wheat ( Triticum aestivum L. em Thell) crosses

The recalcitrancy of durum wheat (Triticum turgidum var. durum) to anther culture, was attempted to be overcome by transferring the responsible genes form bread wheat B-genome to the respective on durum wheat, determining an appropriate induction medium and clarifying the necessity of cold pretreatment. For this, three durum wheat cultivars were crossed to two bread wheat (Triticum aestivum L. em Thell) cultivars. The resulting F₁ plants and their original cultivars were grown in the field and anthers at the appropriate microspore stage were cultured on potato-2 and W₁₄ media with and without low temperature pretreatment. No green plants were produced from the parental durum wheat cultivars. In contrast, green plants were produced from the F₁ plants. The best results in three of the four F₁ hybrids were recorded when potato-2 was used as induction medium. A more variable response of the examined genotypes was noticed with respect to temperature pretreatment. Regarding green plant production, a negative effect of cold pretreatment was observed in two of the F₁ hybrids when they were cultured on potato-2. Chromosome counts on root tips from the resulting green plants revealed that they all carried D-genome chromosomes. The last observation could suggest that D-genome chromosomes are necessary for anther culture response in wheat. Yet, the production of one green plant with 15 chromosomes may indicate that the development of extracted durum genotypes from bread wheat genotypes with good response to in vitro anther culture might be possible. Further work however, is needed for this to be verified.     

Fingerprinting of common wheat cultivars with an Alw44I-based AFLP method

A simplified AFLP method, based on methylation-sensitive Alw44I restriction endonuclease, has been developed and evaluated for fingerprinting 15 wheat cultivars. The selected germplasms represented groups of spring and winter wheats with and without the 1BL.1RS translocation. Ten selective primers yielded 57 markers, including 19 polymorphic bands. Three markers (15.8%) were specific to wheat carrying the 1BL.1RS translocation, thus conflicting with the frequency expected by random marker distribution (2.4%), and suggesting qualitative differences in DNA methylation among winter wheat cultivars with the 1BL.1RS translocation. Mean Dice's similarities ranged from 0.85 to 0.99, thus all cultivars could be identified by the banding profile. Winter wheat cultivars, with and without the 1BL.1RS chromosome, were slightly more similar to one another (0.959) than spring wheat cultivars (0.952). Five (9%) specific markers were obtained from cultivars Sicco, Cheyenne, Fenman, Disponent and Chinese Spring.     

黑麦碱基因（Sec–1）表达缺失的1RS／1BL易位系的鉴定

用改良的Giemsa C－带技术、DNA原位杂交和酸性聚丙烯酰胺凝胶电泳（A-PAGE）对来源于小麦品种绵阳11与不同黑麦自交系远缘杂交获得的高代株系（BC1F7）的染色体结构和醇溶蛋白进行了研究。结果发现,在鉴定的200个株系中,有45个株系经C-带和A-PAGE检测均一致地发现它们含有一对1RS /1BL易位染色体,而一个株系843-1-1,C-带鉴定、原位杂交结果均证明它含有一对1RS/1BL易位染色体,但A-PAGE醇溶蛋白图谱却不具有黑麦1RS染色体臂的黑麦碱特征带,而表达出既不同于黑麦碱又不同于亲本绵阳11的醇溶蛋白带型。这一结果表明,利用不同的黑麦亲本资源,可以获得黑麦碱基因Sec-1表达缺失的新的1RS/1BL易位系。这种新的1RS/1BL易位系缺失了影响小麦品质的黑麦碱蛋白,因此是进一步研究1RS/1BL 易位对小麦品质影响的珍贵材料。研究指出,在利用外源基因的植物育种中,外源种供体材料的遗传多样性是值得重视的基因资源。     

青海省小麦品种中Yr10和Yr15基因及其1BL/1RS易位的分子检测

利用抗条锈病基因Yr10和Yr15的SCAR和Barc8标记以及1BL/1RS易位的复合标记,对青海省育成和引进的137份小麦品种进行检测,以明确Yr10和Yr15基因以及1BL/1RS易位在青海小麦品种资源中的分布.结果显示:在137份材料中,有4份检测到Yr10基因,19份检测到Yr15基因,分别占参试材料的2.9%和13.9%,没有检测到同时携带Yr10和Yr15基因的材料;有22份材料为1BL/1RS易位,占参试材料的16.1%.研究表明,青海省大部分小麦抗锈品种及1BL/1RS易位品种为外引种品种.     

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.     

Nuclear gametophytic genes from chromosome arm 1RS improve regeneration of wheat microspore-derived embryos.

The effect of the 1RS chromosome arm from rye on plant regeneration from microspore-derived embryos was studied using anther culture technology with genotypes carrying the 1BL-1RS translocated chromosomes, the normal wheat chromosome 1BL-1BS, and ditelosomic lines DT 1BS and DT 1BL. A significant difference was observed in microspore-derived green plants between chromosome structure concerned with 1RS and 1BS arms. An analysis of the inheritance of the 1B-1R translocation was performed on the basis of the frequency of male gametes 1BL-1RS in the microspore-derived green plants and that of the 1B-1R translocation inherited through the pollen or the egg cell from structurally heterozygous hybrids 1BL-1BS/1BL-1RS. Both the normal 1B and the translocated 1BL-1RS chromosomes were sexually transmitted through the pollen grains with the same frequency. The 1BL-1RS chromosome is only transmitted through 45% of the egg cells. On the contrary, two-thirds of the microspore-derived green plants regenerated from the anther culture experiments possess the translocated chromosome. The involvement of the rye chromosome arm 1RS from 'Aurora' on regeneration capacity of the microspore-derived embryos has been proposed through the effect of a "gametophytic gene."     

1BL/1RS translocation in durum wheat and its effect on end use quality traits

The gluten proteins document the genotypic identity of a wheat variety, in addition to providing valuable clues about its ancestry and technological properties. In this study, an Indian durum wheat genotype B662 was identified to carry 1BL/1RS translocation and characterized further for its effect on end use quality traits. Comparison of the end use quality traits of B662 with five other durum cultivars without 1BL/1RS, showed decreased gluten content, lower swelling index of glutenins and low MSDS-SV indicating that, B662 with 1BL/1RS is not good for pasta making. In F_2:3 seeds from a durum wheat cross between the 1BL/1RS cultivar B662 and HI8498 without the translocation, the secalin Sec-1 loci segregated in theoretically expected 3:1 proportion and were inherited as a block of the rye chromosome arm. The analysis of F_2:3 harvests for the two most important durum wheat quality tests showed that the presence of 1BL/1RS translocation did not alter the grain protein content values, but was associated with significant reduction of micro SDS-sedimentation volume indicating inferior quality, thus limiting the commercial exploitation of durum wheat genotypes with 1BL/1RS translocation. The cautious use of rye translocation in Indian durum wheat breeding is suggested.     

Transfer of the 1BL/1RS wheat-rye-translocation from hexaploid bread wheat to tetraploid durum wheat

Summary The present study describes a cytological stable alien chromosome translocation in tetraploid durum wheat. By crossing the hexaploid 1BL/1RS wheat-rye translocation line Veery to the tetraploid durum wheat cultivar Cando it was possible to select a 28 chromosomic strain homozygous for the 1BL/1RS translocation. The disease resistance potential of the short arm of rye chromosome 1R, which has been widely introduced in many hexaploid bread wheat cultivars could be now also used for the improvement of durum wheat.     

小麦主栽品种中的1RS分布和兰考90(6)系列白粉病新抗源

利用黑麦染色体臂1RS的特异性PCR标记,对黄淮麦区138个小麦主栽品种、系进行了PCR扩增,结果表明：有42．0%的小麦品种、系携带1RS染色体臂。以六倍体小黑麦Mzalenod Beer为黑麦染色体供体,培育的兰考90(6)系列小麦品系是新的小麦-黑麦1BL／1RS易位系。这些品系对小麦白粉病具有很高的抗性,是小麦抗白粉病育种的新抗源。对兰考90(6)系列品系白粉病抗性进行了研究,结果表明,兰考90(6)系列品系的抗谱与许多已经知道的小麦抗白粉病基因的抗谱不同,并具有数量抗性特点。     

Effects of colchicine on anther and microspore culture of bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

The aim of this work was to study the effects of colchicine application on chromosome doubling and androgenic response in anther and microspore culture of different bread wheat genotypes. Colchicine was applied during a mannitol stress pretreatment or during the first 48 h of culture at concentrations of 0, 150 and 300 mg l⁻¹. When colchicine was applied during stress pretreatment, the percentage of doubling depended on genotype and concentration. A significant increase in doubling was observed with 300 mg l⁻¹ in the low androgenic responding cv. Caramba. Colchicine incorporation during the first hours of culture improved percentage of doubling in all genotypes, in both anther and microspore culture. Application of 300 mg l⁻¹ colchicine improved the percentage of doubling in the two low responding genotypes, to 118% of control in DH24033, and 75% in Caramba in microspore and anther culture, respectively. Concerning the androgenic response, the effect of colchicine on embryo formation and percentage of green plants depended on the genotype and on the culture method. In cv. Pavon, a 2- and a 3-fold increase in percentage of embryogenesis and green plants, respectively, were obtained with 300 mg l⁻¹ colchicine in microspore culture. However, no significant differences in these two variables were observed in anther culture. The number of green doubled haploid (DH) plants reflects the index of success of the procedure. Regardless of the culture method, when colchicine was incorporated during the first hours of culture, the number of green DH plants increased significantly in three of four genotypes. These results confirm the usefulness of colchicine application during the first hours of culture in wheat breeding programs.     

Effect of the 1BL.1RS translocation on the wheat endosperm, as revealed by proteomic analysis

The introduction of the 1RS chromosome of rye into wheat made wheat more resistant to several pathogens. Today, this resistance has been overcome but the 1BL.1RS translocation remains interesting because of the improved yield and despite the lower rheological properties it produces. Nothing has been reported yet on the impact of rye chromatin introgression on the grain proteome of wheat. The comparison of the 2-DE profiles of 16 doubled haploid lines, with or without the 1BL.1RS translocation, revealed quantitative and qualitative proteic variations in prolamins and other endosperm proteins. Eight spots were found specifically in lines having the 1BL.1RS translocation; 16 other spots disappeared from the same lines. Twelve spots, present in both genotypes, met the criteria for up- or down-regulated spots. In translocated genotypes, a highly overexpressed spot, identified as a gamma-gliadin with nine cysteine residues, suggests that the lack of LMW-GS induced by 1BL.1RS is counterbalanced by an overexpression of a relatively similar prolamin. Moreover, a spot that was absent from 1BL.1RS genotypes was identified as a dimeric alpha-amylase inhibitor. It was considered to be a valuable candidate to explain the sticky dough associated with translocated cultivars.     

Identification of the 1RS rye chromosomal segment in wheat by RAPD analysis

The introgression of rye DNA into the wheat genome was studied using random decamer and specific primers with the polymerase chain reaction (PCR). DNA from paired near-isolines in Chisholm and Arkan backgrounds differing with respect to the presence of a 1 RS.1 BL translocation was amplified with 120 arbitrary sequence primers. Two of the primers (OPR 19 and OPJ07) amplified rye-specific DNA fragments. The OPR19 primer amplified a 1.35-kb fragment that appeared to be specific to the 1 RS.1 BL translocation, based on its presence only in lines carrying the 1 RS. 1 BL translocation. A fragment of the same size was also amplified in 1 RS.1 AL translocation lines. This 1 RS. 1 BL marker locus was designated Ximc 1. The other primer, OPJ07, amplified a 1.2-kb DNA sequence, that was designated Ximc 2, specific to the wheat-rye translocation in various wheat backgrounds. The sequences of the two marker loci were found to be different from each other. The Ximc 1 locus was a low-copy sequence which was also present in Balboa rye genomic DNA. Through the use of specific primers, the presence of the rye-specific marker was confirmed in hexaploid as well as in tetraploid wheat backgrounds. The use of RAPDs for the study of smaller alien introgressions into wheat is discussed.     

Chromosome composition of wheat-rye lines and the influence of rye chromosomes on disease resistance and agronomic traits

Identification of the chromosomal composition of common wheat lines with rye chromosomes was carried out using genomic in situ hybridization and 1RS- and 5P-specific PCR markers. It was demonstrated that wheat chromosomes 5A or 5D were substituted by rye chromosome 5R in the wheat-rye lines. It was established that one of the lines with complex disease resistance contained rye chromosome 5R and T1RS.1BL, while another line was found to contain, in addition to T1RS.1BL, a new Robertsonian translocation, T5AS.5RL. Substitution of the wheat chromosome 5A with the dominant Vrn-A1 gene for the Onokhoiskaya rye chromosome 5R led to lengthening of the germination-heading period or to a change in the type of development. A negative influence of T1RS.1BL on SDS sedimentation volume and grain hardness was demonstrated, along with a positive effect of the combination of T1RS.1BL and 5R(5D) substitution on grain protein content. Quantitative traits of the 5R(5A) and 5R(5D) substitution lines were at the level of recipient cultivars. A line with two translocations, T1RS.1BL + T5AS.5Rl, appeared to be more productive as compared to the line carrying T1RS.1BL in combination with the 5R(5D) substitution.     

Development of a wheat genotype combining the recessive crossability alleles kr1kr1kr2kr2 and the 1BL.1RS translocation, for the rapid enrichment of 1RS with new allelic variation

The main objective of the present work was to develop a wheat genotype containing both the recessive crossability alleles (kr1kr1kr2kr2), allowing high crossability between 6x wheat and diploid rye, and the 1BL.1RS wheat/rye translocation chromosome. This wheat genotype could be used as a recipient partner in wheat–rye crosses for the efficient introduction of new allelic variation into 1RS in translocation wheats. After crossing the wheat cultivars ‘Mv Magdaléna’ and ‘Mv Béres’, which carry the 1BL.1RS translocation involving the 1RS chromosome arm from ‘Petkus’, with the line ‘Mv9 kr1’, 117 F₂ plants were analysed for crossability, ten of which had higher than 50% seed set with rye and thus presumably carried the kr1kr1kr2kr2 alleles. Four of the ten plants contained the 1BL.1RS translocation in the disomic condition as detected by genomic in situ hybridization (GISH). The wheat × rye F₁ hybrids produced between these lines and the rye cultivar ‘Kriszta’ were analysed in meiosis using GISH. 1BL.1RS/1R chromosome pairing was detected in 62.4% of the pollen mother cells. The use of fluorescent in situ hybridization (FISH) with the repetitive DNA probes pSc119.2, Afa family and pTa71 allowed the 1R and 1BL.1RS chromosomes to be identified. The presence of the 1RS arm from ‘Kriszta’ besides that of ‘Petkus’ was demonstrated in the F₁ hybrids using the rye SSR markers RMS13 and SCM9. In four of the 22 BC₁ progenies analysed, only ‘Kriszta’-specific bands were observed with these markers, though the presence of the 1BL.1RS translocation was detected using GISH. It can be concluded that recombination occurred between the ‘Petkus’ and ‘Kriszta’ 1RS chromosome arms in the translocated chromosome in these plants.     

Centromere structure and function analysis in wheat–rye translocation lines

1RS.1BL translocations are centric translocations formed by misdivision and have been used extensively in wheat breeding. However, the role that the centromere plays in the formation of 1RS.1BL translocations is still unclear. Fluorescence in situ hybridization (FISH) was applied to detect the fine structures of the centromeres in 130 1RS.1BL translocation cultivars. Immuno‐FISH, chromatin immunoprecipitation (ChIP)‐qPCR and RT‐PCR were used to investigate the functions of the hybrid centromeres in 1RS.1BL translocations. New 1R translocations with different centromere structures were created by misdivision and pollen irradiation to elucidate the role that the centromere plays in the formation of 1RS.1BL translocations. We found that all of the 1RS.1BL translocations detected contained hybrid centromeres and that wheat‐derived CENH3 bound to both the wheat and rye centromeres in the 1RS.1BL translocation chromosomes. Moreover, a rye centromere‐specific retrotransposon was actively transcribed in 1RS.1BL translocations. The frequencies of new 1RS hybrid centromere translocations and group‐1 chromosome translocations were higher during 1R misdivision. Our study demonstrates the hybrid nature of the centromere in 1RS.1BL translocations. New 1R translocations with different centromere structures were created to help understand the fusion centromere used for wheat breeding and for use as breeding material for the improvement of wheat.