Mapping of powdery mildew and leaf rust resistance genes on the wheat-rye translocated chromosome T1BL·1RS using molecular and biochemical markers

Powdery mildew and leaf rust resistance genes on the 1RS arm of the T1BL·1RS translocated chromosome were mapped in relation to the Sec‐1 locus and AFLP and restriction fragment length polymorphism markers, respectively, employing segregating F₃ populations. Integration of molecular markers indicated that Pm17 lies between the Lr26 and Sec‐1 loci, with both resistance genes allocated distally to the Sec‐1 locus in the satellite of the 1RS arm.     

Cumulative and interaction effects of prolamin allelic variation and of 1BL/1RS translocation on flour quality in bread wheat

The allelic variation of prolamin loci was studied in three F₂ progenies from three crosses between the 1BL/1RS cultivar Triana and Yécora Rojo, Pavón and Florence Aurora, cultivars without the translocation. According to the 1:2:1 theoretical proportions observed in the allelic variants of the Glu-B3/Gli-B1 loci of the parent without the translocation, the inheritance as a block of the rye chromosome arm was confirmed. A group of F₃-F₄ recombinant lines, developed from these crosses was evaluated using the SDS-sedimentation test and the mixograph and alveograph tests. The presence of the 1BL/1RS translocation was not associated with significantly lower grain protein content values or with the optimum mixing time in the mixograph of the genotypes. The effect of the 1BL/1RS translocation on most of the quality parameters was highly dependent on the genetic pool. Significant increases in gluten strength and better mixing properties associated with the presence of some alleles of the Glu-A1, Glu-A3/ Gli-A1 and Gli-D2 loci were detected. The additivity and the interaction of prolamin gene effects with the rye translocation in the 1BL/1RS lines and its possible use in plant breeding are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Segregation for isozymes and HMW glutenins in a doubled-haploid cross of winter wheat carrying 1BL.1RS and 5DL.5RS translocations from rye

The doubled haploid (DH) wheat line ‘dh 5841’ carrying two translocations from rye, 5DL.5RS and 1BL.1RS, has been crossed to the subline of wheat cultivar ‘Amadeus 7143’ with a 1BL.1RS translocation. The resulting F₁ hybrid IJ 98 with a heterozygous 5DL.5DS‐5DL.5RS chromosome pair has been used to produce doubled haploids. A total of 57 DH lines were obtained from plantlets regenerated in anther culture after successful colchicine treatment and seed set. These lines were identified regarding the constitution of chromosome 5D (5DL.5DS or 5DL.5RS) by means of isoenzyme marker analysis. Thirty DH lines possessed the 5DL.5DS chromosome, while the remaining 27 lines carried the 5DL.5RS translocation. For some of these lines, the 5DL.5RS chromosome was cytologically confirmed by C‐banding. Furthermore, the DH lines were evaluated for their high molecular weight glutenin subunit composition. All possible combinations for the four independent loci —Skdh, Glu‐Al, Glu‐B1 and Glu‐D1— were detected in only 57 DH lines and no segregation distortion was observed.     

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.     

Chromosomal location of genes for resistance to powdery mildew in common wheat (Triticum aestivum L. em Thell.). 8. Gene Pm32 in a wheat-Aegilops speltoides translocation line

The wheat-Aegilops speltoides translocation line L501 exhibits a disease response pattern distinctive from that of documented powdery mildew genes after inoculation with differential Blumeria graminis tritici isolates. Results based on cytological C-bandings and monosomic analyses reveal that a dominant resistance gene derived from Ae. speltoides is located on a T1BL·1SS chromosome translocation in this line. The new gene is designated Pm32. This revised version was published online in July 2006 with corrections to the Cover Date.     

An STS marker distinguishing the rye-derived powdery mildew resistance alleles at the Pm8/Pm17 locus of common wheat

A sequence‐tagged site marker has been developed from restriction fragment length polymorphism marker probe IAG95 for the rye‐derived powdery mildew resistance Pm8/Pm17 locus of common wheat. This polymerase chain reaction marker enables the amplification of DNA fragments with different sizes from T1AL.1RS and T1BL.1RS wheat‐rye translocation cultivars with chromatin from ‘Insave’ and ‘Petkus’ rye, respectively, and therefore will be very useful in distinguishing Pm8‐carrying cultivars from Pm17‐carrying cultivars. Results obtained with that marker were compared with resistance tests performed on detached primary leaves of 29 wheat lines from two populations derived from doubled haploid production. The molecular assay corresponded well with the resistance tests in all the lines, and therefore will be helpful for the identification of Pm17 in lines in which other Pm genes or quantitative trait loci are present.     

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.     

Characterization of wheat-triticale doubled haploid lines by cytological and biochemical markers

Five wheat-triticale doubled haploid (DH) lines— M08, V209, DH220-14-2, DH696-3-4 and M16 —derived from anther culture of F₁s resulting from crosses involving hexaploid or octoploid triticale × hexaploid wheat, were characterized by cytological and biochemical markers. Cytological evidence from genomic in situ hybridization and C-banding indicated that DH lines M08 and V209 (2n= 42) each contained a pair of 1BL/1RS translocation chromosomes. DH220-14-2 (2n= 42) was also a translocated line with two pairs of chromosomes containing small fragments of rye. One of the translocation fragments carried the Sec-1R gene originating from the satellite region of 1RS; the origin of the other one remains unknown. DH696-3-4 (2n= 42) contained a 3D(3R) substitution. In M16 (2n= 44), three pairs of rye chromosomes, 3R, 4R and 6R, were present, 4R as an addition and 3D(3R) and 6D(6R) as substitutions. Biochemical, isozyme and storage protein markers confirmed the cytological conclusions. The advantages of transferring alien chromosomes or chromosome fragments into wheat and creating alien aneuploid lines by anther culture of hybrid F¹s are discussed.     

SDS-PAGE of the high-molecular-weight subunits of wheat glutenin and the characterization of 1R (1B) substitution and 1BL/1RS translocation lines

Summary The high-molecular-weight subunits of glutenin from wheat 1R(1B) substitution and 1BL/1RS translocation lines were fractionated by SDS-PAGE. Two new subunits denoted R₁ and R₂ were characterized in 1R(1B) substitution, but not in 1BL/1RS translocation lines. R₁ and R₂ were proved to be rye proteins by 2d electrophoresis (NEPHGE x SDS-PAGE).In contrast to literature citations it was demonstrated that the cultivar Winnetou is a 1R(1B) substitution line and the cultivars Clement and Mildress both are 1BL/1RS translocation lines.     

The 1BL/1RS chromosome translocation effect on yield characteristics in a Triticum aestivum L. cross

Comparisons involving 28 random F₂-derived F₆ wheat (Triticum aestivum L.) lines from the cross, ‘Nacozari’/‘Seri 82’, suggested that advanced derivatives with the 1BL/1RS chromosome translocation possess superior agronomic performance in both full and reduced irrigation conditions when compared with 1B derivatives. This performance advantage was attributed to high grain yield, above-ground biomass at maturity, grains/spike, 1000-grain weight and test weight. The 1BL/1RS lines were shorter with delayed flowering and maturity. The superiority of the 1BL/1RS translocation group on grains/m² was expressed only under the full irrigation environment. Higher harvest index, longer spike-length and grain-filling period were detected only under reduced irrigation conditions. A significant grain yield relationship with test weight was detected only among the 1BL/1RS genotypes, indicating that they possess heavier and plumper grains than the 1B genotypes.     

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.     

Fine mapping of Rf2, a major locus controlling pollen fertility restoration in sorghum A1 cytoplasm,encodes a PPR gene and its validation through expression analysis

Sorghum is one of the pioneering cereal crops where cytoplasmic male sterility (CMS) was successfully exploited for mass production of F₁ hybrid seed. Mapping genes for fertility restoration (Rf) is an important aspect of understanding the molecular basis of fertility restoration in crop plants. In this study, we fine‐mapped a fertility restoration locus, Rf2 of sorghum reported earlier (Jordan, Mace, Henzell, Klein, & Klein, 2010 ), involving two F₂ populations (296A × RS29 and 296A × DSV1) and newly developed SSR markers delimited Rf2 locus to 10.32‐kb region on chromosome 2. The Rf2 locus was tightly linked with two new SSRs, MS‐SB02‐3460 (0.14 cM) and MS‐SB02‐3466 (0.75 cM) on both sides, and hosted only one gene (Sobic.002G057050) of PPR gene family. Another new SSR marker developed in the study, MS‐SB02‐37912, forms the part of PPR gene and could act as a perfect marker in marker‐assisted breeding for fertility restoration involving Rf2 in sorghum breeding. The strong involvement of Sobic.002G057050 gene in fertility restoration was supported through RNA expression analysis.     

Evidence of allelism between genes Pm8 and Pm17 and chromosomal location of powdery mildew and leaf rust resistance genes in the common wheat cultivar'Amigo'

TIBL-1RS wheat-rye translocation cultivars utilized in wheat programmes worldwide carry powdery mildew resistance gene Pm8. Cultivar‘Amigo’possesses resistance gene Pm17 on its TIAL-1RS translocated chromosome. To be able to use Pm17efficiently in breeding programmes, this gene was transferred to a TIBL-1RS translocation in line Helami-105, and allelism between Pm8 and Pm17was studied. The progenies of the hybrids in the F₂ generation and F₃ families provided evidence that the two genes are allelic. Genetic studies using monosomic analyses confirmed that in cultivar‘Amigo', Pm17 and leaf rust resistance gene Lr24 are located on a translocated chromosome involving 1 A and 1B, respectively.     

Genetic analysis of falling number in three bi‐parental common winter wheat populations

The objective of the present study was to analyse the genetic basis of falling number in three winter wheat populations. Samples for falling number determination for each population originated from at least three test environments that were free from the occurrence of preharvest sprouting at harvest time. Quantitative trait locus (QTL) analysis employing falling number values from single environments identified eight, five and three QTL in the populations Dream/Lynx, Bussard/W332‐84 and BAUB469511/Format, respectively. A major QTL common to all three populations and consistently detected in each environment mapped to the long arm of chromosome 7B. The QTL was located to a similar genomic region as the previously described major QTL for high‐isoelectric point α‐amylase content. The T1BL.1RS wheat‐rye translocation and the dwarfing gene Rht‐D1 segregating in Dream/Lynx and BAUB469511/Format were found to be important factors of falling number variation. In both populations, the presence of Rht‐D1b or the absence of T1BL.1RS increased falling number. The results indicate that late maturity α‐amylase, responsible for low falling numbers, has now been documented in German wheat germplasm.     

ω-黑麦碱基因沉默对小麦1B/1R易位系加工品质的影响

ω-黑麦碱是造成小麦1B/1R易位系加工品质差的一个重要因素,为探索解决这一问题,构建了ω-黑麦碱基因沉默表达载体,并通过农杆菌介导转化小麦品种金禾9123,获得3个T_0代转基因植株,再经连续的扩繁和PCR检测,获得纯合转基因T_4代株系。酸性PAGE检测结果表明,这些纯合转基因株系中ω-黑麦碱的总表达量平均下降53%。这些ω-黑麦碱基因沉默的转基因株系的面筋指数、沉降值和稳定时间均显著提高,而其农艺性状,如株高、穗粒数、千粒重和小区产量,均没有受到不良影响,说明沉默ω-黑麦碱基因可以在不影响产量的前提下提高小麦1B/1R易位系的加工品质。     

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.     

利用揉面特性鉴定小麦1BL/1RS易位系

1BL/1RS易位系曾广泛用于小麦农艺性状改良,但对加工品质有明显的负面影响。利用404份F₅至F₈高代品系(试验I)和175份山东省主栽品种及高代品系(试验II),研究1BL/1RS易位对小麦揉面参数的影响,分析不同高低分子量蛋白亚基(HWM/LWM-GS)背景下1BL/1RS的揉面特性,探讨利用揉面特性鉴定1BL/1RS易位系的方法。结果表明,1BL/1RS易位系的揉面时间、峰值带宽及峰后1 min带宽显著低于非1BL/1RS易位系,而衰落角和带宽比(峰值带宽/峰后1 min带宽)显著高于非1BL/1RS易位系,说明1BL/1RS易位导致小麦的揉面特性显著变劣。易位系的揉面谱带的主要特征为峰后1 min谱带急剧衰落并变窄,带宽比显著增大,而非1BL/1RS易位系的峰后谱带衰落、变窄平缓或者稳定时间较长,带宽比较小。带宽比1.6可作为判断易位系的有效指标,即大于或等于1.6为1BL/1RS易位系,小于1.6为非1BL/1RS易位系,准确率达85.2%(试验I)和96.8%(试验II)。尽管优质HWM-GS背景对Glu-B3j(1BL/1RS易位系)的揉面特性有一定正向补偿作用,但品质特性仍显著劣于其他Glu-B3位点,带宽比表现尤为突出。因此,揉面特性不仅能测定育种材料的面团流变学特性,而且还能有效鉴别1BL/1RS易位系。     

Distribution of the wheat–rye translocation 1RS.1BL among bread wheat varieties of Bulgaria

The distribution of the wheat–rye translocation 1RS.1BL was studied in 31 winter wheat varieties from Bulgaria. The presence of the translocation was verified in 17 varieties using chromosome N‐banding analysis, PAGE‐analysis of grain storage proteins and DNA‐marker analysis. The 1RS.1BL has been transmitted in 54% of varieties with a known source of the translocation in their pedigree.     

AFLP-based STS markers closely linked to a fertility restoration locus (Rfm1) for cytoplasmic male sterility in barley

The Rfm1 gene restores the fertility of the msm1 and msm² male‐sterile cytoplasms in barley. Rfm1 is located on the short arm of chromosome 6H. To develop molecular markers tightly linked to Rfm1 for use in sophisticated marker‐assisted selection and map‐based cloning, an amplified fragment‐length polymorphism (AFLP) marker system with isogenic lines and a segregating BC₁F₁ population was used. Nine hundred primer combinations were screened and a linkage map was constructed around the Rfm1 locus by using 25 recombinant plants selected from 214 BC₁F₁ plants. Three AFLP markers were identified, e34m2, e46m19 and e48m17, linked to the locus. The most closely linked markers were e34m2, at 1.0 cM distally and e46m19, at 1.1 cM proximally. The two AFLP markers were converted to dominant STS markers. These markers should accelerate programmes for breeding restorer lines and will be useful for map‐based cloning.     

Development of a kompetitive allele‐specific PCR marker for selection of the mutated Wx‐D1d allele in wheat breeding

Waxy (Wx) protein is a key enzyme for synthesis of amylose in endosperm. Amylose content in wheat grain influences the quality of end‐use products. Seven alleles have been described at the Wx‐D1 locus, but only two of them (Wx‐D1b, Wx‐D1e) were genotyped with codominant markers. The waxy wheat line K107Wx1 developed by treating ‘Kanto 107’ seeds with ethyl methanesulphonate carries the Wx‐D1d allele. However, no molecular basis supports this nomenclature. In the present study, DNA sequence analysis confirmed that a single nucleotide polymorphism in the sixth exon of Wx‐D1 changed tryptophan at position 301 into a termination codon. Based on this sequence variation, a PCR‐based KASP marker was developed to detect this point mutation using 68 BC₈F₁ plants and 297 BC₈F₂ lines derived from the cross ‘Ningmai 14’*9/K107Wx1. Combined with codominant markers for the Wx‐A1 and Wx‐B1 alleles, waxy and non‐waxy near‐isogenic lines were distinguished. The KASP marker was efficient in identifying the mutant allele and can be used to transfer waxiness to elite lines.