Rye Parents Research Articles

Assessing How the Aluminum-Resistance Traits in Wheat and Rye Transfer to Hexaploid and Octoploid Triticale.

The mechanisms of aluminum (Al) resistance in wheat and rye involve the release of citrate and malate anions from the root apices. Many of the genes controlling these processes have been identified and their responses to Al treatment described in detail. This study investigated how the major Al resistance traits of wheat and rye are transferred to triticale (x Tritosecale Wittmack) which is a hybrid between wheat and rye. We generated octoploid and hexaploid triticale lines and compared them with the parental lines for their relative resistance to Al, organic anion efflux and expression of some of the genes encoding the transporters involved. We report that the strong Al resistance of rye was incompletely transferred to octoploid and hexaploid triticale. The wheat and rye parents contributed to the Al-resistance of octoploid triticale but the phenotypes were not additive. The Al resistance genes of hexaploid wheat, TaALMT1, and TaMATE1B, were more successfully expressed in octoploid triticale than the Al resistance genes in rye tested, ScALMT1 and ScFRDL2. This study demonstrates that an important stress-tolerance trait derived from hexaploid wheat was expressed in octoploid triticale. Since most commercial triticale lines are largely hexaploid types it would be beneficial to develop techniques to generate genetically-stable octoploid triticale material. This would enable other useful traits that are present in hexaploid but not tetraploid wheat, to be transferred to triticale.

RETRACTED ARTICLE: Analysis of DNA methylation polymorphism in a set of stable chromosome translocation lines

Interspecific hybridization is associated with the origin of novel traits and confers increased vigor compared with the parent lines, although its molecular basis is poorly understood. We report here the identification of genetic and epigenetic changes in a set of wheat–rye translocation lines (R59, R57, and R25) which exhibited novel heritable morphological characteristics compared with the parent lines (MY11 and L155). Genome in situ hybridization and amplified fragment length polymorphism analyses revealed no obvious variations in the primary structure of the genome in different translocation lines, with the exception of the same 1RS chromosome translocation. Global assessment of the extent and pattern of cytosine methylation alterations by methylation-sensitive amplified polymorphism (MSAP) analyses revealed differences in the extent of genomic DNA methylation between the rye and wheat parent lines. Fully-methylated sites were significantly increased and hemi-methylated sites were markedly decreased in the genome of translocation lines compared with the wheat parental cultivar MY11. Comparisons of different MSAP patterns revealed both monomorphic and polymorphic sites between translocation lines and wheat parents. Sequencing of 44 isolated fragments that showed methylation alterations indicated that cellular genes and especially transposable elements were targets for methylation alterations in translocation lines. The present study provides further understanding of the rules governing the distribution and existence of DNA methylation variations induced in the wheat genome during alien germplasm introduction. Furthermore, our study provides insights into the relationship between DNA methylation and hybrid vigor as well as a theoretical basis for further fundamental research and breeding application.

Loss of Parental Coding Sequences in an Early Generation of Wheat-Rye Allopolyploid

During wheat-rye allopolyploidization, the characteristics of the sequences in the bands that appear in both parents and progeny are still unclear. In this study, two different combinations of wheat (Triticum aestivum L.) and rye (Secale cereale L.), including F1 hybrids and the first and second allopolyploid generations, were analyzed by PCR and sequencing using 60 wheat expressed sequence tag (EST)–derived single-sequence repeat markers and EST-derived sequence-tagged site markers. Thirty markers produced the same bands from parental plants, F1 plants, and amphiploids. Seven of the 30 markers amplified identical sequences from wheat and rye parents. Most of these sequences have high similarity between the two parental plants. The variation patterns of sequences in the bands produced by the seven markers were observed. In the F1 hybrids and amphiploids, loss of parental sequences was observed and the frequency of losing rye sequences was higher than that of losing wheat sequences. In addition, a few sequences in these bands exhibited significant differences, indicating that parental sequences changed drastically during allopolyploidization. Therefore, the fact that the parents and progeny contained the same bands should not be regarded as conservation. The results in this study add to the investigations dealing with variation patterns of coding sequences during wheat-rye allopolyploidization.

The significance of organic‐anion exudation for the aluminum resistance of primary triticale derived from wheat and rye parents differing in aluminum resistance

AbstractEight primary octoploid triticale genotypes (xTriticosecale Wittmack) derived from four wheat cultivars (Triticum aestivum L.) and two rye inbred lines (Secale cereale L.) differing in aluminum (Al) resistance were investigated with respect to their response to Al supply. Aluminum‐induced inhibition of root elongation (48 h, 25 µM Al supply), callose formation, and the accumulation of Al in root tips (4 h, 25 µM Al supply) were used as parameters to assess Al resistance. Using these parameters, the existing information on Al resistance of the wheat and rye cultivars was generally confirmed. The triticale cultivars showed a wide range of Al resistance amongst the Al‐sensitive wheat and the Al‐resistant rye cultivars. The rye parents and the Al‐resistant wheat parent Carazinho were characterized by Al‐induced exudation particularly of citrate but also of malate from whole root systems of 14 d old seedlings (8 h, 50 µM Al supply). Regression analysis revealed that the degree of Al resistance of the triticale genotypes was closely related to the Al‐induced citrate exudation, which was mainly controlled by the Al resistance of the wheat parent.

Gel electrophoretic investigations of prolamins in eu- and alloplasmatic octoploid primary triticale forms

Unreduced prolamin fractions of eu- and alloplasmatic octoploid triticale forms were investigated by means of gel electrophoresis. The electrophoretic separation of the prolamin fractions was carried out by using one-dimensional, horizontal, native acidic polyacrylamide gel electrophoresis (APAGE) and gradient gels. A comparison of the electropherogram patterns of triticale forms with those of the genome donors showed that most of the parent prolamins can be found again in the corresponding triticale. However, the bands of the triticale forms exhibited lower intensities than those of the genome donors. On average the gliadin bands of the triticale forms showed equal reductions in intensities, thereby preserving the relationships of the band intensities in most cases. On the other hand, secalin bands which came from the rye parent showed varying reductions in intensities. A comparative analysis of the band patterns revealed that differences could often be found between triticale forms with the same genomic constitution. Often it concerned differences in intensity. In some cases the bands showed changes in mobility or a splitting up into two sub-bands. Starting with the plant material presented here we developed a new nomenclature of the prolamin band patterns of the triticale forms.

Role of rye chromosomes in improvement of zinc efficiency in wheat and triticale

Using the disomic wheat-rye addition lines (Triticum aestivum L., cv. Holdfast-Secale cereale L., cv. King-II) and an octoploid triticale line (xTriticosecale Wittmark L. "PlutoxFakon") as well as the respective wheat and rye parents, greenhouse experiments were carried out to study the role of rye chromosomes on the severity of Zn deficiency symptoms, shoot dry matter production, Zn efficiency, shoot Zn concentration and Zn content. Plants were grown in a Zn-deficient calcareous soil with (10 mg Zn kg-1 soil) and without Zn supply. Zinc efficiency was calculated as the ratio of dry weight produced under Zn deficiency to the dry weight produced under Zn fertilization. In the experiments with addition lines, visual Zn deficiency symptoms were slight in the rye cultivar King-II, but were severe in the wheat cultivar Holdfast. The addition of rye chromosomes, particularly 1R, 2R and 7R, into Holdfast reduced the severity of deficiency symptoms. Holdfast showed higher decreases in shoot dry matter production by Zn deficiency and thus had a low Zn efficiency (53 %), while King-II was less affected by Zn deficiency and had a higher Zn efficiency (89 %). With the exception of the 3R line, all addition lines had higher Zn efficiency than their wheat parent: the 1R line had the highest Zn efficiency (80 %). In the experiment with the triticale cultivar and its parents, rye cv. Pluto and wheat cv. Fakon, Zn deficiency symptoms were absent in Pluto, slight in triticale and very severe in Fakon. Zinc efficiency was 88 % for Pluto, 73 % for triticale and 64% for Fakon. Such differences in Zn efficiency were better related to the total amount of Zn per shoot than to the amount of Zn per unit dry weight of shoot. Only in the rye cultivars, Zn efficiency was closely related with Zn concentration. Triticale was more similar to rye than wheat regarding Zn concentration and Zn accumulation per shoot under both Zn-deficient and Zn-sufficient conditions. The results presented in this study show that rye has an exceptionally high Zn efficiency, and the rye chromosomes, particularly 1R and 7R carry the genes controlling Zn efficiency. To our knowledge, the result with triticale and its rye parents is the first report showing that the genes controlling Zn efficiency in rye are transferable into wheat and can be used for development of new wheat varieties with high Zn efficiency for severely Zn-deficient conditions.

Expression of the cold-induced wheat gene Wcs120 and its homologs in related species and interspecific combinations

Low-temperature response was measured at the whole plant and at the molecular level in wheat-rye amphiploids and in other interspecific combinations. Cold tolerance of interspecifics whose parents diverged widely in hardiness levels resembled the less hardy higher ploidy level wheat parent. Expression of the low-temperature induced Wcs120 gene of wheat (Triticum aestivum L. em. Thell.) has been associated with freezing tolerance and was used here to study mRNA and protein accumulation in interspecific and parental lines during cold acclimation. Northern and Western analyses showed that homologous mRNAs and proteins were present in all the related species used in the experiments. Cold-tolerant rye (Secale cereale L.) produced a strong mRNA signal that was sustained throughout the entire 49-day cold-acclimation period. The wheats produced a mRNA signal that had diminished after 49 days of low-temperature exposure. The wheat-rye triticales did not exhibit the independent accumulation kinetics of the cold-tolerant rye parent but, rather, more closely resembled the wheat parent in that the mRNA signal was greatly diminished after 49 days of low-temperature exposure. The influence of the rye genome was manifest in slightly greater mRNA and protein accumulation in earlier stages of acclimation. Protein accumulations in the triticales were also maintained to a somewhat greater extent than found in the wheats at the end of the 49-day acclimation period. Protein accumulations in the wheat-crested wheatgrass (Agropyron cristatum L. Gaertner) interspecific resembled that of the wheat parent. The influence of the higher ploidy level wheats of the expression of homologous gene families from wheat-related hardy diploids in interspecific combinations may in part explain the poor cold tolerance observed.

The developmental stage of inactivation of rye origin rRNA genes in the embryo and endosperm of wheat x rye F1 hybrids.

To identify the developmental stage during which the preferential inactivation of rRNA genes from the rye parent occurs in wheat x rye hybrids, nucleolar activity was evaluated in the embryo and endosperm of developing seeds of the hybrids. The hybrids were obtained from crosses of euploid and aneuploid lines of hexaploid wheat, Triticum aestivum cv. Chinese Spring, with rye, Secale cereale cv. Centeio do Alto. The number of nucleolar organizing regions (NORs) and nucleoli present in the embryo and endosperm cells of wheat, and wheat x rye F1 hybrids, at different times after fertilization was scored by silver staining. The inactivation of rDNA of rye origin in F1 hybrids occurs simultaneously in the embryo and in the endosperm between 4 and 5 days after fertilization, when these have been through six and 10 cell cycles respectively. We conclude that the genomic interactions leading to the inactivation of the rye origin rDNA is a time-dependent process, related to the developmental stage and independent of the number of cell cycles (DNA replication rounds) they have been through.

Characterization of the 1B/1R translocation in wheat using water extractable protein concentrate

An electrophoretic procedure was developed to obtain patterns of water soluble proteins from the endosperm halves of seeds to detect the 1B/1R translocation in wheat cultivars. The water soluble proteins were precipitated with Coomassie Brilliant Blue R-250 and separated in a 10% polyacrylamide gel with sodium dodecyl sulfate. This procedure extracted protein bands (Mr 40,000, 44,000 and 45,000) corresponding to the ω-secalins of the rye parent which were present only in the wheat cultivars carrying 1B/1R translocation. By simplifying extract preparation and providing clear band resolution this procedure facilitates large scale screening of wheat lines for the rye translocation. Proteins with properties of overlapping solubilities are also discussed.

Triticale, Still a Promise?

AbstractExperiments with primary triticale genotypes produced from defined wheat and rye parents provide a strong indication of a preponderance of specific genome combining ability in the phenotypic expression of triticale. Studying line families developed from specific cross combinations by means of the single seed descent method revealed that, in contrast to wheat, the distribution of genotypes in an F2 population of triticale is strongly skewed, with the majority of them being inferior to the mid‐parent value. This is the case even if recombination is restricted to one fourth of one of the parental components of triticale, i.e. wheat or rye. Correlations of yield components were found to deviate substantially from known types of correlations in wheat, an established natural allopolyploid species. These findings give a strong indication for a genomic inbalance in triticale being a major cause for slow advance in varietal improvement. New breeding strategies designed for the specific genetic structure of triticale are necessary to accelerate breeding progress and to help triticale ultimately to live up to its promise.

The influence of the rye genome on expression of heat shock proteins in triticale

The heat shock protein profiles from Secale cereale L. cv Imperial, Triticum aestivum L. cv Chinese Spring, S. cereale x T. aestivum amphiploid, and the seven disomic S. cereale addition lines to T. aestivum were used to compare the wheat, rye, and triticale Heat Shock Protein profiles and to study the influence of the rye genome on heat shock protein expression in triticale. Three-day-old seedlings were heat shocked for 2 h at 40 °C in the presence of (35)S-methionine, and polypeptides from root tissues were subjected to one- or two-dimensional gel electrophoresis. The wheat and rye heat shock protein profiles each consisted of > 150 heat shock proteins, of which 94 were sufficiently reproducible to construct a standard map. There were 11 unique rye heat shock proteins compared to 22 unique wheat heat shock proteins. The triticale heat shock protein profile resembled the rye parent more than the wheat parent. There were 22 heat shock proteins expressed uniquely by wheat that were not expressed in triticale. Rye chromosomes 1 and 3 exhibited a substantial repressive influence on the expression of 95% of the unique wheat heat shock proteins in triticale, while rye chromosome 4 appeared to have the least repressive influence on expression of the unique wheat heat shock proteins in triticale.

Influence of wheat and rye parents on agronomic characters in primary hexaploid and octoploid triticale

Thirty-five hexaploid and twenty octoploid primary triticales (xTriticosecale Wittmack) derived from homozygous wheat and rye inbred lines were used (1) to investigate the parental wheat, rye, and interaction effects and (2) to estimate quantitative genetic parameters for agronomic traits. The winter triticales were tested in four environments in a three-replicate split-plot design with drilled 1 m(2) plots. Superior performance of hexaploid triticales as compared to the octoploids was revealed. Substantial genetic variation and high heritability estimates were found for nearly all of the characters investigated. Estimates of wheat, rye, and wheat×rye interaction variance components disclosed parental main effects to be the most important source of genetic variation in primary triticales. The rye parent was dominant for all characters affecting fertility, and the wheat parent was more important for vegetative development. Character correlations were very similar for triticales of both ploidy levels. The lack of association between grain yield and tillering and the positive correlation between kernels per spike and thousand kernel weight indicated physiological disorders specific for primary triticales.

Transfer of Hessian fly resistance from ?Chaupon? rye to hexaploid wheat via a 2BS/2RL wheat-rye chromosome translocation

Four wheat-rye lines derived from a cross between hexaploid wheat 'ND 7532' and 'Chaupon' rye were homogeneous for resistance to biotype L of the Hessian fly,Mayetiola destructor. Because the wheat parent was susceptible and the rye parent was resistant to larval feeding, resistance was derived from rye. Resistance of 'Chaupon' and the wheat-rye lines was expressed as larval antibiosis. First-instar larvae died after feeding on plants. Chromosomal analyses using C- and N-banding techniques were performed on plants of each line to identify genomes and structural changes of chromosomes. Results showed that two of the resistant lines were chromosome addition lines carrying either the complete rye chromosome,2R, or only the long arm of2R. The other two resistant lines were identified as being2BS/ 2RL wheat-rye translocation lines. It was concluded, therefore, that the long arm of rye chromosome2R carries a gene or gene complex that conditions antibiosis to Hessian fly larvae and, in the2BS/2RL translocation lines, this rye chromatin is cytologically stable and can be used directly in wheat breeding programs.

C-banding in meiosis: an approach to the study of wheat and rye genome interactions in triticale

Meiosis in four primary hexaploid triticale lines, in their component two tetraploid wheat and two rye parents, and in the hybrids obtained by crossing within each ploidic level was studied using Giemsa banding. The individual chromosomes were identified and their meiotic behaviour at first metaphase was analyzed in each line. In each new triticale line, the level of pairing for wheat chromosomes was moderately reduced and for rye chromosomes was very significantly reduced, in comparison with that of the wheat and rye parents used to synthesize it. The pairing intensity observed suggests the presence of a strong negative intergenomic interaction between the rye and wheat genomes in triticale, irrespective of whether the rye is in a homozygous or heterozygous genotypic condition. The homozygosity or heterozygosity in the wheat constituent does not appear to effect the behaviour of the rye chromosomes in triticale.Key words: triticale, meiosis, C-banding, heterosis.

Hybrid necrosis in triticale and the expression of necrosis genes in allopolyploids

The occurrence in triticale of four different genes causing hybrid necrosis is described: Ne1 and Ne2 in the B genome of wheat and Ner1 and Ner2 in the rye genome. Hybrid necrosis develops due to dominant complementary interaction of two genes. This interaction in triticale, however, may take place not only between genes belonging to the same genome but also between genes of different genomes. In triticale, these genes can cause hybrid necrosis in four different combinations. The inheritance of the phenomenon in triticale is, therefore, more complicated than it is in wheat or rye. To avoid hybrid necrosis in triticale, attention should be paid that no necrosis genes are introduced into the primary triticale stocks from the wheat and rye parents. The expression of necrosis genes is influenced by the level of ploidy. Any additional genome - A, B, D, or R - may exert a suppressing effect on the expression of necrosis genes. Therefore, when identifying genotypes of triticale with regard to their necrosis genes, the level of ploidy has to be accounted for. Moreover, the present results illustrate that gene expression in polyploids is not only determined by interactions with other single genes but that it may also be modified by the total genotype of the respective individual.

Meiotic studies of wheat, rye and 42-chromoaome-Triticales

In 42-chromosome — triticales, chromosome pairing was extremely erratic with very low frequency (60–63 %) of regular bivalents per pollen mother cell. The frequency of univalents was very low or nil in the wheat and rye parents.

Prolamin subunit interactions in hexaploid and octaploid triticales and their wheat and rye parents

The interactions of prolamin subunits encoded by the genomes of wheat (gliadins, glutenins) and rye (secalins) in hexaploid and octaploid Triticales were studied by electrophoresis of fractions extracted sequentially from ground grain and of fractions prepared by gel filtration chromatography of isolated glutens. The electrophoretic studies indicated that the two groups of polymeric secalins (the high-molecular-weight (HMW) secalins and 75K γ-secalins) and wheat glutenin subunits form at least some mixed polymers and oligomers that have solubility properties intermediate between those formed by the same subunits in the parental lines of wheat and rye. The gel filtration studies showed that the 75K γ-secalins are mainly present in lowmolecular-weight (LMW) polymers, but there were no major differences between the elution profiles of the glutens from Triticales and the parental wheat lines. It is concluded that attempts to increase the protein content of wheat by the transfer of genes for 75K γ-secalins from chromosome 2R of rye might have deleterious effects on breadmaking and other technological properties.

Genetic interactions between wheat and rye genomes in triticale

Six primary triticale lines were produced from two advanced breeding lines of Triticum durum and three inbred genotypes of Secale cereale. The wheat and rye parents and the triticale derivatives were crossed in all possible combinations within each species group. Chiasma and univalent frequency of parents and hybrids were determined. The primary triticale lines had more univalents and less chiasmata per pollen mother cell than the corresponding wheat and rye parents together. The parental wheat F1 exhibited negative heterosis for chiasma frequency whereas all rye hybrids had much higher chiasma frequencies than their inbred parents. Triticale F1s generally showed lower chiasma frequencies and more univalents than their parents, but the degree of pairing failure was dependent upon which of the parental species within the triticale, wheat or rye, was in the heterozygous state. F1s with heterozygous wheat genome only showed the least reduction in chiasma number (presumably caused by gene actions within the wheat genome), while F1s with heterozygous rye genome showed high reduction in chiasma frequency and an increase in pairing failure (induced by negative interactions between the heterozygous rye and the wheat genome in triticale). A high correlation was found between the frequency of undisturbed pollen mother cells and the frequency of aneuploids in the subsequent generation. A higher number of aneuploids occurred in those populations which were heterozygous for the rye genome.

Genetic interactions between wheat and rye genomes in triticale

Six primary triticale lines were produced from two advanced breeding lines of Triticum durum and three inbred genotypes of Secale cereale. The wheat and rye parents as well as the triticale derivatives were then crossed each within the same group of species in all possible combinations. Parents, F1s, and F2 populations were used to study the inheritance of a set of morphological and yield characters. The results suggest that, in general, in triticale allelic interactions within the wheat and the rye components are suppressed in favour of intergenomic interactions. Heterozygosity in the rye genome appeared to be detrimental for triticale, whereas heterozygosity in the wheat genome only resulted in positive interactions between certain characters. The retention of a high level of heterosis for kernels per spike in the F2 generation of such hybrids indicates interactions between genes which are in the homozygous state in the rye but remain in the heterozygous state in the wheat genome. If heterozygosity in the wheat component occurs between genes in the A and B genomes (homoeoalleles), it can be fixed in true breeding lines. This condition may ultimately lead to the fixation of their benefical effect on the interaction between wheat and rye genome. Aneuploidy caused a significant decline in performance for most of the investigated characters.

The effect of cytoplasm on cold hardiness in alloplasmic rye (Secale cereale L.) and triticale

Many changes occur within the cytoplasm of plant cells during cold acclimation. However, the cause and effect relationship between cytoplasmic response to low temperature and the development of cold hardiness in cells has been difficult to determine. This study considered the importance of rye (Secale cereale L.) and wheat (Triticum aestivum L. and Triticum tauschii (Coss.) Schmal.) cytoplasmic effects in conditioning plant cold hardiness. The cold hardiness of octoploid triticale (× Triticosecale Wittmack) produced from hardy rye and nonhardy wheat was similar to that of the wheat parent, demonstrating a complete suppression of the rye cold hardiness genes. Similar observations were made for wheat – rye amphiploids from reciprocal crosses, indicating that this suppression was not due to cytoplasmic effects. It is more probable that, because the cold hardiness of octoploid triticale approximates that of the wheat parent, the cold hardiness potential of the rye genome is suppressed by a gene or genes in the wheat complement. The cold hardiness of alloplasmic rye with T. tauschii cytoplasm was similar to that of the rye parent indicating that the cold hardiness genes of rye have normal expression in the T. tauschii cytoplasm. Based on observations made in these two studies, it was concluded that the cytoplasm has little direct effect on cold hardiness, or on the nuclear expression of cold hardiness.Key words: cold hardiness, cytoplasm, Triticum aestivum L., triticale, alloplasmic rye.