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At least 145 records · Page 8Linked to original sources
PubMed2005

PstIAFLP based markers for leaf rust resistance genes in common wheat.

The aim of the present study was to detect candidate DNA markers for selected leaf rust resistance genes. A total number of 286 loci in the 'Thatcher' near-isogenic lines carrying resistance gene Lr1, Lr9, Lr10, Lr13, Lr19, Lr21, Lr24, Lr26, Lr28, Lr35, and Lr37 were screened for DNA polymorphism by the PstIAFLP method. A survey with 33 selective primers yielded 16 candidate markers. Further validation studies on cultivars characterized for the presence and absence of selected resistance genes confirmed specificity of markers for Lr24, Lr26 and Lr37. The AFLP-based marker P42-530 was successfully converted into an STS marker. The new marker was linked with the Lr37-specific marker (CslVrga13) at the distance of 1.7 cM. The PstIAFLP method was found to be effective in the identification of DNA changes induced in hexaploid wheat by translocations from Agropyron elongatum, Secale cereale and Aegilops ventricosa.

Base Sequence↗
PubMed2006

Cloning, characterization and expression analysis of the receptor-like kinase gene (RLK) in common wheat.

To investigate whether homologs of wheat (Triticum aestivum L.) LRK10 gene was expressed in powdery mildew-resistant lines after inoculation with Blumeria graminis f. sp. tritici, one degenerate primer for 5'-RACE was designed according to the 6th kinase subdomain of LRK10 and other plant kinases. 5'-RACE was performed with the template cDNA synthesized with RNA extracted from seedling leaves of a powdery mildew-resistant wheat line "99-2439" after inoculation with B. graminis. One 1551 bp cDNA fragment representing a protein kinase gene was obtained (S1125, GenBank accession number: AY584533). Subsequently, a 2255-bp full-length cDNA clone with a complete encoding region (open reading frame, ORF) was obtained by RACE. The clone encodes a polypeptide consisting of 637 amino acid residues. The result of homology search showed that it belongs to a receptor-like kinase gene family in wheat, which was named as wlrk (wheat leaf rust kinase) previously. Similar to LRK10, this protein kinase has five distinct domains: a hydrophobic signal sequence at the amino-terminus, a putative extracellular domain, a transmembrane domain, a highly charged sequence and a serine/threonine kinase domain at the carboxy-terminus, and thus it was named as TaLRK (Triticum aestivum LRK). The expression pattern of TaLRK at transcription level in leaves after B. graminis infection was investigated by semi-quantitative RT-PCR (semi-QRT-PCR), using wheat actin gene as a control. The result showed that the transcription of TaLRK was significantly enhanced by B. graminis infection. The expression pattern of TaLRK in different tissues showed that this new wheat RLK gene was expressed only in green parts of wheat. This study suggests that TaLRK may function in wheat powdery mildew resistance responses.

Amino Acid Sequence↗
PubMedDate not supplied

[Beginning and duration of expression of photoperiodic response genes in winter common wheat].

The influence of various Ppd genes on the beginning and duration of photoperiodic responce has been investigated in near isogenic lines of winter bread wheat Mironovskaya 808. During ontogenesis the photoperiodic responce is ascertained from the middle 2nd stage of ontogenesis according to Kuperman (usually a week later after vernalization completion in winter genotypes) and it is completed to the late 5th stage (2-3 weeks before heading). Different Ppd alleles do not affect the photoreaction intensity however they have an influence on its duration through the rate of development. Ppd-A1a and Ppd-B1a genes manifest shorter duration of expression when compared to the recessive alleles in the initial Mironovskaya 808 cultivar. Effect of the Ppd-B1a gene is stronger and of the Ppd-A1a is weaker.

Acclimatization↗
PubMed2004

Genome-specific primer sets for starch biosynthesis genes in wheat.

Common wheat (Triticum aestivum L.,2n=6x=42) is an allohexaploid composed of three closely related genomes, designated A, B, and D. Genetic analysis in wheat is complicated, as most genes are present in triplicated sets located in the same chromosomal regions of homoeologous chromosomes. The goal of this report was to use genomic information gathered from wheat-rice sequence comparison to develop genome-specific primer sets for five genes involved in starch biosynthesis. Intron locations in wheat were inferred through the alignment of wheat cDNA sequences with rice genomic sequence.Exon-anchored primers, which amplify across introns,allowed the sequencing of introns from the three genomes for each gene. Sequence variation within introns among the three wheat genomes provided the basis for genome-specific primer design. For three genes, ADP-glucose pyrophosphorylase (Agp-L), sucrose transporter (SUT),and waxy (Wx), genome-specific primer sets were developed for all three genomes. Genome-specific primers were developed for two of the three genomes for Agp-S and starch synthase I (Ssl). Thus, 13 of 15 possible genome-specific primer sets were developed using this strategy. Seven genome-specific primer combinations were used to amplify alleles in hexaploid wheat lines for sequence comparison. Three single nucleotide polymorphisms(SNPs) were identified in a comparison of 5,093 bp among a minimum of ten wheat accessions. Two of theseSNPs could be converted into cleaved amplified polymorphism sequence (CAPS) markers. Our results indicated that the design of genome-specific primer sets using intron-based sequence differences has a high probability of success, while the identification of polymorphism among alleles within a genome may be a challenge.

Base Sequence↗
PubMed2005

[Fragment length polymorphism of Wx-B1 gene digested by BamHI and its relation to amylose content of wheat].

There are two types of starch, amylose and amylopectin of flour. Amylose content (AC) is significantly negatively correlated with noodle quality. The waxy gene (Wx) encodes the granule-bound starch synthase (GBSS, EC 3.4.1.11), or Wx protein, is responsible for the synthesis of amylose in wheat. Common wheat is allohexaploid, it has three different Wx proteins: Wx-A1, Wx-B1, and Wx-D1. Consequently, amylose content and pasting properties of starch were influenced by the lack of the Wx-B1 protein, followed by that of Wx-D1, and Wx-A1. Using STS (sequence-tagged sites) primers, the sequences were amplified near the 4th intron region, and fragments amplified were digested by BamHI in 35 wheat cultivars. The results indicate that some fragments can be digested and the other cannot. The fragments digested showed two length polymorphism, and the length is negatively correlated with amylose content. The fragment in many cultivars with amylose content above 20% can be digested by BamHI, while those with amylose content below 20% cannot. All these indices demonstrate that there is variation exists in amplified region of Wx-B1 gene. This can be useful in breeding program to select wheat cultivars with different amylose content, and improve wheat quality.

Amylose↗
PubMed2004

The transfer and characterization of resistance to common root rot from Thinopyrum ponticum to wheat.

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat - Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat x Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J-Js and Js-J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js-J translocated chromosome. The subtelocentric J-Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.

Ascomycota↗
PubMed2001

Effect of seed treatment with organic acids on the control of common bunt (Tilletia tritici and T. laevis) in wheat.

Common bunt caused by Tilletia tritici and T. laevis is an important disease, causes considerable losses in wheat yield on a world wild. The disease reduces yields, complicates harvesting and lowers the quality of the grain. It occurs more frequently and causes greater damage on winter wheat than on spring wheat. Grain standards designate wheat that has an unmistakable odor of smut or that contains smut balls, portions of balls, or spores of smut in excess of a quantity equal to 14 balls of average size in 250 g of wheat as "light smutty". Samples containing an excess of 30 balls, or their equivalent, in 250 g of wheat are graded as "smutty". Grain in these grades brings lower prices. Using commercial acetic acid and lactic acid, the pathogen was successfully controlled, but the treatment negatively affected seed germination and seedling vitality. Using dilutions of acetic acid and lactic acid, significant control of the pathogen also was achieved with acetic acid without causing phytotoxicity. Dilutions of lactic acid also gave good control, but showed some phytotoxicity. Using 30-50 ml/kg of vinegar, which is a natural source of acetic acid, proved to be one of the most effective alternatives for control of common bunt on wheat. The treatment had no negative effects on seed germination nor on seedling vitality.

Acetic Acid↗
PubMed1992

Variations in chloroplast proteins and nucleotide sequences of three chloroplast genes in Triticum and Aegilops.

Two alloplasmic wheat lines having the same common wheat nucleus but the cytoplasms of Aegilops crassa and Ae. columnaris together with the corresponding normal line (control) were used in the two-dimensional gel electrophoresis of soluble and thylakoid membrane proteins of the chloroplast. Three chloroplast polypeptides: the Rubisco large subunit, the beta subunit of ATP synthase, and an unidentified 31 kDa protein, differed in the common wheat and two Aegilops cytoplasms. Three chloroplast genes, atpB, atpE and trnM, that respectively encode the beta and epsilon subunits of ATP synthase and tRNA(met), were sequenced. The atpB gene differed by two synonymous base substitutions, whereas the other two genes were identical in the two Aegilops cytoplasms. From the predicted amino acid sequences, the beta subunits of the ATP synthase in the Aegilops cytoplasms were assumed to have three amino acid substitutions: Ala by Val, Asp- by Ala, and Gln by Lys+, in contrast to the cytoplasm of common wheat. This accounts for the difference in pI values found for the common wheat and Aegilops cytoplasms. The two base substitutions for the atpE genes of common wheat and the Aegilops cytoplasms were synonymous. The differences detected in the genes encoding the two subunits of ATP synthase do not appear to be ascribable to the differences in phenotypic effects for the common wheat and Aegilops cytoplasms. The base substitution rate of the atpB-atpE-trnM gene cluster was similar to that of the rbcL gene. From the rate for the atpB gene alone, evolutionary divergence of the wheat-Aegilops complex is assumed to have begun ca. 3.0 x 10(6) years ago, as compared to ca. 8.0 x 10(6) years ago for the divergence of the wheat-Aegilops complex and barley.

Amino Acid Sequence↗
PubMed2005

Alien DNA introgression and wheat DNA rearrangements in a stable wheat line derived from the early generation of distant hybridization.

Polyploidy has been found to be common in plants. Bread or common wheat (Triticum aestivum L., 2n=42) is a good example of allopolyploid made up of three diploid genomes A, B and D. In recent years, by the study of mimicking the origination of common wheat, it was found that changes of DNA sequence and gene expression occurred at the early stages of artificial allohexaploid between tetraploid wheat and Aegilops tauschii, which was probably favorable to genetic diploidization of new synthetic hexaploid wheat. Common wheat 99L2 is a new line stable in genetic, which was derived from the early self-pollinated generation of wide hybrids between common wheat and rye. In this study, it was found that at least two rye DNA segments had been introgressed into 99L2. This result suggested that a mechanism of alien DNA introgression may exist, which was different from the traditional mechanism of chromosome pairing and DNA recombination between wheat and alien species. Meanwhile, during the introgression process of alien rye DNA segments, the changes in DNA sequences of wheat itself occurred.

Base Sequence↗
PubMed2002

[Genetic mapping of the intergenomic translocated "taigu" genic sterility gene (Ms2)].

The "Taigu" genic sterility gene Ms2 located on the short arm of the 4D chromosome of common wheat (AABBDD) originally incorporated into hexoploid triticale (AABBRR) and durum wheat (AABB) through intergenomic translocation in distant hybridization was introduced back into the genomes of common wheat. The dominant male sterility was expressed normally in the new "Taigu" genic sterile wheat carrying the intergenomically translocated Ms2, and the female fertility mechanism in its male sterile plants was normal as well. Observation of the chromosome configuration at meiosis of pollen mother cells (PMC) of the young ears of the sterile plants showed that they were euploid plants (2n = 42). No configurations different from those of the "Taigu" genic sterility gene located at the original locus were noticed of the Ms2 intergenomically translocated back into the common wheat. In systematic test crosses with marker genes the intergenomically translocated gene Ms2 was found to be linked with the dominant dwarf marker in common wheat Rht3 and, consequently, remapped and located on the short arm of the 4B chromosome of common wheat with a distance of 9.7 cM from Rht3. The new locus was designated as Ms2 (4BS). Discussions are given of the fate of Ms2 during translocation in the hexoploid triticale, the exchange of the names for 4A and 4B chromosomes in common wheat and the possible exploitation of the new locus Ms2 (4BS), and the following speculations are made: (a) In genic genes of allopolyploid organisms the donor chromosomes tend to be intergenomically translocated to their physiologically and evolutionarily close chromosomes with the same order number and the same arm; (b) it is confirmed that the 7th International Conference of Wheat Genetics was right to exchange the names between chromosomes 4A and 4B of common wheat in 1988; and (c) as a new genetic marker and a breeding tool for all the chromosome B-carrying species in the tribe of Triticeae, Ms2(4BS) may have wide application in building and expanding the gene pool of germplasm resources of various species of wheat.

Chromosome Mapping↗
PubMed2004

[Construction of immune lines with complex resistance to leaf rust and powdery mildew in common spring wheat cultivar Saratovskaya 29].

Immune lines resistant both to leaf rust and to powdery mildew were constructed on the basis of common wheat cultivar Saratovskaya 29. Synthetic wheat Triticum timopheevii/Aegilops squarrosa (AAGGDD, 2n = 42) of Savov (Bulgaria) was used as a source of resistance genes. Using cytological analysis of BC2, we selected resistant plants (21") free from meiosis 1 (M1) defects. With these plants and continuous selection, BC8-BC9 immune lines were obtained. The lines were shown to carry new resistance genes differing from the known ones, and were proposed as donors of immunity to the diseases.

Breeding↗
PubMed2002

Genus-specific localization of the TaiI family of tandem-repetitive sequences in either the centromeric or subtelomeric regions in Triticeae species (Poaceae) and its evolution in wheat.

The TaiI family sequences are classified as tandem repetitive DNA sequences present in the genome of tribe Triticeae, and are localized in the centromeric regions of common wheat, but in the subtelomeric heterochromatic regions of Leymus racemosus and related species. In this study, we investigated the chromosomal distribution of TaiI family sequences in other Triticeae species. The results demonstrated a centromeric localization in genera Triticum and Aegilops and subtelomeric localization in other genera, thus showing a genus-dependent localization of TaiI family sequences in one or the other region. The copy numbers of TaiI family sequences in species in the same genus varied greatly, whether in the centromeric or subtelomeric regions (depending on genus). We also examined the evolution of TaiI family sequences during polyploidization of hexaploid common wheat. A comparison of chromosomal locations of the major TaiI family signals in common wheat and in its ancestral species suggested that the centromeric TaiI family sequences in common wheat were inherited from its ancestors with little modification, whereas a mixed origin for the B genome of common wheat was indicated.

Centromere↗
PubMed2006

Alkylresorcinol content and homologue composition in durum wheat (Triticum durum) kernels and pasta products.

The total alkylresorcinol (AR) content and relative homologue composition of 21 durum wheat (Triticum durum) kernel samples, as well as 5 pasta products and the corresponding flour mixtures, were determined. Durum wheat contained on average 455 microg/g ARs, and the average relative homologue composition was C17:0 (0.4%), C19:0 (14%), C21:0 (58%), C23:0 (21%), and C25:0 (6.5%). The homologue composition was found to be relatively consistent among samples, with durum wheat being different from common wheat by having a higher proportion of the longer homologues. No differences in content or homologue composition were observed in pasta products compared to flour ingredients, showing that alkylresorcinols are stable during pasta processing. The ratio of the homologues C17:0 to C21:0 was < or =0.02 for whole grain durum wheat products, which is different from those of common wheat (0.1) and rye (0.9).

Alkylation↗
PubMed2004

Compared use of HPLC and FZCE for cluster analysis of Triticum spp and for the identification of T. durum adulteration.

Wheat quality criteria continually evolve in response to market pressure and consumer preference. Characterization of cereal cultivars for quality and agronomic properties, have widely shown the importance of the protein content to ensure good quality products. The aim of this work is a comparison of reversed-phase high performance liquid chromatography (RP-HPLC) and free zone capillary electrophoresis (FZCE) in the identification of Italian wheat cultivars and detection of durum wheat flour adulteration. Mainly alcohol soluble (gliadins) and water soluble (albumins) proteins were extracted from 14 common wheat cultivars and from 9 durum wheat cultivars. In RP-HPLC chromatograms, wheat albumins and gliadins eluted between 3 and 9 min and between 10 and 42 min, respectively. Even if the chosen chromatographic conditions (reversed phase) did not permit a complete resolution of hydrophilic proteins such as albumins, a good reproducibility was observed for both albumins and gliadins. In FZCE electropherograms, wheat albumins and gliadins migrated between 8 and 14 min and 16-25 min, respectively. A good reproducibility was found for wheat albumins, while the relatively poor reproducibility of gliadin fractions was a consequence of the selected separation conditions aimed to separate in the same run either hydrophilic (albumins) and alcohol-soluble (gliadins) proteins. The principal component analysis (PCA) of HPLC and FZCE data evidenced that both techniques allowed the univocal identification of the great proportion of investigated wheat cultivars. Three peaks were exclusively detected in RP-HPLC chromatograms of common wheat cultivars, while three unique peaks were found in FZCE electropherograms of common wheat cultivars. These peaks were investigated as a basis for detecting and estimating the adulteration of durum wheat flour with flour from common wheat. The direct relationship between the area of the peaks and adulteration level enabled standard curves to be constructed. The standard curves showed that adulteration may be quantified by either RP-HPLC or FZCE.

Albumins↗
PubMed2006

Advanced resources for plant genomics: a BAC library specific for the short arm of wheat chromosome 1B.

Common wheat (Triticum aestivum L., 2n = 6x = 42) is a polyploid species possessing one of the largest genomes among the cultivated crops (1C is approximately 17 000 Mb). The presence of three homoeologous genomes (A, B and D), and the prevalence of repetitive DNA make sequencing the wheat genome a daunting task. We have developed a novel 'chromosome arm-based' strategy for wheat genome sequencing to simplify this task; this relies on sub-genomic libraries of large DNA inserts. In this paper, we used a di-telosomic line of wheat to isolate six million copies of the short arm of chromosome 1B (1BS) by flow sorting. Chromosomal DNA was partially digested with HindIII and used to construct an arm-specific BAC library. The library consists of 65 280 clones with an average insert size of 82 kb. Almost half of the library (45%) has inserts larger than 100 kb, while 18% of the inserts range in size between 75 and 100 kb, and 37% are shorter than 75 kb. We estimated the chromosome arm coverage to be 14.5-fold, giving a 99.9% probability of identifying a clone corresponding to any sequence on the short arm of 1B. Each chromosome arm in wheat can be flow sorted from an appropriate cytogenetic stock, and we envisage that the availability of chromosome arm-specific BAC resources in wheat will greatly facilitate the development of ready-to-sequence physical maps and map-based gene cloning.

Chromosomes, Artificial, Bacterial↗
PubMedDate not supplied

[Analysis of the short-stem genes in the genotypes of bread wheat cultivars in Ukraine].

Varieties of winter common wheat widely used in breeding programmes for the period of 1912-2002 in Ukraine were investigated using both the microsatellite Xgwm261 marker linked with the gibberellin-sensitive dwarf gene Rht8 and the biochemical test for the sensitivity of seedlings to gibberellic acid. Allelic characteristics of the locus Xgwm261 have been determined for 97 varieties. Near 98% of the modern varieties of winter common wheat derived from Odessa breeding institute and 50% of the varieties derived from the Mironovka wheat institute possess the allel 192 n.p. and gene Rht8 correspondingly. Estimation of sensitivity of the seedlings to gibberellic acid showed that the majority of the varieteis cultivated in Ukraine until the middle of the seventies are sensitive to gibberellic acid. The insusceptibility to gibberellic acid is predominantly manifested in the varieties derived from the south of Ukraine since the eighties owing to the introduction of the dwarf genes into the genotypes. At the same time the varieties of the Mironovka wheat institute still retain the sensitivity.

Alleles↗
PubMed2002

[Molecular analysis of leaf-rust resistant introgression lines obtained by crossing hexaploid wheat Triticum aestivum with tetraploid wheat Triticum timopheevii].

Twenty-four Triticum eastivum x T. timopheevii hybrid lines developed on the basis of five varieties of common wheat and resistant to leaf rust were analyzed by the use of microsatellite markers specific for hexaploid common wheat T. aestivum. Investigation of intervarietal polymorphism of the markers showed that the number of alleles per locus ranged from 1 to 4, depending on the marker (2.5 on average). In T. timopheevii, amplification fragments are produced by 80, 55, and 30% of primers specific to the A, B, and D common wheat genomes, respectively. Microsatellite analysis revealed two major areas of introgression of the T. timopheevii genome: chromosomes of homoeological groups 2 and 5. Translocations were detected in the 2A and 2B chromosomes simultaneously in 11 lines of 24. The length of the translocated fragment in the 2B chromosome was virtually identical in all hybrid lines and did not depend on the parental wheat variety. In 15 lines developed on the basis of the Saratovskaya 29, Irtyshanka, and Tselinnaya 20, changes occurred in the telomeric region of the long arm of the 5A chromosome. Analysis with markers specific to the D genome suggested that introgressions of the T. timopheevii genome occurred in chromosomes of the D genome. However, the location of these markers on T. timopheevii chromosomes is unknown. Our data suggest that the genes for leaf-rust resistance transferred from T. timopheevii to T. aestivum are located chromosomes of homoeological group 2.

Chromosomes↗
PubMedDate not supplied

Evaluation of branched ear derivatives of Triticum aestivum L.

The branched spikes of Triticum turgidum L. have a potential of producing a high number of kernels. Some of the selected lines of T. turgidum yielded up to 150 kernels per spike as compared to 60--70 kernels per spike in the common wheat cultivar Chenab-70. The best of these lines were crossed with the common wheats Chenab-70, Mexipak, and C-271. Among the lines obtained by selection from the advanced generations of the T. turgidum X Chenab-70 cross, some are similar to Chenab-70 with respect to tillering, plant shape, plant height, and leaf position, but their spikes are branched like those of the T. turgidum parent. These lines appear to be fairly homozygous. Chenab-70 produces, on the average, 60 kernels per spike, 34.8 g of grain per plant and has a 1000-kernel weight of 35 g. The number of kernels per spike, the yield of grain per plant and the 1000-kernel weight of the selected hybrid lines ranged from 25 to 133, from 8.5 to 59.6 g, and from 30.0 to 46.0 g, respectively, which shows that the chances of obtaining high-yielding new common wheat cultivars having spikes branched as those of the T. turgidum parent fairly good.

Phenotype↗