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Genetic characterization of a new powdery mildew resistance gene in a common wheat line ATRI3004/79 was conducted by employing a set of Blumeria graminis tritici isolates collected from Europe. Monosomic analysis revealed that a major resistance gene is located on chromosome 1A. Allelism tests of the F2 and F3 populations with other previously known genes on 1A showed that the resistance gene in ATRI3004/79 is closely linked to the Pm3d resistance gene in the German cultivar Syros, whereas it segregated independently from Pm25. Based on its distinct disease response pattern and close linkage to the Pm3 locus, this new resistance gene is tentatively designated PmH1A. A genetic linkage map was constructed for the powdery mildew gene Pm3d, the red glume color gene Rg3, and the gliadin gene Gli-A1 on chromosome 1A, based on data from a F3 population of 120 families derived from the cross Kolibri (Pm3/Gli-A1a/rg3) × F10 Strela (pm3/Gli-A1f/Rg3). Close linkage to an easily visualized morphological character such as red glume color may facilitate the selection of the resistance gene PmH1A.

The genetics of resistance to powdery mildew caused by Blumeria graminis f. sp. avenae of four cultivated oats was studied using monosomic analysis. Cultivar 'Bruno' carries a gene (Pm6) that shows a recessive mode of inheritance and is located on chromosome 10D. Cultivar 'Jumbo' possesses a dominant resistance gene (Pm1) on chromosome 1C. In cultivar 'Rollo', in addition to the gene Pm3 on chromosome 17A, a second dominant resistance gene (Pm8) was identified and assigned to chromosome 4C. In breeding line APR 122, resistance was conditioned by a dominant resistance gene (Pm7) that was allocated to chromosome 13A. Genetic maps established for resistance genes Pm1, Pm6 and Pm7 employing amplified fragment length polymorphism (AFLP) markers indicated that these genes are independent of each other, supporting the results from monosomic analysis.

Brachypodium distachyon, a small wild grass within the Pooideae family, is a new model organism for exploring the functional genomics of cereal crops. It was shown to have close relationships to wheat, barley and rice. Here, we describe the molecular characterisation and evolutionary relationships of high molecular weight glutenin subunits (HMW-GS) genes from B. distachyon. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), high performance capillary electrophoresis (HPCE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses demonstrated that there was no HMW-GS expression in the Brachypodium grains due to the silencing of their encoding genes. Through allele-specific polymerase chain reaction (AS-PCR) amplification and cloning, a total of 13 HMW-GS encoding genes from diploid, tetraploid and hexaploid Brachypodium species were obtained, and all of them had typical structural features of y-type HMW-GS genes from common wheat and related species, particularly more similar to the 1Dy12 gene. However, the presence of an in-frame premature stop codon (TAG) at position 1521 in the coding region resulted in the conversion of all the genes to pseudogenes. Further, quantitative real-time PCR (qRT-PCR) analysis revealed that HMW-GS genes in B. distachyon displayed a similar trend, but with a low transcriptional expression profile during grain development due to the occurrence of the stop codon. Phylogenetic analysis showed that the highly conserved Glu-1-2 loci were presented in B. distachyon, which displayed close phylogenetic evolutionary relationships with Triticum and related species.

Fifteen novel α-gliadin genes were cloned and sequenced from Triticum and related Aegilops genomes by allele-specific polymerase chain reaction (AS-PCR). Sequence comparison displayed high diversities in the α-gliadin gene family. Four toxic epitopes and glutamine residues in the two polyglutamine domains facilitated these α-gliadins to be assigned to specific chromosomes. Five representative α-gliadin genes were successfully expressed in Escherichia coli, and their amount reached a maximum after 4 h induced by isopropyl-β-D-thiogalactoside (IPTG), indicating a high level of expression under the control of T7 promoter. The transcriptional expression of α-gliadin genes during grain development detected by quantitative real-time polymerase chain reaction (qRT-PCR) showed a similar up-down regulation pattern in different genotypes. A neighbor-joining tree constructed with both full-open reading frame (ORF) α-gliadin genes and pseudogenes further revealed the origin and phylogenetic relationships among Triticum and related Aegilops genomes. The evolutionary analysis demonstrated that α-gliadin genes evolved mainly by synonymous substitutions under strong purifying selection during the evolutionary process.

In this study, a novel y-type high molecular weight glutenin subunit (HMW-GS) in wild emmer wheat Triticum turgidum L. var. dicoccoides (Körn.) accession KU1952 was identified by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), capillary electrophoresis (CE) and matrix-assisted laser desorption ionisation/time-of-flight/mass spectrometry (MALDI-TOF-MS). Its electrophoretic mobility and molecular weight were similar to those of 1By16 and was designated as 1By16*. The complete coding sequence of the 1By16* gene isolated by allelic-specific polymerase chain reaction (AS-PCR) consists of 2,157 bp, encoding 729 amino acid residues. The real presence and authenticity of the 1By16* gene in KU1952 were further confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), heterologous expression and Western blotting. The molecular structure as well as phylogenetic analysis revealed that 1By16* had 21 single-nucleotide polymorphism (SNP) variations and possessed greater similarity with superior quality subunits 1By15 and 1By16 of common wheat. Secondary structure prediction displayed higher α-helix and β-strand contents in the 1By16* subunit, which could form a superior gluten structure and, consequently, might have positive effects on dough quality. Our results suggest that 1By16* is expected to be a new potential gene for wheat quality improvement.

Powdery mildew is a prevalent fungal disease affecting oat (Avena sativa L.) production in Europe. Common oat cultivar Rollo was previously shown to carry the powdery mildew resistance gene Eg-3 in common with cultivar Mostyn. The resistance gene was mapped with restriction fragment length polymorphism (RFLP) markers from Triticeae group-1 chromosomes using a population of F(3) lines from a cross between A. byzantina cv. Kanota and A. sativa cv. Rollo. This comparative mapping approach positioned Eg-3 between cDNA-RFLP marker loci cmwg706 and cmwg733. Since both marker loci were derived from the long arm of barley chromosome 1H, the subchromosomal location of Eg-3 was assumed to be on the long arm of oat chromosome 17. Amplified fragment length polymorphism (AFLP) marker technology featured as an efficient means for obtaining markers closely linked to Eg-3.

The winter wheat cultivar Red Chief has been identified as the wheat cultivar most resistant to Pyrenophora tritici-repentis (Ptr). This study was undertaken to determine the inheritance, chromosomal location and molecular mapping of a tan spot resistance gene in Red Chief. χ² analysis of the F2 segregation data of the hybrids between 21 monosomic lines of the susceptible wheat cultivar Chinese Spring and the resistant cultivar Red Chief revealed that tan spot resistance in cv. Red Chief is controlled by a single recessive gene located on chromosome 3A. Linkage analysis using SSR markers in the Red Chief/Chinese Spring F2 population showed that the tsr4 gene is clustered in the region around Xgwm2a, on the short arm of chromosome 3A. This marker has also been identified as the closest marker to the tsr3 locus on chromosome 3D in synthetic wheat lines. Validation analysis of this marker for the tsr3 and tsr4 genes using 28 resistant and 6 susceptible genotypes indicated that the 120 bp allele (the tsr3 gene) specific fragment was observed in 11 resistant genotypes, including the three synthetic lines XX41, XX45 and XX110, while the 130 bp allele was amplified only in cv. Red Chief and Dashen. Xgwm2a can be used to trace the presence of the target gene in successive backcross generations and pyramiding of the tsr3 & tsr4 genes into a commonly grown and adaptable cultivar.