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With 2 figures and 3 tables Abstract Crown rot (CR), caused predominantly by Fusarium pseudograminearum, is a serious cereal disease for semi-arid regions worldwide. Growing resistant cultivars has long been recognized as an essential component in effectively managing this disease, and successful breeding requires quality sources of resistance. This paper reports the first germplasm screening to identify CR resistance sources in barley. A total of 1047 genotypes, selected to represent different geographical origins and plant types, were assessed. Several genotypes with high levels of resistance were identified. As expected, those with the best resistance were predominantly landraces or wild barley accessions. Surprisingly, genotypes with the best CR resistance with known origins were mainly derived from East Asia where CR is not a major cereal disease. Further, the majority of the genotypes with the best CR resistance are slow growing, although such genotypes accounted for only a small proportion of all those assessed in this study. Possible explanations for these intriguing phenomena are discussed. [ABSTRACT FROM AUTHOR]

The spatial characterization of qualities and microbial community of Chinese Baijiu Daqu during solid‐state fermentation remains unclear. The physicochemical indexes and microbial of the core (CDB) and the surface (SDB) of medium‐temperature Daqu (MT‐Daqu) at eight fermenting stages were investigated. The results indicated the difference in physicochemical indices, enzymatic activities, and starch granule fracture between the CDB and SDB. The dominant bacteria were Lactobacillus, Weissella, Pediococcus, and Methylobacterium in the SDB, as Staphylococcus, Bacillus, Thermoactinomyces, and Undibacterium in the CDB. The dominant fungi were Dipodascus, Wickerhamomyces, Hyphopichia, and Saccharomyces in the SDB, like Aspergillus, Thermoacscus, Theromyces, and Candida in the CDB. Redundancy analysis (RDA) showed that different factors strongly affected the bacteria and fungi in the SDB and CDB, respectively. The temperature, moisture, and starch content were the critical factors for the microbial composition of Daqu. This study provides further valuable information for knowing the fermentation mechanism of MT‐Daqu. Novelty impact statement: This study provided information on the spatial characterization of qualities and microbial community of Chinese Baijiu Daqu during solid‐state fermentation of medium‐temperature Daqu (MT‐Daqu).This study revealed the difference between the surface brick samples (SDB) and the core brick samples (CDB) in the fermentation process of Daqu, which increased the diversity of fermentation.The temperature, moisture, and starch content were the critical factors in influencing the difference between Daqu microorganisms of the core (CDB) and the surface (SDB) of medium‐temperature Daqu (MT‐Daqu). [ABSTRACT FROM AUTHOR]

Subgenome asymmetry (SA) has routinely been attributed to different responses between the subgenomes of a polyploid to various stimuli during evolution. Here, we compared subgenome differences in gene ratio and relative diversity between artificial and natural genotypes of several allopolyploid species. Surprisingly, consistent differences were not detected between these two types of polyploid genotypes, although they differ in times exposed to evolutionary selection. The estimated ratio of shared genes between a subgenome and its diploid donor was invariably higher for the artificial allopolyploid genotypes than those for the natural genotypes, which is expected as it is now well-known that many genes in a species are not shared among all individuals. As the exact diploid parent for a given subgenome is unknown, the estimated ratios of shared genes for the natural genotypes would also include difference among individual genotypes of the diploid donor species. Further, we detected the presence of SA in genotypes before the completion of the polyploidization events as well as in those which were not formed via polyploidization. These results indicate that SA may, to a large degree, reflect differences between its diploid donors or that changes occurred during polyploid evolution are defined by their donor genomes. [ABSTRACT FROM AUTHOR]

Highly fertile F1 hybrids were made between Triticum turgidum L. ssp. turgidum (2 n = 28, AABB) and Aegilops tauschii Coss. (2 n = 14, DD) without embryo rescue and hormone treatment. The F1 plants had an average seed set of 25%. Approximately 96% of the F2 seeds were able to germinate normally and about 67% of the F2 plants were spontaneous amphidiploid (2 n = 42, AABBDD). Cytological analysis of male gametogenesis of the F1 plants showed that meiotic restitution is responsible for the high fertility. A mitosis-like meiosis led to meiotic restitution at either of the two meiotic divisions resulting in unreduced gametes. Test crosses of the T. t. turgidum– Ae. tauschii amphidiploid with Ae. variabilis and rye suggested that the mitosis-like meiosis is controlled by one or more nuclear genes that continue to function in derived lines. This discovery indicates a potential application of such genes in producing double haploids . [ABSTRACT FROM AUTHOR]

Summary: De‐domestication is a unique evolutionary process during which crops re‐acquire wild‐like traits to survive and persist in agricultural fields without the need for human cultivation. The re‐acquisition of seed dispersal mechanisms is crucial for crop de‐domestication. Common wheat is an important cereal crop worldwide. Tibetan semi‐wild wheat is a potential de‐domesticated common wheat subspecies. However, the crucial genes responsible for its brittle rachis trait have not been identified.Genetic mapping, functional analyses and phylogenetic analyses were completed to identify the gene associated with Qbr.sau‐5A, which is a major locus for the brittle rachis trait of Tibetan semi‐wild wheat.The cloned Qbr.sau‐5A gene is a new Q allele (Qt) with a 161‐bp transposon insertion in exon 5. Although Qt is expressed normally, its encoded peptide lacks some key features of the APETALA2 family. The abnormal functions of Qt in developing wheat spikes result in brittle rachises. Phylogenetic and genotyping analyses confirmed that Qt originated from Q in common wheat and is naturally distributed only in Tibetan semi‐wild wheat populations.The identification of Qt provides new evidence regarding the origin of Tibetan semi‐wild wheat, and new insights into the re‐acquisition of wild traits during crop de‐domestication. See also the Commentary on this article by Ellstrand, 224: 550–551. [ABSTRACT FROM AUTHOR]

Background: Phytohormones are key regulators of plant growth, development, and signalling networks involved in responses to diverse biotic and abiotic stresses. Transcriptional reference maps of hormone responses have been reported for several model plant species such as Arabidopsis thaliana, Oryza sativa, and Brachypodium distachyon. However, because of species differences and the complexity of the wheat genome, these transcriptome data are not appropriate reference material for wheat studies. Results: We comprehensively analysed the transcriptomic responses in wheat spikes to seven phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), abscisic acid (ABA), ethylene (ET), cytokinin (CK), salicylic acid (SA), and methyl jasmonic acid (MeJA). A total of 3386 genes were differentially expressed at 24 h after the hormone treatments. Furthermore, 22.7% of these genes exhibited overlapping transcriptional responses for at least two hormones, implying there is crosstalk among phytohormones. We subsequently identified genes with expression levels that were significantly and differentially induced by a specific phytohormone (i.e., hormone-specific responses). The data for these hormone-responsive genes were then compared with the transcriptome data for wheat spikes exposed to biotic (Fusarium head blight) and abiotic (water deficit) stresses. Conclusion: Our data were used to develop a transcriptional reference map of hormone responses in wheat spikes. [ABSTRACT FROM AUTHOR]

Key message: This study demonstrates the feasibility of developing co-segregating markers and identifying candidate genes for Fusarium crown rot resistance in barley based on the generation and exploitation of a near-isogenic line-derived large population.Abstract: Fusarium crown rot (FCR) is a chronic and severe disease in cereals in semi-arid regions worldwide. Previous studies showed that FCR assessment could be affected by many factors including plant height, growth rate as well as drought stress. Thus, accurate assessment, which is essential for detailed mapping of any locus conferring FCR resistance, is difficult. Targeting one of the resistance loci reported earlier, we developed a near-isogenic line-derived population consisting of 1820 F9 lines. By analysing this population, the Qcrs.cpi-4H locus was mapped to an interval of 0.09 cM covering a physical distance of about 637 kb and 13 markers co-segregating with the targeted locus were developed. Candidate genes underlying the resistance locus were identified by analysing the expression and sequence variation of genes in the targeted interval. The accurate localization and the development of co-segregating markers should facilitate the incorporation of this large-effect QTL into breeding programmes as well as the cloning of gene(s) underlying the locus. [ABSTRACT FROM AUTHOR]

We evaluated the SGP-1 protein composition of 368 Chinese wheat landraces using SDS-PAGE. The SGP-D1 null type was identified in three accessions (Xiaoqingmang, Pushanbamai, and P119). An 18-bp deletion and 9-bp variation were found at the junction region of the 7th intron and 8th exon, leading to deletion of the intron-exon junction recognition site AG when aligned the 8261-bp DNA sequence of TaSSIIa-D in Pushanbamai with that of Chinese Spring. Four cDNA types with mis-spliced isoforms were subsequently detected through amplification of TaSSIIa-D cDNAs. Among these, nine type II cDNAs with a 16-bp deletion in the 8th exon were detected, indicating that the major transcriptional pattern of TaSSIIa in Pushanbamai is type II. In the type IV cDNA, a 97-bp sequence remains undeleted in the end of the 5th exon. The amylose content in Pushanbamai was significantly higher than that in all control lines under field conditions, which suggested that deletion of SGP-D1 has an efficient impact on amylose content. As the TaSSIIa gene plays an important role in regulating the content of amylose, it is anticipated that these natural variants of TaSSIIa-D will provide useful resources for quality improvement in wheat. [ABSTRACT FROM AUTHOR]

As a primitive hexaploid wheat resource distributed only in Tibet, Tibetan semi-wild wheat ( Triticum aestivum subsp. tibetanum Shao) possesses unique characteristics that could be exploited in wheat breeding programs. Its good root system could offer a stable platform for above-ground components. To detect possible excellent locus for root traits from Tibetan semi-wild wheat, we identified QTLs for root traits using a recombinant inbred line population derived from a cross between Tibetan semi-wild wheat Q1028 and Zhengmai 9023. A total of 15 QTLs on eight chromosomes were detected, including four major QTLs, QMrl.sau-7B, QTrl.sau-4B, QAd.sau-7A, and QSa.sau-4B. The phenotypic variation explained by each of these QTLs ranges from 5.67% to 16.68%. Positive alleles of six QTLs were derived from Q1028. Several novel QTLs for root traits were identified. In addition, significant correlations were detected amongst root traits and agronomic traits. Taken together, these results suggest that Tibetan semi-wild wheat and the newly identified novel QTLs could be useful in future breeding programs. [ABSTRACT FROM AUTHOR]

Leymus Hochst. (Triticeae: Poaceae), a group of allopolyploid species with the NsXm genomes, is a perennial genus with diversity in morphology, cytology, ecology, and distribution in the Triticeae. To investigate the genome origin and evolutionary history of Leymus , three unlinked low-copy nuclear genes ( Acc1 , Pgk1 , and GBSSI ) and three chloroplast regions ( trn L-F, mat K, and rbc L) of 32 Leymus species were analyzed with those of 36 diploid species representing 18 basic genomes in the Triticeae. The phylogenetic relationships were reconstructed using Bayesian inference, Maximum parsimony, and NeighborNet methods. A time-calibrated phylogeny was generated to estimate the evolutionary history of Leymus . The results suggest that reticulate evolution has occurred in Leymus species, with several distinct progenitors contributing to the Leymus . The molecular data in resolution of the Xm-genome lineage resulted in two apparently contradictory results, with one placing the Xm-genome lineage as closely related to the P/F genome and the other splitting the Xm-genome lineage as sister to the Ns-genome donor. Our results suggested that (1) the Ns genome of Leymus was donated by Psathyrostachys , and additional Ns-containing alleles may be introgressed into some Leymus polyploids by recurrent hybridization; (2) The phylogenetic incongruence regarding the resolution of the Xm-genome lineage suggested that the Xm genome of Leymus was closely related to the P genome of Agropyron ; (3) Both Ns- and Xm-genome lineages served as the maternal donor during the speciation of Leymus species; (4) The Pseudoroegneria , Lophopyrum and Australopyrum genomes contributed to some Leymus species. [ABSTRACT FROM AUTHOR]

Two hybrids, BAd7-209 and BAd7-210, were obtained by wide hybridization between wild emmer D97 and weak gluten cultivar CN16. They had a genetic background of common wheat, resulting from continuous selfing over nine times. These hybrids were better than CN16 in dough quality and processing quality tests. BAd7-210 was better than medium gluten wheat cultivar MM37, and BAd7-209 was far better than moderate to strong gluten wheat cultivar SM482. Through chromosome engineering, BAd7-210 possessed the 1Ax2.2 of male D97, and BAd7-209 had the 1Ax1.2 which was caused by complex variation because of cross-parents’ genomic asymmetry. The open reading frames (ORFs) of two novel active Glu-Ax alleles 1Ax2.2 and 1Ax1.2 were 2496 bp and 2514 bp, encoding 830 and 836 amino acid residues, respectively. The 1Ax1.2 was the second longest Glu-Ax gene discovered to date, and it had two deletions and one insertion besides many single nucleotide polymorphisms (SNPs) compared with the 1Ax2.2 and 1Ax1 . The longer polypeptide of 1Ax1.2 should explain why BAd7-209 has better processing quality than BAd7-210. Therefore, wild emmer could be effectively utilized to enrich the 1Ax alleles of common wheat through direct cross transferring and generating novel allele variation, which could significantly enhance the gluten strength. [ABSTRACT FROM AUTHOR]

Key message: A novel Wx-B1 allele was characterized; a transposon insertion resulted in the loss of its function, which is different from the previously reported gene silencing mechanisms at the Wx-B1 locus. Abstract: The waxy protein composition of 53 Chinese wheat landraces was analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional gel electrophoresis; of these, 10 did not show the expression of Wx-A1 (four accession) or Wx-B1 (six accessions) protein. The results of molecular marker detection revealed that the Wx-B1 allele ( Wx-B1n) showed normal expression, inconsistent with the findings of SDS-PAGE for the Xiaobaipi accession. Further cloning of the 9160-bp region covering the Wx-B1 coding region and 3′-downstream region revealed that a 2178-bp transposon fragment had been inserted at 2462 bp within the tenth exon of Wx-B1n ORF, leading to the absence of Wx-B1 protein. Sequence analysis indicated that the insertion possessed the structural features of invert repeat and target repeat elements, we deduced that it was a transposon. Further PCR analysis revealed that this fragment had moved, but not copied itself, from 3B chromosome to the current location in Wx-B1n. Therefore, the reason for the inactivation of Wx-B1n was considerably different from those for the inactivation of Wx-B1b, Wx-B1k, and Wx-B1m; to our knowledge, this kind of structural mutation has never been reported in Wx-B1 alleles. This novel allele is interesting, because it was not associated with the deletion of other quality-related genes included in the 67 kb region lost with the common null allele Wx-B1b. The null Wx-B1n might be useful for investigating gene inactivation and expression as well as for enriching the genetic resource pool for the modification of the amylose/amylopectin ratio, thereby improving wheat quality. [ABSTRACT FROM AUTHOR]

Gene loss during the formation of hexaploid bread wheat has been repeatedly reported. However, our knowledge on genome-wide analysis of the genes present on a single subgenome (SSG) in bread wheat is still limited. In this study, by analysing the 'Chinese Spring' chromosome arm shotgun sequences together with high-confidence gene models, we detected 433 genes on a SSG. Greater gene loss was observed in A and D subgenomes compared with B subgenome. More than 79% of the orthologs for these SSG genes were detected in diploid and tetraploid relatives of hexaploid wheat. Unexpectedly, no bias in expression breadth or in the distribution patterns of GO (gene ontology) terms for these genes was detected among the high-confidence genes. Further, network and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses indicated that most of these genes were not functionally related to each other. Interestingly, 30.7% of these SSG genes were most highly expressed in root, showing biased distribution given the distribution of the whole high-confidence genes. Collectively, these results facilitate our understanding of the loss of the genes that were retained in a SSG during the formation of hexaploid wheat. [ABSTRACT FROM AUTHOR]

Fusarium graminearum is a devastating pathogenic fungus causing fusarium head blight (FHB) of wheat. This fungus can produce indole-3-acetic acid (IAA) and a very large amount of IAA accumulates in wheat head tissues during the first few days of infection by F. graminearum . Using liquid culture conditions, we have determined that F. graminearum can use tryptamine (TAM) and indole-3-acetonitrile (IAN) as biosynthetic intermediates to produce IAA. It is the first time that F. graminearum is shown to use the l -tryptophan-dependent TAM and IAN pathways rather than the indole-3-acetamide or indole-3-pyruvic acid pathways to produce IAA. Our experiments also showed that exogenous IAA was metabolized by F. graminearum . Exogenous IAA, TAM, and IAN inhibited mycelial growth; IAA and IAN also affected the hyphae branching pattern and delayed macroconidium germination. IAA and TAM had a small positive effect on the production of the mycotoxin 15-ADON while IAN inhibited its production. Our results showed that IAA and biosynthetic intermediates had a significant effect on F. graminearum physiology and suggested a new area of exploration for fungicidal compounds. [ABSTRACT FROM AUTHOR]

The H-pyrophosphatase (H -PPase) gene plays an important role in maintaining intracellular proton gradients. Here, we characterized the full-length complementary DNA (cDNA) and DNA of the H -PPase gene ScHP1 in rye ( Secale cereale L. 'Qinling'). We determined the subcellular localization of this gene and predicted the corresponding protein structure. We analysed the evolutionary relationship between ScHP1 and H −PPase genes in other species, and did real-time quantitative polymerase chain reaction to explore the expression patterns of ScHP1 in rye plants subjected to N, P and K deprivation and to cold, high-salt and drought stresses. ScHP1 cDNA included a 2289 bp open reading frame (ORF) encoding 762 amino acid residues with 14 transmembrane domains. The genomic ScHP1 DNA was 4354 bp and contained eight exons and seven introns. ScHP1 was highly homologous with other members of the H -PPase gene family. When the full-length ORF was inserted into the expression vector pA7-YFP, the fluorescent microscopy revealed that ScHP1-YFP fusion protein was located in the plasma membrane. Rye plants that were subjected to N deprivation, cold and high-salt stresses, ScHP1 expression was higher in the leaves than roots. Conversely, plants subjected to P and K deprivation and drought stress, ScHP1 expression was higher in the roots than leaves. Under all the investigated stress conditions, expression of ScHP1 was lower in the stem than in the leaves and roots. Our results imply that ScHP1 functions under abiotic stress response. [ABSTRACT FROM AUTHOR]

In this study, we designed and constructed a super twin T-DNA vector (pTRIDT313-g) containing two independent T-DNA cassettes―one for the selection gene Hyg and the other for the target gene Gus ―to produce marker-free transgenic lines. The resulting vector was transformed into tobacco, and polymerase chain reaction (PCR) analysis showed four types of gene combinations in the T 1 and T 2 generations: Gus only , Hyg only , Gus + Hyg, and untransformed lines. The intermediate region from the T-DNA of the right border of Hyg to the left border of Gus in the Hyg and Gus lines was not amplified. Genome walking confirmed that the Hyg and Gus T-DNA cassettes were independently inserted in different regions of the tobacco genome. Thus, the two T-DNA cassettes were integrated randomly as independent loci into the tobacco genome. The results of reverse transcription-PCR indicated that Hyg could normally be expressed in the roots, stems, and leaves of transgenic lines, and the resistance test showed that all Hyg transgenic lines could grow in the presence of 50 mg/L hygromycin. All Gus transgenic lines showed obvious blue coloration in enzyme activity tests, indicating that the Gus gene could be normally expressed in all the lines. Therefore, the super twin T-DNA vector (pTRIDT313-g) exhibits independent integration, heredity, and normal gene function from two T-DNA cassettes. This vector could be a useful and valuable tool in the production of marker-free transgenic lines. [ABSTRACT FROM AUTHOR]

ADP-glucose pyrophosphorylase (AGP), which consists of two large subunits (AGP-L) and two small subunits (AGP-S), controls the rate-limiting step in the starch biosynthetic pathway. In this study, a full-length open reading frame (ORF) of AGP-L gene (named as Agp2) in wheat and a series of Agp2 gene sequences in wheat relatives were isolated. The coding region of Agp2 contained 15 exons and 14 introns including a full-length ORF of 1566 nucleotides, and the deduced protein contained 522 amino acids (57.8 kDa). Generally, the phylogenetic tree of Agp2 indicated that sequences from A- and D-genome donor species were most similar to each other and sequences from B-genome donor species contained more variation. Starch accumulation and Agp2 expression in wheat grains reached their peak at 21 and 15 days post anthesis (DPA), respectively. [ABSTRACT FROM AUTHOR]

Trigeneric hybrids are commonly used as bridges to transfer genes from some wild species to cultivated wheat and to measure the genomic interaction between donor species. We previously reported that trigeneric germplasms were produced by crossing wheat- Psathyrostachys huashanica amphiploids (PHW-SA, 2n = 8x = 56, AABBDDNsNs) with hexaploid triticale (Zhongsi 828, 2n = 6x = 42, AABBRR). In the present study, chromosome pairing behavior and the genome constitution of the F 4 progenies of wheat-rye- P. huashanica trigeneric hybrids were studied. Cytological analysis showed that the chromosome number of F 4 progenies ranged from 39 to 46, and 57.5% of them had 42 chromosomes. The mean meiotic configuration of F 4 lines was 1.71 univalents, 20.26 bivalents, 0.04 trivalents, and 0.001 quadrivalents per pollen mother cell. Among the lines with 2n = 42, the average pairing configuration was 1.21 univalents, 16.22 ring bivalents, 4.16 rod bivalents, and 0.01 trivalents. This result indicated that these lines were cytologically stable. Other lines with 2n = 39, 40, 41, 43, 44, 45, and 46, bearing a high number of univalents or multivalents, showed abnormal meiotic behavior. Genomic in situ hybridization (GISH) revealed that all F 4 lines had 11-14 rye chromosomes, but no P. huashanica chromosomes. The complete set of 14 rye chromosomes was found in 19 lines. At meiosis, GISH detected 1-6 univalents with hybridization signals of rye in 13 lines. Bivalents with fluorescence signals were identified in each line, ranging from 3 to 7. A quadrivalent with hybridization signals was observed in only 1 line, K13-714-8. Lagging chromosomes, chromosome bridges, micronuclei, and chromosome fragments hybridizing with the probe were not discovered in any of the lines. These results inferred that the behavior of rye chromosomes was normal during meiosis. In addition, 21 lines of 2n = 42 (91.3%) with 12 or 14 rye chromosomes, always contained 6 or 7 bivalents bearing fluorescence signals. This suggested that the rye chromosomes exhibiting complete pairing in these lines were cytologically stable during meiosis and may therefore be considered as new hexaploid triticales. Thus, these lines might be potential materials for further hexaploid triticale improvement. [ABSTRACT FROM AUTHOR]

The adoption of reduced height ( Rht) genes has dramatically enhanced yield potential of cereal crops. The semi-dwarfing gene uzu in barley is widely used in East Asia. Its value as an Rht gene in the warm and dry environments in Australia was evaluated in this study. In addition to plant height, this gene showed significant effects on a wide range of characteristics. It reduced the overall plant height by an average of 33.7 % with the most significant reduction occurred on the internode below the peduncle. The gene reduces spike length by 31.6 % and grain weight by 18.8 %. It increases grain number per spike by 5.6 % and grain density by 51.8 %. Seedling assays suggested that the effects of this gene became more significant with increased temperature. It reduced coleoptile and seedling length by 19.4 % and 15.1 %, respectively at 7 °C. The reduction increased to 61 % and 46.7 %, respectively, at 25 °C. These results indicated that the uzu gene could have limited values in some high temperature and drought prone environments. [ABSTRACT FROM AUTHOR]

Fusarium graminearum is the major causal agent of Fusarium head blight (FHB) of wheat and barley and is considered to be one of the most devastating plant diseases worldwide. Chitin is a critical component of the fungal cell wall and is polymerized from UDP-N-acetyl-alpha-D-glucosamine by chitin synthase. We characterized FgCHS8 , a new class of the chitin synthase gene in F. graminearum . Disruption of FgCHS8 resulted in reduced accumulation of chitin, decreased chitin synthase activity, and had no effect on conidia growth when compared with the wild-type isolate. Δ FgCHS8 had a growth rate comparable to that of the wild-type isolate in vitro . However, Δ FgCHS8 had reduced growth when grown on agar supplemented with either 0.025% SDS or 0.9 mM salicylic acid. Δ FgCHS8 produced significantly less deoxynivalenol and exhibited reduced pathogenicity in wheat spikes. Re-introduction of a functional FgCHS8 gene into the Δ FgCHS8 mutant strain restored the wild-type phenotypes. Fluorescence microscopy revealed that FgCHS8 protein was initially expressed in the septa zone, and then gradually distributed over the entire cellular membrane, indicating that FgCHS8 was required for cell wall development. Our results demonstrated that FgCHS8 is important for cell wall sensitivity to environmental stress factors and deoxynivalenol production in F. graminearum . [ABSTRACT FROM AUTHOR]

The effect of phytohormones on the defense response of wheat against Fusarium graminearum infection was investigated. Infection of heads with F. graminearum induced accumulation of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and indole acetic acid (IAA). Exogenous phytohormone treatments showed crosstalk between them and a complex effect on expression of the genes ATB2 , ExpB6 , LEA Td16 , PR1 , Pdf1.2 , PR4 . JA treatment reduced F. graminearum growth and fusarium head blight (FHB) symptoms while an increase in FHB was observed with ABA. Transient down-regulation of allene oxide synthase ( AOS ) supports a complex role for JA in wheat head. [ABSTRACT FROM AUTHOR]

Aegilops sharonensis is a diploid relative of wheat and has novel high molecular weight glutenin subunits (HMW-GSs) encoded by Glu-1Ssh. Hybrids of tetraploid wheat species and Ae. sharonensis have been successfully created by wild crosses. In our study, we conducted backcrosses and introduced the novel HMW-GSs of Ae. sharonensis into hexaploid wheat species. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and cytogenetics indicated that lines carrying the HMW-GSs encoded by Glu-1Ssh had varied chromosome numbers ranging from 35 to 50. Among these, three lines with 42 chromosomes (25-8, 33-1, and 42-2) were identified by visual examination. Except for possessing the alien HMW-GSs of Ae. sharonensis, the agricultural traits of the three lines were similar to those of common wheat, indicating their potential for wheat breeding. Additionally, we developed two molecular markers specific to the x- and y-type HMW-GSs genes of Ae. sharonensis. These two molecular markers were validated in backcross progenies and were proven to accurately trace and distinguish Ae. sharonensisGlu-1Ssh from Glu-1A, Glu-1B, and Glu-1D of wheat. Therefore, the Glu-1Ssh HMW-GSs lines with 42 chromosomes, together with gene-specific markers, will be valuable for molecular-assisted selection in alien genes utilization and wheat breeding. [ABSTRACT FROM AUTHOR]

The article focuses on a research related to low-molecular-weight glutenin subunits (LMW-GS) associated with dough resistance and extensibility of wheat. Topics discussed include isolation of LMW-GS genes from species of Sitopsis providing positive clones for bidirectional sequencing, putative pseudogenes of clones due to premature translation termination, and phylogentic analysis to be conducted for LMW-GS genes.

Chromosome translocation is an important driving force in shaping genomes during evolution. Detailed knowledge of chromosome translocations in a given species and its close relatives should increase the efficiency and precision of chromosome engineering in crop improvement. To identify genes flanking the breakpoints of translocations and inversions as a step toward identifying breakpoints in bread wheat, we systematically analysed genes in the Brachypodium genome against wheat survey sequences and bin-mapped ESTs (expressed sequence tags) derived from the hexaploid wheat genotype 'Chinese Spring'. In addition to those well-known translocations between group 4, 5, and 7 chromosomes, this analysis identified genes flanking the three pericentric inversions on chromosomes 2B, 4B, and 5A. However, numerous chromosomal rearrangements reported in early studies could not be confirmed. The genes flanking the breakpoints reported in this study are valuable for isolating these breakpoints. [ABSTRACT FROM AUTHOR]

Tibetan semi-wild wheat ( Triticum aestivum ssp. tibetanum Shao) is a hexaploid wheat resource distributed only in Tibet that has an interesting type of seed dormancy in addition to hulled glumes and brittle spikelets. A whole-genome linkage map of T. aestivum ssp. tibetanum was constructed for a population of 186 recombinant inbred lines using 645 diversity array technology (DArT) markers, 127 simple sequence repeat markers and three R- 1 genotyping markers. Seed dormancy was evaluated at five post-ripening stages from 2010 to 2013. Comprehensive quantitative trait locus (QTL) mapping by inclusive composite interval mapping analysis identified seven QTLs for seed dormancy, designated as Qsd.sau- 1B, Qsd.sau- 3A, Qsd.sau- 3B, Qsd.sau- 3D, Qsd.sau- 4A1, Qsd.sau- 4A2, and Qsd.sau- 7A, on chromosomes 1BL, 3AL, 3BL, 3DL, 4AS, 4AL, and 7AL, which explained 8.9, 7.2, 10.8, 7.0, 11.4, 9.4, and 12.7 % of phenotypic variation, respectively. Qsd.sau- 4A1 and Qsd.sau- 7A have only rarely been reported in domesticated common wheat but were prominent in T. aestivum ssp. tibetanum accession Q1028. Qsd.sau- 4A1 was associated with intense, short-duration dormancy and was recognized as an ideal QTL for wheat breeding. [ABSTRACT FROM AUTHOR]

To better understand the contribution of the quantitative fusarium head blight (FHB) resistance locus, 2DL QTL from Wuhan-1, we have characterized two pairs of sister lines carrying either the 2DL QTL or no known QTLs. In wheat spikes, our visual and microscopic observations suggested that the 2DL QTL suppress fungal infection in inoculated spikelets and reduce spread from spikelets to rachis. Transcriptome profiling of infected spikelets showed changes in expression for 487 probe sets between the 2DL-carrying and the null lines. Of 27 transcripts selected for validation, eight candidate genes with similar expression profiles between the two pair of lines were identified. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR) is a serious disease in wheat and barley in semiarid regions worldwide. The feasibility of enhancing FCR resistance by gene pyramiding was investigated by generating and assessing two populations segregating for three large-effect QTL located on the long arms of chromosomes 1H, 3H and 4H, respectively. Significant effects were detected for each of the three QTL in both of the populations assessed. Lines with any combination of two resistant alleles from the three QTL gave, on average, significantly better resistance than those with a single resistant allele only, and lines with resistant alleles from all three of the QTL gave the least FCR symptom. However, wide variations in FCR severity were detected for lines belonging to each of the groups with different numbers of resistant alleles. Significant effects of plant height on FCR were detected in both populations, and a significant association between heading date and FCR severity was detected in one of the two populations assessed. Results from the current study also showed that the effects of a given allele of resistance decreased with the increase in the number of resistant alleles an individual group possessed. Overall, results from this study demonstrate that gene pyramiding can be an effective approach in improving FCR resistance and those lines with resistant alleles from all of the three QTL could be valuable for breeding programs. [ABSTRACT FROM AUTHOR]

Growth duration, the entire developmental period from seed emergence to maturity, plays an important role in wheat adaptation and is a complex trait controlled by multiple genes and influenced by environmental factors. In order to precisely detect quantitative trait loci (QTLs) for wheat growth duration and its timing components, and dissect their genetic relationship, we performed QTL mapping and conditional analysis in a recombinant inbred line population. A total of 17 conditional QTLs and 30 unconditional QTLs were identified in this study, which explained 3.3–34.7 % of the phenotypic variation. Of them, 17 explained more than 10 % of the phenotypic variation and eight were environment-independent. Eight common QTLs were identified on chromosomes 1D, 2A, 2D, 3D, 4A, 5A, 7A and 7D, and explained significant phenotypic variation for two to eight traits. Notably, the QTL on chromosome 2D (genetic region of wPt-7149-wPt-667843) explained major phenotypic variation for emergence time (ET), heading time (HT), maturity time (MT) and growth duration (GD). The QTL on chromosome 3D (wPt-741816-wPt-732611) accounted for significant phenotypic variation for ET, TT and FT. Conditional analysis and unconditional analysis suggested that utilizing the genetic region of wPt-7149-wPt-667843 on chromosome 2D can modify ET, HT, MT and GD simultaneously, whereas the genetic region of wPt-741816-wPt-732611 on chromosome 3D can modify GD components individually to avoid change to the whole GD. This QTL mapping study and genetic relationship analysis between growth duration and its component traits should be of great practical and theoretical value for wheat breeding. [ABSTRACT FROM AUTHOR]

Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) is a semi-wild hexaploid wheat resource that is only naturally distributed in the Qinghai-Tibet Plateau. Brittle rachis and hard threshing are two important characters of Tibetan semi-wild wheat. A whole-genome linkage map of T. aestivum ssp. tibetanum was constructed using a recombinant inbred line population (Q1028×ZM9023) with 186 lines, 564 diversity array technology markers, and 117 simple sequence repeat markers. Phenotypic data on brittle rachis and threshability, as two quantitative traits, were evaluated on the basis of the number of average spike rachis fragments per spike and percent threshability in 2012 and 2013, respectively. Quantitative trait locus (QTL) mapping performed using inclusive composite interval mapping analysis clearly identified four QTLs for brittle rachis and three QTLs for threshability. However, three loci on 2DS, 2DL, and 5AL showed pleiotropism for brittle rachis and threshability; they respectively explained 5.3%, 18.6%, and 18.6% of phenotypic variation for brittle rachis and 17.4%, 13.2%, and 35.2% of phenotypic variation for threshability. A locus on 3DS showed an independent effect on brittle rachis, which explained 38.7% of the phenotypic variation. The loci on 2DS and 3DS probably represented the effect of Tg and Br1, respectively. The locus on 5AL was in very close proximity to the Q gene, but was different from the predicted q in Tibetan semi-wild wheat. To our knowledge, the locus on 2DL has never been reported in common wheat but was prominent in T. aestivum ssp. tibetanum accession Q1028. It remarkably interacted with the locus on 5AL to affect brittle rachis. Several major loci for brittle rachis and threshability were identified in Tibetan semi-wild wheat, improving the understanding of these two characters and suggesting the occurrence of special evolution in Tibetan semi-wild wheat. [ABSTRACT FROM AUTHOR]

Alpha-amylases play essential roles in germination, and the malting and brewing processes, by hydrolyzing starch granules present in the endosperm of barley. Hordeum spontaneum C. Koch, the progenitor of cultivated barley that harbors rich genetic diversity, was collected from seven different environments. To investigate the influence of microclimatic ecological divergence on α-amylase, single nucleotide polymorphisms (SNPs) in amy genes from these populations were determined. A total of 16 and 17 SNPs were detected in the coding sequences of amy1 and amy2, respectively, from the seven wild barley populations. Among these SNPs, three in amy1-2 and nine in amy2-2 were significantly associated with ecological factors. The genetic divergence of amy sequences was significantly different among the populations. Natural microclimatic selection was apparently the major evolutionary driving force causing interslope divergence and adaptive evolution of these genes. The genetic variation in amy1-2 and amy2-2 was at least partly ecologically determined in these populations, representing adaptive patterns generated by natural selection. The SNPs were apparently generated by natural selection in climatic environmental patterns at both the micro ('Evolution Canyon') and macro (across Israel, Galilee, and Negev) scales. [ABSTRACT FROM AUTHOR]

Spike length (SL) is one of the most important components of spike morphology, and the uppermost internode represents an ideal organ to study the transportation system. We performed conditional and unconditional quantitative trait locus (QTL) mapping in two unrelated recombinant inbred line populations to precisely detect QTLs for uppermost internode length (UIL) and SL, and to dissect the genetic relationship between these two factors with plant height (PH). Both of the populations were derived from crosses with synthetic wheat. Ten repetitive QTLs for UIL and six environment-independent QTLs for SL were identified in this study, and twelve of these were completely independent of PH. Conditional QTL mapping analysis indicated that SL was more independent to PH than UIL was. The results indicated that the conditional QTL mapping method could evaluate PH component effects on PH, and thus accelerate the selection of suitable loci that improve commercial wheat morphology yet avoid changes to PH. [ABSTRACT FROM AUTHOR]

Fusarium pathogens cause two major diseases in cereals, Fusarium crown rot (FCR) and head blight (FHB). A large-effect locus conferring resistance to FCR disease was previously located to chromosome arm 3BL (designated as Qcrs-3B) and several independent sets of near isogenic lines (NILs) have been developed for this locus. In this study, five sets of the NILs were used to examine transcriptional changes associated with the Qcrs-3B locus and to identify genes linked to the resistance locus as a step towards the isolation of the causative gene(s). Of the differentially expressed genes (DEGs) detected between the NILs, 12.7% was located on the single chromosome 3B. Of the expressed genes containing SNP (SNP-EGs) detected, 23.5% was mapped to this chromosome. Several of the DEGs and SNP-EGs are known to be involved in host-pathogen interactions, and a large number of the DEGs were among those detected for FHB in previous studies. Of the DEGs detected, 22 were mapped in the Qcrs-3B interval and they included eight which were detected in the resistant isolines only. The enrichment of DEG, and not necessarily those containing SNPs between the resistant and susceptible isolines, around the Qcrs-3B locus is suggestive of local regulation of this region by the resistance allele. Functions for 13 of these DEGs are known. Of the SNP-EGs, 28 were mapped in the Qcrs-3B interval and biological functions for 16 of them are known. These results provide insights into responses regulated by the 3BL locus and identify a tractable number of target genes for fine mapping and functional testing to identify the causative gene(s) at this QTL. [ABSTRACT FROM AUTHOR]

Highlights: [•] Different polyploids have experienced varying fates. [•] Leymus have a higher proportion of species with predominant Ns genomic rDNA type. [•] The geographical structure of rDNA-ITS variation within Leymus was suggested. [•] The ITS clade shared by Leymus growing in cold climates may associated with ancestral ITS homogenization. [Copyright &y& Elsevier]

The article discusses the results of a study which used fluorescence in situ hybridization with a probe specific for rye centromeres to trade their positions and movements during meiosis in pollen mother cells of a wheat-rye hybrid. Topics include the importance of amphitelic orientation of centromeres at metaphase I in univalent-dependent meiotic nonreduction, cytological mechanism for equatorial division with sister chromatic division, and the effect of genotypes on meiotic nonreduction.

Abstract: Despite numerous studies on shrunken endosperm mutants caused by either maternal tissues (seg) or kernel per se (sex) in barley, the molecular mechanism for all of the eight seg mutants (seg1–seg8) and some sex mutants is yet to be uncovered. In this study, we determined the amylose content, characterized granule-binding proteins, analyzed the expression of key genes involved in starch synthesis, and examined starch granule structure of both normal (Bowman and Morex) and shrunken endosperm (seg1, seg3, seg4a, seg4b, seg5, seg6, seg7, and sex1) barley accessions. Our results showed that amylose contents of shrunken endosperm mutants ranged from 8.9% (seg4a) to 25.8% (seg1). SDS-PAGE analysis revealed that 87kDa proteins corresponding to the starch branching enzyme II (SBEII) and starch synthase II (SSII) were not present in seg1, seg3, seg6, and seg7 mutants. Real-time quantitative PCR (RT-qPCR) analysis indicated that waxy expression levels of seg1, seg3, seg6, and seg7 mutants decreased in varying degrees to lower levels until 27days after anthesis (DAA) after reaching the peak at 15–21DAA, which differed from the pattern of normal barley accessions. Further characterization of waxy alleles revealed 7 non-synonymous single nucleotide polymorphisms (SNPs) in the coding sequences and 16 SNPs and 8 indels in the promoter sequences of the mutants. Results from starch granule by scanning electron microscopy (SEM) indicated that, in comparison with normal barley accessions, seg4a, seg4b, and sex1 had fewer starch granules per grain; seg3 and seg6 had less small B-type granules; some large A-type granules in seg7 had a hollow surface. These results improve our understanding about effects of seg and sex mutants on starch biosynthesis and granule structure during endosperm development and provide information for identification of key genes responsible for these shrunken endosperm mutants. [Copyright &y& Elsevier]

Abstract: The WUSCHEL (WUS)-related homeobox (WOX) gene family plays an important role in coordinating gene transcription in the early phases of embryogenesis. In this study, we isolated and characterized WOX5 from common wheat and its relatives Triticum monococcum, Triticum urartu, Aegilops speltoides, Aegilops searsii, Aegilops sharonensis, Aegilops longissima, Aegilops bicornis, Aegilops tauschii, and Triticum turgidum. The size of the characterized WOX5 alleles ranged from 1029 to 1038bp and encompassed the complete open reading frame (ORF) as well as 5′ upstream and 3′ downstream sequences. Domain prediction analysis showed that the putative primary structures of wheat WOX5 protein include the highly conserved homeodomain besides the WUS-box domain and the EAR-like domain, which is/are present in some members of the WOX protein family. The full-length ORF was subcloned into a prokaryotic expression vector pET30a, and an approximate 26-kDa protein was successfully expressed in Escherichia coli BL21 (DE3) cells with IPTG induction. The WOX5 genes from wheat-related species exhibit a similar structure to and high sequence similarity with WOX5 genes from common wheat. The degree of divergence and phylogenetic tree analysis among WOX5 alleles suggested the existence of three homoeologous copies in the A, B, or D genome of common wheat. Quantitative PCR results showed that TaWOX5 was primarily expressed in the root and calli induced by auxin and cytokinin, indicating that TaWOX5 may play a role related to root formation or development and is associated with hormone regulation in somatic embryogenesis. [Copyright &y& Elsevier]

Highlights: [•] Phylogeny of the polyploid genus Elymus s.l. was estimated using the Acc1 and Pgk1 genes. [•] The origin of the St, H, W, Y, and P genomes were identified. [•] Different hexaploid species may derived their StY genomes via independent origins. [•] Introgression involved in some polyploid Elymus s.l. species and monogenomic genera. [•] It is reasonable to partition Elymus s.l. into several strictly genera. [ABSTRACT FROM AUTHOR]

Abstract: High-molecular-weight glutenin subunits (HMW-GSs) are of considerable interest, because they play a crucial role in determining dough viscoelastic properties and end-use quality of wheat flour. In this paper, ChAy/Bx, a novel chimeric HMW-GS gene from Triticum turgidum ssp. dicoccoides (AABB, 2n=4x=28) accession D129, was isolated and characterized. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that the electrophoretic mobility of the glutenin subunit encoded by ChAy/Bx was slightly faster than that of 1Dy12. The complete ORF of ChAy/Bx contained 1671bp encoding a deduced polypeptide of 555 amino acid residues (or 534 amino acid residues for the mature protein), making it the smallest HMW-GS gene known from Triticum species. Sequence analysis showed that ChAy/Bx was neither a conventional x-type nor a conventional y-type subunit gene, but a novel chimeric gene. Its first 1305 nt sequence was highly homologous with the corresponding sequence of 1Ay type genes, while its final 366 nt sequence was highly homologous with the corresponding sequence of 1Bx type genes. The mature ChAy/Bx protein consisted of the N-terminus of 1Ay type subunit (the first 414 amino acid residues) and the C-terminus of 1Bx type subunit (the final 120 amino acid residues). Secondary structure prediction showed that ChAy/Bx contained some domains of 1Ay subunit and some domains of 1Bx subunit. The special structure of this HMW glutenin chimera ChAy/Bx subunit might have unique effects on the end-use quality of wheat flour. Here we propose that homoeologous recombination might be a novel pathway for allelic variation or molecular evolution of HMW-GSs. [Copyright &y& Elsevier]

Structural changes of chromosomes are a primary mechanism of genome rearrangement over the course of evolution and detailed knowledge of such changes in a given species and its close relatives should increase the efficiency and precision of chromosome engineering in crop improvement. We have identified sequences bordering each of the main translocation and inversion breakpoints on chromosomes 4A, 5A and 7B of the modern bread wheat genome. The locations of these breakpoints allow, for the first time, a detailed description of the evolutionary origins of these chromosomes at the gene level. Results from this study also demonstrate that, although the strategy of exploiting sorted chromosome arms has dramatically simplified the efforts of wheat genome sequencing, simultaneous analysis of sequences from homoeologous and non-homoeologous chromosomes is essential in understanding the origins of DNA sequences in polyploid species. [ABSTRACT FROM AUTHOR]

Abstract: Two single-copy nuclear gene (Acc1 and Pgk1) sequences were used to estimate the phylogeny and diversification patterns of the Triticeae. Phylogenetic analyses and diversification patterns suggested that (1) a major radiation occurring in the Triticeae about 6.1–9.2 MYA might have been triggered by the late Miocene climate oscillations; (2) the Triticeae lineages from Mediterranean and Arctic-temperate regions were evolutionarily distinct; (3) the relationship between Thinopyrum bessarabicum and Triticum/Aegilops is more closely than that between Lophopyrum elongatum and Triticum/Aegilops; (4) Pseudoroegneria is closely related to Australopyrum and Lophopyrum; (5) Australopyrum might originate from colonization via South-east Asia during the late Miocene; (6) Habitats, mating systems, and climate oscillations may associated with the diversification rate shifts leading to the majority of Mediterranean lineage. Diversification rate shifts in Mediterranean lineage of the Triticeae not only spur the occurrence of many endemic lineages but also provide opportunity for polyploid crop origin and domestication. [Copyright &y& Elsevier]

The article describes a study that reports on full sequences of 40k ᵞ-secalin genes and characterize their structures. It states that secalins are the major seed storage proteins of rye and rye accessions from different varieties of wheat were used in the study. As stated, DNA extraction, gene cloning and Sequence analysis were performed for the study and the results revealed that eleven of the 36 sequences are potentially functional and the other 25 are pseudogenes.

Abstract: Two y-type high molecular weight glutenin subunits (HMW-GSs) 1Ay12⁎ and 1Ay8⁎ from the two accessions PI560720 and PI345186 of cultivated einkorn wheat (Triticum monococcum ssp. monococcum, AA, 2n=2x=14), were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The mobility of 1Ay12⁎ and 1Ay8⁎ was similar to that of 1Dy12 and 1By8 from common wheat Chinese Spring, respectively. Their ORFs respectively consisted of 1812bp and 1935bp, encoding 602 and 643 amino acid residues with the four typical structural domains of HMW-GS including signal peptide, conserved N-, and C-terminal and central repetitive domains. Compared with the most similar active 1Ay alleles previous published, there were a total of 15 SNPs and 2 InDels in them. Their encoding functions were confirmed by successful heterogeneous expression. The two novel 1Ay alleles were named as 1Ay12⁎ and 1Ay8⁎ with the accession No. JQ318694 and JQ318695 in GenBank, respectively. The two alleles were classed into the two distinct groups, Phe-type and Cys-type, which might be relevant to the differentiation of Glu-A1-2 alleles. Of which, 1Ay8⁎ belonged to Cys-type group, and its protein possessed an additional conserved cysteine residue in central repetitive region besides the six common ones in N- and C-terminal regions of Phe-type group, and was the second longest in all the known active 1Ay alleles. These results suggested that the subunit 1Ay8⁎ of cultivated einkorn wheat accession PI345186 might have a potential ability to strengthen the gluten polymer interactions and be a valuable genetic resource for wheat quality improvement. [Copyright &y& Elsevier]

Fusarium crown rot (FCR), caused by various Fusarium species, is a destructive disease of cereal crops in semiarid regions worldwide. As part of our contribution to the development of Fusarium resistant cultivars, we identified several novel sources of resistance by systematically assessing barley genotypes representing different geographical origins and plant types. One of these sources of resistance was investigated in this study by generating and analysing two populations of recombinant inbred lines. A major locus conferring FCR resistance, designated as Qcrs.cpi-4H, was detected in one of the populations (mapping population) and the effects of the QTL was confirmed in the other population. The QTL was mapped to the distal end of chromosome arm 4HL and it is effective against both of the Fusarium isolates tested, one F. pseudograminearum and the other F. graminearum. The QTL explains up to 45.3% of the phenotypic variance. As distinct from an earlier report which demonstrated co-locations of loci conferring FCR resistance and plant height in barley, a correlation between these two traits was not detected in the mapping population. However, as observed in a screen of random genotypes, an association between FCR resistance and plant growth rate was detected and a QTL controlling the latter was detected near the Qcrs.cpi-4H locus in the mapping population. Existing data indicate that, although growth rate may affect FCR resistance, different genes at this locus are likely involved in controlling these two traits. [ABSTRACT FROM AUTHOR]

Abstract: NAM is an important domestication gene and valuable to enhance grain protein contents (GPCs) of modern wheat cultivars. In the present study, 12 NAM-G1 genes in Triticum timopheevii Zhuk. (AAGG, 2n =4x =28) were cloned. These genes had the same length of 1546bp including two introns and three exons, and encoded a polypeptide of 407 amino acid residues which contained a N-terminal NAC domain with five sub-domains, and a C-terminal transcriptional activation region (TAR). They were highly similar to the previously published functional NAM-B1 gene DQ871219 from T. turgidum ssp. dicoccoides Körn. (AABB, 2n =4x =28) in both the nucleotide and protein sequences, with a very high identity of 99.5%. The differences among the 12 NAM-G1 genes resulted from 17 SNPs including 14 transitions and 3 transversions. They had outstandingly different expression levels in qRT-PCR. And, their relative expression quantities were significantly positively correlated with GPC of the accessions. In addition, the difference in amino acid sequences of the NAM-G1 genes may also affect the GPC variation. [Copyright &y& Elsevier]

A meta-analysis of quantitative trait loci (QTL) associated with tolerance to abiotic stresses in barley was carried out using results from 35 different experiments. 'MetaQTL' software was used to project QTL positions on a reference map. Three hundred and thirty-seven QTL for traits associated with tolerance to abiotic stresses were included in this analysis which identified 79 metaQTL (MQTL) including 26 for drought, 11 for low temperature, 22 for salinity, 17 for water-logging, and 3 for mineral toxicity and deficiency. The distribution of MQTL was similar to that of the initial QTL. Many of these MQTL were located on chromosomes 2H (mainly for water-logging and drought) and 5H (mainly for salinity and low temperature). It inferred that chromosomes 2H and 5H were important for researches on barley abiotic tolerance, and the genes associated with abiotic stresses were concentrated relatively. As expected from trait correlations, 22.8 % of these MQTL displayed overlapping CIs. These overlapping regions were mainly on chromosomes 1H, 2H and 4H. The results indicated that the tolerance to diverse abiotic stresses were associated with each other in barley. Additionally, 67 candidate genes responsive to abiotic stresses were co-located with the abiotic-stress MQTL. Of them, a total of 55 had different conserved motifs. It inferred that the tolerance to abiotic stresses was contributed by multi-genes with diverse functions, though there might be some important genes associated with the tolerance to abiotic stresses in barley. Additionally, of these candidate genes, scsnp02622, scsnp01644 and scsnp19641 could be better for further studies of abiotic stresses tolerance. [ABSTRACT FROM AUTHOR]

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most devastating foliar diseases of common wheat ( Triticum aestivum L.) worldwide. Growing resistant cultivars is the most effective approach to control the disease. To determine inheritance of stripe rust resistance and map the resistance gene in a common wheat line D31, developed from Triticum sphaerococcum Perc. (accession number AS348), F, F, and BC progenies derived from the Taichung 29 × D31 cross were firstly inoculated with Chinese PST race CYR32 during whole growth stages under the field conditions. Genetic analysis indicated that the resistance to CYR32 in the line D31 was conferred by one recessive gene, temporarily designated as YrSph. A total of 400 simple sequence repeat (SSR), 315 pairs of sequence-related amplified polymorphism and 42 pairs of target region amplified polymorphism markers were screened, and four SSR markers and three TRAP markers were found to be polymorphic between the resistant and susceptible DNA bulks as well as their parents. Genetic linkage was tested on segregating F population and indicated that all of the ten markers were linked to the resistance gene, two of which flanked the locus at 8.5 and 6.9 cM, respectively. The SSR markers mapped the resistance gene on chromosome arm 2AS. The results of chromosome location and pedigree analysis indicate that YrSph was probably a novel stripe rust resistance gene. [ABSTRACT FROM AUTHOR]

Abstract: Salicylic acid (SA) is one of the key signal molecules in regulating plant resistance to diverse pathogens. In Arabidopsis thaliana, it is predominantly associated with resistance against biotrophic and hemibiotrophic pathogens, and triggering systemic acquired resistance. In contrast, the effect of SA on the defence efficiency of wheat against fusarium head blight (FHB) and its causal agent, Fusarium graminearum, is still poorly understood. Here we show that the F. graminearum mycelial growth and conidia germination were significantly inhibited, and eventually halted in the presence of increasing concentration of SA in both liquid and solid media. Addition of SA also significantly reduced the production of the mycotoxin deoxynivalenol (DON). However the inhibitory effect of SA required acidic growth conditions to be observed while basic conditions allowed F. graminearum to use SA as a carbon source. High performance liquid chromatography (HPLC) analysis confirmed the capacity of F. graminearum to metabolize SA. To better understand the effect of SA on F. graminearum mycelial growth, we have compared the expression profiles of SA-treated and untreated F. graminearum liquid cultures after 8 and 24 h of treatment, using an F. graminearum custom-commercial microarray. The microarray analysis suggested that F. graminearum can metabolize SA through either the catechol or gentisate pathways that are present in some fungal species. Inoculation of F. graminearum conidia in a SA-containing solution has led to reduced FHB symptoms in the very susceptible Triticum aestivum cv. Roblin. In contrast, no inhibition was observed when SA and conidia were inoculated sequentially. The expression patterns for the wheat PR1, NPR1, Pdf1.2, and PR4 genes, a group of indicator genes for the defence response, suggested that SA-induced resistance contributed little to the reduction of symptoms in our assay conditions. Our results demonstrate that, although F. graminearum has the capacity to metabolize SA, SA has a significant and direct impact on F. graminearum through a reduction in efficiency of germination and growth at higher concentrations. [Copyright &y& Elsevier]

To develop chromosome 6D-specific point mutation (PM) markers for α-gliadin genes, 79 α-gliadin sequences cloned from Aegilops tauschii and another 40 α-gliadin genes with known chromosome locations were used in multi-sequence alignment and phylogenic analysis. Additional multiple alignment adjustments were performed manually to facilitate discovery of putative chromosome 6D-specific point mutations. A total of 85 PM primers were designed to detect 68 candidate chromosome 6D-specific point mutations. Experimental tests revealed 11 chromosome 6D-specific PM markers by using genomic DNA from homoeologous group 6 nullisomic-tetrasomic lines of Chinese Spring and putative diploid and tetraploid ancestors of hexaploid wheat as PCR templates. Detection of PM markers in one synthetic hexaploid wheat and its parental lines indicated that some α-gliadin genes were lost from Gli- 2 loci during the formation of hexaploid wheat by amphidiploidization of the genomes of Triticum turgidum and Ae. tauschii. Detection of these PM markers in Ae. tauschii, T. aestivum and its four subspecies indicated that at least two genetically distinct sources of Ae. tauschii contributed germplasm to the D genome of T. aestivum. [ABSTRACT FROM AUTHOR]

Ten novel α-gliadin genes (Gli-ta, Gli-turg1, Gli-turg2, Gli-turg3, Gli-turg4, Gli-turg5, Gli-turg6, Gli-cs1, Gli-cs2, and Gli-cs3) with unique characteristics were isolated from wheat (Triticum aestivum L.), among which Gli-cs1, Gli-cs2, Gli-cs3, and Gli-turg6 were pseudogenes. Gli-cs3 and nine other sequences were much larger and smaller, respectively, than the typical α-gliadins. This variation was caused by insertion or deletion of the unique domain I and a polyglutamine region, possibly the result of illegitimate recombination. Consequently, Gli-cs3 contained 10 cysteine residues, whereas there were 2 cysteine residues only in the other nine sequences. Gli-ta/Gli-ta-like α-gliadin genes are normally expressed during the development of seeds. SDS-PAGE analysis showed that in-vitro-expressed Gli-ta could form intermolecular disulphide bonds and could be chain extenders. A protein band similar in size to Gli-ta has been observed in seed extracts, and mass spectrometry results confirm that the band contains small molecular mass α-gliadins, which is a characteristic of the novel α-gliadins. Mass spectrometry results also indicated that the two cysteine residues of Gli-ta/Gli-ta-like proteins participated in the formation of intermolecular disulphide bonds in vivo. Dix gènes inédits codant pour des α-gliadines (Gli-ta, Gli-turg1, Gli-turg2, Gli-turg3, Gli-turg4, Gli-turg5, Gli-turg6, Gli-cs1, Gli-cs2 et Gli-cs3) ayant des caractéristiques uniques ont été isolés chez le blé (Triticum aestivum L.) ; de ce nombre, Gli-cs1, Gli-cs2, Gli-cs3 et Gli-turg6 étaient des pseudogènes. Gli-cs3 et neuf autres séquences étaient respectivement beaucoup plus grands et plus petits que des gènes typiques d'α-gliadines. Cette variation était due à l'insertion ou à la délétion du domaine unique I et une région à polyglutamine, possiblement via recombinaison illégitime. En conséquence, Gli-cs3 comptait 10 cystéines, tandis qu'il n'y en avait que 2 chez les neuf autres séquences. Les gènes codant pour des α-gliadines Gli-ta ou de type Gli-ta étaient normalement exprimés au cours du développement des graines. Une analyse SDS-PAGE a montré qu'en expression in vitro Gli-ta pouvait former des ponts disulfures intermoléculaires et pourrait ainsi contribuer à l'extension des chaînes. Une bande protéique de taille semblable à Gli-ta a été observée dans des extraits de graines et les résultats de spectrométrie de masse ont confirmé que cette bande contenait des α-gliadines de faible masse moléculaire, ce qui est une caractéristique de ces nouvelles α-gliadines. Les résultats de la spectrométrie de masse ont également indiqué que les deux cystéines chez les protéines Gli-ta ou de type Gli-ta participent à la formation de ponts disulfures intermoléculaires in vivo. [ABSTRACT FROM AUTHOR]