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1

Genetic map of Triticum turgidum based on a hexaploid wheat population without genetic recombination for D genome  

PubMed Central

Background A synthetic doubled-haploid hexaploid wheat population, SynDH1, derived from the spontaneous chromosome doubling of triploid F1 hybrid plants obtained from the cross of hybrids Triticum turgidum ssp. durum line Langdon (LDN) and ssp. turgidum line AS313, with Aegilops tauschii ssp. tauschii accession AS60, was previously constructed. SynDH1 is a tetraploidization-hexaploid doubled haploid (DH) population because it contains recombinant A and B chromosomes from two different T. turgidum genotypes, while all the D chromosomes from Ae. tauschii are homogenous across the whole population. This paper reports the construction of a genetic map using this population. Results Of the 606 markers used to assemble the genetic map, 588 (97%) were assigned to linkage groups. These included 513 Diversity Arrays Technology (DArT) markers, 72 simple sequence repeat (SSR), one insertion site-based polymorphism (ISBP), and two high-molecular-weight glutenin subunit (HMW-GS) markers. These markers were assigned to the 14 chromosomes, covering 2048.79?cM, with a mean distance of 3.48?cM between adjacent markers. This map showed good coverage of the A and B genome chromosomes, apart from 3A, 5A, 6A, and 4B. Compared with previously reported maps, most shared markers showed highly consistent orders. This map was successfully used to identify five quantitative trait loci (QTL), including two for spikelet number on chromosomes 7A and 5B, two for spike length on 7A and 3B, and one for 1000-grain weight on 4B. However, differences in crossability QTL between the two T. turgidum parents may explain the segregation distortion regions on chromosomes 1A, 3B, and 6B. Conclusions A genetic map of T. turgidum including 588 markers was constructed using a synthetic doubled haploid (SynDH) hexaploid wheat population. Five QTLs for three agronomic traits were identified from this population. However, more markers are needed to increase the density and resolution of this map in the future study.

2012-01-01

2

Genetic analysis of photosynthetic variation in hexaploid and tetraploid wheat and their interspecific hybrids  

Microsoft Academic Search

Intra- and inter-specific variation in CO2 assimilation rate (A) in Triticum spp. is well documented for reproductive growth stages. Research was conducted to characterize early vegetative photosynthetic variation in a diverse set of cultivated hexaploid wheat (T. aestivum L.) germplasm and in wild tetraploid (T. dicoccoides Korn) and hexaploid x tetraploid populations. Choice of hexaploid genotypes was based on maximum

Brett F. Carver; Richard C. Johnson

1989-01-01

3

Synthesizing double haploid hexaploid wheat populations based on a spontaneous alloploidization process.  

PubMed

Doubled haploid (DH) populations are useful to scientists and breeders in both crop improvement and basic research. Current methods of producing DHs usually need in vitro culture for extracting haploids and chemical treatment for chromosome doubling. This report describes a simple method for synthesizing DHs (SynDH) especially for allopolyploid species by utilizing meiotic restitution genes. The method involves three steps: hybridization to induce recombination, interspecific hybridization to extract haploids, and spontaneous chromosome doubling by selfing the interspecific F(1)s. DHs produced in this way contain recombinant chromosomes in the genome(s) of interest in a homogeneous background. No special equipment or treatments are involved in the DH production and it can be easily applied in any breeding and/or genetic program. Triticum turgidum L. and Aegilops tauschii Coss, the two ancestral species of common wheat (Triticum aestivum L.) and molecular markers were used to demonstrate the SynDH method. PMID:21356528

Zhang, Lianquan; Zhang, Li; Luo, Jiangtao; Chen, Wenjie; Hao, Ming; Liu, Baolong; Yan, Zehong; Zhang, Bo; Zhang, Huaigang; Zheng, Youliang; Liu, Dengcai; Yen, Yang

2011-02-23

4

Synthesizing double haploid hexaploid wheat populations based on a spontaneous alloploidization process  

Microsoft Academic Search

Doubled haploid (DH) populations are useful to scientists and breeders in both crop improvement and basic research. Current methods of producing DHs usually need in vitro culture for extracting haploids and chemical treatment for chromosome doubling. This report describes a simple method for synthesizing DHs (SynDH) especially for allopolyploid species by utilizing meiotic restitution genes. The method involves three steps:

Lianquan Zhang; Li Zhang; Jiangtao Luo; Wenjie Chen; Ming Hao; Baolong Liu; Zehong Yan; Bo Zhang; Huaigang Zhang; Youliang Zheng; Dengcai Liu; Yang Yen

2011-01-01

5

Inheritance of Russian wheat aphid resistance from tetraploid wheat accessions during transfer to hexaploid wheat  

Microsoft Academic Search

Identification of new sources of resistance to Russian wheat aphid (RWA) (Diuraphis noxia (Kurdjumov) in wheat (Triticum aestivum L.) has become very important with the identification of several new biotypes since 2003. Our objective was to characterize\\u000a inheritance and expression of resistance to RWA biotype 2 from three tetraploid wheat landraces (Triticum turgidum L. subsp. dicoccon) during transfer to hexaploid

Benjamin M. Beyer; Scott D. Haley; Nora L. V. Lapitan; Junhua H. Peng; Frank B. Peairs

2011-01-01

6

Genetic structure of Argentinean hexaploid wheat germplasm  

PubMed Central

The identification of genetically homogeneous groups of individuals is an ancient issue in population genetics and in the case of crops like wheat, it can be valuable information for breeding programs, genetic mapping and germplasm resources. In this work we determined the genetic structure of a set of 102 Argentinean bread wheat (Triticum aestivum L.) elite cultivars using 38 biochemical and molecular markers (functional, closely linked to genes and neutral ones) distributed throughout 18 wheat chromosomes. Genetic relationships among these lines were examined using model-based clustering methods. In the analysis three subpopulations were identified which correspond largely to the origin of the germplasm used by the main breeding programs in Argentina.

Vanzetti, Leonardo S.; Yerkovich, Nadia; Chialvo, Eugenia; Lombardo, Lucio; Vaschetto, Luis; Helguera, Marcelo

2013-01-01

7

Genetic structure of Argentinean hexaploid wheat germplasm.  

PubMed

The identification of genetically homogeneous groups of individuals is an ancient issue in population genetics and in the case of crops like wheat, it can be valuable information for breeding programs, genetic mapping and germplasm resources. In this work we determined the genetic structure of a set of 102 Argentinean bread wheat (Triticum aestivum L.) elite cultivars using 38 biochemical and molecular markers (functional, closely linked to genes and neutral ones) distributed throughout 18 wheat chromosomes. Genetic relationships among these lines were examined using model-based clustering methods. In the analysis three subpopulations were identified which correspond largely to the origin of the germplasm used by the main breeding programs in Argentina. PMID:24130447

Vanzetti, Leonardo S; Yerkovich, Nadia; Chialvo, Eugenia; Lombardo, Lucio; Vaschetto, Luis; Helguera, Marcelo

2013-08-30

8

Construction of a representative genomic library from a hexaploid wheat  

Microsoft Academic Search

The large genome size and the great amount of DNA repeats make it rather diffiult to obtain a representative hexaploid wheat\\u000a genomic library. The protocol is given with modifications to phage isolation and to purification of vector and plant DNAs\\u000a by electrophoresis in low-concentration SeaKem agarose gels. Representative genomic libraries of the soft wheat variety carrying\\u000a a translocated rye chromosome

S. A. Filichkin; A. P. Tikhonov; A. A. Yephremov

1991-01-01

9

GENETICAL EVENTS OCCURRING DURING & AFTER TRITICUM TURGIDUM VAR. DURUM X DASYPYRUM VILLOSUM HYBRIDIZATION RECAPITULATE THE POPULATION SIZE & TIME SPAN REQUIRED FOR THE TRANSITION FROM TETRAPLOID TO HEXAPLOID WHEAT DOMESTICATI  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hybridization, polyploidization, and mutation played important roles for evolutionary changes and domestication for both tetraploid and hexaploid wheats. Crossability between parental species, occurrence and frequency of viable unreduced gametes for the rise of the first fertile hybrid plant, and th...

10

Studies on chloroplast and nuclear rDNA in hexaploid bread wheat and its relatives  

Microsoft Academic Search

Though allohexaploid bread wheat (Triticum aestivum) is grown on more acreage than any other cereal crop, its evolutionary history and origin of its three genomes have not been cleared up in every detail. The wheats form a polyploid series with diploid, tetraploid and hexaploid forms. Hexaploid wheats (AABBDD) may have evolved by hybridization between the AABB tetraploid as cytoplasm donor

Szabolcs Rudnóy; Zoltán Bratek; Emil Páldi; Ilona Rácz; Demeter Lásztity

11

Quality Characteristics of Waxy Hexaploid Wheat ( Triticum aestivum L.): Properties of Starch Gelatinization and Retrogradation  

Microsoft Academic Search

Cereal Chem. 74(5):576-580 The viscoelastic properties and molecular structure of the starch isolated from waxy (amylose-free) hexaploid wheat (WHW) (Triticum aestivum L.) were examined. WHW starch generally had lower gelatinization onset temperature, peak viscosity, and setback than the starch isolated from normal hexaploid wheat (NHW). Differential scanning calorimetry (DSC) showed that WHW starch had higher transition temperatures (To, Tp, and

Katsuyuki Hayakawa; Keiko Tanaka; Toshiki Nakamura; Shigeru Endo; Tsuguhiro Hoshino

1997-01-01

12

Quantitative Trait Loci Controlling Fusarium Head Blight Resistance and Low Deoxynivalenol Content in Hexaploid Wheat Population from ‘Arina’ and NK93604  

Microsoft Academic Search

Breeding for Fusarium head blight (FHB) resistant wheat adapted to the Norwegian climatic conditions is one of the top priorities in the country. This study was conducted to characterize QTLs for FHB resistance and low deoxynivalenol (DON) content in a population of 93 double haploid lines from a cross between 'Arina' and NK93604. Both parents have moderate levels of resistance

Kassa Semagn; Helge Skinnes; Åsmund Bjørnstad; Anne Guri Marøy; Yalew Tarkegne

2007-01-01

13

Proteome analysis of diploid, tetraploid and hexaploid wheat: towards understanding genome interaction in protein expression.  

PubMed

Hexaploid wheat (Triticum aestivum L.) is derived from a complex hybridization procedure involving three diploid species carrying the A, B and D genomes. The proteome patterns of diploid, tetraploid and hexaploid wheat were analyzed to explore the genome interaction in protein expression. At least two species from each of the diploid and tetraploid were used to compare their proteome maps with a hexaploid wheat cv. Chinese Spring. The ancestral cultivars were selected based on their history of closeness with the cultivated wheat. Proteins were extracted from seed flour and separated by two-dimensional electrophoresis (2-DE) with isoelectric focusing of pH range from 4-10. 2-DE maps of cultivated and ancestral species were analyzed by computer assisted image analyzer. The region of high molecular weight glutenin subunits of hexaploid wheat showed similarity with those of the diploid donors, BB and DD genomes. The omega gliadin, which is controlled by B genome in common wheat, was assumed to have evolved as a result of interaction between AA and BB genomes. The low molecular weight glutenins and alpha and beta gliadin regions were contributed by the three genomes. This result suggests that the function of donor genomes particularly in the expression of proteins in hexaploid wheat is not totally independent; rather it is the product of interactions among the diploid genomes in the hexaploid nuclear constitutions. The expression of nonstorage proteins was affected substantially due to the removal of the D genome from hexaploid constitution. Location of the structural gene controlling one of the alpha amylase inhibitor proteins in the nonstorage protein region was identified in the short arm of chromosome 3D. PMID:12687621

Islam, Nazrul; Tsujimoto, Hisashi; Hirano, Hisashi

2003-04-01

14

Identification and mapping of QTLs for FHB resistance in a synthetic hexaploid wheat line  

Technology Transfer Automated Retrieval System (TEKTRAN)

The synthetic hexaploid wheat (SHW) lines derived from crosses between tetraploid wheat (AABB genome) and Aegilops tauschii (D genome) possess resistance to various diseases including Fusarium head blight (FHB). However, the genetics of FHB resistance in these synthetic lines is poorly understood. B...

15

Genetic association of OPR genes with resistance to Hessian fly in hexaploid wheat  

PubMed Central

Background Hessian fly (Mayetiola destructor) is one of the most destructive pests of wheat. The genes encoding 12-oxo-phytodienoic acid reductase (OPR) and lipoxygenase (LOX) play critical roles in insect resistance pathways in higher plants, but little is known about genes controlling resistance to Hessian fly in wheat. Results In this study, 154 F6:8 recombinant inbred lines (RILs) generated from a cross between two cultivars, ‘Jagger’ and ‘2174’ of hexaploid wheat (2n?=?6?×?=42; AABBDD), were used to map genes associated with resistance to Hessian fly. Two QTLs were identified. The first one was a major QTL on chromosome 1A (QHf.osu-1A), which explained 70% of the total phenotypic variation. The resistant allele at this locus in cultivar 2174 could be orthologous to one or more of the previously mapped resistance genes (H9, H10, H11, H16, and H17) in tetraploid wheat. The second QTL was a minor QTL on chromosome 2A (QHf.osu-2A), which accounted for 18% of the total phenotypic variation. The resistant allele at this locus in 2174 is collinear to an Yr17-containing-fragment translocated from chromosome 2N of Triticum ventricosum (2n?=?4?×?=28; DDNN) in Jagger. Genetic mapping results showed that two OPR genes, TaOPR1-A and TaOPR2-A, were tightly associated with QHf.osu-1A and QHf.osu-2A, respectively. Another OPR gene and three LOX genes were mapped but not associated with Hessian fly resistance in the segregating population. Conclusions This study has located two major QTLs/genes in bread wheat that can be directly used in wheat breeding programs and has also provided insights for the genetic association and disassociation of Hessian fly resistance with OPR and LOX genes in wheat.

2013-01-01

16

Characterization of total, free and esterified phytosterols in tetraploid and hexaploid wheats.  

PubMed

Dietary plant sterols have received increasing attention in recent years due to their favorable health benefits. The present research focused on quantification of phytosterols as free, esterified and total forms in different tetraploid (5 cultivars of Triticum durum Desf., 9 cultivars of Triticum dicoccon Schrank) and hexaploid (5 cultivars of T. aestivum L., 12 cultivars of Triticum spelta L.) wheats. Tetraploid wheats showed the highest content of total sterol (79.4 and 79.5 mg of sterols /100 g dry weight for T. durum and T. dicoccon, respectively). Hexaploid cultivars were the best source of esterified sterols (40.7% and 37.3% of total sterols for Triticum aestivum and T. spelta, respectively). Significant amounts of free sterols (65.5% and 60.7% of total sterols for T. durum and T. dicoccon, respectively) were found in the tetraploid cultivars. The most abundant phytosterol in all wheat samples was sitosterol accounting for 45.1-59.1, 46.6-57.4 and 38.6-59.5% of total, free and esterified sterol fraction, respectively. These results demonstrate that although the sterol profile present in tetraploid and hexaploid wheat species is the same, differences in their relative amounts and distribution allow statistical differentiation between hexaploids and tetraploids, and between soft and durum wheats. PMID:19292465

Iafelice, Giovanna; Verardo, Vito; Marconi, Emanuele; Caboni, Maria Fiorenza

2009-03-25

17

Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat D-genome genetic diversity and pinpoint the geographic origin of hexaploid wheat.  

PubMed

Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes. PMID:23374069

Wang, Jirui; Luo, Ming-Cheng; Chen, Zhongxu; You, Frank M; Wei, Yuming; Zheng, Youliang; Dvorak, Jan

2013-02-04

18

A high-throughput method for the detection of homoeologous gene deletions in hexaploid wheat  

PubMed Central

Background Mutational inactivation of plant genes is an essential tool in gene function studies. Plants with inactivated or deleted genes may also be exploited for crop improvement if such mutations/deletions produce a desirable agronomical and/or quality phenotype. However, the use of mutational gene inactivation/deletion has been impeded in polyploid plant species by genetic redundancy, as polyploids contain multiple copies of the same genes (homoeologous genes) encoded by each of the ancestral genomes. Similar to many other crop plants, bread wheat (Triticum aestivum L.) is polyploid; specifically allohexaploid possessing three progenitor genomes designated as 'A', 'B', and 'D'. Recently modified TILLING protocols have been developed specifically for mutation detection in wheat. Whilst extremely powerful in detecting single nucleotide changes and small deletions, these methods are not suitable for detecting whole gene deletions. Therefore, high-throughput methods for screening of candidate homoeologous gene deletions are needed for application to wheat populations generated by the use of certain mutagenic agents (e.g. heavy ion irradiation) that frequently generate whole-gene deletions. Results To facilitate the screening for specific homoeologous gene deletions in hexaploid wheat, we have developed a TaqMan qPCR-based method that allows high-throughput detection of deletions in homoeologous copies of any gene of interest, provided that sufficient polymorphism (as little as a single nucleotide difference) amongst homoeologues exists for specific probe design. We used this method to identify deletions of individual TaPFT1 homoeologues, a wheat orthologue of the disease susceptibility and flowering regulatory gene PFT1 in Arabidopsis. This method was applied to wheat nullisomic-tetrasomic lines as well as other chromosomal deletion lines to locate the TaPFT1 gene to the long arm of chromosome 5. By screening of individual DNA samples from 4500 M2 mutant wheat lines generated by heavy ion irradiation, we detected multiple mutants with deletions of each TaPFT1 homoeologue, and confirmed these deletions using a CAPS method. We have subsequently designed, optimized, and applied this method for the screening of homoeologous deletions of three additional wheat genes putatively involved in plant disease resistance. Conclusions We have developed a method for automated, high-throughput screening to identify deletions of individual homoeologues of a wheat gene. This method is also potentially applicable to other polyploidy plants.

2010-01-01

19

Genetic and Epigenetic Alteration among Three Homoeologous Genes of a Class E MADS Box Gene in Hexaploid Wheat  

Microsoft Academic Search

Bread wheat (Triticum aestivum) is a hexaploid species with A, B, and D ancestral genomes. Most bread wheat genes are present in the genome as triplicated homoeologous genes (homoeologs) derived from the ancestral species. Here, we re- port that both genetic and epigenetic alterations have occurred in the homoeologs of a wheat class E MADS box gene. Two class E

Naoki Shitsukawa; Chikako Tahira; Ken-ichiro Kassai; Chizuru Hirabayashi; Tomoaki Shimizu; Shigeo Takumi; Keiichi Mochida; Kanako Kawaura; Yasunari Ogihara; Koji Murai

2007-01-01

20

Improvement of green plant regeneration by manipulation of anther culture induction medium of hexaploid wheat  

Microsoft Academic Search

Anthers of three hexaploid wheat (Triticum aestivum L.) genotypes with high frequencies of albino regenerants in anther culture were compared to DH after inoculation on medium\\u000a supplemented with ficoll, colchicine or maltose separately, pair-wise or combined, in an attempt to increase green plant regeneration.\\u000a Maltose treatment produced more green regenerated plants than sucrose for all of the genotypes. The three

Amina Redha; Attia Talaat

2008-01-01

21

Aneuploidy detection with a short-term hexaploid wheat assay.  

PubMed

A new type of assay for the identification of agents causing aneuploidy is described. This assay takes advantage of allohexaploid wheat in which monosomic and nullisomic cell lineages can be genetically detected. The wheat strain used (Neatby's virescens) was homozygous for a pair of recessive alleles (v1) which in homozygous condition interfere with normal pigmentation of the leaves at low temperature whereas at higher temperature nearly normal green color formation is permitted. In a single dose this allele cannot suppress the formation of green color even at low temperature, i.e., it is hemizygous ineffective. This locus is in the short arm of chromosome 3B near the centromere. As a consequence of non-disjunction of this chromosome twin sectors may be detected, in which the monosomic cell lineages appear green whereas the trisomic sectors display with color on a cream-colored background at low temperature. This genetic system can also be used for the detection of deletions or duplications involving the short arm of chromosome 3B, and to some extent the A- and the D-genome homeologues. We have determined the pattern of differentiation of the shoot apex and on that basis we can separate the independent genetic events from reappearance of the sectors of common origin in the successive leaves. Such an understanding of development of the leaf sectors permits a quantitative estimation of the genetic response of the plants to mutagenic factors. We have found that X-rays, gamma-rays, p-fluorophenylalanine, 3-aminotriazole, caffeine, vinblastin sulfate, benzo[a]pyrene and auramine significantly increased aneuploidy, and diethylstilbestrol, sulfacetamide, safrole and dichlorvos caused some increase of sectoring. Cytological data on root tips of irradiated seeds support the interpretation of the mechanism of sector formation in the leaves. The test is simple, fast, inexpensive, and it does not require elaborate facilities or highly trained technicians. The trials were well reproducible during a period of 3 years in 2 laboratories. Therefore we consider the new assay a useful complement to other tests of chemicals or physical agents that may cause non-disjunction and other chromosomal aberrations in human populations. PMID:3173382

Rédei, G P; Sandhu, S S

1988-10-01

22

Analysis of Breeding Systems, Ploidy, and the Role of Hexaploids in Three Hypericum perforatum L. Populations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid seeds are produced by predominantly tetraploid populations of Hypericum perforatum, but the fate of hexaploid seedlings and their reproductive behavior have not been closely examined. We used flow cytometry to analyze single seeds and individual plant samples of three accessions of H. per...

23

Ribosomal RNA cistron multiplicity and nucleolar organizers in hexaploid wheat.  

PubMed

The ribosomal DNA (DNA complementary to ribosomal RNA) content of twelve different wheat genotypes has been studied. Some of these genotypes are aneuploids with deletions or additions of chromosomes bearing nucleolar organisers. The rDNA contents of these genotypes provide several examples of a clear departure from a correlation between the number of rRNA cistrons and the number of nucleolar organisers. Thus the number of rRNA cistrons per nucleolar organiser is not constant in wheat. Wheat DNA was found to have a mean buoyant density of approximately 1.702 g/cc for all genotypes studied and rRNA hybridized selectively to DNA of buoyant density approximately 1.710 g/cc. The thermal stabilities of all the rRNA/DNA hybrids were essentially identical. PMID:4361912

Mohan, J; Flavell, R B

1974-01-01

24

The effect of the crossability loci Kr1 and Kr2 on fertilization frequency in hexaploid wheat x maize crosses  

Microsoft Academic Search

Dominant alleles of the Kr1 and Kr2 genes reduce the crossability of hexaploid wheat with many alien species, including rye and Hordeum bulbosum, with Kr1 having the greater effect. However, a cytological study of wheat ovaries fixed 48 h after pollination showed that the wheat genotypes ‘Highbury’ (kr1, Kr2) and ‘Chinese Spring (Hope 5B)’ (kr1, kr2) were crossable with ‘Seneca

D. A. Laurie; M. D. Bennett

1987-01-01

25

Genome-wide comparative diversity uncovers multiple targets of selection for improvement in hexaploid wheat landraces and cultivars  

PubMed Central

Domesticated crops experience strong human-mediated selection aimed at developing high-yielding varieties adapted to local conditions. To detect regions of the wheat genome subject to selection during improvement, we developed a high-throughput array to interrogate 9,000 gene-associated single-nucleotide polymorphisms (SNP) in a worldwide sample of 2,994 accessions of hexaploid wheat including landraces and modern cultivars. Using a SNP-based diversity map we characterized the impact of crop improvement on genomic and geographic patterns of genetic diversity. We found evidence of a small population bottleneck and extensive use of ancestral variation often traceable to founders of cultivars from diverse geographic regions. Analyzing genetic differentiation among populations and the extent of haplotype sharing, we identified allelic variants subjected to selection during improvement. Selective sweeps were found around genes involved in the regulation of flowering time and phenology. An introgression of a wild relative-derived gene conferring resistance to a fungal pathogen was detected by haplotype-based analysis. Comparing selective sweeps identified in different populations, we show that selection likely acts on distinct targets or multiple functionally equivalent alleles in different portions of the geographic range of wheat. The majority of the selected alleles were present at low frequency in local populations, suggesting either weak selection pressure or temporal variation in the targets of directional selection during breeding probably associated with changing agricultural practices or environmental conditions. The developed SNP chip and map of genetic variation provide a resource for advancing wheat breeding and supporting future population genomic and genome-wide association studies in wheat.

Cavanagh, Colin R.; Chao, Shiaoman; Wang, Shichen; Huang, Bevan Emma; Stephen, Stuart; Kiani, Seifollah; Forrest, Kerrie; Saintenac, Cyrille; Brown-Guedira, Gina L.; Akhunova, Alina; See, Deven; Bai, Guihua; Pumphrey, Michael; Tomar, Luxmi; Wong, Debbie; Kong, Stephan; Reynolds, Matthew; da Silva, Marta Lopez; Bockelman, Harold; Talbert, Luther; Anderson, James A.; Dreisigacker, Susanne; Baenziger, Stephen; Carter, Arron; Korzun, Viktor; Morrell, Peter Laurent; Dubcovsky, Jorge; Morell, Matthew K.; Sorrells, Mark E.; Hayden, Matthew J.; Akhunov, Eduard

2013-01-01

26

Heterochronic development of the floret meristem determines grain number per spikelet in diploid, tetraploid and hexaploid wheats  

PubMed Central

Background and Aims The inflorescence of grass species such as wheat, rice and maize consists of a unique reproductive structure called the spikelet, which is comprised of one, a few, or several florets (individual flowers). When reproductive growth is initiated, the inflorescence meristem differentiates a spikelet meristem as a lateral branch; the spikelet meristem then produces a floret meristem as a lateral branch. Interestingly, in wheat, the number of fertile florets per spikelet is associated with ploidy level: one or two florets in diploid, two or three in tetraploid, and more than three in hexaploid wheats. The objective of this study was to identify the mechanisms that regulate the architecture of the inflorescence in wheat and its relationship to ploidy level. Methods The floral anatomy of diploid (Triticum monococcum), tetraploid (T. turgidum ssp. durum) and hexaploid (T. aestivum) wheat species were investigated by light and scanning electron microscopy to describe floret development and to clarify the timing of the initiation of the floret primordia. In situ hybridization analysis using Wknox1, a wheat knotted1 orthologue, was performed to determine the patterning of meristem formation in the inflorescence. Key Results The recessive natural mutation of tetraploid (T. turgidum ssp. turgidum) wheat, branching head (bh), which produces branched inflorescences, was used to demonstrate the utility of Wknox1 as a molecular marker for meristematic tissue. Then an analysis of Wknox1 expression was performed in diploid, tetraploid and hexaploid wheats and heterochronic development of the floret meristems was found among these wheat species. Conclusions It is shown that the difference in the number of floret primordia in diploid, tetraploid and hexaploid wheats is caused by the heterochronic initiation of floret meristem development from the spikelet meristem.

Shitsukawa, Naoki; Kinjo, Hiroko; Takumi, Shigeo; Murai, Koji

2009-01-01

27

Molecular genetic mapping of quantitative trait loci associated with loaf volume in hexaploid wheat ( Triticum aestivum)  

Microsoft Academic Search

Major efforts in wheat research are being made to improve the yield and quality of wheat. Loaf volume (Lv) is the main quality parameter deciding the bread making potential of wheat. To genetically dissect quantitative trait loci (QTLs) for Lv, a Recombinant Inbred Line (RIL) population (F8) was developed from a cross between two Indian wheat varieties “HI 977” and

M. Elangovan; R. Rai; B. B. Dholakia; M. D. Lagu; R. Tiwari; R. K. Gupta; V. S. Rao; M. S. Röder; V. S. Gupta

2008-01-01

28

CHROMOSOME BIN MAP OF EXPRESSED SEQUENCE TAGS IN HOMOEOLOGOUS GROUP 1 OF HEXAPLOID WHEAT AND HOMOEOLOGY WITH RICE AND ARABIDOPSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A total of 944 expressed sequence tags (ESTs) and the corresponding 2,212 EST loci were mapped to homoeologous group 1 chromosomes in hexaploid wheat (Triticum aestivum L.). Expressed sequence tag deletion maps and the consensus deletion map of group 1 chromosomes were constructed to show EST distri...

29

TYPES AND RATES OF SEQUENCE EVOLUTION AT HMW-GLUTENIN LOCUS IN HEXAPLOID WHEAT AND ITS ANCESTRAL GENOMES  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Glu-1 locus, encoding the High Molecular Weight-glutenin protein subunits, controls bread-making quality in hexaploid wheat (Triticum aestivum) and represents a recently evolved region unique to Triticeae genomes. To understand the molecular evolution of this locus region, three orthologous Glu...

30

Non-gridded library: a new approach for BAC (bacterial artificial chromosome) exploitation in hexaploid wheat (Triticum aestivum)  

PubMed Central

The feasibility of exploiting non-gridded bacterial artificial chromosome (BAC) libraries and some major factors affecting the efficiency of handling such libraries were studied in hexaploid wheat. Even for a bacterial culture containing only 55% recombinants, some 2000 BAC clones with inserts ranging from 45 to 245 kb could be pooled. The pooled BAC clones could be amplified by culturing for up to 6 h without losing any target clones. These results imply that even for hexaploid wheat, which has an extremely large genome, some 250 pools are sufficient for a BAC library that should satisfy many research objectives. This non-gridded strategy would dramatically reduce the cost and make robotic equipment non-essential in exploiting BAC technology. To construct a representative library and to minimise clone competition, thawing and re-freezing ligation mixtures and bacterial cultures should be avoided in BAC library construction and application.

Ma, Zhiying; Weining, Song; Sharp, Peter J.; Liu, Chunji

2000-01-01

31

QTL mapping of terminal heat tolerance in hexaploid wheat (T. aestivum L.).  

PubMed

High temperature (>30 °C) at the time of grain filling is one of the major causes of yield reduction in wheat in many parts of the world, especially in tropical countries. To identify quantitative trait loci (QTL) for heat tolerance under terminal heat stress, a set of 148 recombinant inbred lines was developed by crossing a heat-tolerant hexaploid wheat (Triticum aestivum L.) cultivar (NW1014) and a heat-susceptible (HUW468) cultivar. The F(5), F(6), and F(7) generations were evaluated in two different sowing dates under field conditions for 2 years. Using the trait values from controlled and stressed trials, four different traits (1) heat susceptibility index (HSI) of thousand grain weight (HSITGW); (2) HSI of grain fill duration (HSIGFD); (3) HSI of grain yield (HSIYLD); and (4) canopy temperature depression (CTD) were used to determine heat tolerance. Days to maturity was also investigated. A linkage map comprising 160 simple sequence repeat markers was prepared covering the whole genome of wheat. Using composite interval mapping, significant genomic regions on 2B, 7B and 7D were found to be associated with heat tolerance. Of these, two (2B and 7B) were co-localized QTL and explained more than 15 % phenotypic variation for HSITGW, HSIGFD and CTD. In pooled analysis over three trials, QTL explained phenotypic variation ranging from 9.78 to 20.34 %. No QTL × trial interaction was detected for the identified QTL. The three major QTL obtained can be used in marker-assisted selection for heat stress in wheat. PMID:22476874

Paliwal, Rajneesh; Röder, Marion S; Kumar, Uttam; Srivastava, J P; Joshi, Arun Kumar

2012-04-05

32

Purification and Characterization of the Glutenin Subunits of Triticum tauschii , Progenitor of the D Genome in Hexaploid Bread Wheat  

Microsoft Academic Search

Cereal Chem. 74(2):108-114 N-terminal amino acid sequences and sodium dodecyl sulfate poly- acrylamide gel electrophoresis (SDS-PAGE) molecular weights have been determined for high-performance liquid chromatography (HPLC)- purified high molecular weight (HMW) and low molecular weight (LMW) glutenin subunits (GS) of Triticum tauschii ssp. strangulata, contributor of the D genome to hexaploid bread wheat. The use of three different extraction procedures

William H. Vensel; A. Elva Adalsteins; Donald D. Kasarda

1997-01-01

33

Effects of NaCl on protein profiles of tetraploid and hexaploid wheat species and their diploid wild progenitors  

Microsoft Academic Search

The soluble proteins extracted from the first leaf tissues of cultivated tetraploid ( Triticum durum Desf., genome AB) and hexaploid (T. aestivum L., genome ABD) wheat species and their diploid wild progenitors (T. monococ- cum L. (A), Aegilops speltoides Tausch (B), and Aegilops tauschii Cosson ( D)) exposed to 100 mmol\\/l NaCl stress were separated by two-dimensional (2D) gel electrophoresis.

M. Yildiz; H. Terzi

2008-01-01

34

CONSTRUCTION OF A HEXAPLOID WHEAT (TRITICUM AESTIVUM L.) BACTERIAL ARTIFICIAL CHROMOSOME LIBRARY AND IDENTIFICATION OF CANDIDATE BAC CLONES CONTAINING STRIPE RUST RESISTANCE GENE MARKERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A hexaploid wheat (Triticum astivum L.) bacterial artificial chromosome (BAC) library was constructed for the positional cloning of the wheat strip rust resistance gene Yr5. The Yr5 near-isogenic line were used to isolate the high molecular weight DNA as intact nuclei. The HindIII partial restrict...

35

Meiotic behaviour of tetraploid wheats (Triticum turgidum L.) and their synthetic hexaploid wheat derivates influenced by meiotic restitution and heat stress.  

PubMed

Meiotic restitution is considered to be a common mechanism of polyploidization in plants and hence is one of the most important processes in plant speciation. Meiotic behaviour of plant chromosomes is influenced by both genetic and environmental factors. In this study, the meiotic behaviour of cereal crops was investigated, which includes tetraploid wheat genotypes (with and without the meiotic restitution trait) and their derivates (synthetic hexaploid wheats and a doubled haploid (DH) line), grown at two planting dates in the field. In addition, two local landraces of emmer wheat (Triticum turgidum ssp. dicoccum), one wheat cultivar (Chinese spring), one DH triticale cultivar (Eleanor) and one rye accession were included. Immature spikes of mid-autumn and end-winter sowing plants were collected in April and May 2008, respectively, fixed in Carnoy's solution and stained with hematoxylin. Pollen mother cells (PMCs) from anthers at different stages of meiotic process were analysed for their chromosomal behaviour and irregularities. Meiotic aberrations such as laggards, chromosome bridges, micronuclei, abnormal cytokines, chromatin pulling and meiotic restitution were observed and the studied genotypes were accordingly ranked as follows: triticale > synthetic hexaploid wheats > tetraploid wheats possessing meiotic restitution > tetraploid wheats lacking meiotic restitution > rye. The results indicated that the samples that had been planted in the autumn, thus experiencing an optimum temperature level at the flowering stage, exhibited less meiotic irregularities than winter planting samples that encountered heat stress at the flowering period. PMID:21273690

Rezaei, Masoumeh; Arzani, Ahmad; Sayed-Tabatabaei, Badraldin Ebrahim

2010-12-01

36

Population Dynamics of Diploid and Hexaploid Populations of a Perennial Herb  

PubMed Central

Background and Aims Despite the recent enormous increase in the number of studies on polyploid species, no studies to date have explored the population dynamics of these taxa. It is thus not known whether the commonly reported differences in single life-history traits between taxa of different ploidy levels result in differences in population dynamics. Methods This study explores differences in single life-history traits and in the complete life cycle between populations of different ploidy levels and compares these differences with differences observed between different habitat types and years. Diploid and hexaploid populations of a perennial herb, Aster amellus, are used as the study system. Transition matrix models were used to describe the dynamics of the populations, and population growth rates, elasticity values and life-table response experiments were used to compare the dynamics between populations and years. Key Results The results indicate that between-year variation in population dynamics is much larger than variation between different ploidy levels and different habitat conditions. Significant differences exist, however, in the structure of the transition matrices, indicating that the dynamics of the different ploidy levels are different. Strong differences in probability of extinction of local populations were also found, with hexaploid populations having higher probability than diploid populations, indicating strong potential differences in persistence of these populations. Conclusions This is the first study on complete population dynamics of plants of different ploidy levels. This knowledge will help to understand the ability of new ploidy levels to spread into new areas and persist there, and the interactions of different ploidy levels in secondary contact zones. This knowledge will also contribute to understanding of interactions of different ploidy levels with other plant species or other interacting organisms such as pollinators or herbivores.

Munzbergova, Zuzana

2007-01-01

37

Variation in abscisic acid responsiveness of Aegilops tauschii and hexaploid wheat synthetics due to the D-genome diversity.  

PubMed

Common wheat (Triticum aestivum L.) is an allohexaploid that originated from natural hybridization between tetraploid wheat (Triticum turgidum) and diploid Aegilops tauschii. Ae. tauschii is considered one of the potential sources of new genetic variation in abiotic stress tolerance for improving common wheat. Abscisic acid (ABA) plays an important role in plant adaptation to environmental stresses. In this study, ABA responsiveness of 67 Ae. tauschii accessions and their synthetic hexaploid wheat lines, derived from crosses between T. turgidum cv. Langdon and the Ae. tauschii accessions, was evaluated based on growth inhibition by 20 µM ABA. Wide variation was found in ABA responsiveness for both synthetic wheat lines and their parental Ae. tauschii accessions. The variations due to D-genome found at the diploid level were also expressed in a hexaploid genetic background. Two pairs of synthetic wheat lines differing in ABA responsiveness were then selected for gene expression analysis and to test abiotic stress tolerance, because their parental Ae. tauschii accessions similarly exhibited the differential response to ABA. Gene expression of ABA inducible transcription factor, WABI5, and the downstream Cor/Lea genes (Wrab17, Wdhn13 and Wrab18) were analysed. In one pair, the highly responsive line exhibited higher induction of Wrab17 by ABA treatment, but no significant difference in dehydration or salinity tolerance was observed between these lines. In contrast, in the second pair, the highly ABA-responsive line showed higher levels of Wdhn13 expression and dehydration and salinity tolerance. In synthetic wheat lines, the difference in the ABA responsiveness of the lines appeared to be determined by the different sets of D-genome genes. Our findings suggest that highly ABA-responsive Ae. tauschii accessions should be valuable genetic resources for improving the abiotic stress tolerance of common wheat. PMID:22531790

Iehisa, Julio C M; Takumi, Shigeo

2012-01-01

38

Coexistence of Tetraploid and Hexaploid Naked Wheat in a Neolithic Lake Dwelling of Central Europe: Evidence from Morphology and Ancient DNA  

Microsoft Academic Search

Free-threshing wheat was a principal cereal in Neolithic cultures, as shown by the abundance of grains in the archaeological record. However, the morphology of the mainly charred preserved, prehistoric naked wheat grains is not characteristic of either tetraploid,Triticum durumDesf. andTriticum turgidumL., or of hexaploid, e.g.Triticum aestivumL. We analysed the morphology of charred naked wheat grains originating from a storage assemblage

Angela Schlumbaum; Jean-Marc Neuhaus; Stefanie Jacomet

1998-01-01

39

Identification of Novel QTL for Seeding and Adult Plant Leaf Rust Resistance in a Wheat Doubled Haploid Population  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pyramiding of genes that confer partial resistance is a method for developing wheat (Triticum aestivum L.) cultivars with durable resistance to leaf rust caused by Puccinia triticina. In this research, a doubled haploid (DH) population derived from the cross between the synthetic hexaploid wheat (S...

40

Genotype-dependent Burst of Transposable Element Expression in Crowns of Hexaploid Wheat (Triticum aestivum L.) during Cold Acclimation  

PubMed Central

The expression of 1,613 transposable elements (TEs) represented in the Affymetrix Wheat Genome Chip was examined during cold treatment in crowns of four hexaploid wheat genotypes that vary in tolerance to cold and in flowering time. The TE expression profiles showed a constant level of expression throughout the experiment in three of the genotypes. In winter Norstar, the most cold-hardy of the four genotypes, a subset of the TEs showed a burst of expression after vernalization saturation was achieved. About 47% of the TEs were expressed, and both Class I (retrotransposons) and Class II (DNA transposons) types were well represented. Gypsy and Copia were the most represented among the retrotransposons while CACTA and Mariner were the most represented DNA transposons. The data suggests that the Vrn-A1 region plays a role in the stage-specific induction of TE expression in this genotype.

Laudencia-Chingcuanco, Debbie; Fowler, D. Brian

2012-01-01

41

Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci  

PubMed Central

Background ?-gliadins form a multigene protein family encoded by multiple ?-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The ?-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic ?-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences. Results We detected large differences in relative expression levels of ?-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus'). Conclusion Here, we have shown that large differences exist in relative expression levels of ?-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a 'gene family-specific quantitative transcriptome profiling'.

Salentijn, Elma MJ; Goryunova, Svetlana V; Bas, Noor; van der Meer, Ingrid M; van den Broeck, Hetty C; Bastien, Thomas; Gilissen, Luud JWJ; Smulders, Marinus JM

2009-01-01

42

Lr34 multi-pathogen resistance ABC transporter: molecular analysis of homoeologous and orthologous genes in hexaploid wheat and other grass species.  

PubMed

The Triticum aestivum (bread wheat) disease resistance gene Lr34 confers durable, race non-specific protection against three fungal pathogens, and has been a highly relevant gene for wheat breeding since the green revolution. Lr34, located on chromosome 7D, encodes an ATP-binding cassette (ABC) transporter. Both wheat cultivars with and without Lr34-based resistance encode a putatively functional protein that differ by only two amino acid polymorphisms. In this study, we focused on the identification and characterization of homoeologous and orthologous Lr34 genes in hexaploid wheat and other grasses. In hexaploid wheat we found an expressed and putatively functional Lr34 homoeolog located on chromosome 4A, designated Lr34-B. Another homoeologous Lr34 copy, located on chromosome 7A, was disrupted by the insertion of repetitive elements. Protein sequences of LR34-B and LR34 were 97% identical. Orthologous Lr34 genes were detected in the genomes of Oryza sativa (rice) and Sorghum bicolor (sorghum). Zea mays (maize), Brachypodium distachyon and Hordeum vulgare (barley) lacked Lr34 orthologs, indicating independent deletion of this particular ABC transporter. Lr34 was part of a gene-rich island on the wheat D genome. We found gene colinearity on the homoeologous A and B genomes of hexaploid wheat, but little microcolinearity in other grasses. The homoeologous LR34-B protein and the orthologs from rice and sorghum have the susceptible haplotype for the two critical polymorphisms distinguishing the LR34 proteins from susceptible and resistant wheat cultivars. We conclude that the particular Lr34-haplotype found in resistant wheat cultivars is unique. It probably resulted from functional gene diversification that occurred after the polyploidization event that was at the origin of cultivated bread wheat. PMID:21265893

Krattinger, Simon G; Lagudah, Evans S; Wicker, Thomas; Risk, Joanna M; Ashton, Anthony R; Selter, Liselotte L; Matsumoto, Takashi; Keller, Beat

2010-12-30

43

Genetic and Epigenetic Alteration among Three Homoeologous Genes of a Class E MADS Box Gene in Hexaploid Wheat[W][OA  

PubMed Central

Bread wheat (Triticum aestivum) is a hexaploid species with A, B, and D ancestral genomes. Most bread wheat genes are present in the genome as triplicated homoeologous genes (homoeologs) derived from the ancestral species. Here, we report that both genetic and epigenetic alterations have occurred in the homoeologs of a wheat class E MADS box gene. Two class E genes are identified in wheat, wheat SEPALLATA (WSEP) and wheat LEAFY HULL STERILE1 (WLHS1), which are homologs of Os MADS45 and Os MADS1 in rice (Oryza sativa), respectively. The three wheat homoeologs of WSEP showed similar genomic structures and expression profiles. By contrast, the three homoeologs of WLHS1 showed genetic and epigenetic alterations. The A genome WLHS1 homoeolog (WLHS1-A) had a structural alteration that contained a large novel sequence in place of the K domain sequence. A yeast two-hybrid analysis and a transgenic experiment indicated that the WLHS1-A protein had no apparent function. The B and D genome homoeologs, WLHS1-B and WLHS1-D, respectively, had an intact MADS box gene structure, but WLHS1-B was predominantly silenced by cytosine methylation. Consequently, of the three WLHS1 homoeologs, only WLHS1-D functions in hexaploid wheat. This is a situation where three homoeologs are differentially regulated by genetic and epigenetic mechanisms.

Shitsukawa, Naoki; Tahira, Chikako; Kassai, Ken-ichiro; Hirabayashi, Chizuru; Shimizu, Tomoaki; Takumi, Shigeo; Mochida, Keiichi; Kawaura, Kanako; Ogihara, Yasunari; Murai, Koji

2007-01-01

44

Microsatellite mapping of the genes for brittle rachis on homoeologous group 3 chromosomes in tetraploid and hexaploid wheats.  

PubMed

The brittle rachis character, which causes spontaneous shattering of spikelets, has an adaptive value in wild grass species. The loci Br1 and Br2 in durum wheat (Triticum durum Desf.) and Br3 in hexaploid wheat (T. aestivum L.) determine disarticulation of rachides above the junction of the rachilla with the rachis such that a fragment of rachis is attached below each spikelet. Using microsatellite markers, the loci Br1, Br2 and Br3 were mapped on the homoeologous group 3 chromosomes. The Br2 locus was located on the short arm of chromosome 3A and linked with the centromeric marker, Xgwm32, at a distance of 13.3 cM. The Br3 locus was located on the short arm of chromosome 3B and linked with the centromeric marker, Xgwm72 (at a distance of 14.2 cM). The Br1 locus was located on the short arm of chromosome 3D. The distance of Br1 from the centromeric marker Xgdm72 was 25.3 cM. Mapping the Br1, Br2 and Br3 loci of the brittle rachis suggests the homoeologous origin of these 3 loci for brittle rachides. Since the genes for brittle rachis have been retained in the gene pool of durum wheat, the more closely linked markers with the brittle rachis locus are required to select against brittle rachis genotypes and then to avoid yield loss in improved cultivars. PMID:16682748

Watanabe, Nobuyoshi; Fujii, Youko; Kato, Noriko; Ban, Tomohiro; Martinek, Petr

2006-01-01

45

Cloning and comparative analysis of carotenoid ?-hydroxylase genes provides new insights into carotenoid metabolism in tetraploid (Triticum turgidum ssp. durum) and hexaploid (Triticum aestivum) wheat grains.  

PubMed

Carotenoid ?-hydroxylases attach hydroxyl groups to the ?-ionone rings (?-rings) of carotenoid substrates, resulting in modified structures and functions of carotenoid molecules. We cloned and characterized two genes (each with three homeologs), HYD1 and HYD2, which encode ?-hydroxylases in wheat. The results from bioinformatic and nested degenerate PCR analyses collectively suggest that HYD1 and HYD2 may represent the entire complement of non-heme di-iron ?-hydroxylases in wheat. The homeologs of wheat HYDs exhibited major ?-ring and minor ?-ring hydroxylation activities in carotenoid-accumulating E. coli strains. Distinct expression patterns were observed for different HYD genes and homeologs in vegetative tissues and developing grains of tetraploid and hexaploid wheat, suggesting their functional divergence and differential regulatory control in tissue-, grain development-, and ploidy-specific manners. An intriguing observation was that the expression of HYD1, particularly HYD-B1, reached highest levels at the last stage of tetraploid and hexaploid grain development, suggesting that carotenoids (at least xanthophylls) were still actively synthesized in mature grains. This result challenges the common perception that carotenoids are simply being turned over during wheat grain development after their initial biosynthesis at the early grain development stages. Overall, this improved understanding of carotenoid biosynthetic gene expression and carotenoid metabolism in wheat grains will contribute to the improvement of the nutritional value of wheat grains for human consumption. PMID:23015203

Qin, Xiaoqiong; Zhang, Wenjun; Dubcovsky, Jorge; Tian, Li

2012-09-27

46

Mixed model association mapping for fusarium head blight resistance in tunisian-derived durum wheat populations.  

PubMed

Sources of resistance to Fusarium head blight (FHB) in wheat are mostly restricted to Chinese hexaploid genotypes. The effort to incorporate the resistance from hexaploid wheat or wild relatives to cultivated durum wheat (Triticum turgidum L. var. durum Desf.) have not been successful in providing resistance to the level of the donor parents. In this study, we used 171 BC(1)F(6) and 169 BC(1)F(7) lines derived from crossing of four Tunisian tetraploid sources of resistance (Tun7, Tun18, Tun34, Tun36) with durum cultivars 'Ben,' 'Maier,' 'Lebsock,' and 'Mountrail' for association studies. The Tun18 and Tun7 FHB resistances were found to be comparable to the best hexaploid wheat sources. A new significant QTL for FHB resistance was identified on the long arm of chromosome 5B (Qfhs.ndsu-5BL) with both association and classical QTL mapping analysis. Linkage disequilibrium (LD) blocks extending up to 40 cM were evident in these populations. The linear mixed model considering the structure (Q or P) and the kinship matrix (K(T)) estimated by restricted maximum likelihood (REML) was identified as the best for association studies in a mixture of wheat populations from a breeding program. The results of association mapping analysis also demonstrated a region on the short arm of chromosome 3B as potentially linked to FHB resistance. This region is in proximity of major FHB resistance gene fhb1 reported in hexaploid wheat. A possibility of having susceptibility or suppressor of resistance gene(s) on durum wheat chromosome 2A was further confirmed in this material, explaining the problem in developing resistant genotypes without counter selection against this region. PMID:22384332

Ghavami, Farhad; Elias, Elias M; Mamidi, Sujan; Ansari, Omid; Sargolzaei, Mehdi; Adhikari, Tika; Mergoum, Mohamed; Kianian, Shahryar F

2011-08-01

47

Mixed Model Association Mapping for Fusarium Head Blight Resistance in Tunisian-Derived Durum Wheat Populations  

PubMed Central

Sources of resistance to Fusarium head blight (FHB) in wheat are mostly restricted to Chinese hexaploid genotypes. The effort to incorporate the resistance from hexaploid wheat or wild relatives to cultivated durum wheat (Triticum turgidum L. var. durum Desf.) have not been successful in providing resistance to the level of the donor parents. In this study, we used 171 BC1F6 and 169 BC1F7 lines derived from crossing of four Tunisian tetraploid sources of resistance (Tun7, Tun18, Tun34, Tun36) with durum cultivars ‘Ben,’ ‘Maier,’ ‘Lebsock,’ and ‘Mountrail’ for association studies. The Tun18 and Tun7 FHB resistances were found to be comparable to the best hexaploid wheat sources. A new significant QTL for FHB resistance was identified on the long arm of chromosome 5B (Qfhs.ndsu-5BL) with both association and classical QTL mapping analysis. Linkage disequilibrium (LD) blocks extending up to 40 cM were evident in these populations. The linear mixed model considering the structure (Q or P) and the kinship matrix (KT) estimated by restricted maximum likelihood (REML) was identified as the best for association studies in a mixture of wheat populations from a breeding program. The results of association mapping analysis also demonstrated a region on the short arm of chromosome 3B as potentially linked to FHB resistance. This region is in proximity of major FHB resistance gene fhb1 reported in hexaploid wheat. A possibility of having susceptibility or suppressor of resistance gene(s) on durum wheat chromosome 2A was further confirmed in this material, explaining the problem in developing resistant genotypes without counter selection against this region.

Ghavami, Farhad; Elias, Elias M.; Mamidi, Sujan; Ansari, Omid; Sargolzaei, Mehdi; Adhikari, Tika; Mergoum, Mohamed; Kianian, Shahryar F.

2011-01-01

48

Molecular cloning of three homoeologous cDNAs encoding orthologs of the maize KNOTTED1 homeobox protein from young spikes of hexaploid wheat  

Microsoft Academic Search

The plant knotted1 (kn1)-like homeobox genes are known to play important roles in the maintenance of shoot apical meristem (SAM), determination of cell fate and differentiation of vegetative tissues. To study structural diversity of the three homoeologous loci encoding a KN1-like homeobox protein in the hexaploid wheat genome, we isolated clones from a cDNA library of young spikes of Japanese

Shigeo Takumi; Takayuki Kosugi; Koji Murai; Naoki Mori; Chiharu Nakamura

2000-01-01

49

Expression analysis and physical mapping of low-molecular-weight glutenin loci in hexaploid wheat (Triticum aestivum L.).  

PubMed

Gliadins and glutenins are storage proteins important in determining the bread-, noodle-, and pasta-making quality of wheat. Glutenins consist of HMW and LMW subunits. The Glu-A3, Glu-B3, and Glu-D3 loci on the short arms of chromosomes 1A, 1B, and 1D, respectively, are the major loci for LMW glutenins. To construct physical maps of the Glu-3 loci, a set of 24 high-density filters representing a 3.1x genome coverage hexaploid wheat BAC library was screened by hybridization using a probe made of 3 LMW glutenin sequences. After 2 rounds of hybridization, a subset of 536 BAC clones were selected and fingerprinted. Three developing seed cDNA libraries were also constructed. A total of 5000-6000 ESTs were generated from each library, assembled into contigs and searched by homology for LMW glutenin sequences. In total, 90 full-length LMW glutenin sequences were found to cluster into 8 distinct groups representing at least 21 different LMW glutenin subunits. A set of 24 pairs of PCR primers was designed from these groups and used as markers on the BAC clones. The combined fingerprinting and marker data were used to build the physical maps using FPC software. A total of 91 contigs comprising 254 clones were obtained and 282 clones remained singletons. PMID:16121237

Ozdemir, Nehir; Cloutier, Sylvie

2005-06-01

50

Diversity of agronomic and morphological traits in a mutant population of bread wheat studied in the Healthgrain program  

Microsoft Academic Search

A mutant population of spring wheat cv. Cadenza was produced at Rothamsted Research in 2004–5, both for TILLING and to generate\\u000a variation in the contents of phytochemical components studied in the Healthgrain program. The agronomic and morphological\\u000a properties of this mutant hexaploid wheat population (generations M3–M6) were studied in a 3-year field experiment. Most of the traits were scored according

M. Rakszegi; B. N. Kisgyörgy; K. Tearall; P. R. Shewry; L. Láng; A. Phillips; Z. Bed?

2010-01-01

51

Microarray expression analysis of meiosis and microsporogenesis in hexaploid bread wheat  

Microsoft Academic Search

BACKGROUND: Our understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of

Wayne Crismani; Ute Baumann; Tim Sutton; Neil Shirley; Tracie Webster; German Spangenberg; Peter Langridge; Jason A Able

2006-01-01

52

Overexpression of Three TaEXPA1 Homoeologous Genes with Distinct Expression Divergence in Hexaploid Wheat Exhibit Functional Retention in Arabidopsis  

PubMed Central

Common wheat is a hexaploid species with most of the genes present as triplicate homoeologs. Expression divergences of homoeologs are frequently observed in wheat as well as in other polyploid plants. However, little is known about functional variances among homologous genes arising from polyploidy. Expansins play diverse roles in plant developmental processes related to the action of cell wall loosening. Expression of the three TaEXPA1 homoeologs varied dynamically at different stages and organs, and epigenetic modifications contribute to the expression divergence of three TaEXPA1 homoeologs during wheat development. Nevertheless, their functions remain to be clarified. We found that over expression of TaEXPA1-A, -B and -D produced similar morphological changes in transgenic Arabidopsis plants, including increased germination and growth rate during seedling and adult stages, indicating that the proteins encoded by these three wheat TaEXPA1 homoeologs have similar (or conserved) functions in Arabidopsis. Collectively, our present study provided an example of a set of homoeologous genes expression divergence in different developmental stages and organs in hexaploid wheat but functional retention in transgenic Arabidopsis plants.

Xing, Jiewen; Chen, Yanhong; Han, Zongfu; Yao, Yingyin; Peng, Huiru; Ni, Zhongfu; Sun, Qixin

2013-01-01

53

Variation for tolerance to high concentration of ferrous iron (Fe 2+ ) in Australian hexaploid wheat  

Microsoft Academic Search

High concentration of reduced iron (Fe2+) in waterlogged acid soils is a constraint for growing wheat in high rainfall (waterlogged-prone) areas of Western Australia.\\u000a Growing crop genotypes tolerant to high Fe2+ concentrations may be desirable in such situations, but there is no knowledge about the extent of variability in Fe2+ tolerance in the wheat germplasm. A bioassay for tolerance to

Hossein Khabaz-Saberi; Zed Rengel; Robin Wilson; Timothy L. Setter

2010-01-01

54

Microarray expression analysis of meiosis and microsporogenesis in hexaploid bread wheat  

PubMed Central

Background Our understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of wild wheat relatives in breeding programs has prompted many years of cytogenetic and genetic research to develop an understanding of the control of chromosome pairing and recombination. The rapid advance of biochemical and molecular information on meiosis in model organisms such as yeast provides new opportunities to investigate the molecular basis of chromosome pairing control in wheat. However, building the link between the model and wheat requires points of data contact. Results We report here a large-scale transcriptomics study using the Affymetrix wheat GeneChip® aimed at providing this link between wheat and model systems and at identifying early meiotic genes. Analysis of the microarray data identified 1,350 transcripts temporally-regulated during the early stages of meiosis. Expression profiles with annotated transcript functions including chromatin condensation, synaptonemal complex formation, recombination and fertility were identified. From the 1,350 transcripts, 30 displayed at least an eight-fold expression change between and including pre-meiosis and telophase II, with more than 50% of these having no similarities to known sequences in NCBI and TIGR databases. Conclusion This resource is now available to support research into the molecular basis of pairing and recombination control in the complex polyploid, wheat.

Crismani, Wayne; Baumann, Ute; Sutton, Tim; Shirley, Neil; Webster, Tracie; Spangenberg, German; Langridge, Peter; Able, Jason A

2006-01-01

55

Genetic maps of stem rust resistance gene Sr35 in diploid and hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Puccinia graminis f. sp. tritici is the causal agent of stem rust of wheat. A new race designated TTKSK (also known as Ug99) has recently spread through East Africa, Yemen and on to Iran. TTKSK and its variants (TTKST and TTTSK) are virulent to most of the stem rust resistance genes currently deploy...

56

Conditional QTL mapping for waterlogging tolerance in two RILs populations of wheat.  

PubMed

Waterlogging is a widespread limiting factor for wheat production throughout the world, specially irrigated and high rainfall environments. Only few studies reported QTLs for waterlogging tolerance. To identify quantitative trait loci (QTLs) for waterlogging tolerance, root dry weight index (RDWI), shoot dry weight index (SDWI), total dry weight index (TDWI) were measured at seedling stage in two unrelated recombinant inbred lines (RILs) populations. These populations were International Triticeae Mapping Initiative (ITMI) population 'W7984 / Opata85', and 'SHW-L1 × Chuanmai 32' (SC) population. Conditional QTL mapping and unconditional QTL mapping were studied to dissect the genetic relationship between TDWI and its components of SDWI and TDWI. Total of 36 QTLs for waterlogging tolerance in ITMI population and 10 QTLs in SC population were identified in present study. Of them, 17 alleles from synthetic hexaploid wheat 'W7984' and 3 alleles from synthetic hexaploid wheat 'SHW-L1' contribute positively to waterlogging tolerance. Combinations of conditional and unconditional mapping methods indicate that SDWI showed tighter genetic correlation with TDWI than RDWI. This QTL identification study and dissection provide theoretical basis and application foundation to Marker-assisted selection (MAS) of waterlogging tolerance improvement in wheat. PMID:23750334

Yu, Ma; Chen, Guo-Yue

2013-05-27

57

Transcriptomic Analysis of Starch Biosynthesis in the Developing Grain of Hexaploid Wheat  

PubMed Central

The expression of genes involved in starch synthesis in wheat was analyzed together with the accumulation profiles of soluble sugars, starch, protein, and starch granule distribution in developing caryopses obtained from the same biological materials used for profiling of gene expression using DNA microarrays. Multiple expression patterns were detected for the different starch biosynthetic gene isoforms, suggesting their relative importance through caryopsis development. Members of the ADP-glucose pyrophosphorylase, starch synthase, starch branching enzyme, and sucrose synthase gene families showed different expression profiles; expression of some members of these gene families coincided with a period of high accumulation of starch while others did not. A biphasic pattern was observed in the rates of starch and protein accumulation which paralleled changes in global gene expression. Metabolic and regulatory genes that show a pattern of expression similar to starch accumulation and granule size distribution were identified, suggesting their coinvolvement in these biological processes.

Stamova, Boryana S.; Laudencia-Chingcuanco, Debbie; Beckles, Diane M.

2009-01-01

58

Molecular characterization and chromosomal localization of cytochrome P450 genes involved in the biosynthesis of cyclic hydroxamic acids in hexaploid wheat  

Microsoft Academic Search

The cyclic hydroxamic acids, 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), are defensive secondary metabolites found in gramineous plants including wheat, maize and rye. cDNAs for five cytochromes P450 (P450s) involved in DIBOA biosynthesis (CYP71C6, CYP71C7v2, CYP71C8v2, CYP71C9v1 and CYP71C9v2) were isolated from seedlings of hexaploid wheat [(Triticum aestivum L. cv. Chinese Spring (2n=6x=42, genomes AABBDD)] by RT-PCR and screening of a

T. Nomura; A. Ishihara; H. Imaishi; T. Endo; H. Ohkawa; H. Iwamura

2002-01-01

59

Hemi-nested touchdown PCR combined with primer-template mismatch PCR for rapid isolation and sequencing of low molecular weight glutenin subunit gene family from a hexaploid wheat BAC library  

Microsoft Academic Search

BACKGROUND: Hexaploid wheat (Triticum aestivum L.) possesses a large genome that contains 1.6 × 1010 bp of DNA. Isolation of a large number of gene sequences from complex gene families with a high level of gene sequence identity from genomic DNA is therefore difficult and time-consuming. Bacterial artificial chromosome (BAC) libraries can be useful for such work. Here we report

Xiu-Qiang Huang; Sylvie Cloutier

2007-01-01

60

Molecular Characterization of Rht-1 Dwarfing Genes in Hexaploid Wheat12[C][W][OA  

PubMed Central

The introduction of the Reduced height (Rht)-B1b and Rht-D1b semidwarfing genes led to impressive increases in wheat (Triticum aestivum) yields during the Green Revolution. The reduction in stem elongation in varieties containing these alleles is caused by a limited response to the phytohormone gibberellin (GA), resulting in improved resistance to stem lodging and yield benefits through an increase in grain number. Rht-B1 and Rht-D1 encode DELLA proteins, which act to repress GA-responsive growth, and their mutant alleles Rht-B1b and Rht-D1b are thought to confer dwarfism by producing more active forms of these growth repressors. While no semidwarfing alleles of Rht-A1 have been identified, we show that this gene is expressed at comparable levels to the other homeologs and represents a potential target for producing novel dwarfing alleles. In this study, we have characterized additional dwarfing mutations in Rht-B1 and Rht-D1. We show that the severe dwarfism conferred by Rht-B1c is caused by an intragenic insertion, which results in an in-frame 90-bp insertion in the transcript and a predicted 30-amino acid insertion within the highly conserved amino-terminal DELLA domain. In contrast, the extreme dwarfism of Rht-D1c is due to overexpression of the semidwarfing Rht-D1b allele, caused by an increase in gene copy number. We show also that the semidwarfing alleles Rht-B1d and Rht-B1e introduce premature stop codons within the amino-terminal coding region. Yeast two-hybrid assays indicate that these newly characterized mutations in Rht-B1 and Rht-D1 confer “GA-insensitive” dwarfism by producing DELLA proteins that do not bind the GA receptor GA INSENSITIVE DWARF1, potentially compromising their targeted degradation.

Pearce, Stephen; Saville, Robert; Vaughan, Simon P.; Chandler, Peter M.; Wilhelm, Edward P.; Sparks, Caroline A.; Al-Kaff, Nadia; Korolev, Andrey; Boulton, Margaret I.; Phillips, Andrew L.; Hedden, Peter; Nicholson, Paul; Thomas, Stephen G.

2011-01-01

61

Linkage mapping and transcriptional profiling of resistance to soil- borne viruses in hexaploid wheat (Triticum vulgare ssp. aestivum)  

Microsoft Academic Search

Summary Soil-borne viruses, i.e. Soil-borne wheat mosaic virus (SBWMV), Soil-borne cereal mosaic virus (SBCMV) and Wheat spindle streak mosaic virus (WSSMV) are a serious threat to winter wheat cultivation in Europe. In previous screening programmes cultivars resistant to SBCMV and WSSMV were identified and preliminary results on the genetics of resistance to SBCMV based on the analyses of doubled haploid

D. PEROVIC; J. WEYEN; J. SCHONDELMAIER; J. FÖRSTER; P. DEVAUX; D. HARIRI; D. FEUERHELM; N. STEIN; A. GRANER; F. ORDON

62

MOLECULAR MAPPING OF HYBRID NECROSIS GENES NE1 AND NE2 IN HEXAPLOID WHEAT USING MICROSATELLITE MARKERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hybrid necrosis is the gradual pre-mature death of leaves or plants in certain F1 hybrids of wheat, and it is caused by the interaction of two dominant complementary genes Ne1 and Ne2 located on chromosome arms 5BL and 2BS, respectively. To date, molecular markers linked to these genes have not been...

63

Integration of mate pair sequences to improve shotgun assemblies of flow-sorted chromosome arms of hexaploid wheat  

PubMed Central

Background The assembly of the bread wheat genome sequence is challenging due to allohexaploidy and extreme repeat content (>80%). Isolation of single chromosome arms by flow sorting can be used to overcome the polyploidy problem, but the repeat content cause extreme assembly fragmentation even at a single chromosome level. Long jump paired sequencing data (mate pairs) can help reduce assembly fragmentation by joining multiple contigs into single scaffolds. The aim of this work was to assess how mate pair data generated from multiple displacement amplified DNA of flow-sorted chromosomes affect assembly fragmentation of shotgun assemblies of the wheat chromosomes. Results Three mate pair (MP) libraries (2 Kb, 3 Kb, and 5 Kb) were sequenced to a total coverage of 89x and 64x for the short and long arm of chromosome 7B, respectively. Scaffolding using SSPACE improved the 7B assembly contiguity and decreased gene space fragmentation, but the degree of improvement was greatly affected by scaffolding stringency applied. At the lowest stringency the assembly N50 increased by ~7 fold, while at the highest stringency N50 was only increased by ~1.5 fold. Furthermore, a strong positive correlation between estimated scaffold reliability and scaffold assembly stringency was observed. A 7BS scaffold assembly with reduced MP coverage proved that assembly contiguity was affected only to a small degree down to ~50% of the original coverage. Conclusion The effect of MP data integration into pair end shotgun assemblies of wheat chromosome was moderate; possibly due to poor contig assembly contiguity, the extreme repeat content of wheat, and the use of amplified chromosomal DNA for MP library construction.

2013-01-01

64

Photosynthetic Parameters at the Vegetative Stage and during Grain Development of Two Hexaploid Wheat Cultivars Differing in Salt Tolerance  

Microsoft Academic Search

Response of two spring wheat (Triticum aestivum L.) cultivars, salt tolerant SARC-I and salt sensitive Potohar, to different concentrations of NaCl was examined under glasshouse conditions. Eighteen-day-old plants of both the lines grown in sand culture were irrigated with 0 (control), 80, 160 or 240 mM NaCl in full strength Hoagland's nutrient solution. Shoot fresh and dry masses, and leaf

M. Ashraf; N. Parveen

2002-01-01

65

Vrn-D4 is a vernalization gene located on the centromeric region of chromosome 5D in hexaploid wheat  

Microsoft Academic Search

Natural variation in wheat requirement of long exposures to cold temperatures to accelerate flowering (vernalization) is mainly\\u000a controlled by the Vrn-1, Vrn-2, Vrn-3, and Vrn-4 loci. The first three loci have been well characterized, but limited information is available for Vrn-4. So far, natural variation for Vrn-4 has been detected only in the D genome (Vrn-D4), and genetic stocks for

Tetsuya Yoshida; Hidetaka Nishida; Jie Zhu; Rebecca Nitcher; Assaf Distelfeld; Yukari Akashi; Kenji Kato; Jorge Dubcovsky

2010-01-01

66

RAPDs as molecular markers for the detection of Aegilops markgrafii chromatin in addition and euploid introgression lines of hexaploid wheat  

Microsoft Academic Search

Aegilops markgrafii contains resistance genes to powdery mildew, leaf rust and stripe rust, and also has high crude protein and lysine contents,\\u000a which can be useful for wheat improvement. These important traits are localized on different chromosomes. Disomic Triticum aestivum-Ae. markgrafii addition lines and euploid introgression lines showing leaf-rust and powdery mildew resistance were screened with RAPDs to\\u000a detect chromosome-specific

A. Peil; V. Schubert; E. Schumann; W. E. Weber

1997-01-01

67

A high-density genetic map of hexaploid wheat (Triticum aestivum L.) from the cross Chinese Spring x SQ1 and its use to compare QTLs for grain yield across a range of environments.  

PubMed

A population of 96 doubled haploid lines (DHLs) was prepared from F1 plants of the hexaploid wheat cross Chinese Spring x SQ1 (a high abscisic acid-expressing breeding line) and was mapped with 567 RFLP, AFLP, SSR, morphological and biochemical markers covering all 21 chromosomes, with a total map length of 3,522 cM. Although the map lengths for each genome were very similar, the D genome had only half the markers of the other two genomes. The map was used to identify quantitative trait loci (QTLs) for yield and yield components from a combination of 24 site x treatment x year combinations, including nutrient stress, drought stress and salt stress treatments. Although yield QTLs were widely distributed around the genome, 17 clusters of yield QTLs from five or more trials were identified: two on group 1 chromosomes, one each on group 2 and group 3, five on group 4, four on group 5, one on group 6 and three on group 7. The strongest yield QTL effects were on chromosomes 7AL and 7BL, due mainly to variation in grain numbers per ear. Three of the yield QTL clusters were largely site-specific, while four clusters were largely associated with one or other of the stress treatments. Three of the yield QTL clusters were coincident with the dwarfing gene Rht-B1 on 4BS and with the vernalisation genes Vrn-A1 on 5AL and Vrn-D1 on 5DL. Yields of each DHL were calculated for trial mean yields of 6 g plant(-1) and 2 g plant(-1) (equivalent to about 8 t ha(-1) and 2.5 t ha(-1), respectively), representing optimum and moderately stressed conditions. Analyses of these yield estimates using interval mapping confirmed the group-7 effects on yield and, at 2 g plant(-1), identified two additional major yield QTLs on chromosomes 1D and 5A. Many of the yield QTL clusters corresponded with QTLs already reported in wheat and, on the basis of comparative genetics, also in rice. The implications of these results for improving wheat yield stability are discussed. PMID:15719212

Quarrie, S A; Steed, A; Calestani, C; Semikhodskii, A; Lebreton, C; Chinoy, C; Steele, N; Pljevljakusi?, D; Waterman, E; Weyen, J; Schondelmaier, J; Habash, D Z; Farmer, P; Saker, L; Clarkson, D T; Abugalieva, A; Yessimbekova, M; Turuspekov, Y; Abugalieva, S; Tuberosa, R; Sanguineti, M-C; Hollington, P A; Aragués, R; Royo, A; Dodig, D

2005-02-18

68

Mapping and validation of Yr48 and other QTL conferring partial resistance to broadly virulent post-2000 North American races of stripe rust in hexaploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

A mapping population of 188 recombinant inbred lines developed from a cross between UC1110, an adapted California spring wheat, and PI610750, a synthetic derivative from CIMMYT's wide-cross program, was evaluated for its response to current California races of stripe rust (Puccinia striiformis f.sp....

69

Development and Characterization of a New TILLING Population of Common Bread Wheat (Triticum aestivum L.)  

PubMed Central

Mutagenesis is an important tool in crop improvement. However, the hexaploid genome of wheat (Triticum aestivum L.) presents problems in identifying desirable genetic changes based on phenotypic screening due to gene redundancy. TILLING (Targeting Induced Local Lesions IN Genomes), a powerful reverse genetic strategy that allows the detection of induced point mutations in individuals of the mutagenized populations, can address the major challenge of linking sequence information to the biological function of genes and can also identify novel variation for crop breeding. Wheat is especially well-suited for TILLING due to the high mutation densities tolerated by polyploids. However, only a few wheat TILLING populations are currently available in the world, which is far from satisfying the requirement of researchers and breeders in different growing environments. In addition, current TILLING screening protocols require costly fluorescence detection systems, limiting their use, especially in developing countries. We developed a new TILLING resource comprising 2610 M2 mutants in a common wheat cultivar ‘Jinmai 47’. Numerous phenotypes with altered morphological and agronomic traits were observed from the M2 and M3 lines in the field. To simplify the procedure and decrease costs, we use unlabeled primers and either non-denaturing polyacrylamide gels or agarose gels for mutation detection. The value of this new resource was tested using PCR with RAPD and Intron-spliced junction (ISJ) primers, and also TILLING in three selected candidate genes, in 300 and 512 mutant lines, revealing high mutation densities of 1/34 kb by RAPD/ISJ analysis and 1/47 kb by TILLING. In total, 31 novel alleles were identified in the 3 targeted genes and confirmed by sequencing. The results indicate that this mutant population represents a useful resource for the wheat research community. We hope that the use of this reverse genetics resource will provide novel allelic diversity for wheat improvement and functional genomics.

Chen, Liang; Huang, Linzhou; Min, Donghong; Phillips, Andy; Wang, Shiqiang; Madgwick, Pippa J.; Parry, Martin A. J.; Hu, Yin-Gang

2012-01-01

70

Molecular characterization of the celiac disease epitope domains in ?-gliadin genes in Aegilops tauschii and hexaploid wheats (Triticum aestivum L.).  

PubMed

Nineteen novel full-ORF ?-gliadin genes and 32 pseudogenes containing at least one stop codon were cloned and sequenced from three Aegilops tauschii accessions (T15, T43 and T26) and two bread wheat cultivars (Gaocheng 8901 and Zhongyou 9507). Analysis of three typical ?-gliadin genes (Gli-At4, Gli-G1 and Gli-Z4) revealed some InDels and a considerable number of SNPs among them. Most of the pseudogenes were resulted from C to T change, leading to the generation of TAG or TAA in-frame stop codon. The putative proteins of both Gli-At3 and Gli-Z7 genes contained an extra cysteine residue in the unique domain II. Analysis of toxic epitodes among 19 deduced ?-gliadins demonstrated that 14 of these contained 1-5 T cell stimulatory toxic epitopes while the other 5 did not contain any toxic epitopes. The glutamine residues in two specific ployglutamine domains ranged from 7 to 27, indicating a high variation in length. According to the numbers of 4 T cell stimulatory toxic epitopes and glutamine residues in the two ployglutamine domains among the 19 ?-gliadin genes, 2 were assigned to chromosome 6A, 5 to chromosome 6B and 12 to chromosome 6D. These results were consistent with those from wheat cv. Chinese Spring nulli-tetrasomic and phylogenetic analysis. Secondary structure prediction showed that all ?-gliadins had high content of ?-strands and most of the ?-helixes and ?-strands were present in two unique domains. Phylogenetic analysis demonstrated that ?-gliadin genes had a high homology with ?-gliadin, B-hordein, and LMW-GS genes and they diverged at approximate 39 MYA. Finally, the five ?-gliadin genes were successfully expressed in E. coli, and their expression amount reached to the maximum after 4 h induced by IPTG, indicating that the ?-gliadin genes can express in a high level under the control of T(7) promoter. PMID:20556595

Xie, Zhenze; Wang, Congyan; Wang, Ke; Wang, Shunli; Li, Xiaohui; Zhang, Zhao; Ma, Wujun; Yan, Yueming

2010-06-17

71

Population- and genome-specific patterns of linkage disequilibrium and SNP variation in spring and winter wheat (Triticum aestivum L.)  

PubMed Central

Background Single nucleotide polymorphisms (SNPs) are ideally suited for the construction of high-resolution genetic maps, studying population evolutionary history and performing genome-wide association mapping experiments. Here, we used a genome-wide set of 1536 SNPs to study linkage disequilibrium (LD) and population structure in a panel of 478 spring and winter wheat cultivars (Triticum aestivum) from 17 populations across the United States and Mexico. Results Most of the wheat oligo pool assay (OPA) SNPs that were polymorphic within the complete set of 478 cultivars were also polymorphic in all subpopulations. Higher levels of genetic differentiation were observed among wheat lines within populations than among populations. A total of nine genetically distinct clusters were identified, suggesting that some of the pre-defined populations shared significant proportion of genetic ancestry. Estimates of population structure (FST) at individual loci showed a high level of heterogeneity across the genome. In addition, seven genomic regions with elevated FST were detected between the spring and winter wheat populations. Some of these regions overlapped with previously mapped flowering time QTL. Across all populations, the highest extent of significant LD was observed in the wheat D-genome, followed by lower LD in the A- and B-genomes. The differences in the extent of LD among populations and genomes were mostly driven by differences in long-range LD ( > 10 cM). Conclusions Genome- and population-specific patterns of genetic differentiation and LD were discovered in the populations of wheat cultivars from different geographic regions. Our study demonstrated that the estimates of population structure between spring and winter wheat lines can identify genomic regions harboring candidate genes involved in the regulation of growth habit. Variation in LD suggests that breeding and selection had a different impact on each wheat genome both within and among populations. The higher extent of LD in the wheat D-genome versus the A- and B-genomes likely reflects the episodes of recent introgression and population bottleneck accompanying the origin of hexaploid wheat. The assessment of LD and population structure in this assembled panel of diverse lines provides critical information for the development of genetic resources for genome-wide association mapping of agronomically important traits in wheat.

2010-01-01

72

Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease  

Microsoft Academic Search

Gluten proteins from wheat can induce celiac disease (CD) in genetically susceptible individuals. Specific gluten peptides\\u000a can be presented by antigen presenting cells to gluten-sensitive T-cell lymphocytes leading to CD. During the last decades,\\u000a a significant increase has been observed in the prevalence of CD. This may partly be attributed to an increase in awareness\\u000a and to improved diagnostic techniques,

Hetty C. van den Broeck; Hein C. de Jong; Elma M. J. Salentijn; Liesbeth Dekking; Dirk Bosch; Rob J. Hamer; Ludovicus J. W. J. Gilissen; Ingrid M. van der Meer; Marinus J. M. Smulders

2010-01-01

73

Fusarium head blight resistance in hexaploid wheat ( Triticum aestivum )- Lophopyrum genetic lines and tagging of the alien chromatin by PCR markers  

Microsoft Academic Search

The objective of this research was to identify Fusarium head blight (FHB) resistance in wheat ( Triticum aestivum)- Lophopyrum genetic lines that might complement FHB resistance in common wheat; and to identify DNA markers that can be used to tag the resistance gene in the alien chromatin (E or el 2 genome) for the development of improved wheat cultivars. FHB

Xiaorong Shen; Lingrang Kong; Herbert Ohm

2004-01-01

74

A highly conserved gene island of three genes on chromosome 3B of hexaploid wheat: diverse gene function and genomic structure maintained in a tightly linked block  

Microsoft Academic Search

BACKGROUND: The complexity of the wheat genome has resulted from waves of retrotransposable element insertions. Gene deletions and disruptions generated by the fast replacement of repetitive elements in wheat have resulted in disruption of colinearity at a micro (sub-megabase) level among the cereals. In view of genomic changes that are possible within a given time span, conservation of genes between

James M Breen; Thomas Wicker; Xiuying Kong; Juncheng Zhang; Wujun Ma; Etienne Paux; Catherine Feuillet; Rudi Appels; Matthew Bellgard

2010-01-01

75

Effects of wheat germ on a population of hyperlipidemic patients  

Microsoft Academic Search

Purpose – Reducing fat intake or inhibiting fat absorption is a useful solution for blood lipid reduction. It is shown that there are some proteins in wheat germ with pancreatic lipase inhibiting properties that have hypolipidemic effects. This paper aims to evaluate the possible beneficial effects of a daily intake of 30 g of raw wheat germ in a population

Hamid Reza Zakeri; Asal Ataie Jafari; Mohammad Rajabi; Saeed Hosseini

2009-01-01

76

Suppressed recombination rate in 6VS\\/6AL translocation region carrying the Pm21 locus introgressed from Haynaldia villosa into hexaploid wheat  

Microsoft Academic Search

Pm21 is an effective gene for powdery mildew resistance transferred from Haynaldia villosa into common wheat cultivars. No virulence against this gene has been detected so far. A set of 42 powdery mildew isolates\\u000a collected in Israel and tested in the current study also revealed no virulence against this gene. Pm21 was previously reported to be located on the short

Weilong XieRoi; Roi Ben-David; Bin Zeng; Amos Dinoor; Chaojie Xie; Qixin Sun; Marion S. Röder; Amalid Fahoum; Tzion Fahima

77

Transfer of powdery mildew resistance from Aegilops variabilis into bread wheat  

Microsoft Academic Search

Winter hexaploid wheat (Triticum aestivum L.) was crossed with Aegilops variabilis to transfer resistance to powdery mildew into wheat. Following two backcrosses to wheat and from 5 to 9 generations of selfing, several disomic addition and substitution lines of hexaploid wheat resistant to the mildew pathogen were isolated. A pair of short satellited chromosomes was always observed in the resistant

Penko Spetsov; Dominique Mingeot; Jean Marie Jacquemin; Krassiana Samardjieva; Elena Marinova

1997-01-01

78

An analysis of dormancy, ABA responsiveness, after-ripening and pre-harvest sprouting in hexaploid wheat (Triticum aestivum L.) caryopses  

PubMed Central

Embryo and caryopsis dormancy, abscisic acid (ABA) responsiveness, after-ripening (AR), and the disorder pre-harvest sprouting (PHS) were investigated in six genetically related wheat varieties previously characterized as resistant, intermediate, or susceptible to PHS. Timing of caryopsis AR differed between varieties; AR occurred before harvest ripeness in the most PHS-susceptible, whereas AR was slowest in the most PHS-resistant. Whole caryopses of all varieties showed little ABA-responsiveness during AR; PHS-susceptible varieties were responsive at the beginning of the AR period whereas PHS-resistant showed some responsiveness throughout. Isolated embryos showed relatively little dormancy during grain-filling and most varieties exhibited a window of decreased ABA-responsiveness around the period of maximum dry matter accumulation (physiological maturity). Susceptibility to PHS was assessed by overhead misting of either isolated ears or whole plants during AR; varieties were clearly distinguished using both methods. These analyses allowed an investigation of the interactions between the different components of seed development, compartments, and environment for the six varieties. There was no direct relationship between speed of caryopsis AR and embryo dormancy or ABA-responsiveness during seed maturation. However, the velocity of AR of a variety was closely associated with the degree of susceptibility to PHS during AR suggesting that these characters are developmentally linked. Investigation of genetic components of AR may therefore aid breeding approaches to reduce susceptibility to PHS.

Gerjets, Tanja; Scholefield, Duncan; Foulkes, M. John; Lenton, John R.; Holdsworth, Michael J.

2010-01-01

79

Genetic diversity of wheat storage proteins and bread wheat quality  

Microsoft Academic Search

To understand the genetic and biochemical basis of the bread makingquality of wheat varieties, a large experiment was carried out with a set of162 hexaploid bread wheat varieties registered in the French or EuropeanWheat Catalogue. This material was used to analyse their allelic compositionat the twelve main storage protein loci. A large genetic and biochemicaldiversity of the gluten proteins was

G. Branlard; M. Dardevet; R. Saccomano; F. Lagoutte; J. Gourdon

2001-01-01

80

Cytotype distribution at a diploid-hexaploid contact zone in Aster amellus (Asteraceae)  

PubMed Central

Background and Aims The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. Methods Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4?,6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. Key Results The diploid–hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. Conclusions The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus.

Castro, S.; Loureiro, J.; Prochazka, T.; Munzbergova, Z.

2012-01-01

81

Evolutionary history of the mitochondrial genome in Mycosphaerella populations infecting bread wheat, durum wheat and wild grasses.  

PubMed

Plant pathogens emerge in agro-ecosystems following different evolutionary mechanisms over different time scales. Previous analyses based on sequence variation at six nuclear loci indicated that Mycosphaerella graminicola diverged from an ancestral population adapted to wild grasses during the process of wheat domestication approximately 10,500 years ago. We tested this hypothesis by conducting coalescence analyses based on four mitochondrial loci using 143 isolates that included four closely related pathogen species originating from four continents. Pathogen isolates from bread and durum wheat were included to evaluate the emergence of specificity towards these hosts in M. graminicola. Although mitochondrial and nuclear genomes differed greatly in degree of genetic variability, their coalescence was remarkably congruent, supporting the proposed origin of M. graminicola through host tracking. The coalescence analysis was unable to trace M. graminicola host specificity through recent evolutionary time, indicating that the specificity towards durum or bread wheat emerged following the domestication of the pathogen on wheat. PMID:21145978

Torriani, Stefano F F; Brunner, Patrick C; McDonald, Bruce A

2010-12-09

82

The structure and genetic control of a new class of disulphide-linked proteins in wheat endosperm  

Microsoft Academic Search

Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of unreduced total protein extracts from the endosperm of hexaploid wheat revealed three high molecular weight protein bands (triplet bands) in a zone of heavy background streaking. Electrophoretic examination of 135 hexaploid cultivars showed at least five different patterns of these triplet bands. Nine durum wheat cultivars showed a single band only. Analysis of

N. K. Singh; K. W. Shepherd

1985-01-01

83

Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species.  

PubMed

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. PMID:23047200

Yu, Q; Ahmad-Hamdani, M S; Han, H; Christoffers, M J; Powles, S B

2012-10-10

84

BIOTYPIC VARIATION AMOUNG NORTH AMERICAN RUSSIAN WHEAT APHID (Homoptera: Aphididae) POPULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Technical Abstract for: J.D. Burd, D.R. Porter, G.J. Puterka, S.D. Haley, and F.B. Peairs. Biotypic variation among North American Russian wheat aphid populations. The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has been a major economic pest of small grains in the western United State...

85

Molecular mapping of Fusarium head blight resistance in the winter wheat population Dream\\/Lynx  

Microsoft Academic Search

Fusarium head blight (FHB), mainly caused by Fusarium graminearum and F. culmorum, can significantly reduce the grain quality of wheat (Triticum aestivum L.) due to mycotoxin contamination. The objective of this study was to identify quantitative trait loci (QTLs) for FHB resistance in a winter wheat population developed by crossing the resistant German cultivar Dream with the susceptible British cultivar

M. Schmolke; G. Zimmermann; H. Buerstmayr; G. Schweizer; T. Miedaner; V. Korzun; E. Ebmeyer; L. Hartl

2005-01-01

86

WHEAT RHIZOSPHERE-MICROBE INTERACTIONS--FACTORS AND GENES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Host genes are likely to have important roles in interactions with both root pathogens and beneficial soil microbes that suppress such pathogens. Triticum aestivum (hexaploid wheat) has limited genetic resistance to the necrotrophic fungal pathogens Pythium, Rhizoctonia, Gaeumannomyces, and Fusarium...

87

A microsatellite map of wheat.  

PubMed Central

Hexaploid bread wheat (Triticum aestivum L. em. Thell) is one of the world's most important crop plants and displays a very low level of intraspecific polymorphism. We report the development of highly polymorphic microsatellite markers using procedures optimized for the large wheat genome. The isolation of microsatellite-containing clones from hypomethylated regions of the wheat genome increased the proportion of useful markers almost twofold. The majority (80%) of primer sets developed are genome-specific and detect only a single locus in one of the three genomes of bread wheat (A, B, or D). Only 20% of the markers detect more than one locus. A total of 279 loci amplified by 230 primer sets were placed onto a genetic framework map composed of RFLPs previously mapped in the reference population of the International Triticeae Mapping Initiative (ITMI) Opata 85 x W7984. Sixty-five microsatellites were mapped at a LOD >2.5, and 214 microsatellites were assigned to the most likely intervals. Ninety-three loci were mapped to the A genome, 115 to the B genome, and 71 to the D genome. The markers are randomly distributed along the linkage map, with clustering in several centromeric regions.

Roder, M S; Korzun, V; Wendehake, K; Plaschke, J; Tixier, M H; Leroy, P; Ganal, M W

1998-01-01

88

Large deletions in the CBF gene cluster at the Fr-B2 locus are associated with reduced frost tolerance in wheat.  

PubMed

Wheat plants which are exposed to periods of low temperatures (cold acclimation) exhibit increased survival rates when they are subsequently exposed to freezing temperatures. This process is associated with large-scale changes in the transcriptome which are modulated by a set of tandemly duplicated C-repeat Binding Factor (CBF) transcription factors located at the Frost Resistance-2 (Fr-2) locus. While Arabidopsis has three tandemly duplicated CBF genes, the CBF family in wheat has undergone an expansion and at least 15 CBF genes have been identified, 11 of which are present at the Fr-2 loci on homeologous group 5 chromosomes. We report here the discovery of three large deletions which eliminate 6, 9, and all 11 CBF genes from the Fr-B2 locus in tetraploid and hexaploid wheat. In wild emmer wheat, the Fr-B2 deletions were found only among the accessions from the southern sub-populations. Among cultivated wheats, the Fr-B2 deletions were more common among varieties with a spring growth habit than among those with a winter growth habit. Replicated freezing tolerance experiments showed that both the deletion of nine CBF genes in tetraploid wheat and the complete Fr-B2 deletion in hexaploid wheat were associated with significant reductions in survival after exposure to freezing temperatures. Our results suggest that selection for the wild-type Fr-B2 allele may be beneficial for breeders selecting for varieties with improved frost tolerance. PMID:23884601

Pearce, Stephen; Zhu, Jie; Boldizsár, Akos; Vágújfalvi, Attila; Burke, Adrienne; Garland-Campbell, Kimberley; Galiba, Gábor; Dubcovsky, Jorge

2013-07-25

89

Irrigation Differentially Impacts Populations of Indigenous Antibiotic-Producing Pseudomonas spp. in the Rhizosphere of Wheat  

PubMed Central

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz+) and 2,4-diacetylphloroglucinol (Phl+) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz+ and Phl+ Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz+ bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g?1 of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl+ and Phz+ Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl+ bacteria whereas only 8 to 50% of plants harbored Phz+ bacteria. In addition, Phz+ Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat.

Mavrodi, Olga V.; Mavrodi, Dmitri V.; Parejko, James A.; Thomashow, Linda S.

2012-01-01

90

Irrigation differentially impacts populations of indigenous antibiotic-producing pseudomonas spp. in the rhizosphere of wheat.  

PubMed

This work determined the impact of irrigation on the seasonal dynamics of populations of Pseudomonas spp. producing the antibiotics phenazine-1-carboxylic acid (Phz(+)) and 2,4-diacetylphloroglucinol (Phl(+)) in the rhizosphere of wheat grown in the low-precipitation zone (150 to 300 mm annually) of the Columbia Plateau of the Inland Pacific Northwest. Population sizes and plant colonization frequencies of Phz(+) and Phl(+) Pseudomonas spp. were determined in winter and spring wheat collected during the growing seasons from 2008 to 2009 from selected commercial dryland and irrigated fields in central Washington State. Only Phz(+) bacteria were detected on dryland winter wheat, with populations ranging from 4.8 to 6.3 log CFU g(-1) of root and rhizosphere colonization frequencies of 67 to 100%. The ranges of population densities of Phl(+) and Phz(+) Pseudomonas spp. recovered from wheat grown under irrigation were similar, but 58 to 100% of root systems were colonized by Phl(+) bacteria whereas only 8 to 50% of plants harbored Phz(+) bacteria. In addition, Phz(+) Pseudomonas spp. were abundant in the rhizosphere of native plant species growing in nonirrigated areas adjacent to the sampled dryland wheat fields. This is the first report that documents the impact of irrigation on indigenous populations of two closely related groups of antibiotic-producing pseudomonads that coinhabit the rhizosphere of an economically important cereal crop. These results demonstrate how crop management practices can influence indigenous populations of antibiotic-producing pseudomonads with the capacity to suppress soilborne diseases of wheat. PMID:22389379

Mavrodi, Olga V; Mavrodi, Dmitri V; Parejko, James A; Thomashow, Linda S; Weller, David M

2012-03-02

91

End Use Quality of Waxy Wheat Flour in Various Grain-Based Foods  

Microsoft Academic Search

Cereal Chem. 81(5):666-672 The practical applications of flour from waxy (amylose-free) hexaploid wheat (Triticum aestivum L.) were assessed. The applications evaluated were bread, cakes, white salted noodles, and pasta for gyoza. An excessive addition of waxy hexaploid wheat flour to total wheat flour (>20%) resulted in poorer functional properties (sticky, lumpy, or less crispy textures) in almost every end use

K. Hayakawa; K. Tanaka; T. Nakamura; S. Endo; T. Hoshino

2004-01-01

92

Recent insertion of a 52-kb mitochondrial DNA segment in the wheat lineage  

Microsoft Academic Search

The assembly of a 1.3-Mb size region of the wheat genome has provided the opportunity to study a recent nuclear mitochondrial\\u000a DNA insertion (NUMT). In the present study, we have studied two bacterial artificial chromosomes (BACs) and characterized\\u000a a 52-kb NUMT segment from the tetraploid and hexaploid wheat BAC libraries. The conserved orthologous NUMT regions from tetraploid\\u000a and hexaploid wheat

Juncheng Zhang; Jizeng Jia; James Breen; Xiuying Kong

93

Chapter 6: Floral Transformation of Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid wheat is one of the world’s most important staple crops but genetic transformation is still challenging. We are developing a floral transformation protocol for wheat that does not require tissue culture. Several T-DNA transformants have been produced in the high quality, hard red germpla...

94

Structural characterization, expression analysis and evolution of the red\\/far-red sensing photoreceptor gene, phytochrome C ( PHYC ), localized on the ‘B’ genome of hexaploid wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Phytochromes are a family of red\\/far-red light perceiving photoreceptors.The monocot phytochrome family is represented by three members, PHYA, PHYB and PHYC. We have isolated and characterized the first PHY gene member (TaPHYC) from common wheat, Triticum aestivum var. CPAN1676. It codes for a species of the photoreceptor, phyC, which is known to be light-stable in all plants analyzed so far.

R. Kulshreshtha; N. Kumar; H. S. Balyan; P. K. Gupta; P. Khurana; A. K. Tyagi; J. P. Khurana

2005-01-01

95

Genetic analysis of salt tolerance in a recombinant inbred population of wheat ( Triticum aestivum L.)  

Microsoft Academic Search

A population of 114 recombinant inbred lines (RILs), derived from the cross Opata85 × W7984, was used to genetically analyze\\u000a the response of wheat to salt stress. This analysis resulted in the identification of 47 QTL mapping to all wheat chromosomes\\u000a except 1B, 1D, 4B, 5D and 7D. Of these QTL, 10 were effective during the germination stage, and 37 at the

Liqing Ma; Erfeng Zhou; Naxing Huo; Ronghua Zhou; Guoying Wang; Jizeng Jia

2007-01-01

96

ESTIMATING POPULATIONS OF GRAIN BEETLES USING PROBE TRAPS IN WHEAT-FILLED CONCRETE SILOS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Probe traps are sensitive tools for detecting populations of beetles in stored grain, but their utility for estimating insect density in concrete silos has not been established. Populations of grain beetles infesting wheat in concrete silos at two commercial storage facilities in north central Okla...

97

EFFECT OF HERBICIDES AND WHEAT POPULATION ON CONTROL OF WEEDS IN WHEAT  

Microsoft Academic Search

Field studies were undertaken at Agricultural Research Farm, NWFP Agriculture University Peshawar during 'Rabi' 2003-04 to investigate the effect of planting density and post- emergence herbicides on wheat. The experiment was laid out in Randomized Complete Block (RCB) design with split-plot arrangements. Four seeding rates viz., 100,120,140 and 160 kg ha-1 were assigned to main plots, whereas herbicides to the

Shahida Bibi; Khan Bahadar Marwat; Gul Hassan; Noor Maula Khan

98

REGISTRATION OF THREE PARTIAL WAXY WINTER WHEATS  

Technology Transfer Automated Retrieval System (TEKTRAN)

This paper describes the release of three partial (reduced amylose) waxy wheat germplasm lines: PI 617069 (96MD7413-58), PI 617070 (96MD7413-36) and PI 617071 (96MD7110-71). These partial waxy wheats carry non-functional (null) alleles (Wx-A1b, and Wx-B1b) at two of the three hexaploid wheat Wx loc...

99

Effect of different agricultural practices on spiders and their prey populations in small wheat fields  

Microsoft Academic Search

The influence of different agricultural practices (viz., edge crop, zero tillage sowing and low input of fertilizers) on the density and diversity of spider populations of small wheat fields present in close vicinity were compared in experiments conducted from 2007–2009. The study was conducted in district Sheikhupura, Punjab province, Pakistan. Five fields with different management activities were sampled for spiders

Abida Butt; Sher Muhammad Sherawat

2012-01-01

100

Effect of different agricultural practices on spiders and their prey populations in small wheat fields  

Microsoft Academic Search

The influence of different agricultural practices (viz., edge crop, zero tillage sowing and low input of fertilizers) on the density and diversity of spider populations of small wheat fields present in close vicinity were compared in experiments conducted from 2007–2009. The study was conducted in district Sheikhupura, Punjab province, Pakistan. Five fields with different management activities were sampled for spiders

Abida Butt; Sher Muhammad Sherawat

2011-01-01

101

Epidemiology and simulation of population development of Sitobion avenae in winter wheat  

Microsoft Academic Search

The epidemiology ofSitobion avenae and its natural enemies in winter wheat was studied in 1975, 1976 and 1977. Immigration was important until the end of flowering. The alate immigrants had apterous offspring. These became the driving force in population growth. Their offspring were mostly alatae which usually left the field. A model of the epidemic was developed. Quantitative relations between

R. Rabbinge; G. W. Ankersmit; G. A. Pak

1979-01-01

102

Identification of a complete set of isogenic wheat\\/rye D-genome substitution lines by means of Giemsa C-banding  

Microsoft Academic Search

A complete set of isogenic wheat\\/rye D-genome substitutions were produced by crossing an inbred line of spring rye Secale cereale L. cv. “Prolific” to a tetraploid wheat, the A-and B-genomes of which had previously been extracted from hexaploid wheat, Triticum aestivum L. em Thell. cv. “Thatcher”. After chromosome doubling, the derived hexaploid triticale (x Triticosecale Wittmack) was backcrossed to 6x

B. Friebe; E. N. Larter

1988-01-01

103

Molecular characterization of Ph1 as a major chromosome pairing locus in polyploid wheat  

Microsoft Academic Search

The foundation of western civilization owes much to the high fertility of bread wheat, which results from the stability of its polyploid genome. Despite possessing multiple sets of related chromosomes, hexaploid (bread) and tetraploid (pasta) wheat both behave as diploids at meiosis. Correct pairing of homologous chromosomes is controlled by the Ph1 locus. In wheat hybrids, Ph1 prevents pairing between

Simon Griffiths; Rebecca Sharp; Tracie N. Foote; Isabelle Bertin; Michael Wanous; Steve Reader; Isabelle Colas; Graham Moore

2006-01-01

104

Evaluation of seedling resistance to tan spot and Stagonospora nodorum blotch in tetraploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tetraploid durum wheat (Triticum turgidum L. ssp. durum, 2n = 4x = 28, AABB) is an important cereal specifically used for making pasta products but its production is more vulnerable to various wheat diseases than hexaploid bread wheat (T. aestivum L., 2n = 6x = 42, AABBDD). In order to identify res...

105

IDENTIFICATION OF A FUSARIUM HEAD BLIGHT RESISTANCE QTL ON CHROMOSOME 6B IN TETRAPLOID WHEAT.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is one of the most devastating diseases of bread wheat (Triticum aestivum L., 2n=6x=42) and durum wheat (T. turgidum L., 2n=4x=28). Resistant sources of hexaploid bread wheat have been identified and are currently being employed in breeding programs, but development of re...

106

Different recombination frequencies in wheat doubled haploid populations obtained through maize pollination and anther culture  

Microsoft Academic Search

This study compared the meiotic recombination frequency between wheat doubled haploid (DH) populations obtained through two\\u000a different methods, maize pollination (MP?) and anther culture (AC?). The comparison was based on a genetic linkage analysis,\\u000a performed with DNA markers. Thirty-five polymorphic markers (15 SSR, 15 AFLP, 5 RAPD) were screened in MP? and AC? doubled\\u000a haploids populations, derived from the same hybrid

Justyna Guzy-Wróbelska; Anna Labocha-Pawlowska; Miroslaw Kwasniewski; Iwona Szarejko

2007-01-01

107

Construction and Evaluation of cDNA Libraries for Large-Scale Expressed Sequence Tag Sequencing in Wheat (Triticum aestivum L.)  

Microsoft Academic Search

A total of 37 original cDNA libraries and 9 derivative libraries enriched for rare sequences were produced from Chinese Spring wheat (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86), tetraploid durum wheat (T. turgidum L.), diploid wheat (T. monococcum L.), and two other diploid members of the grass tribe Triticeae (Aegilops speltoides Tausch

D. Zhang; D. W. Choi; S. Wanamaker; R. D. Fenton; A. Chin; M. Malatrasi; Y. Turuspekov; H. Walia; E. D. Akhunov; P. Kianian; C. Otto; K. Simons; K. R. Deal; V. Echenique; B. Stamova; K. Ross; G. E. Butler; L. Strader; S. D. Verhey; R. Johnson; S. Altenbach; K. Kothari; C. Tanaka; M. M. Shah; D. Laudencia-Chingcuanco; P. Han; R. E. Miller; C. C. Crossman; S. Chao; G. R. Lazo; N. Klueva; J. P. Gustafson; S. F. Kianian; J. Dubcovsky; M. K. Walker-Simmons; K. S. Gill; J. Dvor; O. D. Anderson; M. E. Sorrells; P. E. McGuire; C. O. Qualset; H. T. Nguyen; T. J. Close

2004-01-01

108

A multiparent advanced generation inter-cross population for genetic analysis in wheat.  

PubMed

We present the first results from a novel multiparent advanced generation inter-cross (MAGIC) population derived from four elite wheat cultivars. The large size of this MAGIC population (1579 progeny), its diverse genetic composition and high levels of recombination all contribute to its value as a genetic resource. Applications of this resource include interrogation of the wheat genome and the analysis of gene-trait association in agronomically important wheat phenotypes. Here, we report the utilization of a MAGIC population for the first time for linkage map construction. We have constructed a linkage map with 1162 DArT, single nucleotide polymorphism and simple sequence repeat markers distributed across all 21 chromosomes. We benchmark this map against a high-density DArT consensus map created by integrating more than 100 biparental populations. The linkage map forms the basis for further exploration of the genetic architecture within the population, including characterization of linkage disequilibrium, founder contribution and inclusion of an alien introgression into the genetic map. Finally, we demonstrate the application of the resource for quantitative trait loci mapping using the complex traits plant height and hectolitre weight as a proof of principle. PMID:22594629

Huang, Bevan E; George, Andrew W; Forrest, Kerrie L; Kilian, Andrzej; Hayden, Matthew J; Morell, Matthew K; Cavanagh, Colin R

2012-05-17

109

Genetic Determination of Breadmaking Quality in Wheat  

Microsoft Academic Search

Allelic variability of different protein and molecular markers and evaluation of their potential for bread-making quality prediction in 150 hexaploid wheat genotypes were discused. Seventeen Glu-1 alleles were scored, 3 at the Glu-A1, 11 at the Glu-B1, and 3 at the Glu-D1. Typical HMW glutenin composition was 2* 7+9 5+10. Wheat-rye translocation 1BL\\/1RS was present in 20,7% genotypes. According to

Dragana OBREHT; Borislav KOBILJSKI; Milutin BEDE

110

Inferring recent outcrossing rates using multilocus individual heterozygosity: application to evolving wheat populations.  

PubMed Central

Using multilocus individual heterozygosity, a method is developed to estimate the outcrossing rates of a population over a few previous generations. Considering that individuals originate either from outcrossing or from n successive selfing generations from an outbred ancestor, a maximum-likelihood (ML) estimator is described that gives estimates of past outcrossing rates in terms of proportions of individuals with different n values. Heterozygosities at several unlinked codominant loci are used to assign n values to each individual. This method also allows a test of whether populations are in inbreeding equilibrium. The estimator's reliability was checked using simulations for different mating histories. We show that this ML estimator can provide estimates of outcrossing rates for the final generation outcrossing rate (t(0)) and a mean of the preceding rates (t(p)) and can detect major temporal variation in the mating system. The method is most efficient for low to intermediate outcrossing levels. Applied to nine populations of wheat, this method gave estimates of t(0) and t(p). These estimates confirmed the absence of outcrossing t(0) = 0 in the two populations subjected to manual selfing. For free-mating wheat populations, it detected lower final generation outcrossing rates t(0) = 0-0.06 than those expected from global heterozygosity t = 0.02-0.09. This estimator appears to be a new and efficient way to describe the multilocus heterozygosity of a population, complementary to Fis and progeny analysis approaches.

Enjalbert, J; David, J L

2000-01-01

111

Acc homoeoloci and the evolution of wheat genomes  

Microsoft Academic Search

The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome),

D. Chalupska; H. Y. Lee; J. D. Faris; A. Evrard; B. Chalhoub; R. Haselkorn; P. Gornicki

2008-01-01

112

Identification and validation of a major quantitative trait locus for slow-rusting resistance to stripe rust in wheat.  

PubMed

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Eriks (Pst), is one of the most important wheat (Triticum aestivum L.) diseases and causes significant yield losses. A recombinant inbred (RI) population derived from a cross between Yanzhan 1 and Xichang 76-9 cultivars was evaluated for resistance to wheat stripe rust strain CYR32 at both the seedling and adult plant stages. Four resistance quantitative trait loci (QTLs) were detected in this population, in which the major one, designated as Yrq1, was mapped on chromosome 2DS. The strategy of using the Brachypodium distachyon genome, wheat expressed sequence tags and a draft DNA sequences (scaffolds) of the D-genome (Aegilops tauschii Coss.) for the development of simple sequence repeat (SSR) markers was successfully used to identify 147 SSRs in hexaploid wheat. Of the 19 polymorphic SSRs in the RI population, 17 SSRs were mapped in the homeologous group 2 chromosomes near Yrq1 region and eight SSRs were genetically mapped in the 2.7 cM region of Yrq1, providing abundant DNA markers for fine-mapping of Yrq1 and marker-assisted selection in wheat breeding program. The effectiveness of Yrq1 was validated in an independent population, indicating that this resistance QTL can be successfully transferred into a susceptible cultivar for improvement of stripe rust resistance. PMID:22349012

Cao, Xiaohua; Zhou, Jianghong; Gong, Xiaoping; Zhao, Guangyao; Jia, Jizeng; Qi, Xiaoquan

2012-05-01

113

Association Analysis of Historical Bread Wheat Germplasm Using Additive Genetic Covariance of Relatives and Population Structure  

PubMed Central

Linkage disequilibrium can be used for identifying associations between traits of interest and genetic markers. This study used mapped diversity array technology (DArT) markers to find associations with resistance to stem rust, leaf rust, yellow rust, and powdery mildew, plus grain yield in five historical wheat international multienvironment trials from the International Maize and Wheat Improvement Center (CIMMYT). Two linear mixed models were used to assess marker–trait associations incorporating information on population structure and covariance between relatives. An integrated map containing 813 DArT markers and 831 other markers was constructed. Several linkage disequilibrium clusters bearing multiple host plant resistance genes were found. Most of the associated markers were found in genomic regions where previous reports had found genes or quantitative trait loci (QTL) influencing the same traits, providing an independent validation of this approach. In addition, many new chromosome regions for disease resistance and grain yield were identified in the wheat genome. Phenotyping across up to 60 environments and years allowed modeling of genotype × environment interaction, thereby making possible the identification of markers contributing to both additive and additive × additive interaction effects of traits.

Crossa, Jose; Burgueno, Juan; Dreisigacker, Susanne; Vargas, Mateo; Herrera-Foessel, Sybil A.; Lillemo, Morten; Singh, Ravi P.; Trethowan, Richard; Warburton, Marilyn; Franco, Jorge; Reynolds, Matthew; Crouch, Jonathan H.; Ortiz, Rodomiro

2007-01-01

114

Characterisation of a gene encoding wheat endosperm starch branching enzyme-I  

Microsoft Academic Search

A genomic DNA fragment from Triticum tauschii, the donor of the wheat D genome, contains a starch branching enzyme-I (SBE-I) gene spread over 6.5?kb. This gene (designated\\u000a wSBE?I-D4) encodes an amino acid sequence identical to that determined for the N-terminus of SBE-I from the hexaploid wheat (T. aestivum) endosperm. Cognate cDNA sequences for wSBE I-D4 were isolated from hexaploid wheat

S. Rahman; Z. Li; S. Abrahams; D. Abbott; R. Appels; M. K. Morell

1999-01-01

115

Impact of wheat-mung bean intercropping on English grain aphid (Hemiptera: Aphididae) populations and its natural enemy.  

PubMed

The effects of intercropping wheat, Triticum aestivum L., with mung bean, Vigna radiate L., on the populations of English grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae), and its natural enemies were evaluated by field and laboratory experiments. The population densities of aphids and their natural enemies were evaluated in the intercropped field against different row ratio combinations of wheat-mung bean. Results showed that wheat-mung bean intercropping caused a drop in aphid densities, and the ratio 12 wheat: 4 mung bean brought about the largest drop (> 8%). In addition, the population densities of coccinellids (ladybirds) and parasitoids and the species diversity of all the natural enemies of aphid were higher in the intercropped field than in the field planted only with wheat. However, intercropping did not influence the community indices (evenness and index of dominance concentration) of the natural enemies. Y-tube olfactometer bioassays were carried out in the laboratory to test whether odor blends of host and nonhost plants affect the host selection of S. avenae. Bioassays indicated that both apterous and alate aphids significantly preferred host plant odor over odor blends of host and intercropped species. Hence, the olfactory-based host location of aphids in the field might be affected by intercropping. The intercropping experiment clearly showed that increased crop species diversity suppresses aphid population growth and preserves the population of natural enemies of aphids. Our results also provide support for the "resource concentration hypothesis" and the "enemies hypothesis". PMID:22812121

Xie, Hai-Cui; Chen, Ju-Lian; Cheng, Deng-Fa; Zhou, Hai-Bo; Sun, Jing-Rui; Liu, Yong; Francis, Frédéric

2012-06-01

116

The Major Threshability Genes Soft Glume (sog) and Tenacious Glume (Tg), of Diploid and Polyploid Wheat, Trace Their Origin to Independent Mutations at Non-Orthogous Loci  

Technology Transfer Automated Retrieval System (TEKTRAN)

Threshability is an important crop domestication trait. The wild wheat progenitors have tough glumes enveloping the floret that make spikes difficult to thresh, whereas cultivated wheats have soft glumes and are free-threshing. In hexaploid wheat, the glume tenacity gene Tg along with the major dome...

117

Mapping QTL for agronomic traits on wheat chromosome 3A and a comparison of recombinant inbred chromosome line populations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Variation for wheat (Triticum aestivum L.) grain yield and its component traits was documented in a ‘Cheyenne’ x Cheyenne (‘Wichita’ 3A) recombinant inbred chromosome line population. In the present study, a population of 223 Cheyenne (Wichita 3A) recombinant inbred chromosome lines was used to map ...

118

A Comparative Analysis of Free, Bound and Total Lipid Content on Spelt and Winter Wheat Wholemeal  

Microsoft Academic Search

Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method in whole ground spelt (Triticum aestivum ssp. spelta L.) and hexaploid winter wheat (T. aestivum) samples. Ninety-one samples of spelt and 78 samples of winter wheat were analysed in the present study. The available material is representative of the wide variability found in spelt

Nike L. Ruibal-Mendieta; Dominique L. Delacroix; Marc Meurens

2002-01-01

119

Transcriptome profiling and expression analyses of genes critical to wheat adaptation to low temperature  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome microarray. We compared the expressi...

120

Wheat cytogenetics in the genomics era and its relevance to breeding  

Microsoft Academic Search

Hexaploid wheat is a species that has been subjected to most extensive cytogenetic studies. This has contributed to understanding the mechanism of the evolution of polyploids involving diploidization through genetic restriction of chromosome pairing to only homologous chromosomes. The availability of a variety of aneuploids and the ph mutants (Ph1 and Ph2) in bread wheat also allowed chromosome manipulations leading

P. K. Gupta; P. L. Kulwal; S. Rustgi

2005-01-01

121

Identification of a novel Fusarium head blight resistance QTL on chromosome 7A in tetraploid wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most destructive diseases of durum (Triticum turgidum ssp. durum) and common wheat (T. aestivum). Promising sources of FHB resistance have been identified among common (hexaploid) wheats, but the same is not true for durum (tetr...

122

Evidence for stable transformation of wheat by floraldip in Agrobacterium tumefaciens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hexaploid wheat is one of the world’s most important staple crops but genetic transformation is still challenging. We have developed a floral transformation protocol that does not utilize tissue culture. Three T-DNA wheat transformants have been produced in the germplasm line, Crocus, using this p...

123

Impact of Field Release of Genetically Modified Pseudomonas fluorescens on Indigenous Microbial Populations of Wheat  

PubMed Central

In a field release experiment, an isolate of Pseudomonas fluorescens, which was chromosomally modified with two reporter gene cassettes (lacZY and Kan(supr)-xylE), was applied to spring wheat as a seed coating and subsequently as a foliar spray. The wild-type strain was isolated from the phylloplane of sugar beet but was found to be a common colonizer of both the rizosphere and phylloplane of wheat as well. The impact on the indigenous microbial populations resulting from release of this genetically modified microorganism (GMM) was compared with the impact of the unmodified, wild-type strain and a nontreated control until 1 month after harvest of the crop. The release of the P. fluorescens GMM and the unmodified, wild-type strain resulted in significant but transient perturbations of some of the culturable components of the indigenous microbial communities that inhabited the rhizosphere and phylloplane of wheat, but no significant perturbations of the indigenous culturable microbial populations in nonrhizosphere soil were found. Fast-growing organisms that did not produce resting structures (for example, fluorescent pseudomonads and yeasts) seemed to be most sensitive to perturbation. In terms of hazard and risk to the environment, the observed microbial perturbations that resulted from this GMM release may be considered minor for several reasons. First, the recombinant P. fluorescens strain caused changes that were, in general, not significantly different from those caused by the unmodified wild-type strain; second, perturbations resulting from bacterial inoculations were mainly small; and third, the release of bacteria had no obvious effects on plant growth and plant health.

De Leij, F.; Sutton, E. J.; Whipps, J. M.; Fenlon, J. S.; Lynch, J. M.

1995-01-01

124

Rapid Differentiation of Experimental Populations of Wheat for Heading Time in Response to Local Climatic Conditions  

PubMed Central

• Background and Aims Dynamic management (DM) of genetic resources aims at maintaining genetic variability between different populations evolving under natural selection in contrasting environments. In 1984, this strategy was applied in a pilot experiment on wheat (Triticum aestivum). Spatio-temporal evolution of earliness and its components (partial vernalization sensitivity, daylength sensitivity and earliness per se that determines flowering time independently of environmental stimuli) was investigated in this multisite and long-term experiment. • Methods Heading time of six populations from the tenth generation was evaluated under different vernalization and photoperiodic conditions. • Key Results Although temporal evolution during ten generations was not significant, populations of generation 10 were genetically differentiated according to a north–south latitudinal trend for two components out of three: partial vernalization sensitivity and narrow-sense earliness. • Conclusions It is concluded that local climatic conditions greatly influenced the evolution of population earliness, thus being a major factor of differentiation in the DM system. Accordingly, a substantial proportion (?25?%) of genetic variance was distributed among populations, suggesting that diversity was on average conserved during evolution but was differently distributed by natural selection (and possibly drift). Earliness is a complex trait and each genetic factor is controlled by multiple homeoalleles; the next step will be to look for spatial divergence in allele frequencies.

GOLDRINGER, ISABELLE; PROUIN, CLAIRE; ROUSSET, MICHEL; GALIC, NATHALIE; BONNIN, ISABELLE

2006-01-01

125

Homoeologous gene silencing in tissue cultured wheat callus  

Microsoft Academic Search

BACKGROUND: In contrast to diploids, most polyploid plant species, which include the hexaploid bread wheat, possess an additional layer of epigenetic complexity. Several studies have demonstrated that polyploids are affected by homoeologous gene silencing, a process in which sub-genomic genomic copies are selectively transcriptionally inactivated. This form of silencing can be tissue specific and may be linked to developmental or

Andrew Bottley; Natalie H Chapman

2008-01-01

126

Induction and characterization of Ph1 wheat mutants.  

PubMed Central

The cloning of genes for complex traits in polyploid plants that possess large genomes, such as hexaploid wheat, requires an efficient strategy. We present here one such strategy focusing on the homologous pairing suppressor (Ph1) locus of wheat. This locus has been shown to affect both premeiotic and meiotic processes, possibly suggesting a complex control. The strategy combined the identification of lines carrying specific deletions using multiplex PCR screening of fast-neutron irradiated wheat populations with the approach of physically mapping the region in the rice genome equivalent to the deletion to reveal its gene content. As a result, we have located the Ph1 factor controlling the euploid-like level of homologous chromosome pairing to the region between two loci (Xrgc846 and Xpsr150A). These loci are located within 400 kb of each other in the rice genome. By sequencing this region of the rice genome, it should now be possible to define the nature of this factor.

Roberts, M A; Reader, S M; Dalgliesh, C; Miller, T E; Foote, T N; Fish, L J; Snape, J W; Moore, G

1999-01-01

127

[Effects of population distribution pattern and irrigation schedule on radiation utilization in winter wheat farmland].  

PubMed

A field experiment was conducted in 2006-2008 to study the effects of different population distribution pattern and irrigation schedule on the radiation utilization in a winter wheat farmland at the same population density (2.04 x 10(6) plant x hm(-2)). Four population distribution patterns were designed, i.e., row spacing (cm) x plant spacing (cm) 7 x 7 (A), 14 x 3.5 (B), 24.5 x 2 (C), and 49 x 1 (D), and each pattern had four irrigation schedules, i. e., no-irrigation, irrigation at jointing stage, irrigation at jointing and heading stages, and irrigation at jointing, heading and filling stages. The irrigation amount was 0.60 m3 each time. In the patterns A and B, the tiller number and leaf area index (LIA) were significantly higher than those in C and D (P< 0.05). With the increase of row spacing, the photosynthetically active radiation (PAR) transmittance ratio increased gradually, while the PAR capture ratio had a decreasing trend. Increasing irrigation times increased the tiller number and LAI, but decreased the transmittance ratio of PAR, resulting in a significant increase of PAR capture ratio (P<0.05). The PAR capture ratio in the crop canopy was higher in upper layers, compared with that in lower layers. Relatively uniform population distribution and irrigation increased the PAR capture ratio in the upper 40 cm canopy layers significantly. The radiation use efficiency (RUE) decreased with increasing row spacing, with the two year's average total RUE in A, B, C, and D being 1.24%, 1.27%, 1.21% and 1.06%, respectively, and that in B was 5.21% and 19.56% higher than that in C and D, respectively, with the difference being significant. It was suggested that relatively uniform population distribution improved the winter wheat population structure and PAR capture, being beneficial to the fully use of radiation, and irrigation also had positive effects on the population structure, being helpful to the increase of crop RUE. PMID:19947205

Yang, Guo-Min; Sun, Shu-Juan; Zhou, Xun-Bo; Chen, Yu-Hai; Qi, Lin; Gao, Hui-Jun; Liu, Yan

2009-08-01

128

Evolutionary Genomics of Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is the world’s largest and most important food crop for direct human consumption, therefore, continued wheat improvement is paramount for feeding an ever-increasing human population. Wheat improvement is tightly associated with the characterization and understanding of wheat evolution and gene...

129

POPULATION GENETICS OF THE WHEAT LEAF RUST FUNGUS, PUCCINIA TRITICINA IN CENTRAL ASIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat leaf rust, caused by Puccinia triticina, is a major disease of wheat in Central Asia. Single uredinial isolates from Armenia, Azerbaijan, Tajikistan, Kazakhstan, Uzbekistan, and Kyrgyzstan, 131 in total, were tested for virulence to 20 isolines of Thatcher wheat with single leaf rust resistan...

130

POPULATION GENETICS OF THE WHEAT LEAF RUST FUNGUS, PUCCINIA TRITICINA IN CENTRAL ASIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat leaf rust, caused by Puccinia triticina, is a major disease of wheat in Central Asia. Single uredinial isolates from Armenia, Azerbaijan, Tajikistan, Kazakhstan, Uzbekistan, and Kyrgyzstan, 131 in total, were tested for virulence to 20 isolines of Thatcher wheat with single leaf rust resistanc...

131

Estimation of Long-Term Effective Population Sizes Through the History of Durum Wheat Using Microsatellite Data  

Microsoft Academic Search

Estimation of long-term effective population size (Ne) from polymorphism data alone requires an independent knowledge of mutation rate. Microsatellites provide the opportunity to estimate Ne because their high mutation rate can be estimated from observed mutations. We used this property to estimate Ne in allotetraploid wheat Triticum turgidum at four stages of its history since its domestication. We estimated the

A.-C. Thuillet; T. Bataillon; S. Poirier; S. Santoni; J. L. David

2005-01-01

132

POPULATIONS OF 2,4-DIACETYLPHLOROGLUCINOL (DAPG)-PRODUCING PSEUDOMONAS FLUORESCENS IN THE RHIZOSPHERE OF PYTHIUM-INFECTED WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Root infections by soilborne pathogens can either positively or negatively affect root colonization and antibiotic production by beneficial bacteria. We tested the impact of four Pythium spp. on colonization of wheat roots by indigenous populations of 2,4-diacetylphloroglucinol (DAPG)-producing Pse...

133

Stably Expressed D Genome-derived HMW Glutenin Subunit Genes Transformed Into Different Durum Wheat Genotypes Change Dough Mixing Properties  

Technology Transfer Automated Retrieval System (TEKTRAN)

The glutenin subunits 1Dx5 and 1Dy10 are encoded by chromosome 1D and associated with higher dough strength in hexaploid bread wheats. In order to study the effects of their expression in different durum wheat genotypes, four cultivars commonly grown in the Mediterranean area were co-transformed, vi...

134

Molecular cytogenetic identification of wheat-Elymus tsukushiense introgression lines  

Microsoft Academic Search

Elymus tsukushiense Honda (syn. Roegneria kamoji C. Koch) (2n = 6x = 42, StsStsHtsHtsYtsYts) is a hexaploid species, distantly related to bread wheat Triticum aestivum L. em Thell (2n = 6x = 42, AABBDD). Apart from\\u000a the delineation of evolutionary relationships, this species is a potential source of resistance to scab, a devastating disease\\u000a of wheat caused by Fusarium graminearum

S. L. Wang; L. L. Qi; P. D. Chen; D. J. Liu; B. Friebe; B. S. Gill

1999-01-01

135

Wheat artificial amphiploids involving the Triticum timopheevii genome: their studies, preservation and reproduction  

Microsoft Academic Search

The effective utilisation of available genetic resources of related species is essential for successful crops breeding and\\u000a maintaining genetic variability within crops. Bread wheat, the basic cultivated wheat species, is an amphiploid (2n = 6x = 42) and, therefore, the production of new synthetic amphiploids using genomes of related species should reduce the difficulties\\u000a caused by direct crossings, for example, between hexaploid wheat and

N. P. Goncharov; S. V. Bannikova; T. Kawahara

2007-01-01

136

Experimental Estimation of Mutation Rates in a Wheat Population With a Gene Genealogy Approach  

PubMed Central

Microsatellite markers are extensively used to evaluate genetic diversity in natural or experimental evolving populations. Their high degree of polymorphism reflects their high mutation rates. Estimates of the mutation rates are therefore necessary when characterizing diversity in populations. As a complement to the classical experimental designs, we propose to use experimental populations, where the initial state is entirely known and some intermediate states have been thoroughly surveyed, thus providing a short timescale estimation together with a large number of cumulated meioses. In this article, we derived four original gene genealogy-based methods to assess mutation rates with limited bias due to relevant model assumptions incorporating the initial state, the number of new alleles, and the genetic effective population size. We studied the evolution of genetic diversity at 21 microsatellite markers, after 15 generations in an experimental wheat population. Compared to the parents, 23 new alleles were found in generation 15 at 9 of the 21 loci studied. We provide evidence that they arose by mutation. Corresponding estimates of the mutation rates ranged from 0 to 4.97 × 10?3 per generation (i.e., year). Sequences of several alleles revealed that length polymorphism was only due to variation in the core of the microsatellite. Among different microsatellite characteristics, both the motif repeat number and an independent estimation of the Nei diversity were correlated with the novel diversity. Despite a reduced genetic effective size, global diversity at microsatellite markers increased in this population, suggesting that microsatellite diversity should be used with caution as an indicator in biodiversity conservation issues.

Raquin, Anne-Laure; Depaulis, Frantz; Lambert, Amaury; Galic, Nathalie; Brabant, Philippe; Goldringer, Isabelle

2008-01-01

137

Population Dynamics of Active and Total Ciliate Populations in Arable Soil Amended with Wheat  

PubMed Central

Soil protozoa are characterized by their ability to produce cysts, which allows them to survive unfavorable conditions (e.g., desiccation) for extended periods. Under favorable conditions, they may rapidly excyst and begin feeding, but even under optimal conditions, a large proportion of the population may be encysted. The factors governing the dynamics of active and encysted cells in the soil are not well understood. Our objective was to determine the dynamics of active and encysted populations of ciliates during the decomposition of freshly added organic material. We monitored, in soil microcosms, the active and total populations of ciliates, their potential prey (bacteria and small protozoa), their potential competitors (amoebae, flagellates, and nematodes), and their potential predators (nematodes). We sampled with short time intervals (2 to 6 days) and generated a data set, suitable for mathematical modeling. Following the addition of fresh organic material, bacterial numbers increased more than 1,400-fold. There was a temporary increase in the number of active ciliates, followed by a rapid decline, although the size of the bacterial prey populations remained high. During this initial burst of ciliate growth, the population of cystic ciliates increased 100-fold. We suggest that internal population regulation is the major factor governing ciliate encystment and that the rate of encystment depends on ciliate density. This model provides a quantitative explanation of ciliatostasis and can explain why protozoan growth in soil is less than that in aquatic systems. Internally governed encystment may be an essential adaptation to an unpredictable environment in which individual protozoa cannot predict when the soil will dry out and will survive desiccation only if they have encysted in time.

Ekelund, Flemming; Frederiksen, Helle B.; R?nn, Regin

2002-01-01

138

Wheat Evolution, Domestication, and Improvement  

Microsoft Academic Search

SUMMARY (1) Wheat is the world's largest and most important food crop for direct human con- sumption; therefore, continued wheat improvement is paramount for feeding an ever-increasing human population. (2) Wheat improvement is tightly associated with the characterization and understand- ing of wheat evolution and the genetic diversifi cation of various wheat species and relatives. The evolution of the genus

Perry Gustafson; Olga Raskina; XueFeng Ma; Eviatar Nevo

139

Association Analysis of Historical Bread Wheat Germplasm Using Additive Genetic Covariance of Relatives and Population Structure  

Microsoft Academic Search

Linkage disequilibrium can be used for identifying associations between traits of interest and genetic markers. This study used mapped diversity array technology (DArT) markers to find associations with resistance to stem rust, leaf rust, yellow rust, and powdery mildew, plus grain yield in five historical wheat international multienvironment trials from the International Maize and Wheat Improvement Center (CIMMYT). Two linear

J. Crossa; J. Burgueno; S. Dreisigacker; M. Vargas; S. A. Herrera-Foessel; M. Lillemo; R. P. Singh; R. Trethowan; M. Warburton; J. Franco; M. Reynolds; J. H. Crouch; R. Ortiz

2007-01-01

140

Transcripts of Vp-1 homeologues are misspliced in modern wheat and ancestral species  

PubMed Central

The maize (Zea mays) Viviparous 1 (Vp1) transcription factor has been shown previously to be a major regulator of seed development, simultaneously activating embryo maturation and repressing germination. Hexaploid bread wheat (Triticum aestivum) caryopses are characterized by relatively weak embryo dormancy and are susceptible to preharvest sprouting (PHS), a phenomenon that is phenotypically similar to the maize vp1 mutation. Analysis of Vp-1 transcript structure in wheat embryos during grain development showed that each homeologue produces cytoplasmic mRNAs of different sizes. The majority of transcripts are spliced incorrectly, contain insertions of intron sequences or deletions of coding region, and do not have the capacity to encode full-length proteins. Several VP-1-related lower molecular weight protein species were present in wheat embryo nuclei. Embryos of a closely related tetraploid species (Triticum turgidum) and ancestral diploids also contained misspliced Vp-1 transcripts that were structurally similar or identical to those found in modern hexaploid wheat, which suggests that compromised structure and expression of Vp-1 transcripts in modern wheat are inherited from ancestral species. Developing embryos from transgenic wheat grains expressing the Avena fatua Vp1 gene showed enhanced responsiveness to applied abscisic acid compared with the control. In addition, ripening ears of transgenic plants were less susceptible to PHS. Our results suggest that missplicing of wheat Vp-1 genes contributes to susceptibility to PHS in modern hexaploid wheat varieties and identifies a possible route to increase resistance to this environmentally triggered disorder.

McKibbin, Rowan S.; Wilkinson, Mark D.; Bailey, Paul C.; Flintham, John E.; Andrew, Lucy M.; Lazzeri, Paul A.; Gale, Mike D.; Lenton, John R.; Holdsworth, Michael J.

2002-01-01

141

Transcripts of Vp-1 homeologues are misspliced in modern wheat and ancestral species.  

PubMed

The maize (Zea mays) Viviparous 1 (Vp1) transcription factor has been shown previously to be a major regulator of seed development, simultaneously activating embryo maturation and repressing germination. Hexaploid bread wheat (Triticum aestivum) caryopses are characterized by relatively weak embryo dormancy and are susceptible to preharvest sprouting (PHS), a phenomenon that is phenotypically similar to the maize vp1 mutation. Analysis of Vp-1 transcript structure in wheat embryos during grain development showed that each homeologue produces cytoplasmic mRNAs of different sizes. The majority of transcripts are spliced incorrectly, contain insertions of intron sequences or deletions of coding region, and do not have the capacity to encode full-length proteins. Several VP-1-related lower molecular weight protein species were present in wheat embryo nuclei. Embryos of a closely related tetraploid species (Triticum turgidum) and ancestral diploids also contained misspliced Vp-1 transcripts that were structurally similar or identical to those found in modern hexaploid wheat, which suggests that compromised structure and expression of Vp-1 transcripts in modern wheat are inherited from ancestral species. Developing embryos from transgenic wheat grains expressing the Avena fatua Vp1 gene showed enhanced responsiveness to applied abscisic acid compared with the control. In addition, ripening ears of transgenic plants were less susceptible to PHS. Our results suggest that missplicing of wheat Vp-1 genes contributes to susceptibility to PHS in modern hexaploid wheat varieties and identifies a possible route to increase resistance to this environmentally triggered disorder. PMID:12119408

McKibbin, Rowan S; Wilkinson, Mark D; Bailey, Paul C; Flintham, John E; Andrew, Lucy M; Lazzeri, Paul A; Gale, Mike D; Lenton, John R; Holdsworth, Michael J

2002-07-15

142

Population increase and damage by three species of mites on wheat at 20°C and two humidities  

Microsoft Academic Search

Twenty bisected grains of wheat infested with five pairs of the three commonest British grain-storage mites,Acarus siro L., Glycyphagus destructor (Shrank) andTyrophagus longior (Gervais), were examined every week for 20 weeks. Mite populations, the resulting damage to germ and endosperm, and visible fungal growth were observed at 20°C and relative humidities (r.h.) of 90% and 75%.

C. L. Parkinson

1990-01-01

143

Aneuploidy among androgenic progeny of hexaploid triticale (X Triticosecale Wittmack)  

Microsoft Academic Search

Doubled haploids are an established tool in plant breeding and research. Of several methods for their production, androgenesis\\u000a is technically simple and can efficiently produce substantial numbers of lines. It is well suited to such crops as hexaploid\\u000a triticale. Owing to meiotic irregularities of triticale hybrids, aneuploidy may affect the efficiency of androgenesis more\\u000a severely than in meiotically stable crops.

Sylwia Oleszczuk; Julita Rabiza-Swider; Janusz Zimny; Adam J. Lukaszewski

2011-01-01

144

High resolution melting analysis for the detection of EMS induced mutations in wheat SbeIIa genes  

PubMed Central

Background Manipulation of the amylose-amylopectin ratio in cereal starch has been identified as a major target for the production of starches with novel functional properties. In wheat, silencing of starch branching enzyme genes by a transgenic approach reportedly caused an increase of amylose content up to 70% of total starch, exhibiting novel and interesting nutritional characteristics. In this work, the functionality of starch branching enzyme IIa (SBEIIa) has been targeted in bread wheat by TILLING. An EMS-mutagenised wheat population has been screened using High Resolution Melting of PCR products to identify functional SNPs in the three homoeologous genes encoding the target enzyme in the hexaploid genome. Results This analysis resulted in the identification of 56, 14 and 53 new allelic variants respectively for SBEIIa-A, SBEIIa-B and SBEIIa-D. The effects of the mutations on protein structure and functionality were evaluated by a bioinformatic approach. Two putative null alleles containing non-sense or splice site mutations were identified for each of the three homoeologous SBEIIa genes; qRT-PCR analysis showed a significant decrease of their gene expression and resulted in increased amylose content. Pyramiding of different single null homoeologous allowed to isolate double null mutants showing an increase of amylose content up to 21% compared to the control. Conclusion TILLING has successfully been used to generate novel alleles for SBEIIa genes known to control amylose content in wheat. Single and double null SBEIIa genotypes have been found to show a significant increase in amylose content.

2011-01-01

145

Physiological attributes associated with yield and stability in selected lines of a durum wheat population  

Microsoft Academic Search

Further increasing yield potential remains one of the main objectives of wheat breeding, even in stressful environments. In\\u000a general, past genetic gains were associated with increases in harvest index, and future gains should be related to greater\\u000a biomass. Identifying genetic sources for such improvement may be relevant. Researchers of TRITIMED identified DH lines of\\u000a durum wheat apparently possessing not only

Anna Pedro; Roxana Savin; Dimah Z. Habash; Gustavo A. Slafer

2011-01-01

146

Microspore culture in wheat ( Triticum aestivum ) – doubled haploid production via induced embryogenesis  

Microsoft Academic Search

The inherent potential to produce plants from microspores or immature pollen exists naturally in many plant species. Some genotypes in hexaploid wheat (Triticum aestivum L.) also exhibit the trait for androgenesis. Under most circumstances, however, an artificial manipulation, in the form of physical, physiological and\\/or chemical treatment, need to be employed to switch microspores from gametophytic development to a sporophytic

Ming Y. Zheng

2003-01-01

147

Seedling tolerance to Rhizoctonia and Pythium in wheat chromosome group 4 addition lines from Thinopyrum spp  

Technology Transfer Automated Retrieval System (TEKTRAN)

Chromosome 4 from Thinopyrum spp. confers regrowth after a sexual cycle and senescence in hexaploid wheat (Triticum aestivum), and is associated with resistance to the necrotrophic eyespot pathogen, Tapesia yallundae. We sought to determine whether robust root growth or other traits expressed in ch...

148

Cytoplasmic effects on the tissue culture response of wheat ( Triticum aestivum ) callus  

Microsoft Academic Search

Calli were initiated from immature embryos of eight lines of hexaploid wheat (Triticum aestivum L. em. Thell) with different cytoplasms, the euplasmic nuclear donor ‘Chinese Spring’ and seven alloplasmic lines derived from wild relative species of the genera Triticum and Aegilops. The calli were found to differ in their initial growth rates, their sensitivity to 2,4-D and their ability to

R. J. Mathias; K. Fukui; C. N. Law

1986-01-01

149

Fine mapping a domestication-related QTL for spike-related traits in a synthetic wheat.  

PubMed

QTL analysis using a BC5F2:3 mapping population derived from a cross between Am3, a synthetic hexaploid wheat as a donor parent, and Laizhou953, a Chinese winter wheat cultivar as a recurrent parent, showed that variation at the microsatellite locus Xgwm113 on chromosome 4B was associated with variation in grain number per spike (GN), spike length (SL), and spikelet number per spike (SPI). The Qgn.caas-4B, Qsl.caas-4B, and Qspi.caas-4B were responsible for 16.6%-35.6%, 18.0%-32.3%, and 23.7%-25.9% of the phenotypic variation present in two environments, respectively. Segregation for GN fit a Mendelian monogenic ratio. A subpopulation consisting of 497 plants was used to map the QTL to a 1.2 cM interval between Xgwm113 and Xgwm857. The three spike traits, GN, SL, and SPI, were correlated and were thus probably under the pleiotropic control of the QTL. The Am3 allele had a reduction effect on all three spike traits. Evidence for positive selective history on SSR locus Xgwm113 was supported using Ewens-Watterson's statistic test on a germplasm panel of wild and landrace entries, suggesting that this genomic region may contain genes under selection during wheat domestication. PMID:20962886

Wang, Jin; Liao, Xiangzheng; Li, Yulian; Zhou, Ronghua; Yang, Xueju; Gao, Lifeng; Jia, Jizeng

2010-10-01

150

Quantifying the effect of bacterial antagonists on the relationship between phyllosphere population sizes of Xanthomonas translucens pv. translucens and subsequent bacterial leaf streak severity on wheat seedlings  

Microsoft Academic Search

The influence of bacterial antagonists on the relationship between leaf-associated population sizes of Xanthomonas translucens pv. translucens (Xtt) and subsequent bacterial leaf streak (BLS) severity on wheat seedlings was investigated when antagonists were challenged with the pathogen. Bacterial antagonists (108CFU\\/ml) were inoculated individually onto 10-day-old wheat seedlings maintained in a growth chamber. Antagonists were challenged 48h later with a single

K. D. Stromberg; L. L. Kinkel; K. J. Leonard

2004-01-01

151

Aeration management for stored hard red winter wheat: simulated impact on rusty grain beetle (Coleoptera: Cucujidae) populations.  

PubMed

Simulation studies were conducted to determine temperature accumulations below defined thresholds and to show the impact of controlled aeration on populations of the rusty grain beetle, Cryptolestes ferrigineus (Stephens), a major secondary pest of stored wheat, Triticum aestivum (L.). Recorded data from weather stations in Texas, Oklahoma, Kansas, eastern New Mexico, and eastern Colorado (356 total) were used to determine hours of temperature accumulation below 23.9 degrees C in June and July, 15.6 degrees C in September and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m3/s/m3 (0.1 cubic ft3/min/bu), which requires 120 h of temperatures below the specified threshold to complete an aeration cycle, summer cooling at 23.9 degrees C in bulk-stored wheat could be completed throughout the hard red winter wheat zone except for extreme southern Texas. An early-autumn cooling cycle at 15.6 degrees C could not be completed throughout most of Texas and Oklahoma before the end of September. The late-autumn cooling cycle could be completed in all states except Texas by the end of November. Five geographic regions were delineated and the times required for completion of the summer, early-autumn, and late-autumn cooling cycles within each region were estimated. Population growth of the rusty grain beetle was modeled for San Antonio, TX; Abilene, TX; Tulsa, OK; Topeka KS; and Goodland, KS, by predicting the numbers of adults in the top, outer middle, outer periphery, and the center of the bin during a 1-yr storage season. Populations of C. ferrugineus in San Antonio and Austin were predicted to exceed the Federal Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during the winter, and increase the following spring. In Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the top and outer middle of the bin, whereas populations in the Kansas locations were not predicted to exceed the threshold at any time. PMID:10985054

Arthur, F H; Flinn, P W

2000-08-01

152

Exploring the diploid wheat ancestral A genome through sequence comparison at the high-molecular-weight glutenin locus region.  

PubMed

The polyploid nature of hexaploid wheat (T. aestivum, AABBDD) often represents a great challenge in various aspects of research including genetic mapping, map-based cloning of important genes, and sequencing and accurately assembly of its genome. To explore the utility of ancestral diploid species of polyploid wheat, sequence variation of T. urartu (A(u)A(u)) was analyzed by comparing its 277-kb large genomic region carrying the important Glu-1 locus with the homologous regions from the A genomes of the diploid T. monococcum (A(m)A(m)), tetraploid T. turgidum (AABB), and hexaploid T. aestivum (AABBDD). Our results revealed that in addition to a high degree of the gene collinearity, nested retroelement structures were also considerably conserved among the A(u) genome and the A genomes in polyploid wheats, suggesting that the majority of the repetitive sequences in the A genomes of polyploid wheats originated from the diploid A(u) genome. The difference in the compared region between A(u) and A is mainly caused by four differential TE insertion and two deletion events between these genomes. The estimated divergence time of A genomes calculated on nucleotide substitution rate in both shared TEs and collinear genes further supports the closer evolutionary relationship of A to A(u) than to A(m). The structure conservation in the repetitive regions promoted us to develop repeat junction markers based on the A(u) sequence for mapping the A genome in hexaploid wheat. Eighty percent of these repeat junction markers were successfully mapped to the corresponding region in hexaploid wheat, suggesting that T. urartu could serve as a useful resource for developing molecular markers for genetic and breeding studies in hexaploid wheat. PMID:23052831

Dong, Lingli; Huo, Naxin; Wang, Yi; Deal, Karin; Luo, Ming-Cheng; Wang, Daowen; Anderson, Olin D; Gu, Yong Qiang

2012-09-28

153

Polymorphisms in two homeologous ?-gliadin genes and the evolution of cultivated wheat  

Microsoft Academic Search

The polymorphisms in two ?-gliadin genes GAG56D and GAG56B on the D- and B-genomes of polyploid wheat, respectively, were investigated by sequencing PCR products and by PCR-RFLP. Of GAG56D, two alleles fo and ok were previously known to occur in hexaploid wheat. Here, we found that 16 sequenced fragments of GAG56D from six recognized subspecies of Triticum aestivum, including 13

Michael von Büren

2001-01-01

154

Effect of mechanical weeding on wild chamomile (Matricaria chamomilla L.) populations in winter wheat crop (Triticum aestivum L.).  

PubMed

Currently, economic, agronomic and environmental concerns lead to reduce the use of herbicides. Mechanical weeding can help to reach this objective. Dynamics and biology of wild chamomile (Matricaria chamomilla L.) populations were assessed as well as dynamic of winter wheat (Triticum aestivum L.) for four level of application of a weeder-harrow (0, 1, 2, 3 treatment(s)). After each treatment, an effect of mechanical weeding on wild chamomile density was observed. Density of wild chamomile decreased significantly with intensification of mechanical weeding. A third treatment allowed eliminating late emerged plants. PMID:23878991

Jaunard, D; Bizoux, J P; Monty, A; Henriet, F; De Proft, M; Vancutsem, F; Mahy, G; Bodson, B

2012-01-01

155

Analysis of storage proteins (prolamines, puroindolines and Waxy) in common wheat lines Triticum aestivum L. × ( Triticum timopheevii Zhuk. × Triticum tauschii ) with complex resistance to fungal infections  

Microsoft Academic Search

Storage proteins (prolamines, puroindolines, and Waxy) were studied in common wheat introgression lines obtained with the\\u000a use of the Saratovskaya 29 (S29) cultivar line and synthetic hexaploid wheat (Triticum timopheevii Zhuk. × T. tauschii) (Sintetik, Sin.) displaying complex resistance to fungal infections. Comparative analysis of storage proteins in the introgression\\u000a lines of common wheat Triticum aestivum L. and in the

L. V. Obukhova; L. I. Laikova; V. K. Shumny

2010-01-01

156

Composition of the Fusarium graminearum species complex populations in wheat cropping environments in Southern Brazil  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Fusarium graminearum species complex (FGSC) comprises several toxigenic species that cause Fusarium head blight (FHB) in wheat. In this study, high number (n=671 isolates) of pathogenic isolates (isolated from infected spikes) was obtained from a 3-year large-scale survey (2009-2011) conducted o...

157

EVOLUTION OF WHEAT STREAK MOSAIC VIRUS: Dynamics of Population Growth Within Plants May Explain Limited Variation  

Microsoft Academic Search

Like many other plant RNA viruses, Wheat streak mosaic virus (WSMV) sequence diversity within and among infected plants is low given the large number of virions produced. This may be explained by considering aspects of plant virus life history. Intracellular replication of RNA viruses is predominately linear, not exponential, which means that the rate at which mutations accumulate also is

Roy C. French; Drake C. Stenger

2003-01-01

158

Use of winter wheat x Triticum tauschii backcross populations for germplasm evaluation  

Microsoft Academic Search

The wild diploid goatgrass, Triticum tauschii (Coss.) Schmal., is an important source of genes for resistance to both diseases and insects in common wheat (Triticum aestivum L.) We have evaluated grain yield, kernel weight, protein concentration, and kernel hardness of 641 BC2 F1-derived families from direct crosses involving four T. aestivum cultivars and 13 T. tauschii accessions over 2 years

T. S. Cox; R. G. Sears; R. K. Bequette

1995-01-01

159

Establishing an Efficient Way to Utilize the Drought Resistance Germplasm Population in Wheat  

PubMed Central

Drought resistance breeding provides a hopeful way to improve yield and quality of wheat in arid and semiarid regions. Constructing core collection is an efficient way to evaluate and utilize drought-resistant germplasm resources in wheat. In the present research, 1,683 wheat varieties were divided into five germplasm groups (high resistant, HR; resistant, R; moderate resistant, MR; susceptible, S; and high susceptible, HS). The least distance stepwise sampling (LDSS) method was adopted to select core accessions. Six commonly used genetic distances (Euclidean distance, Euclid; Standardized Euclidean distance, Seuclid; Mahalanobis distance, Mahal; Manhattan distance, Manhat; Cosine distance, Cosine; and Correlation distance, Correlation) were used to assess genetic distances among accessions. Unweighted pair-group average (UPGMA) method was used to perform hierarchical cluster analysis. Coincidence rate of range (CR) and variable rate of coefficient of variation (VR) were adopted to evaluate the representativeness of the core collection. A method for selecting the ideal constructing strategy was suggested in the present research. A wheat core collection for the drought resistance breeding programs was constructed by the strategy selected in the present research. The principal component analysis showed that the genetic diversity was well preserved in that core collection.

Wang, Jiancheng; Guan, Yajing; Wang, Yang; Zhu, Liwei; Wang, Qitian; Hu, Qijuan; Hu, Jin

2013-01-01

160

MARKER ASSISTED SELECTION FOR FHB RESISTANCE IN SOFT RED WHEAT FROM DOUBLE HAPLOID POPULATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fusarium head blight (FHB) is caused by Fusarium graminearum Schwabe. The fungus can degenerate the wheat grain tissue and produce deoxynivalenol (DON) which is toxic to both human and animals. Epidemics of FHB can result in severe loss of yield and grain quality. Cultural or/and chemical control of...

161

Variability and uniformity of mitochondrial DNA in populations of putative diploid ancestors of common wheat  

Microsoft Academic Search

By using restriction endonuclease digestion patterns, the degree of intraspecific polymorphism of mitochondrial DNA in four diploid species of wheat and Aegilops, Ae. speltoides, Ae. longissima, Ae. squarrosa, and Triticum monococcum, was assessed. The outbreeding Ae. speltoides was found to possess the highest degree of variability, the mean number of nucleotide substitutions among conspecific individuals being 0.027 substitutions per nucleotide

A. Breiman; M. Bogher; H. Sternberg; D. Graur

1991-01-01

162

Molecular genetic analysis of five spike-related traits in wheat using RIL and immortalized F2 populations.  

PubMed

Kernel number per spike is one of the most important yield components of wheat. To map QTLs related to kernel number including spike length (SPL), spikelet number per spike (SPN), fertile spikelet number (FSPN), sterile spikelet number (SSPN) and compactness, and to characterize the inheritance modes of the QTLs and two-locus interactions, 136 recombinant inbred lines (RILs) derived from 'Nanda2419' x 'Wangshuibai' and an immortalized F(2 )population (IF(2)) generated by randomly permutated intermating of these RILs were investigated. QTL mapping made use of the previously constructed over 3300 cM linkage map of the RIL population. Three, five, two, two and six chromosome regions were identified, respectively, for their association with SPL, SPN, FSPN, SSPN, and compactness in at least two of the three environments examined. All compactness QTLs but one shared the respective intervals of QSpn.nau-5A and the SPL QTLs. Xcfd46-Xwmc702 interval on chromosome 7D was related to all traits but SSPN and had consistently the largest effects. The fact that not all the compactness QTL intervals were related to both SPL and SPN indicates that compactness is regulated by different mechanisms. Interval coincidence between QTLs of SPL and SPN and between QTLs of FSPN and SSPN was minimal. For all the traits, favorable alleles exist in both parents. Inheritance modes from additiveness to overdominance of the QTLs were revealed and two-locus interactions were detected, implying that the traits studied are under complex genetic control. The results could contribute to wheat yield improvement and better use of Wangshuibai and Nanda2419 the two special germplasms in wheat breeding program. PMID:17033810

Ma, Zhengqiang; Zhao, Dongmei; Zhang, Caiqin; Zhang, Zhengzhi; Xue, Shulin; Lin, Feng; Kong, Zhongxin; Tian, Dagang; Luo, Qingyun

2006-10-11

163

Effect of genome and ploidy on photosynthesis of wheat  

Microsoft Academic Search

We assessed (1) the effects of addition and doses of the D genome from different sources and (2) the addition of either the\\u000a A genome or the D genome on the photosynthesis of synthesized hexaploid wheats. On average, the increased doses of the D genome\\u000a reduced photosynthesis, but the depression was dependent on the source of the D genome. Two

N. Watanabe; S. Kobayashi; Y. Furuta

1997-01-01

164

Resistance to Soil-borne cereal mosaic virus in durum wheat is controlled by a major QTL on chromosome arm 2BS and minor loci.  

PubMed

Soil-borne cereal mosaic (SBCM) is a viral disease, which seriously affects hexaploid as well as tetraploid wheat crops in Europe. In durum wheat (Triticum durum Desf.), the elite germplasm is characterized by a wide range of responses to SBCMV, from susceptibility to almost complete resistance. In this study, the genetic analysis of SBCMV resistance was carried out using a population of 181 durum wheat recombinant inbred lines (RILs) obtained from Meridiano (resistant) × Claudio (moderately susceptible), which were profiled with SSR and DArT markers. The RILs were characterized for SBCMV response in the field under severe and uniform SBCMV infection during 2007 and 2008. A wide range of disease reactions (as estimated by symptom severity and DAS-ELISA) was observed. A large portion of the variability for SBCMV response was explained by a major QTL (QSbm.ubo-2BS) located in the distal telomeric region of chromosome 2BS near the marker triplet Xbarc35-Xwmc661-Xgwm210, with R(2) values ranging from 51.6 to 91.6%. The favorable allele was contributed by Meridiano. Several QTLs with minor effects on SBCMV response were also detected. Consistently with the observed transgressive segregation, the resistance alleles at minor QTLs were contributed by both parents. The presence and effects of QSbm.ubo-2BS were validated through association mapping in a panel of 111 elite durum wheat accessions. PMID:21594676

Maccaferri, Marco; Ratti, Claudio; Rubies-Autonell, Concepcion; Vallega, Victor; Demontis, Andrea; Stefanelli, Sandra; Tuberosa, Roberto; Sanguineti, Maria Corinna

2011-05-19

165

Identification and phylogenetic analysis of a CC-NBS-LRR encoding gene assigned on chromosome 7B of wheat.  

PubMed

Hexaploid wheat displays limited genetic variation. As a direct A and B genome donor of hexaploid wheat, tetraploid wheat represents an important gene pool for cultivated bread wheat. Many disease resistant genes express conserved domains of the nucleotide-binding site and leucine-rich repeats (NBS-LRR). In this study, we isolated a CC-NBS-LRR gene locating on chromosome 7B from durum wheat variety Italy 363, and designated it TdRGA-7Ba. Its open reading frame was 4014 bp, encoding a 1337 amino acid protein with a complete NBS domain and 18 LRR repeats, sharing 44.7% identity with the PM3B protein. TdRGA-7Ba expression was continuously seen at low levels and was highest in leaves. TdRGA-7Ba has another allele TdRGA-7Bb with a 4 bp deletion at position +1892 in other cultivars of tetraploid wheat. In Ae. speltoides, as a B genome progenitor, both TdRGA-7Ba and TdRGA-7Bb were detected. In all six species of hexaploid wheats (AABBDD), only TdRGA-7Bb existed. Phylogenic analysis showed that all TdRGA-7Bb type genes were grouped in one sub-branch. We speculate that TdRGA-7Bb was derived from a TdRGA-7Ba mutation, and it happened in Ae. speltoides. Both types of TdRGA-7B participated in tetraploid wheat formation. However, only the TdRGA-7Bb was retained in hexaploid wheat. PMID:23887654

Gong, Caiyan; Cao, Shuanghe; Fan, Renchun; Wei, Bo; Chen, Guiping; Wang, Xianping; Li, Yiwen; Zhang, Xiangqi

2013-07-24

166

Identification and Phylogenetic Analysis of a CC-NBS-LRR Encoding Gene Assigned on Chromosome 7B of Wheat  

PubMed Central

Hexaploid wheat displays limited genetic variation. As a direct A and B genome donor of hexaploid wheat, tetraploid wheat represents an important gene pool for cultivated bread wheat. Many disease resistant genes express conserved domains of the nucleotide-binding site and leucine-rich repeats (NBS-LRR). In this study, we isolated a CC-NBS-LRR gene locating on chromosome 7B from durum wheat variety Italy 363, and designated it TdRGA-7Ba. Its open reading frame was 4014 bp, encoding a 1337 amino acid protein with a complete NBS domain and 18 LRR repeats, sharing 44.7% identity with the PM3B protein. TdRGA-7Ba expression was continuously seen at low levels and was highest in leaves. TdRGA-7Ba has another allele TdRGA-7Bb with a 4 bp deletion at position +1892 in other cultivars of tetraploid wheat. In Ae. speltoides, as a B genome progenitor, both TdRGA-7Ba and TdRGA-7Bb were detected. In all six species of hexaploid wheats (AABBDD), only TdRGA-7Bb existed. Phylogenic analysis showed that all TdRGA-7Bb type genes were grouped in one sub-branch. We speculate that TdRGA-7Bb was derived from a TdRGA-7Ba mutation, and it happened in Ae. speltoides. Both types of TdRGA-7B participated in tetraploid wheat formation. However, only the TdRGA-7Bb was retained in hexaploid wheat.

Gong, Caiyan; Cao, Shuanghe; Fan, Renchun; Wei, Bo; Chen, Guiping; Wang, Xianping; Li, Yiwen; Zhang, Xiangqi

2013-01-01

167

Evolution of polyploid triticum wheats under cultivation: the role of domestication, natural hybridization and allopolyploid speciation in their diversification.  

PubMed

The evolution of the polyploid Triticum wheats is distinctive in that domestication, natural hybridization and allopolyploid speciation have all had significant impacts on their diversification. In this review, I outline the phylogenetic relationships of cultivated wheats and their wild relatives and provide an overview of the recent progress and remaining issues in understanding the genetic and ecological factors that favored their evolution. An attempt is made to view the evolution of the polyploid Triticum wheats as a continuous process of diversification that was initiated by domestication of tetraploid emmer wheat and driven by various natural events ranging from interploidy introgression via hybridization to allopolyploid speciation of hexaploid common wheat, instead of viewing it as a group of discrete evolutionary processes that separately proceeded at the tetraploid and hexaploid levels. This standpoint underscores the important role of natural hybridization in the reticulate diversification of the tetraploid-hexaploid Triticum wheat complex and highlights critical, but underappreciated, issues that concern the allopolyploid speciation of common wheat. PMID:21317146

Matsuoka, Yoshihiro

2011-02-10

168

Accumulation of an Acidic Dehydrin in the Vicinity of the Plasma Membrane during Cold Acclimation of Wheat  

Microsoft Academic Search

Expression of the acidic dehydrin gene wcor410 was found to be associated with the development of freezing tolerance in several Gramineae species. This gene is part of a family of three homologous members, wcor410 , wcor410b , and wcor410c , that have been mapped to the long arms of the homologous group 6 chromosomes of hexaploid wheat. To gain insight

Jean Danyluk; André Perron; Mario Houde; Allen Limin; Brian Fowler; Nicole Benhamou; Fathey Sarhan

1998-01-01

169

CHROMOSOMAL LOCATIONS OF GENES FOR STEM RUST RESISTANCE IN MONOGENIC LINES DERIVED FROM TETRAPLOID WHEAT ACCESSION ST464  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genetics of resistance to stem rust (Puccinia graminis Pers.:Pers. f. sp. tritici Eriks. & Henn.) in durum (Triticum turgidum L. ssp. durum) is not as well understood as for hexaploid wheat (T. aestivum L.). Our objective was to determine the chromosomal location of genes for stem rust resistan...

170

MICROARRAY EXPRESSION PROFILES OF WHEAT ROOTS AND SHOOTS DURING COLD STRESS AND ROOT COLONIZATION BY BIOCONTROL PSEUDOMONAS FLUORESCENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop plant varieties having tolerance to multiple stresses are valuable in the face of the changing environment, growth habitat, and natural resources. In the Pacific Northwest (PNW), Triticum aestivum (hexaploid wheat) must be able to survive freezing temperatures and absence of irrigation. In addi...

171

The effect of specific chromosome and cytoplasm substitutions on the tissue culture response of wheat ( Triticum aestivum ) callus  

Microsoft Academic Search

Calli were initiated from immature embryos of four lines of hexaploid wheat (Triticum aestivum L. em. Thell), the euplasmic nuclear donor ‘Chinese Spring’, ‘Chinese Spring’ in which both 4B chromosomes were substituted by those of the variety ‘Cappelle-Desprez’ and two alloplasmic lines in which these nuclei were substituted into the cytoplasm of Aegilops ovata. The calli were found to differ

R. J. Mathias; K. Fukui

1986-01-01

172

The interaction of genotype and culture medium on the tissue culture responses of wheat (Triticum aestivum L. em. thell) callus  

Microsoft Academic Search

The effect of the interaction of genotype and culture medium on the initiation of callus from immature embryos and subsequent plant regeneration was investigated in eight hexaploid wheat lines. Intervarietal differences in culture response and interaction of the genotype with coconut milk are reported. The relative contributions of media and genotype effects to culture performance are assessed. The observation that

Raymond J. Mathias; Eric S. Simpson

1986-01-01

173

High-density mapping and marker development for the powdery mildew resistance gene PmAS846 derived from wild emmer wheat (Triticum turgidum var. dicoccoides).  

PubMed

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important foliar disease of wheat worldwide. The dominant powdery mildew resistance gene PmAS846 was transferred to the hexaploid wheat lines N9134 and N9738 from wild emmer wheat (Triticum dicoccoides) in 1995, and it is still one of the most effective resistance genes in China. A high resolution genetic map for PmAS846 locus was constructed using two F(2) populations and corresponding F(2:3) families developed from the crosses of N9134/Shaanyou 225 and N9738/Huixianhong. Synteny between wheat and Brachypodium distachyon and rice was used to develop closely linked molecular markers to reduce the genetic interval around PmAS846. Twenty-six expressed sequence tag-derived markers were mapped to the PmAS846 locus. Five markers co-segregated with PmAS846 in the F(2) population of N9134/Shaanyou 225. PmAS846 was physically located to wheat chromosome 5BL bin 0.75-0.76 within a gene-rich region. The markers order is conserved between wheat and Brachypodium distachyon, but rearrangements are present in rice. Two markers, BJ261635 and CJ840011 flanked PmAS846 and narrowed PmAS846 to a region that is collinear with 197 and 112 kb genomic regions on Brachypodium chromosome 4 and rice chromosome 9, respectively. The genes located on the corresponding homologous regions in Brachypodium, rice and barley could be considered for further marker saturation and identification of potential candidate genes for PmAS846. The markers co-segregating with PmAS846 provide a potential target site for positional cloning of PmAS846, and can be used for marker-assisted selection of this gene. PMID:22350087

Xue, Fei; Ji, Wanquan; Wang, Changyou; Zhang, Hong; Yang, Baoju

2012-02-18

174

Quantitative trait loci for resistance against powdery mildew in a segregating wheat×spelt population  

Microsoft Academic Search

Powdery mildew is one of the major diseases of wheat in regions with a maritime or semi-continental climate and can strongly\\u000a affect grain yield. The attempt to control powdery mildew with major resistance genes (Pm genes) has not provided a durable resistance. Breeding for quantitative resistance to powdery mildew is more promising, but\\u000a is difficult to select on a phenotypic

M. Keller; B. Keller; G. Schachermayr; M. Winzeler; J. E. Schmid; P. Stamp; M. M. Messmer

1999-01-01

175

Influence of within-field and landscape factors on aphid predator populations in wheat  

Microsoft Academic Search

The influence of prey density, within-field vegetation, and the composition and patchiness of the surrounding landscape on the abundance of insect predators of cereal aphids was studied in wheat fields in eastern South Dakota, USA. Cereal aphids, aphid predators, and within-field vegetation were sampled in 104 fields over a three year period (1988–1990). The composition and patchiness of the landscape

Norman C. Elliott; Robert W. Kieckhefer; Jang-Hoon Lee; Bryan W. French

1999-01-01

176

Effects of Metsulfuron-Methyl on the Microbial Population and Enzyme Activities in Wheat Rhizosphere Soil  

Microsoft Academic Search

The effects of metsulfuron-methyl, a sulfonylurea herbicide, on the wheat soil microorganisms were evaluated by the methods of microbial inoculation culture, and the activities of three enzymes were measured using the colorimetric method. The tolerant microorganisms that can resist 500 ? g·g metsulfuron-methyl in the counting culture medium were studied specially. Metsulfuron-methyl distinctly inhibited the common aerobic heterotriphic bacteria, but

YONG HUA HE; DONG SHENG SHEN; CHENG RAN FANG; RUO HE; YIN MEI ZHU

2006-01-01

177

DNA markers for Fusarium head blight resistance QTLs in two wheat populations  

Microsoft Academic Search

Genetic resistance to Fusarium head blight (FHB), caused by Fusarium graminearum, is necessary to reduce the wheat grain yield and quality losses caused by this disease. Development of resistant cultivars\\u000a has been slowed by poorly adapted and incomplete resistance sources and confounding environmental effects that make screening\\u000a of germplasm difficult. DNA markers for FHB resistance QTLs have been identified and

J. A. Anderson; R. W. Stack; S. Liu; B. L. Waldron; A. D. Fjeld; C. Coyne; B. Moreno-Sevilla; J. Mitchell Fetch; Q. J. Song; P. B. Cregan; R. C. Frohberg

2001-01-01

178

Deciphering the genetics of flowering time by an association study on candidate genes in bread wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Earliness is very important for the adaptation of wheat to environmental conditions and the achievement of high grain yield.\\u000a A detailed knowledge of key genetic components of the life cycle would enable an easier control by the breeders. The objective\\u000a of the study was to investigate the effect of candidate genes on flowering time. Using a collection of hexaploid wheat

Michel Rousset; Isabelle Bonnin; Carine Remoué; Matthieu Falque; Bénédicte Rhoné; Jean-Baptiste Veyrieras; Delphine Madur; Alain Murigneux; François Balfourier; Jacques Le Gouis; Sylvain Santoni; Isabelle Goldringer

179

Chromosomes 3B and 4D are associated with several milling and baking quality traits in a soft white spring wheat (Triticum aestivum L.) population  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat is marketed based on end-use quality characteristics and better knowledge of the underlying genetics of specific quality parameters is essential to enhance the breeding process. A set of 188 recombinant inbred lines from a ‘Louise’ by ‘Penawawa’ mapping population was grown in two crop years a...

180

Embryo lethality in wheat × rye hybrids—mode of inheritance and the identification of a complementary gene in wheat  

Microsoft Academic Search

Crosses between hexaploid wheat and rye can only succeed when pre- and post-zygotic barriers have been overcome. A rye gene\\u000a determining embryo lethality (Eml-R1), which is involved in post-zygotic isolation, has been mapped to chromosome 6R. In the present paper the mode of inheritance\\u000a of Eml-R1 was studied by employing a wheat\\/rye chromosome 6R addition line. We show that Eml-R1

N. Tikhenko; N. Tsvetkova; A. Voylokov; O. Dobrovolskaya; K. Zaynali Nezhad; M. S. Röder; A. Börner

2010-01-01

181

[Manaca, sweet potato and yam: possible substitutes of wheat in foods for two ethnic population in Venezuelan Amazon].  

PubMed

In this study, flours from manaca or acai (Euterpe oleracea Mart), sweet potato (Ipomea batatas), and yam (Dioscorea spp.), species grown in the Venezuelan Amazon, were obtained. The proximal composition, water activity (a(w)), Fe, Ca, Zn, Mg, Cu, Na and K content were determined for the flours of manaca, sweet potato and yam. These flours were used as ingredients of products for the inhabitants of the indigenous populations of the Venezuelan Amazon (Piaroa and Hiwi). Two types of products that traditionally contain wheat flour in their formulation (ingredient they know by transculturation) were formulated; an attempt to substitute it totally or partially by the manaca, sweet potato and/or yam flours was made. For the selection of the products to be formulated, the preferences and eating habits of the indigenous communities and ease and simplicity of the preparations to be developed, were considered. The two products formulated were cookies and "small cakes". To decide on the formulation(s) of the final product(s), sensorial evaluations were made in the laboratory and in the indigenous communities Piaroa and Hiwi. High fat content (16%), dietetic fiber (59.7%) and iron (25 mg / 100 g) in manaca or acai flour were remarkable. Two types of cookies and two of "small cakes" were equally accepted by the indigenous communities. Cookies supply a high iron amount (about 24%). The feasibility of substituting the wheat flour by manaca, sweet potato and yam flour in products accepted by two ethnic populations of the Venezuelan Amazon was demonstrated. PMID:16786737

Sangronis, Elba; Teixeira, Patricia; Otero, Mariana; Guerra, Marisa; Hidalgo, Glida

2006-03-01

182

Diversity of long terminal repeat retrotransposon genome distribution in natural populations of the wild diploid wheat Aegilops speltoides.  

PubMed

The environment can have a decisive influence on the structure of the genome, changing it in a certain direction. Therefore, the genomic distribution of environmentally sensitive transposable elements may vary measurably across a species area. In the present research, we aimed to detect and evaluate the level of LTR retrotransposon intraspecific variability in Aegilops speltoides (2n = 2x = 14), a wild cross-pollinated relative of cultivated wheat. The interretrotransposon amplified polymorphism (IRAP) protocol was applied to detect and evaluate the level of retrotransposon intraspecific variability in Ae. speltoides and closely related species. IRAP analysis revealed significant diversity in TE distribution. Various genotypes from the 13 explored populations significantly differ with respect to the patterns of the four explored LTR retrotransposons (WIS2, Wilma, Daniela, and Fatima). This diversity points to a constant ongoing process of LTR retrotransposon fraction restructuring in populations of Ae. speltoides throughout the species' range and within single populations in time. Maximum changes were recorded in genotypes from small stressed populations. Principal component analysis showed that the dynamics of the Fatima element significantly differ from those of WIS2, Wilma, and Daniela. In terms of relationships between Sitopsis species, IRAP analysis revealed a grouping with Ae. sharonensis and Ae. longissima forming a separate unit, Ae. speltoides appearing as a dispersed group, and Ae. bicornis being in an intermediate position. IRAP display data revealed dynamic changes in LTR retrotransposon fractions in the genome of Ae. speltoides. The process is permanent and population specific, ultimately leading to the separation of small stressed populations from the main group. PMID:22042572

Hosid, Elena; Brodsky, Leonid; Kalendar, Ruslan; Raskina, Olga; Belyayev, Alexander

2011-10-31

183

Identification of quantitative trait loci and associated candidate genes for low-temperature tolerance in cold-hardy winter wheat.  

PubMed

Low-temperature (LT) tolerance is an important economic trait in winter wheat (Triticum aestivum L.) that determines the plants' ability to cope with below freezing temperatures. Essential elements of the LT tolerance mechanism are associated with the winter growth habit controlled by the vernalization loci (Vrn-1) on the group 5 chromosomes. To identify genomic regions, which in addition to vrn-1 determine the level of LT tolerance in hexaploid wheat, two doubled haploid (DH) mapping populations were produced using parents with winter growth habit (vrn-A1, vrn-B1, and vrn-D1) but showing different LT tolerance levels. A total of 107 DH lines were analyzed by genetic mapping to produce a consensus map of 2,873 cM. The LT tolerance levels for the Norstar (LT(50)=-20.7 degrees C) x Winter Manitou (LT(50)=-14.3 degrees C) mapping population ranged from -12.0 to -22.0 degrees C. Single marker analysis and interval mapping of phenotyped lines revealed a major quantitative trait locus (QTL) on chromosome 5A and a weaker QTL on chromosome 1D. The 5A QTL located 46 cM proximal to the vrn-A1 locus explained 40% of the LT tolerance variance. Two C-repeat Binding Factor (CBF) genes expressed during cold acclimation in Norstar were located at the peak of the 5A QTL. PMID:16775685

Båga, Monica; Chodaparambil, Sanjay V; Limin, Allen E; Pecar, Marin; Fowler, D Brian; Chibbar, Ravindra N

2006-06-15

184

Chromosome translocations in wild populations of tetraploid emmer wheat in Israel and Turkey.  

PubMed

Translocation frequencies (as compared to the standard chromosome arrangement typified by that in 'Chinese Spring') in 9 or more genotypes from each of 15 populations of Triticum dicoccoides in Israel were determined. Data also were obtained from 2 genotypes of the southernmost population (Jaba). A single population from Turkey was also investigated. There were 119 genotypes with translocations in the sample of 171 genotypes investigated (70%). The frequency of translocations in different populations varied from 0.27 to 1.00, and all populations had 1 or more genotypes with one or more translocations. Some populations such as Qazrin appeared to be homogeneous for translocations, but most populations were heterogeneous. A sample of 17 genotypes from 12 of the populations were crossed with the Langdon D-genome disomic substitutions to determine the identity of the chromosomes involved in the translocations. There were nine genotypes with translocations and with the exception of a 2A/2B translocation, none of them involved the same chromosomes. The B-genome chromosomes were involved in translocations more frequently than the A-genome chromosomes. Translocation frequencies (TF) of the various populations were correlated with environmental variables, primarily with water availability and humidity, and possibly also with soil type. In general, TF was higher in peripheral populations in the ecologically heterogeneous frontiers of species distribution than in the central populations located in the catchment area of the upper Jordan valley. PMID:24169905

Joppa, L R; Nevo, E; Beiles, A

1995-10-01

185

Genetic transformation of Indian bread (T. aestivum) and pasta (T. durum) wheat by particle bombardment of mature embryo-derived calli  

Microsoft Academic Search

BACKGROUND: Particle bombardment has been successfully employed for obtaining transgenics in cereals in general and wheat in particular. Most of these procedures employ immature embryos which are not available throughout the year. The present investigation utilizes mature seeds as the starting material and the calli raised from the hexaploid Triticum aestivum and tetraploid Triticum durum display a high regeneration response

Debasis Patnaik; Paramjit Khurana

2003-01-01

186

Differential expression of the pathogenesis-related protein 1 (PR-1) gene family in stem rust (Puccinia graminis f. sp. tritici )-wheat interactions  

Technology Transfer Automated Retrieval System (TEKTRAN)

The group 1 pathogenesis-related (PR-1) proteins, known as hallmarks of defense pathways, are encoded by a multigene family in hexaploid wheat (Triticum aestivum L.) that includes at least 12 closely related TaPr-1 genes responsive to infection by the necrotrophic pathogen Stagonospora nodorum (Sn) ...

187

Population Analysis of the Fusarium graminearum Species Complex from Wheat in China Show a Shift to More Aggressive Isolates  

PubMed Central

A large number of Fusarium isolates was collected from blighted wheat spikes originating from 175 sampling sites, covering 15 provinces in China. Species and trichothecene chemotype determination by multilocus genotyping (MLGT) indicated that F. graminearum s. str. with the 15-acetyl deoxynivalenol (15ADON) chemotype and F. asiaticum with either the nivalenol (NIV) or the 3-acetyl deoxynivalenol (3ADON) chemotype were the dominant causal agents. Bayesian model-based clustering with allele data obtained with 12 variable number of tandem repeats (VNTR) markers, detected three genetic clusters that also show distinct chemotypes. High levels of population genetic differentiation and low levels of effective number of migrants were observed between these three clusters. Additional genotypic analyses revealed that F. graminearum s. str. and F. asiaticum are sympatric. In addition, composition analysis of these clusters indicated a biased gene flow from 3ADON to NIV producers in F. asiaticum. In phenotypic analyses, F. asiaticum that produce 3ADON revealed significant advantages over F. asiaticum that produce NIV in pathogenicity, growth rate, fecundity, conidial length, trichothecene accumulation and resistance to benzimidazole. These results suggest that natural selection drives the spread of a more vigorous, more toxigenic pathogen population which also shows higher levels of fungicide resistance.

Zhang, Hao; Van der Lee, Theo; Waalwijk, Cees; Chen, Wanquan; Xu, Jin; Xu, Jingsheng; Zhang, Ye; Feng, Jie

2012-01-01

188

A NEW HOST SELECTIVE TOXIN PRODUCED BY STAGONOSPORA NODORUM AND ITS SIGNIFICANCE IN DISEASE USING A SEGREGATING WHEAT MAPPING POPULATION.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stagonospora nodorum blotch is a devastating disease of wheat and durum throughout the world. We have recently identified a new host selective toxin (SnTox2) from culture filtrates of Stagonospora nodorum. The toxin shows selective action on several different wheat genotypes indicating that it is...

189

Conditional QTL mapping for plant height with respect to the length of the spike and internode in two mapping populations of wheat  

Microsoft Academic Search

Plant height (PH) in wheat is a complex trait; its components include spike length (SL) and internode lengths. To precisely\\u000a analyze the factors affecting PH, two F8:9 recombinant inbred line (RIL) populations comprising 485 and 229 lines were generated. Crosses were performed between Weimai\\u000a 8 and Jimai 20 (WJ) and between Weimai 8 and Yannong 19 (WY). Possible genetic relationships

Fa CuiJun; Jun Li; Anming Ding; Chunhua Zhao; Lin Wang; Xiuqin Wang; Sishen Li; Yinguang Bao; Xingfeng Li; Deshun Feng; Lingrang Kong; Honggang Wang

2011-01-01

190

Wheat Allergy  

MedlinePLUS

... years. Most children with wheat allergy have other food allergies. Children usually outgrow wheat allergy between ages 3 and ... Hand Scheduled Section Focus Related Links Related Guides Children Parent Food allergy References Inomata N. Wheat allergy. Current Opinion ...

191

A Novel Retrotransposon Inserted in the Dominant Vrn-B1 Allele Confers Spring Growth Habit in Tetraploid Wheat (Triticum turgidum L.).  

PubMed

Vernalization genes determine winter/spring growth habit in temperate cereals and play important roles in plant development and environmental adaptation. In wheat (Triticum L. sp.), it was previously shown that allelic variation in the vernalization gene VRN1 was due to deletions or insertions either in the promoter or in the first intron. Here, we report a novel Vrn-B1 allele that has a retrotransposon in its promoter conferring spring growth habit. The VRN-B1 gene was mapped in a doubled haploid population that segregated for winter-spring growth habit but was derived from two spring tetraploid wheat genotypes, the durum wheat (T. turgidum subsp. durum) variety 'Lebsock' and T. turgidum subsp. carthlicum accession PI 94749. Genetic analysis revealed that Lebsock carried the dominant Vrn-A1 and recessive vrn-B1 alleles, whereas PI 94749 had the recessive vrn-A1 and dominant Vrn-B1 alleles. The Vrn-A1 allele in Lebsock was the same as the Vrn-A1c allele previously reported in hexaploid wheat. No differences existed between the vrn-B1 and Vrn-B1 alleles, except that a 5463-bp insertion was detected in the 5'-UTR region of the Vrn-B1 allele. This insertion was a novel retrotransposon (designated as retrotrans_VRN), which was flanked by a 5-bp target site duplication and contained primer binding site and polypurine tract motifs, a 325-bp long terminal repeat, and an open reading frame encoding 1231 amino acids. The insertion of retrotrans_VRN resulted in expression of Vrn-B1 without vernalization. Retrotrans_VRN is prevalent among T. turgidum subsp. carthlicum accessions, less prevalent among T. turgidum subsp. dicoccum accessions, and rarely found in other tetraploid wheat subspecies. PMID:22384375

Chu, C-G; Tan, C T; Yu, G-T; Zhong, S; Xu, S S; Yan, L

2011-12-01

192

A Novel Retrotransposon Inserted in the Dominant Vrn-B1 Allele Confers Spring Growth Habit in Tetraploid Wheat (Triticum turgidum L.)  

PubMed Central

Vernalization genes determine winter/spring growth habit in temperate cereals and play important roles in plant development and environmental adaptation. In wheat (Triticum L. sp.), it was previously shown that allelic variation in the vernalization gene VRN1 was due to deletions or insertions either in the promoter or in the first intron. Here, we report a novel Vrn-B1 allele that has a retrotransposon in its promoter conferring spring growth habit. The VRN-B1 gene was mapped in a doubled haploid population that segregated for winter-spring growth habit but was derived from two spring tetraploid wheat genotypes, the durum wheat (T. turgidum subsp. durum) variety ‘Lebsock’ and T. turgidum subsp. carthlicum accession PI 94749. Genetic analysis revealed that Lebsock carried the dominant Vrn-A1 and recessive vrn-B1 alleles, whereas PI 94749 had the recessive vrn-A1 and dominant Vrn-B1 alleles. The Vrn-A1 allele in Lebsock was the same as the Vrn-A1c allele previously reported in hexaploid wheat. No differences existed between the vrn-B1 and Vrn-B1 alleles, except that a 5463-bp insertion was detected in the 5?-UTR region of the Vrn-B1 allele. This insertion was a novel retrotransposon (designated as retrotrans_VRN), which was flanked by a 5-bp target site duplication and contained primer binding site and polypurine tract motifs, a 325-bp long terminal repeat, and an open reading frame encoding 1231 amino acids. The insertion of retrotrans_VRN resulted in expression of Vrn-B1 without vernalization. Retrotrans_VRN is prevalent among T. turgidum subsp. carthlicum accessions, less prevalent among T. turgidum subsp. dicoccum accessions, and rarely found in other tetraploid wheat subspecies.

Chu, C.-G.; Tan, C. T.; Yu, G.-T; Zhong, S.; Xu, S. S.; Yan, L.

2011-01-01

193

Transferability of wheat microsatellites to diploid Triticeae species carrying the A, B and D genomes  

Microsoft Academic Search

Hexaploid wheat (Triticum aestivum L em Thell) is derived from a complex hybridization procedure involving three diploid species carrying the A, B and D genomes.\\u000a In this study, we evaluated the ability of microsatellite sequences from T. aestivum to be revealed on different ancestral diploid species more or less closely related, i.e. to test for their transferability.\\u000a Fifty five primer

P. Sourdille; M. Tavaud; G. Charmet; M. Bernard

2001-01-01

194

Analysis of hybrid lethality in F 1 wheat-rye hybrid embryos  

Microsoft Academic Search

The effect of the Embryo lethality mutant (Eml) of rye was studied in crosses between hexaploid wheat and corresponding inbred rye line (L2). Histological analysis of hybrid\\u000a embryos revealed morphological differences 16 days after pollination. Eml was found to arrest the formation of shoot meristem but had no influence on root meristem formation. The effect of Eml cannot be overcome by

N. Tikhenko; T. Rutten; A. Voylokov; A. Houben

2008-01-01

195

Acc homoeoloci and the evolution of wheat genomes.  

PubMed

The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3-2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. PMID:18599450

Chalupska, D; Lee, H Y; Faris, J D; Evrard, A; Chalhoub, B; Haselkorn, R; Gornicki, P

2008-07-03

196

Population-Specific Patterns of Linkage Disequilibrium and SNP Variation in Spring and Winter Polyploid Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Single nucleotide polymorphisms (SNPs) are ideally suited for the construction of high-resolution genetic maps, studying population evolutionary history and performing genome-wide association mapping experiments. Here we used a genome-wide set of 1536 SNPs to study linkage disequilibrium (LD) and po...

197

Distribution and habitat segregation on different spatial scales among diploid, tetraploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps  

PubMed Central

Background and Aims The spatial distribution of cytotypes can provide valuable insights into evolutionary patterns of polyploid complexes. In a previous study the macro-scale distribution of the three main cytotypes in Senecio carniolicus (Asteraceae) within the Eastern Alps was characterized. Employing a roughly 12-fold extended sampling, the present study focuses on unravelling patterns of cytotype distribution on the meso- and microscale and on correlating those with ecological properties of the growing sites. Methods DAPI flow cytometry of dried samples was used to determine DNA ploidy level in 5033 individuals from 100 populations spread over the entire Eastern Alpine distribution area of S. carniolicus. Descriptors of microhabitats as well as spatial data were recorded in the field, and analysed with a mixed-effects ANOVA. Key Results Extensive variation in DNA ploidy levels (2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x) was detected. Of the main cytotypes, diploids and hexaploids were widespread and had strongly overlapping distributions resulting in the frequent occurrence of cytotype mixtures (half of the investigated populations), whereas tetraploids were disjunctly distributed and occurred in the south-west and the east of the species' distribution area. In spite of the frequent co-occurrence of cytotypes, only 1 % of the samples belonged to secondary cytotypes (3x, 5x, 7x, 8x, 9x). Diploids, tetraploids and hexaploids were altitudinally segregated, but with broad overlap. Similarly, highly significant differences in vegetation and rock cover as well as microhabitat exposure were found between the main cytotypes. Conclusions Senecio carniolicus shows a remarkable diversity of cytotypes. The distribution of the three main cytotypes (2x, 4x, 6x) has been shaped by Pleistocene glaciations to different extents. Whereas tetraploids are nearly entirely restricted to refugia, hexaploids colonized areas that were extensively glaciated. Diploid and hexaploid individuals often co-occur in mixed populations, where they are spatially and ecologically segregated at both the meso-scale (altitudinal differentiation, exposure of the growing site) and the micro-scale (cover of vegetation and bare rock). With regard to the ecological parameters investigated, the tetraploid cytotype occupies an intermediate position. The rareness of secondary cytotypes suggests the presence of strong pre- or post-zygotic mating barriers.

Sonnleitner, Michaela; Flatscher, Ruth; Escobar Garcia, Pedro; Rauchova, Jana; Suda, Jan; Schneeweiss, Gerald M.; Hulber, Karl; Schonswetter, Peter

2010-01-01

198

Heat and drought adaptive QTL in a wheat population designed to minimize confounding agronomic effects  

Microsoft Academic Search

A restricted range in height and phenology of the elite Seri\\/Babax recombinant inbred line (RIL) population makes it ideal\\u000a for physiological and genetic studies. Previous research has shown differential expression for yield under water deficit associated\\u000a with canopy temperature (CT). In the current study, 167 RILs plus parents were phenotyped under drought (DRT), hot irrigated\\u000a (HOT), and temperate irrigated (IRR)

R. Suzuky Pinto; Matthew P. Reynolds; Ky L. Mathews; C. Lynne McIntyre; Juan-Jose Olivares-Villegas; Scott C. Chapman

2010-01-01

199

A high-throughput method for the detection of homoeologous gene deletions in hexaploid wheat  

Microsoft Academic Search

BACKGROUND: Mutational inactivation of plant genes is an essential tool in gene function studies. Plants with inactivated or deleted genes may also be exploited for crop improvement if such mutations\\/deletions produce a desirable agronomical and\\/or quality phenotype. However, the use of mutational gene inactivation\\/deletion has been impeded in polyploid plant species by genetic redundancy, as polyploids contain multiple copies of

Timothy L Fitzgerald; Kemal Kazan; Zhongyi Li; Matthew K Morell; John M Manners

2010-01-01

200

Starch waxiness in hexaploid wheat (Triticum aestivum L.) by NIR reflectance spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch, the primary energy storage component of plants, consists of two large macromolecules, amylose and amylopectin. Each molecule is composed of long chains of alpha-D-glucopyranosyl units, with branching present in amylopectin and absent in amylose. The relative abundance of these two molecules ...

201

Diversity arrays technology (DArT) for high-throughput profiling of the hexaploid wheat genome  

Microsoft Academic Search

Despite a substantial investment in the development of panels of single nucleotide polymorphism (SNP) markers, the simple sequence repeat (SSR) technology with a limited multiplexing capability remains a standard, even for applications requiring whole-genome information. Diversity arrays technology (DArT) types hundreds to thousands of genomic loci in parallel, as previously demonstrated in a number diploid plant species. Here we show

Mona Akbari; Peter Wenzl; Vanessa Caig; Jason Carling; Ling Xia; Shiying Yang; Grzegorz Uszynski; Volker Mohler; Anke Lehmensiek; Haydn Kuchel; Mathew J. Hayden; Neil Howes; Peter Sharp; Peter Vaughan; Bill Rathmell; Eric Huttner; Andrzej Kilian

2006-01-01

202

The chromosomal locations of leaf peroxidase genes in hexaploid wheat, rye and barley  

Microsoft Academic Search

Eight leaf peroxidase isozymes were distinguished by IEF in ‘Chinese Spring’. Two genes which control the production of three of these isozymes were located on chromosome arms 1BS and 1DS by nullisomic analysis. These loci probably form part of a homoeoallelic series and have been designated Per-B1 and Per-D1 respectively. Analysis of chromosome 1B short arm terminal deletion stocks indicated

C. C. Ainsworth; H. M. Johnson; E. A. Jackson; T. E. Miller; M. D. Gale

1984-01-01

203

The origin of the B-genome of bread wheat (Triticum aestivum L.).  

PubMed

Understanding the origin of cultivated wheats would further their genetic improvement. The hexaploid bread wheat (Triticum aestivum L., AABBDD) is believed to have originated through one or more rare hybridization events between Aegilops tauschii (DD) and the tetraploid T. turgidum (AABB). Progenitor of the A-genome of the tetraploid and hexaploid wheats has generally been accepted to be T. urartu. In spite of the large number of attempts and published reports about the origin of the B-genome in cultivated wheats, the donor of the B-genome is still relatively unknown and controversial and, hence, remains open. This genome has been found to be closely related to the S-genome of the Sitopsis section (Ae. speltoides, Ae. longissima, Ae. sharonensis, Ae. searsii, and Ae. bicornis) of the genus Aegilops L. Among Sitopsis species, the most positive evidence has been accumulated for Ae. speltoides as the progenitor of the B-genome. Therefore, one or more of the Sitopsis species were proposed frequently as the B-genome donor. Although several reviews have been written on the origin of the genomes of wheat over the years, this paper will attempt for the first time to review the immense literature on the subject, with a particular emphasis on the B-genome which has attracted a huge attention over some 100 years. The ambiguity and conflicting results in most of the methods employed in deducing the precise B-genome donor/s to bread wheat are also discussed. PMID:23755530

Haider, N

2013-03-01

204

Taxonomic Structure and Monitoring of the Dominant Population of Lactic Acid Bacteria during Wheat Flour Sourdough Type I Propagation Using Lactobacillus sanfranciscensis Starters?  

PubMed Central

The structure and stability of the dominant lactic acid bacterium population were assessed during wheat flour sourdough type I propagation by using singly nine strains of Lactobacillus sanfranciscensis. Under back-slopping propagation with wheat flour type 0 F114, cell numbers of presumptive lactic acid bacteria varied slightly between and within starters. As determined by randomly amplified polymorphic DNA-PCR and restriction endonuclease analysis-pulsed-field gel electrophoresis analyses, only three (LS8, LS14, and LS44) starters dominated throughout 10 days of propagation. The others progressively decreased to less than 3 log CFU g?1. Partial sequence analysis of the 16S rRNA and recA genes and PCR-denaturating gradient gel electrophoresis analysis using the rpoB gene allowed identification of Weissella confusa, Lactobacillus sanfranciscensis, Lactobacillus plantarum, Lactobacillus rossiae, Lactobacillus brevis, Lactococcus lactis subsp. lactis, Pediococcus pentosaceus, and Lactobacillus spp. as the dominant species of the raw wheat flour. At the end of propagation, one autochthonous strain of L. sanfranciscensis was found in all the sourdoughs. Except for L. brevis, strains of the above species were variously found in the mature sourdoughs. Persistent starters were found in association with other biotypes of L. sanfranciscensis and with W. confusa or L. plantarum. Sourdoughs were characterized for acidification, quotient of fermentation, free amino acids, and community-level catabolic profiles by USING Biolog 96-well Eco microplates. In particular, catabolic profiles of sourdoughs containing persistent starters behaved similarly and were clearly differentiated from the others. The three persistent starters were further used for the production of sourdoughs and propagated by using another wheat flour whose lactic acid bacterium population in part differed from the previous one. Also, in this case all three starter strains persisted during propagation.

Siragusa, Sonya; Di Cagno, Raffaella; Ercolini, Danilo; Minervini, Fabio; Gobbetti, Marco; De Angelis, Maria

2009-01-01

205

Heat and drought adaptive QTL in a wheat population designed to minimize confounding agronomic effects  

PubMed Central

A restricted range in height and phenology of the elite Seri/Babax recombinant inbred line (RIL) population makes it ideal for physiological and genetic studies. Previous research has shown differential expression for yield under water deficit associated with canopy temperature (CT). In the current study, 167 RILs plus parents were phenotyped under drought (DRT), hot irrigated (HOT), and temperate irrigated (IRR) environments to identify the genomic regions associated with stress-adaptive traits. In total, 104 QTL were identified across a combination of 115 traits × 3 environments × 2 years, of which 14, 16, and 10 QTL were associated exclusively with DRT, HOT, and IRR, respectively. Six genomic regions were related to a large number of traits, namely 1B-a, 2B-a, 3B-b, 4A-a, 4A-b, and 5A-a. A yield QTL located on 4A-a explained 27 and 17% of variation under drought and heat stress, respectively. At the same location, a QTL explained 28% of the variation in CT under heat, while 14% of CT variation under drought was explained by a QTL on 3B-b. The T1BL.1RS (rye) translocation donated by the Seri parent was associated with decreased yield in this population. There was no co-location of consistent yield and phenology or height-related QTL, highlighting the utility of using a population with a restricted range in anthesis to facilitate QTL studies. Common QTL for drought and heat stress traits were identified on 1B-a, 2B-a, 3B-b, 4A-a, 4B-b, and 7A-a confirming their generic value across stresses. Yield QTL were shown to be associated with components of other traits, supporting the prospects for dissecting crop performance into its physiological and genetic components in order to facilitate a more strategic approach to breeding. Electronic supplementary material The online version of this article (doi:10.1007/s00122-010-1351-4) contains supplementary material, which is available to authorized users.

Pinto, R. Suzuky; Mathews, Ky L.; McIntyre, C. Lynne; Olivares-Villegas, Juan-Jose; Chapman, Scott C.

2010-01-01

206

Conditional and unconditional QTL mapping of drought-tolerance-related traits of wheat seedling using two related RIL populations.  

PubMed

For discovering the quantitative trait loci (QTLs) contributing to early seedling growth and drought tolerance during germination, conditional and unconditional analyses of 12 traits of wheat seedlings: coleoptile length, seedling height, longest root length, root number, seedling fresh weight, stem and leaves fresh weight, root fresh weight, seedling dry weight, stem and leaves dry weight, root dry weight, root to shoot fresh weight ratio, root-to-shoot dry weight ratio, were conducted under two water conditions using two F8:9 recombinant inbred line (RIL) populations. The results of unconditional analysis are as follows: 88 QTLs accounting for 3.33-77.01% of the phenotypic variations were detected on chromosomes 1A, 1B, 1D, 2A, 2B, 2D, 3A, 3B, 4A, 4B, 4D, 5A, 5B, 5D, 6A, 6B, 6D, 7A, 7B and 7D. Among these QTLs, 19 were main-effect QTLs with a contribution rate greater than 10%. The results of the conditional QTL analysis of 12 traits under osmotic stress on normal water conditions were as follows: altogether 22 QTLs concerned with drought tolerance were detected on chromosomes 1B, 2A, 2B, 3B, 4A, 5D, 6A, 6D, 7B, and 7D. Of these QTLs, six were main-effect QTLs. These 22 QTLs were all special loci directly concerned with drought tolerance and most of them could not be detected by unconditional analysis. The finding of these QTLs has an important significance for fine-mapping technique, map-based cloning, and molecular marker-assisted selection of early seedling traits, such as growth and drought tolerance. PMID:23970077

Zhang, Hong; Cui, Fa; Wang, Lin; Li, Jun; Ding, Anming; Zhao, Chunhua; Bao, Yinguang; Yang, Qiuping; Wang, Honggang

2013-08-01

207

Major genes for Na+ exclusion, Nax1 and Nax2 (wheat HKT1;4 and HKT1;5), decrease Na+ accumulation in bread wheat leaves under saline and waterlogged conditions.  

PubMed

Two major genes for Na(+) exclusion in durum wheat, Nax1 and Nax2, that were previously identified as the Na(+) transporters TmHKT1;4-A2 and TmHKT1;5-A, were transferred into bread wheat in order to increase its capacity to restrict the accumulation of Na(+) in leaves. The genes were crossed from tetraploid durum wheat (Triticum turgidum ssp. durum) into hexaploid bread wheat (Triticum aestivum) by interspecific crossing and marker-assisted selection for hexaploid plants containing one or both genes. Nax1 decreased the leaf blade Na(+) concentration by 50%, Nax2 decreased it by 30%, and both genes together decreased it by 60%. The signature phenotype of Nax1, the retention of Na(+) in leaf sheaths resulting in a high Na(+) sheath:blade ratio, was found in the Nax1 lines. This conferred an extra advantage under a combination of waterlogged and saline conditions. The effect of Nax2 on lowering the Na(+) concentration in bread wheat was surprising as this gene is very similar to the TaHKT1;5-D Na(+) transporter already present in bread wheat, putatively at the Kna1 locus. The results indicate that both Nax genes have the potential to improve the salt tolerance of bread wheat. PMID:21357768

James, Richard A; Blake, Carol; Byrt, Caitlin S; Munns, Rana

2011-02-28

208

Population structure within lineages of Wheat streak mosaic virus derived from a common founding event exhibits stochastic variation inconsistent with the deterministic quasi-species model  

SciTech Connect

Structure of Wheat streak mosaic virus (WSMV) populations derived from a common founding event and subjected to serial passage at high multiplicity of infection (MOI) was evaluated. The founding population was generated by limiting dilution inoculation. Lineages of known pedigree were sampled at passage 9 (two populations) and at passage 15, with (three populations) or without mixing (four populations) of lineages at passage 10. Polymorphism within each population was assessed by sequencing 17-21 clones containing a 1371 nt region (WSMV-Sidney 81 nts 8001-9371) encompassing the entire coat protein cistron and flanking regions. Mutation frequency averaged {approx}5.0 x 10{sup -4}/nt across all populations and ranged from 2.4 to 11.6 x 10{sup -4}/nt within populations, but did not consistently increase or decrease with the number of passages removed from the founding population. Shared substitutions (19 nonsynonymous, 10 synonymous, and 3 noncoding) occurred at 32 sites among 44 haplotypes. Only four substitutions became fixed (frequency = 100%) within a population and nearly one third (10/32) never achieved a frequency of 10% or greater in any sampled population. Shared substitutions were randomly distributed with respect to genome position, with transitions outnumbering transversions 5.4:1 and a clear bias for A to G and U to C substitutions. Haplotype composition of each population was unique with complexity of each population varying unpredictably, in that the number and frequency of haplotypes within a lineage were not correlated with number of passages removed from the founding population or whether the population was derived from a single or mixed lineage. The simplest explanation is that plant virus lineages, even those propagated at high MOI, are subject to frequent, narrow genetic bottlenecks during systemic movement that result in low effective population size and stochastic changes in population structure upon serial passage.

French, Roy [Agricultural Research Service, United States Department of Agriculture and Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583 (United States); Stenger, Drake C. [Agricultural Research Service, United States Department of Agriculture and Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583 (United States)]. E-mail: dstenger@unlnotes.unl.edu

2005-12-20

209

A New Class of Wheat Gliadin Genes and Proteins  

PubMed Central

The utility of mining DNA sequence data to understand the structure and expression of cereal prolamin genes is demonstrated by the identification of a new class of wheat prolamins. This previously unrecognized wheat prolamin class, given the name ?-gliadins, is the most direct ortholog of barley ?3-hordeins. Phylogenetic analysis shows that the orthologous ?-gliadins and ?3-hordeins form a distinct prolamin branch that existed separate from the ?-gliadins and ?-hordeins in an ancestral Triticeae prior to the branching of wheat and barley. The expressed ?-gliadins are encoded by a single gene in each of the hexaploid wheat genomes. This single ?-gliadin/?3-hordein ortholog may be a general feature of the Triticeae tribe since examination of ESTs from three barley cultivars also confirms a single ?3-hordein gene. Analysis of ESTs and cDNAs shows that the genes are expressed in at least five hexaploid wheat cultivars in addition to diploids Triticum monococcum and Aegilops tauschii. The latter two sequences also allow assignment of the ?-gliadin genes to the A and D genomes, respectively, with the third sequence type assumed to be from the B genome. Two wheat cultivars for which there are sufficient ESTs show different patterns of expression, i.e., with cv Chinese Spring expressing the genes from the A and B genomes, while cv Recital has ESTs from the A and D genomes. Genomic sequences of Chinese Spring show that the D genome gene is inactivated by tandem premature stop codons. A fourth ?-gliadin sequence occurs in the D genome of both Chinese Spring and Ae. tauschii, but no ESTs match this sequence and limited genomic sequences indicates a pseudogene containing frame shifts and premature stop codons. Sequencing of BACs covering a 3 Mb region from Ae. tauschii locates the ?-gliadin gene to the complex Gli-1 plus Glu-3 region on chromosome 1.

Anderson, Olin D.; Dong, Lingli; Huo, Naxin; Gu, Yong Q.

2012-01-01

210

Cbf14 copy number variation in the A, B, and D genomes of diploid and polyploid wheat.  

PubMed

Freezing tolerance and winter hardiness are complex traits. In the Triticeae, two loci on the group 5 chromosome homoeologs are repeatedly identified as having major effects on these traits. Recently, we found that segments of the genomic region at one of these loci, Frost resistance-2 (Fr-2) is copy number variable in barley. Freezing-tolerant winter-hardy genotypes have greater tandem copy numbers of the genomic region encompassing the C-repeat binding factor genes Cbf2A and Cbf4B at Fr-H2 than the less freezing-tolerant nonwinter-hardy genotypes. Here we report that in wheat the Cbf14 gene at Fr-2 is copy number variable. Using DNA blot hybridizations, we estimated copy numbers of Cbf14 across the different genomes of diploid and polyploid wheat. Copy numbers of Cbf14 are lower in the B genome than in the A and D genomes across all ploidy levels. Among hexaploid red wheats, winter genotypes harbor greater Cbf14 copy numbers than spring genotypes. Cbf14 copy numbers also vary across the red winter wheats such that hard wheats harbor greater copy numbers than soft wheats. Analysis of hexaploid wheat chromosome 5 substitution lines indicates that Cbf14 copy numbers in the introgressions are stable in the different backgrounds. Taken together our data suggest that higher copy number states existed in the diploid wild ancestors prior to the polyploidization events and that the loss of Cbf14 copies occurred in the cultivated germplasm. PMID:23918064

Dhillon, Taniya; Stockinger, Eric J

2013-08-06

211

Mapping of QTL for tiller number at different stages of growth in wheat using double haploid and immortalized F2 populations.  

PubMed

Effective tiller number is one of the most important traits for wheat (Triticum aestivum L.) yield, but the inheritance of tillering is poorly understood. A set of 168 doubled haploid (DH) lines derivatives of a cross between two winter wheat cultivars (Huapei 3 and Yumai 57), and an immortalized F(2) (IF(2)) population generated by randomly permutated intermating of these DHs were investigated, and QTLs of tillering related to the maximum tillering of pre-winter (MTW), maximum tillering in spring (MTS), and effective tillering in harvest (ETH) were mapped. Phenotypic data were collected for the two populations from two different environments. Using inclusive composite interval mapping (ICIM), a total of 9 and 18 significant QTL were detected across environments for tillering in the DH and IF(2) populations, respectively. Four QTLs were common between two populations. A major QTL located on the 5D chromosome with the allele originating from Yumai 57 was detected and increased 1.92 and 3.55 tillers in MTW and MTS, respectively. QTLs (QMts6D, QEth6D) having a neighbouring marker interval at Xswes679.1 and Xcfa2129 on chromosome 6D was detected in MTS and ETH. These results provide a better understanding of the genetic factors for selectively expressing the control of tiller number in different growth stages and facilitate marker-assisted selection strategy in breeding. PMID:21273691

Li, Zhuokun; Peng, Tao; Xie, Quangang; Han, Shuxiao; Tian, Jichun

2010-12-01

212

Evolution of the Oat Genetic Road Map: From Tetraploid to Hexaploid  

Technology Transfer Automated Retrieval System (TEKTRAN)

The development of a genetic linkage map for hexaploid oat (Avena sativa L. 2n = 6 x = 42) that defines all 21 chromosomes has been hindered due to the lack of oat-based markers and the size and complexity of the oat genome. Recent efforts in oat DArT, SSR, and SNP marker development should improve...

213

Does exogenous application of 24-epibrassinolide ameliorate salt induced growth inhibition in wheat ( Triticum aestivum L.)?  

Microsoft Academic Search

A greenhouse experiment was conducted to assess whether exogenously applied 24-epibrassionlide (24-epiBL) could alleviate\\u000a the adverse effects of salt on wheat. Two hexaploid wheat (Triticum aestivum L.) cultivars, S-24 (salt tolerant) and MH-97 (moderately salt sensitive), were grown under control (0 mM NaCl in full strength\\u000a Hoagland’s nutrient solution) or saline conditions (150 mM of NaCl in full strength Hoagland’s nutrient solution).

Muhammad Shahbaz; Muhammad Ashraf; Habib-ur-Rehman Athar

2008-01-01

214

Development of high amylose wheat through TILLING  

PubMed Central

Background Wheat (Triticum spp.) is an important source of food worldwide and the focus of considerable efforts to identify new combinations of genetic diversity for crop improvement. In particular, wheat starch composition is a major target for changes that could benefit human health. Starches with increased levels of amylose are of interest because of the correlation between higher amylose content and elevated levels of resistant starch, which has been shown to have beneficial effects on health for combating obesity and diabetes. TILLING (Targeting Induced Local Lesions in Genomes) is a means to identify novel genetic variation without the need for direct selection of phenotypes. Results Using TILLING to identify novel genetic variation in each of the A and B genomes in tetraploid durum wheat and the A, B and D genomes in hexaploid bread wheat, we have identified mutations in the form of single nucleotide polymorphisms (SNPs) in starch branching enzyme IIa genes (SBEIIa). Combining these new alleles of SBEIIa through breeding resulted in the development of high amylose durum and bread wheat varieties containing 47-55% amylose and having elevated resistant starch levels compared to wild-type wheat. High amylose lines also had reduced expression of SBEIIa RNA, changes in starch granule morphology and altered starch granule protein profiles as evaluated by mass spectrometry. Conclusions We report the use of TILLING to develop new traits in crops with complex genomes without the use of transgenic modifications. Combined mutations in SBEIIa in durum and bread wheat varieties resulted in lines with significantly increased amylose and resistant starch contents.

2012-01-01

215

Haplotype variation of glu-d1 locus and the origin of glu-d1d allele conferring superior end-use qualities in common wheat.  

PubMed

In higher plants, seed storage proteins (SSPs) are frequently expressed from complex gene families, and allelic variation of SSP genes often affects the quality traits of crops. In common wheat, the Glu-D1 locus, encoding 1Dx and 1Dy SSPs, has multiple alleles. The Glu-D1d allele frequently confers superior end-use qualities to commercial wheat varieties. Here, we studied the haplotype structure of Glu-D1 genomic region and the origin of Glu-D1d. Using seven diagnostic DNA markers, 12 Glu-D1 haplotypes were detected among common wheat, European spelt wheat (T. spelta, a primitive hexaploid relative of common wheat), and Aegilops tauschii (the D genome donor of hexaploid wheat). By comparatively analyzing Glu-D1 haplotypes and their associated 1Dx and 1Dy genes, we deduce that the haplotype carrying Glu-D1d was likely differentiated in the ancestral hexaploid wheat around 10,000 years ago, and was subsequently transmitted to domesticated common wheat and T. spelta. A group of relatively ancient Glu-D1 haplotypes was discovered in Ae. tauschii, which may serve for the evolution of other haplotypes. Moreover, a number of new Glu-D1d variants were found in T. spelta. The main steps in Glu-D1d differentiation are proposed. The implications of our work for enhancing the utility of Glu-D1d in wheat quality improvement and studying the SSP alleles in other crop species are discussed. PMID:24098671

Dong, Zhenying; Yang, Yushuang; Li, Yiwen; Zhang, Kunpu; Lou, Haijuan; An, Xueli; Dong, Lingli; Gu, Yong Qiang; Anderson, Olin D; Liu, Xin; Qin, Huanju; Wang, Daowen

2013-09-30

216

Haplotype Variation of Glu-D1 Locus and the Origin of Glu-D1d Allele Conferring Superior End-Use Qualities in Common Wheat  

PubMed Central

In higher plants, seed storage proteins (SSPs) are frequently expressed from complex gene families, and allelic variation of SSP genes often affects the quality traits of crops. In common wheat, the Glu-D1 locus, encoding 1Dx and 1Dy SSPs, has multiple alleles. The Glu-D1d allele frequently confers superior end-use qualities to commercial wheat varieties. Here, we studied the haplotype structure of Glu-D1 genomic region and the origin of Glu-D1d. Using seven diagnostic DNA markers, 12 Glu-D1 haplotypes were detected among common wheat, European spelt wheat (T. spelta, a primitive hexaploid relative of common wheat), and Aegilops tauschii (the D genome donor of hexaploid wheat). By comparatively analyzing Glu-D1 haplotypes and their associated 1Dx and 1Dy genes, we deduce that the haplotype carrying Glu-D1d was likely differentiated in the ancestral hexaploid wheat around 10,000 years ago, and was subsequently transmitted to domesticated common wheat and T. spelta. A group of relatively ancient Glu-D1 haplotypes was discovered in Ae. tauschii, which may serve for the evolution of other haplotypes. Moreover, a number of new Glu-D1d variants were found in T. spelta. The main steps in Glu-D1d differentiation are proposed. The implications of our work for enhancing the utility of Glu-D1d in wheat quality improvement and studying the SSP alleles in other crop species are discussed.

Li, Yiwen; Zhang, Kunpu; Lou, Haijuan; An, Xueli; Dong, Lingli; Gu, Yong Qiang; Anderson, Olin D.; Liu, Xin; Qin, Huanju; Wang, Daowen

2013-01-01

217

Delineating the role of polyphenol oxidase in the darkening of alkaline wheat noodles.  

PubMed

This study evaluated the effects of inhibitors on polyphenol oxidase (PPO) activity, the effect of the PPO inhibitor tropolone on noodle darkening, and the correlation of PPO activity with darkening of alkaline noodles. The PPO inhibitors tropolone and salicylhydroxamic acid (each at 1 microM) reduced kernel PPO activity by approximately 50% in three hexaploid wheat cultivars but did not inhibit PPO activity in the two very low PPO cultivars, durum Langdon, and the synthetic hexaploid-derived ID580. Tropolone (100 microg/g flour) inhibited alkaline noodle darkening (deltaL*) by 13-25% in the low PPO wheat cultivar, ID377s, and by 39-54% in the high PPO wheat cultivar, Klasic. Alkaline noodle darkening among 502 wheat samples was correlated with kernel PPO activity (r = 0.64). Results substantiate the hypothesis that PPO plays a major role in darkening of alkaline noodles. However, results also indicate that substantial darkening would occur even at zero PPO activity, as measured in the kernel PPO assay. Therefore, darkening of alkaline noodles is probably due to the cultivar-specific level of PPO activity and the presence of at least one additional darkening mechanism. Further investigation is required to identify the phenolic discoloration agent(s) and to determine the potential roles of non-PPO discoloration mechanisms, both enzymatic and nonenzymatic, in wheat products. PMID:16536622

Fuerst, E Patrick; Anderson, James V; Morris, Craig F

2006-03-22

218

Analysis of ascorbate peroxidase genes expressed in resistant and susceptible wheat lines infected by the cereal cyst nematode, Heterodera avenae  

Microsoft Academic Search

Changes in ascorbate peroxidase (APX) enzyme activity in response to nematode (Heterodera avenae) attack were studied in roots of three hexaploid wheat lines carrying Cre2, Cre5, or Cre7 nematode resistance genes and the susceptible Triticum aestivum cv. Anza. A spectrophotometric analysis was carried out with root extracts of infected plants 4, 7, 11, and 14 days after\\u000a nematode inoculation using uninfected

Ester Simonetti; Eva Alba; María Jesús Montes; Ángeles Delibes; Isidoro López-Braña

2010-01-01

219

Isolation and sequence analysis of wheat NBS-LRR type disease resistance gene analogs using degenerate PCR primers  

Microsoft Academic Search

Isolation of disease resistance gene analogs (RGAs) using the conserved motifs of the resistance genes has attracted considerable\\u000a attention since it was first reported more than a decade ago. In this study, RGAs are isolated using homology-based PCR to\\u000a target the nucleotide binding site (NBS) conserved regions from hexaploid wheat varieties and a few accessions of wild types.\\u000a Based on

O. Bozkurt; E. E. Hakki; M. S. Akkaya

2007-01-01

220

The isolation of high molecular weight DNA from wheat, barley and rye for analysis by pulse-field gel electrophoresis  

Microsoft Academic Search

A method is presented for the preparation of large DNA molecules from protoplasts embedded in agarose blocks of three different cereals-hexaploid bread wheat (Triticum aestivum), barley (Hordeum vulgare) and rye (Secale cereale). Pulse-field gel electrophoresis (PFGE) analysis of these DNA preparations using a contour-clamped homogeneous field (CHEF) apparatus indicated that the size of the DNA molecules was greater than 6

Wing Y. Cheung; Michael D. Gale

1990-01-01

221

Amplification of DNA sequences in wheat and its relatives: the Dgas44 and R350 families of repetitive sequences.  

PubMed

The sequence of a Triticum tauschii genomic clone representing a family of D-genome amplified DNA sequences, designated Dgas44, is reported. The Dgas44 sequence occurs on all chromosomes of the D genome of wheat, Triticum aestivum, and in situ hybridization revealed it to be evenly dispersed on all seven chromosome pairs. An internal HindIII fragment of Dgas44, designated Dgas44-3, defines the highly amplified region that is specific to the D genome. The polymerase chain reaction was used to amplify a 236-bp fragment within Dgas44-3 from chromosomes 1D, 2D, 3D, 4D, 5D, and 7D, and identical copies of this region of the Dgas44-3 sequence were found among the isolates from each of the chromosomes. The Dgas44-3 sequence population from specific chromosomes differed on average by 0.22% from the original Dgas44 sequence. The Dgas44 sequence was found to differentiate between the D genome present in T. aestivum, T. tauschii, hexaploid T. crassum, T. cylindricum, T. ventricosum, in which the sequence was present in a highly amplified form and T. juvenale, T. syriacum, and tetraploid T. crassum where the sequence family was difficult to detect. Another class of amplified sequences previously considered to be rye "specific." R350, was isolated from tetraploid wheat and its dispersed distribution on chromosomes was similar to the Dgas44 family in T. tauschii. In contrast with the Dgas44 sequence family, genome specificity for the remnant R350 sequence family was not evident since it was present on all wheat chromosomes. PMID:8200519

McNeil, D; Lagudah, E S; Hohmann, U; Appels, R

1994-04-01

222

Analysis of wheat SAGE tags reveals evidence for widespread antisense transcription  

PubMed Central

Background Serial Analysis of Gene Expression (SAGE) is a powerful tool for genome-wide transcription studies. Unlike microarrays, it has the ability to detect novel forms of RNA such as alternatively spliced and antisense transcripts, without the need for prior knowledge of their existence. One limitation of using SAGE on an organism with a complex genome and lacking detailed sequence information, such as the hexaploid bread wheat Triticum aestivum, is accurate annotation of the tags generated. Without accurate annotation it is impossible to fully understand the dynamic processes involved in such complex polyploid organisms. Hence we have developed and utilised novel procedures to characterise, in detail, SAGE tags generated from the whole grain transcriptome of hexaploid wheat. Results Examination of 71,930 Long SAGE tags generated from six libraries derived from two wheat genotypes grown under two different conditions suggested that SAGE is a reliable and reproducible technique for use in studying the hexaploid wheat transcriptome. However, our results also showed that in poorly annotated and/or poorly sequenced genomes, such as hexaploid wheat, considerably more information can be extracted from SAGE data by carrying out a systematic analysis of both perfect and "fuzzy" (partially matched) tags. This detailed analysis of the SAGE data shows first that while there is evidence of alternative polyadenylation this appears to occur exclusively within the 3' untranslated regions. Secondly, we found no strong evidence for widespread alternative splicing in the developing wheat grain transcriptome. However, analysis of our SAGE data shows that antisense transcripts are probably widespread within the transcriptome and appear to be derived from numerous locations within the genome. Examination of antisense transcripts showing sequence similarity to the Puroindoline a and Puroindoline b genes suggests that such antisense transcripts might have a role in the regulation of gene expression. Conclusion Our results indicate that the detailed analysis of transcriptome data, such as SAGE tags, is essential to understand fully the factors that regulate gene expression and that such analysis of the wheat grain transcriptome reveals that antisense transcripts maybe widespread and hence probably play a significant role in the regulation of gene expression during grain development.

Poole, Rebecca L; Barker, Gary LA; Werner, Kay; Biggi, Gaia F; Coghill, Jane; Gibbings, J George; Berry, Simon; Dunwell, Jim M; Edwards, Keith J

2008-01-01

223

Fungicide sensitivity of Tapesia yallundae populations collected from 15 wheat fields in the Western Cape of South Africa  

Microsoft Academic Search

In the Western Cape province of South Africa, eyespot disease (Tapesia yallundae) of wheat is primarily controlled by fungicide applications. Previous studies have shown, however, that isolates of T. yallundae vary in their response to fungicides. In the present study, 20 isolates from each of 15 fields with different fungicide histories were screened against carbendazim at 1 ¿g\\/ml; propiconazole, tebuconazole

K. Ntushelo; P. W. Crous

2004-01-01

224

Population Structure, Linkage Disequilibrium, and Genetic Diversity in Soft Winter Wheat Enriched for Fusarium Head Blight Resistance  

Technology Transfer Automated Retrieval System (TEKTRAN)

The occurrence of epidemics of Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe, in U.S. winter wheat (Triticum aestivum L.) during the past two decades has resulted in increased emphasis on development of resistant cultivars. Understanding the effect of focused breeding efforts fo...

225

FALL FORAGE BIOMASS AND N COMPOSITION OF WINTER WHEAT POPULATIONS SELECTED FROM GRAIN-ONLY AND DUAL-PURPOSE ENVIRONMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter wheat (Triticum aestivum L.) is the foundation of agricultural enterprises in the southern Great Plains and is grown primarily as grain-only (GO) and dual-purpose (DP, grazing plus grain) crops. Traditionally, cultivars are developed in GO systems. Because of genotype by system interactions, ...

226

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs  

Microsoft Academic Search

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination

Roel Van der Meulen; Ilse Scheirlinck; Ann Van Schoor; Geert Huys; Marc Vancanneyt; Peter Vandamme; Luc De Vuyst

2007-01-01

227

Identification of novel quantitative trait loci for days to ear emergence and flag leaf glaucousness in a bread wheat (Triticum aestivum L.) population adapted to southern Australian conditions.  

PubMed

In southern Australia, where the climate is predominantly Mediterranean, achieving the correct flowering time in bread wheat minimizes the impact of in-season cyclical and terminal drought. Flag leaf glaucousness has been hypothesized as an important component of drought tolerance but its value and genetic basis in locally adapted germplasm is unknown. From a cross between Kukri and RAC875, a doubled-haploid (DH) population was developed. A genetic linkage map consisting of 456 DArT and SSR markers was used to detect QTL affecting time to ear emergence and Zadoks growth score in seven field experiments. While ear emergence time was similar between the parents, there was significant transgressive segregation in the population. This was the result of segregation for the previously characterized Ppd-D1a and Ppd-B1 photoperiod responsive alleles. QTL of smaller effect were also detected on chromosomes 1A, 4A, 4B, 5A, 5B, 7A and 7B. A novel QTL for flag leaf glaucousness of large, repeatable effect was detected in six field experiments, on chromosome 3A (QW.aww-3A) and accounted for up to 52 percent of genetic variance for this trait. QW.aww-3A was validated under glasshouse conditions in a recombinant inbred line population from the same cross. The genetic basis of time to ear emergence in this population will aid breeders' understanding of phenological adaptation to the local environment. Novel loci identified for flag leaf glaucousness and the wide phenotypic variation within the DH population offers considerable scope to investigate the impact and value of this trait for bread wheat production in southern Australia. PMID:22045047

Bennett, Dion; Izanloo, Ali; Edwards, James; Kuchel, Haydn; Chalmers, Ken; Tester, Mark; Reynolds, Matthew; Schnurbusch, Thorsten; Langridge, Peter

2011-11-02

228

Developmental pattern of hexaploid mouse embryos produced by blastomere fusion of diploid and tetraploid embryos at the 2-cell stage.  

PubMed

Polyploid mouse embryos are important models for understanding the mechanisms of cleavage and preimplantation development in mammals. In this study, hexaploid (6n) mouse embryos were produced by the electrofusion of blastomeres from diploid (2n) and tetraploid (4n) embryos at the 2-cell stage. Furthermore, the developmental pattern of hexaploid embryos was evaluated by blastocyst rate, cell number, karyotype analysis, cytoskeleton staining and Oct-4 immunofluorescence. The results showed that 72.7% of the hexaploid embryos were able to develop to the blastocyst stage, which is a lower number than that found with normal diploid embryos (98.0%, p < 0.05). The cell number in hexaploid blastocyst was 12.3 +/- 2.0, which was less than that found in diploid or tetraploid blastocysts (41.2 +/- 7.2; 18.4 +/- 3.5). Karyotype analysis confirmed that the number of chromosomes in hexaploid embryos was 120. beta-Tubulin and Oct-4 immunofluorescence indicated that the hexaploid blastocysts were nearly lacking inner cell mass (ICM), but some blastomeres did show Oct-4-positive expression. PMID:19232146

Lei, Lei; Guan, Na; Xu, Yan-Ning; Zhang, Qing-Hua; Shen, Jing-Ling; Jin, Lian-Hong

2009-02-23

229

Prevalence of gene expression additivity in genetically stable wheat allohexaploids.  

PubMed

The reprogramming of gene expression appears as the major trend in synthetic and natural allopolyploids where expression of an important proportion of genes was shown to deviate from that of the parents or the average of the parents. In this study, we analyzed gene expression changes in previously reported, highly stable synthetic wheat allohexaploids that combine the D genome of Aegilops tauschii and the AB genome extracted from the natural hexaploid wheat Triticum aestivum. A comprehensive genome-wide analysis of transcriptional changes using the Affymetrix GeneChip Wheat Genome Array was conducted. Prevalence of gene expression additivity was observed where expression does not deviate from the average of the parents for 99.3% of 34,820 expressed transcripts. Moreover, nearly similar expression was observed (for 99.5% of genes) when comparing these synthetic and natural wheat allohexaploids. Such near-complete additivity has never been reported for other allopolyploids and, more interestingly, for other synthetic wheat allohexaploids that differ from the ones studied here by having the natural tetraploid Triticum turgidum as the AB genome progenitor. Our study gave insights into the dynamics of additive gene expression in the highly stable wheat allohexaploids. PMID:23278496

Chelaifa, Houda; Chagué, Véronique; Chalabi, Smahane; Mestiri, Imen; Arnaud, Dominique; Deffains, Denise; Lu, Yunhai; Belcram, Harry; Huteau, Virginie; Chiquet, Julien; Coriton, Olivier; Just, Jérémy; Jahier, Joseph; Chalhoub, Boulos

2012-12-21

230

Dispersion and domestication shaped the genome of bread wheat.  

PubMed

Despite the international significance of wheat, its large and complex genome hinders genome sequencing efforts. To assess the impact of selection on this genome, we have assembled genomic regions representing genes for chromosomes 7A, 7B and 7D. We demonstrate that the dispersion of wheat to new environments has shaped the modern wheat genome. Most genes are conserved between the three homoeologous chromosomes. We found differential gene loss that supports current theories on the evolution of wheat, with greater loss observed in the A and B genomes compared with the D. Analysis of intervarietal polymorphisms identified fewer polymorphisms in the D genome, supporting the hypothesis of early gene flow between the tetraploid and hexaploid. The enrichment for genes on the D genome that confer environmental adaptation may be associated with dispersion following wheat domestication. Our results demonstrate the value of applying next-generation sequencing technologies to assemble gene-rich regions of complex genomes and investigate polyploid genome evolution. We anticipate the genome-wide application of this reduced-complexity syntenic assembly approach will accelerate crop improvement efforts not only in wheat, but also in other polyploid crops of significance. PMID:23346876

Berkman, Paul J; Visendi, Paul; Lee, Hong C; Stiller, Jiri; Manoli, Sahana; Lorenc, Micha? T; Lai, Kaitao; Batley, Jacqueline; Fleury, Delphine; Simková, Hana; Kubaláková, Marie; Weining, Song; Doležel, Jaroslav; Edwards, David

2013-01-24

231

On-farm dynamic management of genetic diversity: the impact of seed diffusions and seed saving practices on a population-variety of bread wheat.  

PubMed

Since the domestication of crop species, humans have derived specific varieties for particular uses and shaped the genetic diversity of these varieties. Here, using an interdisciplinary approach combining ethnobotany and population genetics, we document the within-variety genetic structure of a population-variety of bread wheat (Triticum aestivum L.) in relation to farmers' practices to decipher their contribution to crop species evolution. Using 19 microsatellites markers, we conducted two complementary graph theory-based methods to analyze population structure and gene flow among 19 sub-populations of a single population-variety [Rouge de Bordeaux (RDB)]. The ethnobotany approach allowed us to determine the RDB history including diffusion and reproduction events. We found that the complex genetic structure among the RDB sub-populations is highly consistent with the structure of the seed diffusion and reproduction network drawn based on the ethnobotanical study. This structure highlighted the key role of the farmer-led seed diffusion through founder effects, selection and genetic drift because of human practices. An important result is that the genetic diversity conserved on farm is complementary to that found in the genebank indicating that both systems are required for a more efficient crop diversity conservation. PMID:23346224

Thomas, Mathieu; Demeulenaere, Elise; Dawson, Julie C; Khan, Abdul Rehman; Galic, Nathalie; Jouanne-Pin, Sophie; Remoue, Carine; Bonneuil, Christophe; Goldringer, Isabelle

2012-12-01

232

Effect of hosts on competition among clones and evidence of differential selection between pathogenic and saprophytic phases in experimental populations of the wheat pathogen Phaeosphaeria nodorum  

PubMed Central

Background Monoculture, multi-cropping and wider use of highly resistant cultivars have been proposed as mechanisms to explain the elevated rate of evolution of plant pathogens in agricultural ecosystems. We used a mark-release-recapture experiment with the wheat pathogen Phaeosphaeria nodorum to evaluate the impact of two of these mechanisms on the evolution of a pathogen population. Nine P. nodorum isolates marked with ten microsatellite markers and one minisatellite were released onto five replicated host populations to initiate epidemics of Stagonospora nodorum leaf blotch. The experiment was carried out over two consecutive host growing seasons and two pathogen collections were made during each season. Results A total of 637 pathogen isolates matching the marked inoculants were recovered from inoculated plots over two years. Genetic diversity in the host populations affected the evolution of the corresponding P. nodorum populations. In the cultivar mixture the relative frequencies of inoculants did not change over the course of the experiment and the pathogen exhibited a low variation in selection coefficients. Conclusions Our results support the hypothesis that increasing genetic heterogeneity in host populations may retard the rate of evolution in associated pathogen populations. Our experiment also provides indirect evidence of fitness costs associated with host specialization in P. nodorum as indicated by differential selection during the pathogenic and saprophytic phases.

2011-01-01

233

Analysis of the bread wheat genome using whole genome shotgun sequencing  

PubMed Central

Summary Bread wheat (Triticum aestivum) is a globally important crop, accounting for 20% of the calories consumed by mankind. We sequenced its large and challenging 17 Gb hexaploid genome using 454 pyrosequencing and compared this with the sequences of diploid ancestral and progenitor genomes. Between 94,000-96,000 genes were identified, and two-thirds were assigned to the A, B and D genomes. High-resolution synteny maps identified many small disruptions to conserved gene order. We show the hexaploid genome is highly dynamic, with significant loss of gene family members upon polyploidization and domestication, and an abundance of gene fragments. Several classes of genes involved in energy harvesting, metabolism and growth are among expanded gene families that could be associated with crop productivity. Our analyses, coupled with the identification of extensive genetic variation, provide a new resource for accelerating gene discovery and improving this major crop.

Brenchley, Rachel; Spannagl, Manuel; Pfeifer, Matthias; Barker, Gary L.A.; D'Amore, Rosalinda; Allen, Alexandra M.; McKenzie, Neil; Kramer, Melissa; Kerhornou, Arnaud; Bolser, Dan; Kay, Suzanne; Waite, Darren; Trick, Martin; Bancroft, Ian; Gu, Yong; Huo, Naxin; Luo, Ming-Cheng; Sehgal, Sunish; Kianian, Sharyar; Gill, Bikram; Anderson, Olin; Kersey, Paul; Dvorak, Jan; McCombie, Richard; Hall, Anthony; Mayer, Klaus F.X.; Edwards, Keith J.; Bevan, Michael W.; Hall, Neil

2012-01-01

234

Effect of Introduced Pseudomonas fluorescens Strains on Soil Nematode and Protozoan Populations in the Rhizosphere of Wheat and Pea  

Microsoft Academic Search

Previous studies have shown that inoculation of pea seeds with Pseudomonas fluorescens strains F113lacZY or F113G22 increased mineralization of organic nitrogen in the rhizosphere. In contrast, inoculation of the same strains\\u000a onto wheat seeds reduced mineralization of N from organic residues incorporated into soil. In the present study, we report\\u000a on a likely explanation of this phenomenon, which appears to

M. J. Brimecombe; F. A. A. M. De Leij; J. M. Lynch

1999-01-01

235

Molecular genetic analysis of flour color using a doubled haploid population in bread wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Flour color is an important trait in the assessment of flour quality for the production of many end products. In this study,\\u000a quantitative trait loci (QTLs) with additive effects, epistatic effects, and QTL × environment (QE) interactions for flour\\u000a color in bread wheat (Triticum aestivum L.) were studied, using a set of 168 doubled haploid (DH) lines derived from a Huapei 3 × Yumai 57 cross.

Kun-Pu Zhang; Guang-Feng Chen; Liang Zhao; Bin Liu; Xian-Bin Xu; Ji-Chun Tian

2009-01-01

236

Photoperiod insensitive Ppd-A1a mutations in tetraploid wheat (Triticum durum Desf.).  

PubMed

Variation in photoperiod response plays an important role in adapting crops to agricultural environments. In hexaploid wheat, mutations conferring photoperiod insensitivity (flowering after a similar time in short or long days) have been mapped on the 2B (Ppd-B1) and 2D (Ppd-D1) chromosomes in colinear positions to the 2H Ppd-H1 gene of barley. No A genome mutation is known. On the D genome, photoperiod insensitivity is likely to be caused by deletion of a regulatory region that causes misexpression of a member of the pseudo-response regulator (PRR) gene family and activation of the photoperiod pathway irrespective of day length. Photoperiod insensitivity in tetraploid (durum) wheat is less characterized. We compared pairs of near-isogenic lines that differ in photoperiod response and showed that photoperiod insensitivity is associated with two independent deletions of the A genome PRR gene that cause altered expression. This is associated with induction of the floral regulator FT. The A genome deletions and the previously described D genome deletion of hexaploid wheat remove a common region, suggesting a shared mechanism for photoperiod insensitivity. The identification of the A genome mutations will allow characterization of durum wheat germplasm and the construction of genotypes with novel combinations of photoperiod insensitive alleles. PMID:18839130

Wilhelm, Edward P; Turner, Adrian S; Laurie, David A

2008-10-07

237

Meiotic restitution in wheat polyhaploids (amphihaploids): a potent evolutionary force.  

PubMed

Polyploidy is well recognized as a major force in plant speciation. Among the polyploids in nature, allopolyploids are preponderant and include important crop plants like bread wheat, Triticum aestivum L. (2n = 6x = 42; AABBDD genomes). Allopolyploidy must result through concomitant or sequential events that entail interspecific or intergeneric hybridization and chromosome doubling in the resultant hybrids. To gain insight into the mechanism of evolution of wheat, we extracted polyhaploids of 2 cultivars, Chinese Spring (CS) and Fukuhokomugi (Fuko), of bread wheat by crossing them with maize, Zea mays L. ssp. mays. The derived Ph1-polyhaploids (2n = 3x = 21; ABD) showed during meiosis mostly univalents, which produced first-division restitution (FDR) nuclei that in turn gave rise to unreduced (2n) male gametes with 21 chromosomes. The haploids on maturity set some viable seed. The mean number of seeds per spike was 1.45 +/- 0.161 in CS and 2.3 +/- 0.170 in Fuko. Mitotic chromosome preparations from root tips of the derived plantlets revealed 2n = 42 chromosomes, that is, twice that of the parental polyhaploid, which indicated that they arose by fusion of unreduced male and female gametes formed by the polyhaploid. The Ph1-induced univalency must have produced 2n gametes and hence bilateral sexual polyploidization and reconstitution of disomic bread wheat. These findings highlight the quantum jump by which bread wheat evolved from durum wheat in nature. Thus, bread wheat offers an excellent example of rapid evolution by allopolyploidy. In the induced polyhaploids (ABD) that are equivalent of amphihaploids, meiotic phenomena such as FDR led to regeneration of parental bread wheat, perhaps a simulation of the evolutionary steps that occurred in nature at the time of the origin of hexaploid wheat. PMID:17416932

Jauhar, Prem P

2007-04-08

238

Development of a simple, antibody-based test for granule-bound starch synthase Wx-B1b (Null4A) wheat varieties  

Microsoft Academic Search

Alignment of the mature protein sequences of the three isoforms of granule-bound starch synthase 1 (GBSS1) of hexaploid wheat Triticum aestivum was used to identify regions showing sequence divergence. Two synthetic peptides based on the Wx-B1 sequence and differing from the corresponding Wx-A1 and Wx-D1 sequences by two or three amino acids were used to immunise rabbits. One peptide elicited

K. R. Gale; M. J. Blundell; A. S. Hill

2004-01-01

239

Characterisation and marker development for low molecular weight glutenin genes from Glu-A3 alleles of bread wheat ( Triticum aestivum. L)  

Microsoft Academic Search

PCR was used to amplify low-molecular-weight (LMW) glutenin genes from the Glu-A3 loci of hexaploid wheat cultivars containing different Glu-A3 alleles. The complete coding sequence of one LMW glutenin gene was obtained for each of the seven alleles Glu-A3a to Glu-A3g. Chromosome assignment of PCR products using Chinese Spring nulli-tetrasomic lines confirmed the amplified products were from chromosome 1A. All

W. Zhang; M. C. Gianibelli; L. R. Rampling; K. R. Gale

2004-01-01

240

Genes encoding plastid acetylCoA carboxylase and 3-phosphoglycerate kinase of the Triticum\\/Aegilops complex and the evolutionary history of polyploid wheat  

Microsoft Academic Search

The classic wheat evolutionary history is one of adaptive radiation of the diploid Triticum\\/Aegilops species (A, S, D), genome convergence and divergence of the tetraploid (Triticum turgidum AABB, and Triticum timopheevii AAGG) and hexaploid (Triticum aestivum, AABBDD) species. We analyzed Acc-1 (plastid acetyl-CoA carboxylase) and Pgk-1 (plastid 3-phosphoglycerate kinase) genes to determine phylogenetic relationships among Triticum and Aegilops species of

Shaoxing Huang; Anchalee Sirikhachornkit; Xiujuan Su; Justin Faris; Bikram Gill; Robert Haselkorn; Piotr Gornicki

2002-01-01

241

Analysis of the Endophytic Actinobacterial Population in the Roots of Wheat (Triticum aestivum L.) by Terminal Restriction Fragment Length Polymorphism and Sequencing of 16S rRNA Clones  

Microsoft Academic Search

The endophytic actinobacterial population in the roots of wheat grown in three different soils obtained from the southeast part of South Australia was investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of the amplified 16S rRNA genes. A new, validated approach was applied to the T-RFLP analysis in order to estimate, to the genus level, the actinobacterial population that

Vanessa M. Conn; Christopher M. M. Franco

2004-01-01

242

Population diversity of yeasts and lactic acid bacteria in pig feed fermented with whey, wet wheat distillers' grains, or water at different temperatures.  

PubMed

The diversity of populations of yeast and lactic acid bacteria (LAB) in pig feeds fermented at 10, 15, or 20 degrees C was characterized by rRNA gene sequencing of isolates. The feeds consisted of a cereal grain mix blended with wet wheat distillers' grains (WWDG feed), whey (W feed), or tap water (WAT feed). Fermentation proceeded for 5 days without disturbance, followed by 14 days of daily simulated feed outtakes, in which 80% of the contents were replaced with fresh feed mixtures. In WWDG feed, Pichia galeiformis became the dominant yeast species, independent of the fermentation temperature and feed change. The LAB population was dominated by Pediococcus pentosaceus at the start of the fermentation period. After 3 days, the Lactobacillus plantarum population started to increase in feeds at all temperatures. The diversity of LAB increased after the addition of fresh feed components. In W feed, Kluyveromyces marxianus dominated, but after the feed change, the population diversity increased. With increasing fermentation temperatures, there was a shift toward Pichia membranifaciens as the dominant species. L. plantarum was the most prevalent LAB in W feed. The WAT feed had a diverse microbial flora, and the yeast population changed throughout the whole fermentation period. Pichia anomala was the most prevalent yeast species, with increasing occurrence at higher fermentation temperatures. Pediococcus pentosaceus was the most prevalent LAB, but after the feed change, L. plantarum started to proliferate. The present study demonstrates that the species composition in fermented pig feed may vary considerably, even if viable cell counts indicate stable microbial populations. PMID:18223110

Olstorpe, Matilda; Lyberg, Karin; Lindberg, Jan Erik; Schnürer, Johan; Passoth, Volkmar

2008-01-25

243

Eat Wheat!  

ERIC Educational Resources Information Center

This pamphlet contains puzzles, games, and a recipe designed to teach elementary school pupils about wheat. It includes word games based on the U.S. Department of Agriculture Food Guide Pyramid and on foods made from wheat. The Food Guide Pyramid can be cut out of the pamphlet and assembled as a three-dimensional information source and food guide.…

Idaho Wheat Commission, Boise.

244

Population dynamics and metabolite target analysis of lactic acid bacteria during laboratory fermentations of wheat and spelt sourdoughs.  

PubMed

Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem. PMID:17557853

Van der Meulen, Roel; Scheirlinck, Ilse; Van Schoor, Ann; Huys, Geert; Vancanneyt, Marc; Vandamme, Peter; De Vuyst, Luc

2007-06-08

245

Wheat CBF gene family: identification of polymorphisms in the CBF coding sequence.  

PubMed

Expression of cold-regulated genes needed for protection against freezing stress is mediated, in part, by the CBF transcription factor family. Previous studies with temperate cereals suggested that the CBF gene family in wheat was large, and that CBF genes were at the base of an important low temperature tolerance trait. Therefore, the goal of our study was to identify the CBF repertoire in the freezing-tolerant hexaploid wheat cultivar Norstar, and then to examine if the coding region of CBF genes in two spring cultivars contain polymorphisms that could affect the protein sequence and structure. Our analyses reveal that hexaploid wheat contains a complex CBF family consisting of at least 65 CBF genes of which 60 are known to be expressed in the cultivar Norstar. They represent 27 paralogous genes with 1-3 homeologous copies for the A, B, and D genomes. The cultivar Norstar contains two pseudogenes and at least 24 additional proteins having sequences and (or) structures that deviate from the consensus in the conserved AP2 DNA-binding and (or) C-terminal activation-domains. This suggests that in cultivars such as Norstar, low temperature tolerance may be increased through breeding of additional optimal alleles. The examination of the CBF repertoire present in the two spring cultivars, Chinese Spring and Manitou, reveals that they have additional polymorphisms affecting conserved positions in these domains. Understanding the effects of these polymorphisms will provide additional information for the selection of optimum CBF alleles in Triticeae breeding programs. PMID:23231605

Mohseni, Sara; Che, Hua; Djillali, Zakia; Dumont, Estelle; Nankeu, Joseph; Danyluk, Jean

2012-12-05

246

WheatGenome.info: an integrated database and portal for wheat genome information.  

PubMed

Bread wheat (Triticum aestivum) is one of the most important crop plants, globally providing staple food for a large proportion of the human population. However, improvement of this crop has been limited due to its large and complex genome. Advances in genomics are supporting wheat crop improvement. We provide a variety of web-based systems hosting wheat genome and genomic data to support wheat research and crop improvement. WheatGenome.info is an integrated database resource which includes multiple web-based applications. These include a GBrowse2-based wheat genome viewer with BLAST search portal, TAGdb for searching wheat second-generation genome sequence data, wheat autoSNPdb, links to wheat genetic maps using CMap and CMap3D, and a wheat genome Wiki to allow interaction between diverse wheat genome sequencing activities. This system includes links to a variety of wheat genome resources hosted at other research organizations. This integrated database aims to accelerate wheat genome research and is freely accessible via the web interface at http://www.wheatgenome.info/. PMID:22009731

Lai, Kaitao; Berkman, Paul J; Lorenc, Michal Tadeusz; Duran, Chris; Smits, Lars; Manoli, Sahana; Stiller, Jiri; Edwards, David

2011-10-18

247

Staining efficiency of specific proteins depends on the staining method: wheat gluten proteins.  

PubMed

To analyze gluten proteins involved in celiac disease (CD) by proteomic analysis, prolamins extracted from hexaploid wheat varieties were analyzed by SDS-PAGE and 2-DE. Differences between staining methods (CBB, silver nitrate, SYPRO Ruby, and CyDye) were analyzed in comparison to immunoblotting. Staining efficiency varied per protein across methods, and complete staining of all gluten proteins could not be achieved by one of these methods. Care should be taken in the selection of staining method especially if one wants to relate the results to data obtained by immunoblotting. PMID:18398878

van den Broeck, Hetty C; America, Antoine H P; Smulders, Marinus J M; Gilissen, Ludovicus J W J; van der Meer, Ingrid M

2008-05-01

248

Wheat: The Whole Story.  

ERIC Educational Resources Information Center

|This publication presents information on wheat. Wheat was originally a wild grass and not native to the United States. Wheat was not planted there until 1777 (and then only as a hobby crop). Wheat is grown on more acres than any other grain in this country. Soft wheats are grown east of the Mississippi River, and hard wheats are grown west of the…

Oklahoma State Dept. of Education, Oklahoma City.

249

GENETIC DEMARCATION OF THE NORTH AMERICAN WHEAT STEM SAWFLY POPULATIONS CEPHUS CINCTUS NORTON, (HYMENOPTERA: CEPHIDAE)N REVEALED BY MOLECULAR MARKERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

In North America, the wheat stem sawfly, Cephus cinctus Norton, and associated parasitoids were originally recovered from wild grasses ranging from California to Manitoba.This sawfly rapidly adapted to wheat, (Triticum aestivum L.), and is currently a chronic pest of economic importance in the north...

250

Association between simple sequence repeat-rich chromosome regions and intergenomic translocation breakpoints in natural populations of allopolyploid wild wheats  

PubMed Central

Background and Aims Repetitive DNA sequences are thought to be involved in the formation of chromosomal rearrangements. The aim of this study was to analyse the distribution of microsatellite clusters in Aegilops biuncialis and Aegilops geniculata, and its relationship with the intergenomic translocations in these allotetraploid species, wild genetic resources for wheat improvement. Methods The chromosomal localization of (ACG)n and (GAA)n microsatellite sequences in Ae. biuncialis and Ae. geniculata and in their diploid progenitors Aegilops comosa and Aegilops umbellulata was investigated by sequential in situ hybridization with simple sequence repeat (SSR) probes and repeated DNA probes (pSc119·2, Afa family and pTa71) and by dual-colour genomic in situ hybridization (GISH). Thirty-two Ae. biuncialis and 19 Ae. geniculata accessions were screened by GISH for intergenomic translocations, which were further characterized by fluorescence in situ hybridization and GISH. Key Results Single pericentromeric (ACG)n signals were localized on most U and on some M genome chromosomes, whereas strong pericentromeric and several intercalary and telomeric (GAA)n sites were observed on the Aegilops chromosomes. Three Ae. biuncialis accessions carried 7Ub–7Mb reciprocal translocations and one had a 7Ub–1Mb rearrangement, while two Ae. geniculata accessions carried 7Ug–1Mg or 5Ug–5Mg translocations. Conspicuous (ACG)n and/or (GAA)n clusters were located near the translocation breakpoints in eight of the ten translocated chromosomes analysed, SSR bands and breakpoints being statistically located at the same chromosomal site in six of them. Conclusions Intergenomic translocation breakpoints are frequently mapped to SSR-rich chromosomal regions in the allopolyploid species examined, suggesting that microsatellite repeated DNA sequences might facilitate the formation of those chromosomal rearrangements. The (ACG)n and (GAA)n SSR motifs serve as additional chromosome markers for the karyotypic analysis of UM genome Aegilops species.

Molnar, Istvan; Cifuentes, Marta; Schneider, Annamaria; Benavente, Elena; Molnar-Lang, Marta

2011-01-01

251

Structural organization of the barley D-hordein locus in comparison with its orthologous regions of wheat genomes.  

PubMed

D hordein, a prolamin storage protein of barley endosperms, is highly homologous to the high molecular weight (HWM) glutenin subunits, which are the major determinants of bread-making quality in wheat flour. In hexaploid wheat (AABBDD), each genome contains two paralogous copies of HMW-glutenin genes that encode the x- and y-type HMW-glutenin subunits. Previously, we reported the sequence analysis of a 102-kb genomic region that contains the HMW-glutenin locus of the D genome from Aegilops tauschii, the donor of the D genome of hexaploid wheat. Here, we present the sequence analysis of a 120-kb D-hordein region of the barley genome, a more distantly related member of the Triticeae grass tribe. Comparative sequence analysis revealed that gene content and order are generally conserved. Genes included in both of these orthologous regions are arranged in the following order: a Xa21-like receptor kinase, an endosperm globulin, an HMW prolamin, and a serine (threonine) protein kinase. However, in the wheat D genome, a region containing both the globulin and HMW-glutenin gene was duplicated, indicating that this duplication event occurred after the separation of the wheat and barley genomes. The intergenic regions are divergent with regard to the sequence and structural organization. It was found that different types of retroelements are responsible for the intergenic structure divergence in the wheat and barley genomes. In the barley region, we identified 16 long terminal repeat (LTR) retrotransposons in three distinct nested clusters. These retroelements account for 63% of the contig sequence. In addition, barley D hordein was compared with wheat HMW glutenins in terms of cysteine residue conservation and repeat domain organization. PMID:14663527

Gu, Yong Qiang; Anderson, Olin D; Londeorë, Cynthia F; Kong, Xiuying; Chibbar, Ravindra N; Lazo, Gerard R

2003-12-01

252

The usefulness of fungicide mixtures and alternation for delaying the selection for resistance in populations of Mycosphaerella graminicola on winter wheat: a modeling analysis.  

PubMed

A fungicide resistance model (reported and tested previously) was amended to describe the development of resistance in Mycosphaerella graminicola populations in winter wheat (Triticum aestivum) crops in two sets of fields, connected by spore dispersal. The model was used to evaluate the usefulness of concurrent, alternating, or mixture use of two high-resistance-risk fungicides as resistance management strategies. We determined the effect on the usefulness of each strategy of (i) fitness costs of resistance, (ii) partial resistance to fungicides, (iii) differences in the dose-response curves and decay rates between fungicides, and (iv) different frequencies of the double-resistant strain at the start of a treatment strategy. Parameter values for the quinine outside inhibitor pyraclostrobin were used to represent two fungicides with differing modes of action. The effectiveness of each strategy was quantified as the maximum number of growing seasons that disease was effectively controlled in both sets of fields. For all scenarios, the maximum effective lives achieved by the use of the strategies were in the order mixtures ? alternation ? concurrent use. Mixtures were of particular benefit where the pathogen strain resistant to both modes of action incurred a fitness penalty or was present at a low initial frequency. PMID:23384858

Hobbelen, P H F; Paveley, N D; Oliver, R P; van den Bosch, F

2013-07-01

253

Impacts of climate change on winter wheat production in China  

Microsoft Academic Search

Climate is changing due to increasing concentration of greenhouse gases, affecting many economic sectors, e.g. agriculture and forestry. Agriculture is a basic sector, especially to China with the most population. Wheat is the second most important staple crops in China. Therefore, assessment of the impacts of climate change on winter wheat is essential for policy maker and wheat producers for

Zhan Tian; Zhiqiang Gao; Yinlong Xu; Hua Chen

2005-01-01

254

The Protein Disulfide Isomerase gene family in bread wheat (T. aestivum L.)  

PubMed Central

Background The Protein Disulfide Isomerase (PDI) gene family encodes several PDI and PDI-like proteins containing thioredoxin domains and controlling diversified metabolic functions, including disulfide bond formation and isomerisation during protein folding. Genomic, cDNA and promoter sequences of the three homoeologous wheat genes encoding the "typical" PDI had been cloned and characterized in a previous work. The purpose of present research was the cloning and characterization of the complete set of genes encoding PDI and PDI like proteins in bread wheat (Triticum aestivum cv Chinese Spring) and the comparison of their sequence, structure and expression with homologous genes from other plant species. Results Eight new non-homoeologous wheat genes were cloned and characterized. The nine PDI and PDI-like sequences of wheat were located in chromosome regions syntenic to those in rice and assigned to eight plant phylogenetic groups. The nine wheat genes differed in their sequences, genomic organization as well as in the domain composition and architecture of their deduced proteins; conversely each of them showed high structural conservation with genes from other plant species in the same phylogenetic group. The extensive quantitative RT-PCR analysis of the nine genes in a set of 23 wheat samples, including tissues and developmental stages, showed their constitutive, even though highly variable expression. Conclusions The nine wheat genes showed high diversity, while the members of each phylogenetic group were highly conserved even between taxonomically distant plant species like the moss Physcomitrella patens. Although constitutively expressed the nine wheat genes were characterized by different expression profiles reflecting their different genomic organization, protein domain architecture and probably promoter sequences; the high conservation among species indicated the ancient origin and diversification of the still evolving gene family. The comprehensive structural and expression characterization of the complete set of PDI and PDI-like wheat genes represents a basis for the functional characterization of this gene family in the hexaploid context of bread wheat.

2010-01-01

255

The role of selection on the genetic structure of pathogen populations: Evidence from field experiments with Mycosphaerella graminicola on wheat  

Microsoft Academic Search

Coevolution refers to reciprocal genetic changes that occur in two or more ecologically interacting species. In agricultural ecosystems, we are especially concerned with the genetic response of pathogen populations to resistant cultivars produced by plant breeding programs. It would be useful to be able to predict whether disease resistance is likely to be durable or ephemeral before a cultivar is

Bruce A. McDonald; Christopher C. Mundt; Ruey-Shyang Chen

1996-01-01

256

The localization and expression of the class II starch synthases of wheat.  

PubMed

The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat. PMID:10444098

Li, Z; Chu, X; Mouille, G; Yan, L; Kosar-Hashemi, B; Hey, S; Napier, J; Shewry, P; Clarke, B; Appels, R; Morell, M K; Rahman, S

1999-08-01

257

The Localization and Expression of the Class II Starch Synthases of Wheat1  

PubMed Central

The starch granules of hexaploid wheat (Triticum aestivum) contain a group of three proteins known as SGP-1 (starch granule protein-1) proteins, which have apparent molecular masses of 100, 108, and 115 kD. The nature and role of these proteins has not been defined previously. We demonstrate that these polypeptides are starch synthases that are present in both the starch granule and the soluble fraction at the early stages of wheat endosperm development, but that are exclusively granule bound at mid and late endosperm development. A partial cDNA clone encoding a fragment of the 100-kD protein was obtained by screening a wheat endosperm cDNA expression library using monoclonal antibodies. Three classes of cDNA were subsequently isolated from a wheat endosperm cDNA library by nucleic acid hybridization and were shown to encode the 100-, 108-, and 115-kD proteins. The cDNA sequences are highly homologous to class II starch synthases and have the highest homology with the maize SSIIa (starch synthase IIa) gene. mRNA for the SGP-1 proteins was detected in the leaf, pre-anthesis florets, and endosperm of wheat and is highly expressed in the leaf and in the grain during the early to mid stages of development. We discuss the roles of the SGP-1 proteins in starch biosynthesis in wheat.

Li, Zhongyi; Chu, Xiusheng; Mouille, Gregory; Yan, Liuling; Kosar-Hashemi, Behjat; Hey, Sandra; Napier, Johnathan; Shewry, Peter; Clarke, Bryan; Appels, Rudi; Morell, Matthew K.; Rahman, Sadequr

1999-01-01

258

Quantifying production potentials of winter wheat in the North China Plain  

Microsoft Academic Search

The North China Plain (NCP) is one of the major winter wheat (Triticum aestivum L.) producing areas in China. Current wheat yields in the NCP stabilize around 5Mgha?1 while the demand for wheat in China is growing due to the increase in population and the change in diet. Since options for area expansion of winter wheat are limited, the production

Dingrong Wu; Qiang Yu; Changhe Lu; Huib Hengsdijk

2006-01-01

259

Quantifying production potential of winter wheat in the North China Plain  

Microsoft Academic Search

The North China Plain (NCP) is one of the major winter wheat (Triticum aestivum L.) producing areas in China. Current wheat yields in the NCP stabilize around 5 Mg ha¿1 while the demand for wheat in China is growing due to the increase in population and the change in diet. Since options for area expansion of winter wheat are limited,

D. Wu; Q. Yu; C. Lu; H. Hengsdijk

2006-01-01

260

Small RNAs, DNA methylation and transposable elements in wheat  

PubMed Central

Background More than 80% of the wheat genome is composed of transposable elements (TEs). Since active TEs can move to different locations and potentially impose a significant mutational load, their expression is suppressed in the genome via small non-coding RNAs (sRNAs). sRNAs guide silencing of TEs at the transcriptional (mainly 24-nt sRNAs) and post-transcriptional (mainly 21-nt sRNAs) levels. In this study, we report the distribution of these two types of sRNAs among the different classes of wheat TEs, the regions targeted within the TEs, and their impact on the methylation patterns of the targeted regions. Results We constructed an sRNA library from hexaploid wheat and developed a database that included our library and three other publicly available sRNA libraries from wheat. For five completely-sequenced wheat BAC contigs, most perfectly matching sRNAs represented TE sequences, suggesting that a large fraction of the wheat sRNAs originated from TEs. An analysis of all wheat TEs present in the Triticeae Repeat Sequence database showed that sRNA abundance was correlated with the estimated number of TEs within each class. Most of the sRNAs perfectly matching miniature inverted repeat transposable elements (MITEs) belonged to the 21-nt class and were mainly targeted to the terminal inverted repeats (TIRs). In contrast, most of the sRNAs matching class I and class II TEs belonged to the 24-nt class and were mainly targeted to the long terminal repeats (LTRs) in the class I TEs and to the terminal repeats in CACTA transposons. An analysis of the mutation frequency in potentially methylated sites revealed a three-fold increase in TE mutation frequency relative to intron and untranslated genic regions. This increase is consistent with wheat TEs being preferentially methylated, likely by sRNA targeting. Conclusions Our study examines the wheat epigenome in relation to known TEs. sRNA-directed transcriptional and post-transcriptional silencing plays important roles in the short-term suppression of TEs in the wheat genome, whereas DNA methylation and increased mutation rates may provide a long-term mechanism to inactivate TEs.

2010-01-01

261

FT genome A and D polymorphisms are associated with the variation of earliness components in hexaploid wheat  

Microsoft Academic Search

The transition from vegetative to floral meristems in higher plants is determined by the coincidence of internal and environmental\\u000a signals. Contrary to the photoperiod pathway, convergent evolution of the cold-dependent pathway has implicated different\\u000a genes between dicots and monocots. Whereas no association between natural variation in vernalization requirement and Flowering\\u000a time locus T (FT) gene polymorphism has been described in

Isabelle Bonnin; Michel Rousset; Delphine Madur; Pierre Sourdille; Céline Dupuits; Dominique Brunel; Isabelle Goldringer

2008-01-01

262

Novel Genetic Variants of GA-Insensitive Rht-1 Genes in Hexaploid Wheat and Their Potential Agronomic Value  

PubMed Central

This study has found numerous novel genetic variants of GA-insensitive dwarfing genes with potential agricultural value for crop improvement. The cultivar, Spica is a tall genotype and possesses the wild-type genes of Rht-A1a, Rht-B1a and Rht-D1a. The cultivar Quarrion possesses a null mutant in the DELLA motif in each of the 3 genomes. This is a first report of a null mutant of Rht-A1. In addition, novel null mutants which differ from reported null alleles of Rht-B1b, Rht-B1e and Rht-D1b have been found in Quarrion, Carnamah and Whistler. The accession, Aus1408 has an allele of Rht-B1 with a mutation in the conserved ‘TVHYNP’ N-terminal signal binding domain with possible implications on its sensitivity to GA. Mutations in the conserved C-terminal GRAS domain of Rht-A1 alleles with possible effects on expression have been found in WW1842, Quarrion and Drysdale. Genetic variants with putative spliceosomal introns in the GRAS domain have been found in all accessions except Spica. Genome-specific cis-sequences about 124 bp upstream of the start codon of the Rht-1 gene have been identified for each of the three genomes.

Tan, Mui-Keng; Koval, Jason; Ghalayini, Aida

2013-01-01

263

Duplication and partitioning in evolution and function of homoeologous Q loci governing domestication characters in polyploid wheat  

PubMed Central

The Q gene encodes an AP2-like transcription factor that played an important role in domestication of polyploid wheat. The chromosome 5A Q alleles (5AQ and 5Aq) have been well studied, but much less is known about the q alleles on wheat homoeologous chromosomes 5B (5Bq) and 5D (5Dq). We investigated the organization, evolution, and function of the Q/q homoeoalleles in hexaploid wheat (Triticum aestivum L.). Q/q gene sequences are highly conserved within and among the A, B, and D genomes of hexaploid wheat, the A and B genomes of tetraploid wheat, and the A, S, and D genomes of the diploid progenitors, but the intergenic regions of the Q/q locus are highly divergent among homoeologous genomes. Duplication of the q gene 5.8 Mya was likely followed by selective loss of one of the copies from the A genome progenitor and the other copy from the B, D, and S genomes. A recent V329-to-I mutation in the A lineage is correlated with the Q phenotype. The 5Bq homoeoalleles became a pseudogene after allotetraploidization. Expression analysis indicated that the homoeoalleles are coregulated in a complex manner. Combined phenotypic and expression analysis indicated that, whereas 5AQ plays a major role in conferring domestication-related traits, 5Dq contributes directly and 5Bq indirectly to suppression of the speltoid phenotype. The evolution of the Q/q loci in polyploid wheat resulted in the hyperfunctionalization of 5AQ, pseudogenization of 5Bq, and subfunctionalization of 5Dq, all contributing to the domestication traits.

Zhang, Zengcui; Belcram, Harry; Gornicki, Piotr; Charles, Mathieu; Just, Jeremy; Huneau, Cecile; Magdelenat, Ghislaine; Couloux, Arnaud; Samain, Sylvie; Gill, Bikram S.; Rasmussen, Jack B.; Barbe, Valerie; Faris, Justin D.; Chalhoub, Boulos

2011-01-01

264

Winter and Specialty Wheat  

Microsoft Academic Search

Wheat is the most widely grown crop in the world. Winter wheat is primarily common wheat (2n = 6x = 42) which has extensive germplasm resources that are used in breeding, often for disease and insect resistance. Though\\u000a wheat can be used as a forage crop and its grain for animal feed, the primary uses of common wheat are to

P. Baenziger; R. Graybosch; D. Van Sanford; W. Berzonsky

265

Structural Analysis of the Wheat Genes Encoding NADH-Dependent Glutamine-2-oxoglutarate Amidotransferases and Correlation with Grain Protein Content  

PubMed Central

Background Nitrogen uptake and the efficient absorption and metabolism of nitrogen are essential elements in attempts to breed improved cereal cultivars for grain or silage production. One of the enzymes related to nitrogen metabolism is glutamine-2-oxoglutarate amidotransferase (GOGAT). Together with glutamine synthetase (GS), GOGAT maintains the flow of nitrogen from NH4+ into glutamine and glutamate, which are then used for several aminotransferase reactions during amino acid synthesis. Results The aim of the present work was to identify and analyse the structure of wheat NADH-GOGAT genomic sequences, and study the expression in two durum wheat cultivars characterized by low and high kernel protein content. The genomic sequences of the three homoeologous A, B and D NADH-GOGAT genes were obtained for hexaploid Triticum aestivum and the tetraploid A and B genes of Triticum turgidum ssp. durum. Analysis of the gene sequences indicates that all wheat NADH-GOGAT genes are composed of 22 exons and 21 introns. The three hexaploid wheat homoeologous genes have high conservation of sequence except intron 13 which shows differences in both length and sequence. A comparative analysis of sequences among di- and mono-cotyledonous plants shows both regions of high conservation and of divergence. qRT-PCR performed with the two durum wheat cvs Svevo and Ciccio (characterized by high and low protein content, respectively) indicates different expression levels of the two NADH-GOGAT-3A and NADH-GOGAT-3B genes. Conclusion The three hexaploid wheat homoeologous NADH-GOGAT gene sequences are highly conserved – consistent with the key metabolic role of this gene. However, the dicot and monocot amino acid sequences show distinctive patterns, particularly in the transit peptide, the exon 16–17 junction, and the C-terminus. The lack of conservation in the transit peptide may indicate subcellular differences between the two plant divisions - while the sequence conservation within enzyme functional domains remains high. Higher expression levels of NADH-GOGAT are associated with higher grain protein content in two durum wheats.

Nigro, Domenica; Gu, Yong Q.; Huo, Naxin; Marcotuli, Ilaria; Blanco, Antonio; Gadaleta, Agata; Anderson, Olin D.

2013-01-01

266

Wheat Lipids  

Technology Transfer Automated Retrieval System (TEKTRAN)

This article is a chapter of a book entitled “Wheat: Chemistry and Technology”, the 4th edition, K. Khan and P.R. Shewry (eds.), to be published in 2007 following the 3rd edition, Y. Pomeranz (ed.), published in 1988 by AACC International Inc., St. Paul, MN. The chapter covers the subject area of wh...

267

Assessment of genetic diversity among Syrian durum (Triticum turgidum ssp. durum) and bread wheat (Triticum aestivum L.) using SSR markers.  

PubMed

Genetic diversity among 49 wheat varieties (37 durum and 12 bread wheat) was assayed using 32 microsatellites representing 34 loci covering almost the whole wheat genome. The polymorphic information content (PIC) across the tested loci ranged from 0 to 0.88 with average values of 0.57 and 0.65 for durum and bread wheat respectively. B genome had the highest mean number of alleles (10.91) followed by A genome (8.3) whereas D genome had the lowest number (4.73). The correlation between PIC and allele number was significant in all genome groups accounting for 0.87, 074 and 0.84 for A, B and D genomes respectively, and over all genomes, the correlation was higher in tetraploid (0.8) than in hexaploid wheat varieties (0.5). The cluster analysis discriminated all varieties and clearly divided the two ploidy levels into two separate clusters that reflect the differences in genetic diversity within each cluster. This study demonstrates that microsatellites markers have unique advantages compared to other molecular and biochemical fingerprinting techniques in revealing the genetic diversity in Syrian wheat varieties that is crucial for wheat improvement. PMID:21254727

Achtar, S; Moualla, M Y; Kalhout, A; Röder, M S; MirAli, N

2010-11-01

268

Genetic and comparative genomics mapping reveals that a powdery mildew resistance gene Ml3D232 originating from wild emmer co-segregates with an NBS-LRR analog in common wheat (Triticum aestivum L.).  

PubMed

Powdery mildew caused by Blumeria graminis f. sp. tritici is one of the most important wheat diseases worldwide and breeding for resistance using diversified disease resistance genes is the most promising approach to prevent outbreaks of powdery mildew. A powdery mildew resistance gene, originating from wild emmer wheat (Triticum turgidum var. dicoccoides) accessions collected from Israel, has been transferred into the hexaploid wheat line 3D232 through crossing and backcrossing. Inoculation results with 21 B. graminis f. sp. tritici races indicated that 3D232 is resistant to all of the powdery mildew isolates tested. Genetic analyses of 3D232 using an F(2) segregating population and F(3) families indicated that a single dominant gene, Ml3D232, confers resistance in the host seedling stage. By applying molecular markers and bulked segregant analysis (BSA), we have identified polymorphic simple sequence repeats (SSR), expressed sequence tags (EST) and derived sequence tagged site (STS) markers to determine that the Ml3D232 is located on chromosome 5BL bin 0.59-0.76. Comparative genetic analyses using mapped EST markers and genome sequences of rice and Brachypodium established co-linearity of the Ml3D232 genomic region with a 1.4 Mb genomic region on Brachypodium distachyon chromosome 4, and a 1.2 Mb contig located on the Oryza sativa chromosome 9. Our comparative approach enabled us to develop new EST-STS markers and to delimit the genomic region carrying Ml3D232 to a 0.8 cM segment that is collinear with a 558 kb region on B. distachyon. Eight EST markers, including an NBS-LRR analog, co-segregated with Ml3D232 to provide a target site for fine genetic mapping, chromosome landing and map-based cloning of the powdery mildew resistance gene. This newly developed common wheat germplasm provides broad-spectrum resistance to powdery mildew and a valuable resource for wheat breeding programs. PMID:20686747

Zhang, Hongtao; Guan, Haiying; Li, Jingting; Zhu, Jie; Xie, Chaojie; Zhou, Yilin; Duan, Xiayu; Yang, Tsomin; Sun, Qixin; Liu, Zhiyong

2010-08-05

269

Successful induction of trigenomic hexaploid Brassica from a triploid hybrid of B. napus L. and B. nigra (L.) Koch  

Microsoft Academic Search

A triploid hybrid with an ABC genome constitution, produced from an interspecific cross between Brassica napus (AACC genome) and B. nigra (BB genome), was used as source material for chromosome doubling. Two approaches were undertaken for the production of hexaploids:\\u000a firstly, by self-pollination and open-pollination of the triploid hybrid; and secondly, by application of colchicine to axillary\\u000a meristems of triploid

Aneeta Pradhan; Julie A. Plummer; Matthew N. Nelson; Wallace A. Cowling; Guijun Yan

2010-01-01

270

Aegilops tauschii draft genome sequence reveals a gene repertoire for wheat adaptation.  

PubMed

About 8,000 years ago in the Fertile Crescent, a spontaneous hybridization of the wild diploid grass Aegilops tauschii (2n = 14; DD) with the cultivated tetraploid wheat Triticum turgidum (2n = 4x = 28; AABB) resulted in hexaploid wheat (T. aestivum; 2n = 6x = 42; AABBDD). Wheat has since become a primary staple crop worldwide as a result of its enhanced adaptability to a wide range of climates and improved grain quality for the production of baker's flour. Here we describe sequencing the Ae. tauschii genome and obtaining a roughly 90-fold depth of short reads from libraries with various insert sizes, to gain a better understanding of this genetically complex plant. The assembled scaffolds represented 83.4% of the genome, of which 65.9% comprised transposable elements. We generated comprehensive RNA-Seq data and used it to identify 43,150 protein-coding genes, of which 30,697 (71.1%) were uniquely anchored to chromosomes with an integrated high-density genetic map. Whole-genome analysis revealed gene family expansion in Ae.?tauschii of agronomically relevant gene families that were associated with disease resistance, abiotic stress tolerance and grain quality. This draft genome sequence provides insight into the environmental adaptation of bread wheat and can aid in defining the large and complicated genomes of wheat species. PMID:23535592

Jia, Jizeng; Zhao, Shancen; Kong, Xiuying; Li, Yingrui; Zhao, Guangyao; He, Weiming; Appels, Rudi; Pfeifer, Matthias; Tao, Yong; Zhang, Xueyong; Jing, Ruilian; Zhang, Chi; Ma, Youzhi; Gao, Lifeng; Gao, Chuan; Spannagl, Manuel; Mayer, Klaus F X; Li, Dong; Pan, Shengkai; Zheng, Fengya; Hu, Qun; Xia, Xianchun; Li, Jianwen; Liang, Qinsi; Chen, Jie; Wicker, Thomas; Gou, Caiyun; Kuang, Hanhui; He, Genyun; Luo, Yadan; Keller, Beat; Xia, Qiuju; Lu, Peng; Wang, Junyi; Zou, Hongfeng; Zhang, Rongzhi; Xu, Junyang; Gao, Jinlong; Middleton, Christopher; Quan, Zhiwu; Liu, Guangming; Wang, Jian; Yang, Huanming; Liu, Xu; He, Zhonghu; Mao, Long; Wang, Jun

2013-03-24

271

Development of an Expressed Sequence Tag (EST) Resource for Wheat (Triticum aestivum L.)  

PubMed Central

This report describes the rationale, approaches, organization, and resource development leading to a large-scale deletion bin map of the hexaploid (2n = 6x = 42) wheat genome (Triticum aestivum L.). Accompanying reports in this issue detail results from chromosome bin-mapping of expressed sequence tags (ESTs) representing genes onto the seven homoeologous chromosome groups and a global analysis of the entire mapped wheat EST data set. Among the resources developed were the first extensive public wheat EST collection (113,220 ESTs). Described are protocols for sequencing, sequence processing, EST nomenclature, and the assembly of ESTs into contigs. These contigs plus singletons (unassembled ESTs) were used for selection of distinct sequence motif unigenes. Selected ESTs were rearrayed, validated by 5? and 3? sequencing, and amplified for probing a series of wheat aneuploid and deletion stocks. Images and data for all Southern hybridizations were deposited in databases and were used by the coordinators for each of the seven homoeologous chromosome groups to validate the mapping results. Results from this project have established the foundation for future developments in wheat genomics.

Lazo, G. R.; Chao, S.; Hummel, D. D.; Edwards, H.; Crossman, C. C.; Lui, N.; Matthews, D. E.; Carollo, V. L.; Hane, D. L.; You, F. M.; Butler, G. E.; Miller, R. E.; Close, T. J.; Peng, J. H.; Lapitan, N. L. V.; Gustafson, J. P.; Qi, L. L.; Echalier, B.; Gill, B. S.; Dilbirligi, M.; Randhawa, H. S.; Gill, K. S.; Greene, R. A.; Sorrells, M. E.; Akhunov, E. D.; Dvorak, J.; Linkiewicz, A. M.; Dubcovsky, J.; Hossain, K. G.; Kalavacharla, V.; Kianian, S. F.; Mahmoud, A. A.; Miftahudin; Ma, X.-F.; Conley, E. J.; Anderson, J. A.; Pathan, M. S.; Nguyen, H. T.; McGuire, P. E.; Qualset, C. O.; Anderson, O. D.

2004-01-01

272

Functional characterisation of wheat Pgip genes reveals their involvement in the local response to wounding.  

PubMed

Polygalacturonase-inhibiting proteins (PGIPs) are cell wall leucine-rich repeat (LRR) proteins involved in plant defence. The hexaploid wheat (Triticum aestivum, genome AABBDD) genome contains one Pgip gene per genome. Tapgip1 (B genome) and Tapgip2 (D genome) are expressed in all tissues, whereas Tapgip3 (A genome) is inactive because of a long terminal repeat, Copia retrotransposon insertion within the coding region. To verify whether Tapgip1 and Tapgip2 encode active PGIPs and are involved in the wheat defence response, we expressed them transiently and analysed their expression under stress conditions. Neither TaPGIP1 nor TaPGIP2 showed inhibition activity in vitro against fungal polygalacturonases. Moreover, a wheat genotype (T. turgidum ssp. dicoccoides) lacking active homologues of Tapgip1 or Tapgip2 possesses PGIP activity. At transcript level, Tapgip1 and Tapgip2 were both up-regulated after fungal infection and strongly induced following wounding. This latter result has been confirmed in transgenic wheat plants expressing the ?-glucuronidase (GUS) gene under control of the 5'-flanking region of Tdpgip1, a homologue of Tapgip1 with an identical sequence. Strong and transient GUS staining was mainly restricted to the damaged tissues and was not observed in adjacent tissues. Taken together, these results suggest that Tapgips and their homologues are involved in the wheat defence response by acting at the site of the lesion caused by pathogen infection. PMID:23574379

Janni, M; Bozzini, T; Moscetti, I; Volpi, C; D'Ovidio, R

2013-04-10

273

Genome merger: from sequence rearrangements in triticale to their elimination in wheat-rye addition lines.  

PubMed

Genetic and epigenetic modifications resulting from different genomes adjusting to a common nuclear environment have been observed in polyploids. Sequence restructuring within genomes involving retrotransposon/microsatellite-rich regions has been reported in triticale. The present study uses inter-retrotransposon amplified polymorphisms (IRAP) and retrotransposon microsatellite amplified polymorphisms (REMAP) to assess genome rearrangements in wheat-rye addition lines obtained by the controlled backcrossing of octoploid triticale to hexaploid wheat followed by self-fertilization. The comparative analysis of IRAP and REMAP banding profiles, involving a complete set of wheat-rye addition lines, and their parental species revealed in those lines the presence of wheat-origin bands absent in triticale, and the absence of rye-origin and triticale-specific bands. The presence in triticale x wheat backcrosses (BC) of rye-origin bands that were absent in the addition lines demonstrated that genomic rearrangement events were not a direct consequence of backcrossing, but resulted from further genome structural rearrangements in the BC plant progeny. PCR experiments using primers designed from different rye-origin sequences showed that the absence of a rye-origin band in wheat-rye addition lines results from sequence elimination rather than restrict changes on primer annealing sites, as noted in triticale. The level of genome restructuring events evaluated in all seven wheat-rye addition lines, compared to triticale, indicated that the unbalanced genome merger situation observed in the addition lines induced a new round of genome rearrangement, suggesting that the lesser the amount of rye chromatin introgressed into wheat the larger the outcome of genome reshuffling. PMID:20383487

Bento, Miguel; Gustafson, Perry; Viegas, Wanda; Silva, Manuela

2010-04-10

274

Relationships of Polymeric Proteins with Dough and Bread-making Quality in a Recombinant Inbred Population of Hard Red Spring Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Variation in wheat (Triticum aestivum L.) polymeric proteins is known to be associated with grain quality. In this study, our objective was to investigate the composition of polymeric proteins and their associations with dough mixing strength and bread-making characteristics in a segregating populat...

275

Quantitative trait loci (QTL) of stem strength and related traits in a doubled-haploid population of wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Scoring for lodging resistance is difficult under natural field conditions. The stem strength of wheat has been used as an index of lodging resistance. However, this is a complex trait comprised of two characters, i.e. stem mechanical elasticity and rigidity. Therefore it is closely associated with stem morphological and anatomical features. A study of the genetics of stem strength and

Lin Hai; Huijun Guo; Shihe Xiao; Guoliang Jiang; Xiuying Zhang; Changsheng Yan; Zhiyong Xin; Jizeng Jia

2005-01-01

276

Genes encoding plastid acetyl-CoA carboxylase and 3-phosphoglycerate kinase of the Triticum/Aegilops complex and the evolutionary history of polyploid wheat.  

PubMed

The classic wheat evolutionary history is one of adaptive radiation of the diploid Triticum/Aegilops species (A, S, D), genome convergence and divergence of the tetraploid (Triticum turgidum AABB, and Triticum timopheevii AAGG) and hexaploid (Triticum aestivum, AABBDD) species. We analyzed Acc-1 (plastid acetyl-CoA carboxylase) and Pgk-1 (plastid 3-phosphoglycerate kinase) genes to determine phylogenetic relationships among Triticum and Aegilops species of the wheat lineage and to establish the timeline of wheat evolution based on gene sequence comparisons. Triticum urartu was confirmed as the A genome donor of tetraploid and hexaploid wheat. The A genome of polyploid wheat diverged from T. urartu less than half a million years ago (MYA), indicating a relatively recent origin of polyploid wheat. The D genome sequences of T. aestivum and Aegilops tauschii are identical, confirming that T. aestivum arose from hybridization of T. turgidum and Ae. tauschii only 8,000 years ago. The diploid Triticum and Aegilops progenitors of the A, B, D, G, and S genomes all radiated 2.5-4.5 MYA. Our data suggest that the Acc-1 and Pgk-1 loci have different histories in different lineages, indicating genome mosaicity and significant intraspecific differentiation. Some loci of the S genome of Aegilops speltoides and the G genome of T. timophevii are closely related, suggesting the same origin of some parts of their genomes. None of the Aegilops genomes analyzed is a close relative of the B genome, so the diploid progenitor of the B genome remains unknown. PMID:12060759

Huang, Shaoxing; Sirikhachornkit, Anchalee; Su, Xiujuan; Faris, Justin; Gill, Bikram; Haselkorn, Robert; Gornicki, Piotr

2002-06-11

277

Partial characterization of glutathione S-transferases from wheat (Triticum spp.) and purification of a safener-induced glutathione S-transferase from Triticum tauschii.  

PubMed Central

Hexaploid wheat (Triticum aestivum L.) has very low constitutive glutathione S-transferase (GST) activity when assayed with the chloroacetamide herbicide dimethenamid as a substrate, which may account for its low tolerance to dimethenamid in the field. Treatment of seeds with the herbicide safener fluxofenim increased the total GST activity extracted from T. aestivum shoots 9-fold when assayed with dimethenamid as a substrate, but had no effect on glutathione levels. Total GST activity in crude protein extracts from T. aestivum, Triticum durum, and Triticum tauschii was separated into several component GST activities by anion-exchange fast-protein liquid chromatography. These activities (isozymes) differed with respect to their activities toward dimethenamid or 1-chloro-2,4-dinitrobenzene as substrates and in their levels of induction by safener treatment. A safener-induced GST isozyme was subsequently purified by anion-exchange and affinity chromatography from etiolated shoots of the diploid wheat species T. tauschii (a progenitor of hexaploid wheat) treated with the herbicide safener cloquintocet-mexyl. The isozyme bound to a dimethenamid-affinity column and had a subunit molecular mass of 26 kD based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme (designated GST TSI-1) was recognized by an antiserum raised against a mixture of maize (Zea mays) GSTs. Amino acid sequences obtained from protease-digested GST TSI-1 had significant homology with the safener-inducible maize GST V and two auxin-regulated tobacco (Nicotiana tabacum) GST isozymes.

Riechers, D E; Irzyk, G P; Jones, S S; Fuerst, E P

1997-01-01

278

Evaluation of the safety of ancient strains of wheat in coeliac disease reveals heterogeneous small intestinal T cell responses suggestive of coeliac toxicity.  

PubMed

BACKGROUND & AIMS: Coeliac disease is a chronic small intestinal immune-mediated enteropathy triggered by dietary gluten in genetically predisposed individuals. Since it is unknown if all wheat varieties are equally toxic to coeliac patients seven Triticum accessions showing different origin (ancient/modern) and ploidy (di-, tetra- hexaploid) were studied. MATERIALS AND METHODS: Selected strains of wheat were ancient Triticum monococcum precoce (AA genome) and Triticum speltoides (BB genome), accessions of Triticum turgidum durum (AABB genome) including two ancient (Graziella Ra and Kamut) and two modern (Senatore Cappelli and Svevo) durum strains of wheat and Triticum aestivum compactum (AABBDD genome). Small intestinal gluten-specific T-cell lines generated from 13 coeliac patients were tested with wheat accessions by proliferation assays. RESULTS: All strains of wheat independent of ploidy or ancient/modern origin triggered heterogeneous responses covering wide ranges of stimulation indices. CONCLUSION: Ancient strains of wheat, although previously suggested to be low or devoid of coeliac toxicity, should be tested for immunogenicity using gluten-specific T-cell lines from multiple coeliac patients rather than gluten-specific clones to assess their potential toxicity. Our findings provide further evidence for the need for a strict gluten-free diet in coeliac patients, including avoidance of ancient strains of wheat. PMID:23465776

Suligoj, Tanja; Gregorini, Armando; Colomba, Mariastella; Ellis, H Julia; Ciclitira, Paul J

2013-02-14

279

AI-lnduced, 51 -Kilodalton, Membrane-Bound Proteins Are Associated with Resistance to AI in a Segregating Population of Wheat  

Microsoft Academic Search

~~ lncorporation of 35S into protein is reduced by exposure to AI in wheat (Trificum aestivum), but the effects are genotype-specific. Exposure to 10 to 75 p~ AI had little effect on 35S incorporation into total protein, nuclear and mitochondrial protein, microsomal protein, and cytosolic protein in the AI-resistant cultivar PT741. In contrast, 10 p~ AI reduced incorporation by 21

Gregory J. Taylor; Atanu Basu; Urmila Basu; Jan J. Slaski; Cuichang Zhang; Allen Good

1997-01-01

280

Dispersed benzoxazinone gene cluster: molecular characterization and chromosomal localization of glucosyltransferase and glucosidase genes in wheat and rye.  

PubMed

Benzoxazinones (Bxs) are major defensive secondary metabolites in wheat (Triticum aestivum), rye (Secale cereale), and maize (Zea mays). Here, we identified full sets of homeologous and paralogous genes encoding Bx glucosyltransferase (GT) and Bx-glucoside glucosidase (Glu) in hexaploid wheat (2n = 6x = 42; AABBDD). Four GT loci (TaGTa-TaGTd) were mapped on chromosomes 7A, 7B (two loci), and 7D, whereas four glu1 loci (Taglu1a-Taglu1d) were on chromosomes 2A, 2B (two loci), and 2D. Transcript levels differed greatly among the four loci; B-genome loci of both TaGT and Taglu1 genes were preferentially transcribed. Catalytic properties of the enzyme encoded by each homeolog/paralog also differed despite high levels of identity among amino acid sequences. The predominant contribution of the B genome to GT and Glu reactions was revealed, as observed previously for the five Bx biosynthetic genes, TaBx1 to TaBx5, which are separately located on homeologous groups 4 and 5 chromosomes. In rye, where the ScBx1 to ScBx5 genes are dispersed to chromosomes 7R and 5R, ScGT and Scglu were located separately on chromosomes 4R and 2R, respectively. The dispersal of Bx-pathway loci to four distinct chromosomes in hexaploid wheat and rye suggests that the clustering of Bx-pathway genes, as found in maize, is not essential for coordinated transcription. On the other hand, barley (Hordeum vulgare) was found to lack the orthologous GT and glu loci like the Bx1 to Bx5 loci despite its close phylogenetic relationship with wheat and rye. These results contribute to our understanding of the evolutionary processes that the Bx-pathway loci have undergone in grasses. PMID:21875895

Sue, Masayuki; Nakamura, Chihiro; Nomura, Taiji

2011-08-29

281

Wheat grass selection  

NSDL National Science Digital Library

The wheat grass on the right is not tolerant of high salinity, or high salt conditions. The wheat grass on the left is a hybrid that has a high salt tolerance. It grows well in high salinity environments.

Richard Wang (USDA;ARS)

2006-09-25

282

Solid-Stemmed Wheat Does Not Affect Overwintering Mortality of the Wheat Stem Sawfly, Cephus cinctus  

PubMed Central

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America. Host plant resistance in the form of solid-stemmed wheat cultivars is the main control strategy for C. cinctus. This study investigated the effect of novel and traditional solid wheat hosts on the overwintering mortality and cold-hardiness of C. cinctus. Field conditions from 2003–2005 showed that overwintering mortality in various wheat cultivars averaged 8% and was not related to the type of wheat cultivar. Similarly, supercooling points (-22° C) were not influenced by wheat host type. C. cintus are cold-hardy; up to 80% survive 10 days at -20° C and 10% survive 40 days. Its overwintering microhabitat near the crown area of the plant is well insulated for temperatures above -10° C and remains ? 20° C above ambient minima. These data suggest that winter mortality is a minor factor in the population dynamics of wheat stem sawfly, and despite clear detrimental effects on larval weight and adult fitness, solid-stemmed cultivars do not reduce the ability of larvae to survive winters.

Carcamo, Hector A.; Beres, Brian L.; Herle, Carolyn E.; McLean, Hugh; McGinne, Sean

2011-01-01

283

Solid-stemmed wheat does not affect overwintering mortality of the wheat stem sawfly, Cephus cinctus.  

PubMed

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America. Host plant resistance in the form of solid-stemmed wheat cultivars is the main control strategy for C. cinctus. This study investigated the effect of novel and traditional solid wheat hosts on the overwintering mortality and cold-hardiness of C. cinctus. Field conditions from 2003-2005 showed that overwintering mortality in various wheat cultivars averaged 8% and was not related to the type of wheat cultivar. Similarly, supercooling points (-22° C) were not influenced by wheat host type. C. cintus are cold-hardy; up to 80% survive 10 days at -20° C and 10% survive 40 days. Its overwintering microhabitat near the crown area of the plant is well insulated for temperatures above -10° C and remains ~ 20° C above ambient minima. These data suggest that winter mortality is a minor factor in the population dynamics of wheat stem sawfly, and despite clear detrimental effects on larval weight and adult fitness, solid-stemmed cultivars do not reduce the ability of larvae to survive winters. PMID:22235942

Cárcamo, Héctor A; Beres, Brian L; Herle, Carolyn E; McLean, Hugh; McGinne, Sean

2011-01-01

284

TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice  

PubMed Central

Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat.

Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Lan, Xiujin; Mao, Long

2013-01-01

285

TaCPK2-A, a calcium-dependent protein kinase gene that is required for wheat powdery mildew resistance enhances bacterial blight resistance in transgenic rice.  

PubMed

Calcium-dependent protein kinases (CPKs) are important Ca2+ signalling components involved in complex immune and stress signalling networks; but the knowledge of CPK gene functions in the hexaploid wheat is limited. Previously, TaCPK2 was shown to be inducible by powdery mildew (Blumeria graminis tritici, Bgt) infection in wheat. Here, its functions in disease resistance are characterized further. This study shows the presence of defence-response and cold-response cis-elements on the promoters of the A subgenome homoeologue (TaCPK2-A) and D subgenome homoeologue (TaCPK2-D), respectively. Their expression patterns were then confirmed by quantitative real-time PCR (qRT-PCR) using genome-specific primers, where TaCPK2-A was induced by Bgt treatment while TaCPK2-D mainly responded to cold treatment. Downregulation of TaCPK2-A by virus-induced gene silencing (VIGS) causes loss of resistance to Bgt in resistant wheat lines, indicating that TaCPK2-A is required for powdery mildew resistance. Furthermore, overexpression of TaCPK2-A in rice enhanced bacterial blight (Xanthomonas oryzae pv. oryzae, Xoo) resistance. qRT-PCR analysis showed that overexpression of TaCPK2-A in rice promoted the expression of OsWRKY45-1, a transcription factor involved in both fungal and bacterial resistance by regulating jasmonic acid and salicylic acid signalling genes. The opposite effect was found in wheat TaCPK2-A VIGS plants, where the homologue of OsWRKY45-1 was significantly repressed. These data suggest that modulation of WRKY45-1 and associated defence-response genes by CPK2 genes may be the common mechanism for multiple disease resistance in grass species, which may have undergone subfunctionalization in promoters before the formation of hexaploid wheat. PMID:23918959

Geng, Shuaifeng; Li, Aili; Tang, Lichuan; Yin, Lingjie; Wu, Liang; Lei, Cailin; Guo, Xiuping; Zhang, Xin; Jiang, Guanghuai; Zhai, Wenxue; Wei, Yuming; Zheng, Youliang; Lan, Xiujin; Mao, Long

2013-08-01

286

Processing Wheat for Food  

NSDL National Science Digital Library

Teachers' Domain presents this interactive lesson on wheat processing, including an introduction to the five kinds of wheat grown in the US and the anatomy of wheat. The module then moves through the six steps in wheat processing: cleaning, conditioning, blending, breaking, sieving, and reducing. Each step is animated to help students visualize the process. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.

2010-10-07

287

Dynamic changes of anti-oxidative enzymes of 10 wheat genotypes at soil water deficits  

Microsoft Academic Search

Drought is a world-spread problem seriously influencing crop production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Wheat is the staple food for more than 35% of world population, so wheat anti-drought physiology study is of importance to wheat production and biological breeding for the

Hong Bo Shao; Zong Suo Liang; Ming An Shao; Qun Sun

2005-01-01

288

U. S. Wheat Industry.  

National Technical Information Service (NTIS)

U.S. wheat production doubled between 1950 and 1975. Improved yields per acre accounted for most of the increase. Since 1974, however, the growth in U.S. wheat yields per acre has leveled off. About half of the U.S. wheat crop is exported, but the somewha...

W. G. Heid

1979-01-01

289

Wheat Stripe Rust  

Technology Transfer Automated Retrieval System (TEKTRAN)

This is a chapter on wheat stripe rust in a book entitled “Wheat: Science and Trade”. The chapter provides an overview on various aspects of wheat stripe rust and control, including distribution and epidemiology; origin and historical importance; taxonomy, lifecycle, and host range; genetic variati...

290

Discovery and mapping of single feature polymorphisms in wheat using Affymetrix arrays  

PubMed Central

Background Wheat (Triticum aestivum L.) is a staple food crop worldwide. The wheat genome has not yet been sequenced due to its huge genome size (~17,000 Mb) and high levels of repetitive sequences; the whole genome sequence may not be expected in the near future. Available linkage maps have low marker density due to limitation in available markers; therefore new technologies that detect genome-wide polymorphisms are still needed to discover a large number of new markers for construction of high-resolution maps. A high-resolution map is a critical tool for gene isolation, molecular breeding and genomic research. Single feature polymorphism (SFP) is a new microarray-based type of marker that is detected by hybridization of DNA or cRNA to oligonucleotide probes. This study was conducted to explore the feasibility of using the Affymetrix GeneChip to discover and map SFPs in the large hexaploid wheat genome. Results Six wheat varieties of diverse origins (Ning 7840, Clark, Jagger, Encruzilhada, Chinese Spring, and Opata 85) were analyzed for significant probe by variety interactions and 396 probe sets with SFPs were identified. A subset of 164 unigenes was sequenced and 54% showed polymorphism within probes. Microarray analysis of 71 recombinant inbred lines from the cross Ning 7840/Clark identified 955 SFPs and 877 of them were mapped together with 269 simple sequence repeat markers. The SFPs were randomly distributed within a chromosome but were unevenly distributed among different genomes. The B genome had the most SFPs, and the D genome had the least. Map positions of a selected set of SFPs were validated by mapping single nucleotide polymorphism using SNaPshot and comparing with expressed sequence tags mapping data. Conclusion The Affymetrix array is a cost-effective platform for SFP discovery and SFP mapping in wheat. The new high-density map constructed in this study will be a useful tool for genetic and genomic research in wheat.

Bernardo, Amy N; Bradbury, Peter J; Ma, Hongxiang; Hu, Shengwa; Bowden, Robert L; Buckler, Edward S; Bai, Guihua

2009-01-01

291

EPIDEMIOLOGY AND CONTROL OF STRIPE RUST ON WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat worldwide. This review presents basic and recent information on stripe rust epidemiology, pathogen virulence changes and population structure, and movement of the pathogen in the Unit...

292

Aphid Feeding Activates Expression of a Transcriptome of Oxylipin-Based Defense Signals in Wheat Involved in Resistance to Herbivory  

Technology Transfer Automated Retrieval System (TEKTRAN)

Damage by the Russian wheat aphid (RWA), Diuraphis noxia, significantly reduces wheat and barley yields worldwide. In compatible interactions, virulent RWA populations flourish and susceptible plants suffer extensive leaf chlorophyll loss. In incompatible interactions, RWA reproduction and populatio...

293

Changes of some anti-oxidative physiological indices under soil water deficits among 10 wheat ( Triticum aestivum L.) genotypes at tillering stage  

Microsoft Academic Search

Drought is one of the major ecological factors limiting crop production and food quality globally, especially in the arid and semi-arid areas of the world. Wheat is the staple food for more than 35% of world population and wheat cultivation is mainly restricted to such zones with scarcity of water, so wheat anti-drought physiology study is of importance to wheat

Hong-Bo Shao; Li-Ye Chu; Gang Wu; Jin-Heng Zhang; Zhao-Hua Lu; Ya-Chen Hu

2007-01-01

294

Nucleotide diversity maps reveal variation in diversity among wheat genomes and chromosomes  

PubMed Central

Background A genome-wide assessment of nucleotide diversity in a polyploid species must minimize the inclusion of homoeologous sequences into diversity estimates and reliably allocate individual haplotypes into their respective genomes. The same requirements complicate the development and deployment of single nucleotide polymorphism (SNP) markers in polyploid species. We report here a strategy that satisfies these requirements and deploy it in the sequencing of genes in cultivated hexaploid wheat (Triticum aestivum, genomes AABBDD) and wild tetraploid wheat (Triticum turgidum ssp. dicoccoides, genomes AABB) from the putative site of wheat domestication in Turkey. Data are used to assess the distribution of diversity among and within wheat genomes and to develop a panel of SNP markers for polyploid wheat. Results Nucleotide diversity was estimated in 2114 wheat genes and was similar between the A and B genomes and reduced in the D genome. Within a genome, diversity was diminished on some chromosomes. Low diversity was always accompanied by an excess of rare alleles. A total of 5,471 SNPs was discovered in 1791 wheat genes. Totals of 1,271, 1,218, and 2,203 SNPs were discovered in 488, 463, and 641 genes of wheat putative diploid ancestors, T. urartu, Aegilops speltoides, and Ae. tauschii, respectively. A public database containing genome-specific primers, SNPs, and other information was constructed. A total of 987 genes with nucleotide diversity estimated in one or more of the wheat genomes was placed on an Ae. tauschii genetic map, and the map was superimposed on wheat deletion-bin maps. The agreement between the maps was assessed. Conclusions In a young polyploid, exemplified by T. aestivum, ancestral species are the primary source of genetic diversity. Low effective recombination due to self-pollination and a genetic mechanism precluding homoeologous chromosome pairing during polyploid meiosis can lead to the loss of diversity from large chromosomal regions. The net effect of these factors in T. aestivum is large variation in diversity among genomes and chromosomes, which impacts the development of SNP markers and their practical utility. Accumulation of new mutations in older polyploid species, such as wild emmer, results in increased diversity and its more uniform distribution across the genome.

2010-01-01

295

Population.  

ERIC Educational Resources Information Center

In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

International Planned Parenthood Federation, London (England).

296

Revealed Competitive Advantage for Wheat.  

National Technical Information Service (NTIS)

A new indicator of trade performance, called 'revealed competitive advantage' (RCA), is used to examine the changing nature of wheat competitiveness and noncompetitiveness. Time series RCA measures for 5 wheat-exporting countries and 20 wheat-importing co...

T. Vollrath

1987-01-01

297

Molecular cytogenetic analysis of wheat - Elymus repens introgression lines with resistance to Fusarium head blight.  

PubMed

Elymus repens (L.) Gould (2n = 6x = 42, StStStStHH) is a hexaploid perennial wheatgrass species from the tribe Triticeae, distantly related to bread wheat Triticum aestivum L. (2n = 6x = 42, AABBDD). As a potential source of resistance to Fusarium head blight (FHB), E. repens was crossed to common wheat to transfer resistance genes. The progeny were advanced to homozygosity by single seed descent. A total of eight BC(1)F(9) progeny lines were selected and characterized in this study. The chromosome numbers of these derived lines ranged from 42 to 56, including lines with 44, 52, and 54 chromosomes. All of the lines were cytologically stable in terms of meiotic chromosome behavior. The univalent frequency in the lines varied between 0.34 and 2.36 per cell. Similarly, the multivalent frequency did not exceed 1% in any of the lines. GISH analysis revealed that the number of intact wheat chromosomes in the various lines varied between 40 and 44. Numerous translocated chromosomes were detected in all lines. The translocations involved chromosomal segments from wheat, and the St and H genomes of E. repens. Furthermore, trigenomic translocated chromosomes were detected in some of the lines. The introgression into wheat chromosomes included not only terminal types but also interstitial segments. The Fusarium head blight resistance of the eight lines, following point inoculation, varied from 5.65% infected florets to 11.46% compared with the check cultivars T. aestivum 'Roblin' and T. aestivum 'Crocus' at 100% and 85%, respectively. PMID:23379340

Zeng, J; Cao, W; Hucl, P; Yang, Y; Xue, A; Chi, D; Fedak, G

2013-01-29

298

Wheat Evolution: Dough Washing  

NSDL National Science Digital Library

In this activity (page 5), learners investigate the evolution of wheat by washing different types of dough with water and comparing the results. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant.

Council, Biotechnology A.

2012-01-01

299

Evolution of new disease specificity at a simple resistance locus in a crop-weed complex: reconstitution of the Lr21 gene in wheat.  

PubMed

The wheat leaf-rust resistance gene Lr21 was first identified in an Iranian accession of goatgrass, Aegilops tauschii Coss., the D-genome donor of hexaploid bread wheat, and was introgressed into modern wheat cultivars by breeding. To elucidate the origin of the gene, we analyzed sequences of Lr21 and lr21 alleles from 24 wheat cultivars and 25 accessions of Ae. tauschii collected along the Caspian Sea in Iran and Azerbaijan. Three basic nonfunctional lr21 haplotypes, H1, H2, and H3, were identified. Lr21 was found to be a chimera of H1 and H2, which were found only in wheat. We attempted to reconstitute a functional Lr21 allele by crossing the cultivars Fielder (H1) and Wichita (H2). Rust inoculation of 5876 F(2) progeny revealed a single resistant plant that proved to carry the H1H2 haplotype, a result attributed to intragenic recombination. These findings reflect how plants balance the penalty and the necessity of a resistance gene and suggest that plants can reuse "dead" alleles to generate new disease-resistance specificity, leading to a "death-recycle" model of plant-resistance gene evolution at simple loci. We suggest that selection pressure in crop-weed complexes contributes to this process. PMID:19364806

Huang, Li; Brooks, Steven; Li, Wanlong; Fellers, John; Nelson, James C; Gill, Bikram

2009-04-13

300

MOLECULAR MARKERS, GENOMICS AND GENETIC ENGINEERING IN WHEAT. (ARTICLE IN BOOK "GLOBAL IMPACT OF GENETIC ENGINEERING ON FOOD AND ENVIRONMENT"  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bread wheat, Triticum aestivum L. (2n = 6x = 42; AABBDD genomes), is the most widely grown cereal crop and is the staple food for 15% of the world's population. Durum wheat or macaroni wheat (Triticum turgidum, 2n = 4x = 28; AABB genomes) is also an important cereal used for human consumption worldw...

301

Alpha-gliadin genes from the A, B, and D genomes of wheat contain different sets of celiac disease epitopes  

Microsoft Academic Search

BACKGROUND: Bread wheat (Triticum aestivum) is an important staple food. However, wheat gluten proteins cause celiac disease (CD) in 0.5 to 1% of the general population. Among these proteins, the ?-gliadins contain several peptides that are associated to the disease. RESULTS: We obtained 230 distinct ?-gliadin gene sequences from severaldiploid wheat species representing the ancestral A, B, and D genomes

Teun WJM van Herpen; Svetlana V Goryunova; Johanna van der Schoot; Makedonka Mitreva; Elma Salentijn; Oscar Vorst; Martijn F Schenk; Peter A van Veelen; Frits Koning; Loek JM van Soest; Ben Vosman; Dirk Bosch; Rob J Hamer; Luud JWJ Gilissen; Marinus JM Smulders

2006-01-01

302

Wheat Quality Council Hard Spring Wheat Technical Committee 2010 Crop  

Technology Transfer Automated Retrieval System (TEKTRAN)

Breeders’ experimental lines of wheat are evaluated for overall quality before being released for commercial production. The Hard Spring Wheat Technical Committee provides milling and baking quality data on breeders’ experimental lines of wheat that are annually submitted to the Wheat Quality Counc...

303

Investigating the Role of Respiration in Plant Salinity Tolerance by Analyzing Mitochondrial Proteomes from Wheat and a Salinity-Tolerant Amphiploid (Wheat × Lophopyrum elongatum).  

PubMed

The effect of salinity on mitochondrial properties was investigated by comparing the reference wheat variety Chinese Spring (CS) to a salt-tolerant amphiploid (AMP). The octoploid AMP genotype was previously generated by combining hexaploid bread wheat (CS) with the diploid wild wheatgrass adapted to salt marshes, Lophopyrum elongatum. Here we used a combination of physiological, biochemical, and proteomic analyses to explore the mitochondrial and respiratory response to salinity in these two genotypes. The AMP showed greater growth tolerance to salinity treatments and altered respiration rate in both roots and shoots. A proteomic workflow of 2D-DIGE and MALDI TOF/TOF mass spectrometry was used to compare the protein composition of isolated mitochondrial samples from roots and shoots of both genotypes, following control or salt treatment. A large set of mitochondrial proteins were identified as responsive to salinity in both genotypes, notably enzymes involved in detoxification of reactive oxygen species. Genotypic differences in mitochondrial composition were also identified, with AMP exhibiting a higher abundance of manganese superoxide dismutase, serine hydroxymethyltransferase, aconitase, malate dehydrogenase, and ?-cyanoalanine synthase compared to CS. We present peptide fragmentation spectra derived from some of these AMP-specific protein spots, which could serve as biomarkers to track superior protein variants. PMID:23895732

Jacoby, Richard P; Millar, A Harvey; Taylor, Nicolas L

2013-08-16

304

Infestation of transgenic powdery mildew-resistant wheat by naturally occurring insect herbivores under different environmental conditions.  

PubMed

A concern associated with the growing of genetically modified (GM) crops is that they could adversely affect non-target organisms. We assessed the impact of several transgenic powdery mildew-resistant spring wheat lines on insect herbivores. The GM lines carried either the Pm3b gene from hexaploid wheat, which confers race-specific resistance to powdery mildew, or the less specific anti-fungal barley seed chitinase and ?-1,3-glucanase. In addition to the non-transformed control lines, several conventional spring wheat varieties and barley and triticale were included for comparison. During two consecutive growing seasons, powdery mildew infection and the abundance of and damage by naturally occurring herbivores were estimated under semi-field conditions in a convertible glasshouse and in the field. Mildew was reduced on the Pm3b-transgenic lines but not on the chitinase/glucanase-expressing lines. Abundance of aphids was negatively correlated with powdery mildew in the convertible glasshouse, with Pm3b wheat plants hosting significantly more aphids than their mildew-susceptible controls. In contrast, aphid densities did not differ between GM plants and their non-transformed controls in the field, probably because of low mildew and aphid pressure at this location. Likewise, the GM wheat lines did not affect the abundance of or damage by the herbivores Oulema melanopus (L.) and Chlorops pumilionis Bjerk. Although a previous study has revealed that some of the GM wheat lines show pleiotropic effects under field conditions, their effect on herbivorous insects appears to be low. PMID:21829479

Álvarez-Alfageme, Fernando; von Burg, Simone; Romeis, Jörg

2011-07-28

305

Coverage and Consistency: Bioinformatics Aspects of the Analysis of Multirun iTRAQ Experiments with Wheat Leaves.  

PubMed

The hexaploid genome of bread wheat (Triticum aestivum) is large (17 Gb) and repetitive, and this has delayed full sequencing and annotation of the genome, which is a prerequisite for effective quantitative proteomics analysis. Aware of these constraints we investigated the most effective approaches for shotgun proteomic analyses of bread wheat that would support large-scale quantitative comparisons using iTRAQ reagents. We used a data set that was generated by two-dimensional LC-MS of iTRAQ labeled peptides from wheat leaves. The main items considered in this study were the choice of sequence database for matching LC-MS data, the consistency of identification when multiple LC-MS runs were acquired, and the options for downstream functional analysis to generate useful insight. For peptide identification we examined the extensive NCBInr plant database, a smaller composite cereals database, the Brachypodium distachyon model plant genome, the EST-based SuperWheat database, as well as the genome sequence from the recently sequenced D-genome progenitor Aegilops tauschii. While the most spectra were assigned by using the SuperWheat database, this extremely large database could not be readily manipulated for the robust protein grouping that is required for large-scale, multirun quantitative experiments. We demonstrated a pragmatic alternative of using the composite cereals database for peptide spectra matching. The stochastic aspect of protein grouping across LC-MS runs was investigated using the smaller composite cereals database where we found that attaching the Brachypodium best BLAST hit reduced this problem. Further, assigning quantitation to the best Brachypodium locus yielded promising results enabling integration with existing downstream data mining and functional analysis tools. Our study demonstrated viable approaches for quantitative proteomics analysis of bread wheat samples and shows how these approaches could be similarly adopted for analysis of other organisms with unsequenced or incompletely sequenced genomes. PMID:24015675

Pascovici, Dana; Gardiner, Donald M; Song, Xiaomin; Breen, Edmond; Solomon, Peter S; Keighley, Tim; Molloy, Mark P

2013-09-20

306

Agrometeorology and Wheat Production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Winter wheat phenology varies among shoots on the plant to main stems on plants within a plot to locations across a landscape. Most often phenological measurements have focused on small treatment plots under presumably similar soils and topography. Many models exist to predict wheat phenology for sm...

307

Registration of 'Snowmass' wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Snowmass’ (Reg. No. CV-1050, PI 658597) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in July 2009 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State Uni...

308

Registration of ‘Ripper’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Ripper’ (Reg. No. CV-1016, PI 644222) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2006 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado S...

309

Registration of ‘Kelse’ wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard red spring (HRS) wheat (Triticum aestivum L.) grain must have high grain protein concentration (GPC) to maximize market value. The objective of this research was to develop a HRS wheat cultivar with high GPC and durable resistance to stripe rust (Puccinia striiformis Westend f. sp. tritici), a ...

310

INVISIBLE COATINGS FOR WHEAT KERNELS  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is occasionally necessary to tag wheat kernels without altering their appearance. Coatings have potential applications to tag wheat of a particular color or protein class, diseased wheat such as karnal bunt or genetically modified wheat. This methodology will aid in the development of calibrati...

311

The impact of Ty3-gypsy group LTR retrotransposons Fatima on B-genome specificity of polyploid wheats  

PubMed Central

Background Transposable elements (TEs) are a rapidly evolving fraction of the eukaryotic genomes and the main contributors to genome plasticity and divergence. Recently, occupation of the A- and D-genomes of allopolyploid wheat by specific TE families was demonstrated. Here, we investigated the impact of the well-represented family of gypsy LTR-retrotransposons, Fatima, on B-genome divergence of allopolyploid wheat using the fluorescent in situ hybridisation (FISH) method and phylogenetic analysis. Results FISH analysis of a BAC clone (BAC_2383A24) initially screened with Spelt1 repeats demonstrated its predominant localisation to chromosomes of the B-genome and its putative diploid progenitor Aegilops speltoides in hexaploid (genomic formula, BBAADD) and tetraploid (genomic formula, BBAA) wheats as well as their diploid progenitors. Analysis of the complete BAC_2383A24 nucleotide sequence (113 605 bp) demonstrated that it contains 55.6% TEs, 0.9% subtelomeric tandem repeats (Spelt1), and five genes. LTR retrotransposons are predominant, representing 50.7% of the total nucleotide sequence. Three elements of the gypsy LTR retrotransposon family Fatima make up 47.2% of all the LTR retrotransposons in this BAC. In situ hybridisation of the Fatima_2383A24-3 subclone suggests that individual representatives of the Fatima family contribute to the majority of the B-genome specific FISH pattern for BAC_2383A24. Phylogenetic analysis of various Fatima elements available from databases in combination with the data on their insertion dates demonstrated that the Fatima elements fall into several groups. One of these groups, containing Fatima_2383A24-3, is more specific to the B-genome and proliferated around 0.5-2.5 MYA, prior to allopolyploid wheat formation. Conclusion The B-genome specificity of the gypsy-like Fatima, as determined by FISH, is explained to a great degree by the appearance of a genome-specific element within this family for Ae. speltoides. Moreover, its proliferation mainly occurred in this diploid species before it entered into allopolyploidy. Most likely, this scenario of emergence and proliferation of the genome-specific variants of retroelements, mainly in the diploid species, is characteristic of the evolution of all three genomes of hexaploid wheat.

2011-01-01

312

Effects of combined thiamethoxam and diatomaceous earth on mortality and progeny production of four Pakistani populations of Rhyzopertha dominica (Coleoptera: Bostrychidae) on wheat, rice and maize  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bioassays were conducted to evaluate the effects of combining thiamethoxam at 0.25, 0.5 and 0.75 mg/kg with the diatomaceous earth (DE) formulation, SilicoSec, at the rate of 100 mg/kg against four diverse populations of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) th...

313

Sequence-Based Mapping of the Polyploid Wheat Genome  

PubMed Central

The emergence of new sequencing technologies has provided fast and cost-efficient strategies for high-resolution mapping of complex genomes. Although these approaches hold great promise to accelerate genome analysis, their application in studying genetic variation in wheat has been hindered by the complexity of its polyploid genome. Here, we applied the next-generation sequencing of a wheat doubled-haploid mapping population for high-resolution gene mapping and tested its utility for ordering shotgun sequence contigs of a flow-sorted wheat chromosome. A bioinformatical pipeline was developed for reliable variant analysis of sequence data generated for polyploid wheat mapping populations. The results of variant mapping were consistent with the results obtained using the wheat 9000 SNP iSelect assay. A reference map of the wheat genome integrating 2740 gene-associated single-nucleotide polymorphisms from the wheat iSelect assay, 1351 diversity array technology, 118 simple sequence repeat/sequence-tagged sites, and 416,856 genotyping-by-sequencing markers was developed. By analyzing the sequenced megabase-size regions of the wheat genome we showed that mapped markers are located within 40?100 kb from genes providing a possibility for high-resolution mapping at the level of a single gene. In our population, gene loci controlling a seed color phenotype cosegregated with 2459 markers including one that was located within the red seed color gene. We demonstrate that the high-density reference map presented here is a useful resource for gene mapping and linking physical and genetic maps of the wheat genome.

Saintenac, Cyrille; Jiang, Dayou; Wang, Shichen; Akhunov, Eduard

2013-01-01

314

Wheat Evolution: Sedimentation Testing  

NSDL National Science Digital Library

In this activity (p.8-9 of PDF), learners investigate the evolution of wheat by conducting sedimentation tests on different flours. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant. Note: Sedimentation test can also be done using SDS detergent and lactic acid instead of soap and vinegar.

Council, Biotechnology A.

2012-01-01

315

Wheat Evolution: Dough Rising  

NSDL National Science Digital Library

In this activity (p.6-7 of PDF), learners investigate the evolution of wheat by creating dough from different flours, observing the samples of dough as they rise, and then baking the dough. The evolution of wheat from wild grasses demonstrates the dramatic effect of both natural and directed evolution on the structure of a crop plant and the chemical makeup of the product harvested from it. These activities illustrate the changes to both the structure and the chemistry of the wheat plant.

Council, Biotechnology A.

2012-01-01

316

Frequent gene movement and pseudogene evolution is common to the large and complex genomes of wheat, barley, and their relatives.  

PubMed

All six arms of the group 1 chromosomes of hexaploid wheat (Triticum aestivum) were sequenced with Roche/454 to 1.3- to 2.2-fold coverage and compared with similar data sets from the homoeologous chromosome 1H of barley (Hordeum vulgare). Six to ten thousand gene sequences were sampled per chromosome. These were classified into genes that have their closest homologs in the Triticeae group 1 syntenic region in Brachypodium, rice (Oryza sativa), and/or sorghum (Sorghum bicolor) and genes that have their homologs elsewhere in these model grass genomes. Although the number of syntenic genes was similar between the homologous groups, the amount of nonsyntenic genes was found to be extremely diverse between wheat and barley and even between wheat subgenomes. Besides a small core group of genes that are nonsyntenic in other grasses but conserved among Triticeae, we found thousands of genic sequences that are specific to chromosomes of one single species or subgenome. By examining in detail 50 genes from chromosome 1H for which BAC sequences were available, we found that many represent pseudogenes that resulted from transposable element activity and double-strand break repair. Thus, Triticeae seem to accumulate nonsyntenic genes frequently. Since many of them are likely to be pseudogenes, total gene numbers in Triticeae are prone to pronounced overestimates. PMID:21622801

Wicker, Thomas; Mayer, Klaus F X; Gundlach, Heidrun; Martis, Mihaela; Steuernagel, Burkhard; Scholz, Uwe; Simková, Hana; Kubaláková, Marie; Choulet, Frédéric; Taudien, Stefan; Platzer, Matthias; Feuillet, Catherine; Fahima, Tzion; Budak, Hikmet; Dolezel, Jaroslav; Keller, Beat; Stein, Nils

2011-05-27

317

Effects of heavy-ion beams on chromosomes of common wheat, Triticum aestivum.  

PubMed

To investigate the nature of plant chromosomes irradiated by heavy-ion beams, the effects of nitrogen (N) and neon (Ne) ion beams on hexaploid wheat chromosomes were compared with those of X-ray. Chromosome aberrations, such as short, ring and dicentric chromosomes appeared in high frequency. The average numbers of chromosome breaks at LD-50 by irradiation with X-ray, N and Ne ion beams were 32, 20 and 20, respectively. These values may be underestimated because chromosome rearrangement without change in chromosome morphology was not counted. Thus, we subsequently used a wheat line with a pair of extra chromosomes from an alien species (Leymus racemosus) and observed the fate of the irradiated marker chromosomes by genomic in situ hybridization. This analysis revealed that 50Gy of neon beam induced about eight times more breaks than those induced by X-ray. This result suggests that heavy-ion beams induce chromosome rearrangement in high frequency rather than loss of gene function. This suggests further that most of the novel mutations produced by ion beam irradiation, which have been used in plant breeding, may not be caused by ordinary gene disruption but by chromosome rearrangements. PMID:19442674

Kikuchi, Shinji; Saito, Yoshinaka; Ryuto, Hiromichi; Fukunishi, Nobuhisa; Abe, Tomoko; Tanaka, Hiroyuki; Tsujimoto, Hisashi

2009-05-13

318

Metabolite profiling of a diverse collection of wheat lines using ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry.  

PubMed

Genetic differences among major types of wheat are well characterized; however, little is known about how these distinctions affect the small molecule profile of the wheat seed. Ethanol/water (65% v/v) extracts of seed from 45 wheat lines representing 3 genetically distinct classes, tetraploid durum (Triticum turgidum subspecies durum) (DW) and hexaploid hard and soft bread wheat (T. aestivum subspecies aestivum) (BW) were subjected to ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS). Discriminant analyses distinguished DW from BW with 100% accuracy due to differences in expression of nonpolar and polar ions, with differences attributed to sterol lipids/fatty acids and phospholipids/glycerolipids, respectively. Hard versus soft BW was distinguished with 100% accuracy by polar ions, with differences attributed to heterocyclic amines and polyketides versus phospholipid ions, respectively. This work provides a foundation for identification of metabolite profiles associated with desirable agronomic and human health traits and for assessing how environmental factors impact these characteristics. PMID:22957002

Matthews, Shawna B; Santra, Meenakshi; Mensack, Meghan M; Wolfe, Pamela; Byrne, Patrick F; Thompson, Henry J

2012-08-30

319

Metabolite Profiling of a Diverse Collection of Wheat Lines Using Ultraperformance Liquid Chromatography Coupled with Time-of-Flight Mass Spectrometry  

PubMed Central

Genetic differences among major types of wheat are well characterized; however, little is known about how these distinctions affect the small molecule profile of the wheat seed. Ethanol/water (65% v/v) extracts of seed from 45 wheat lines representing 3 genetically distinct classes, tetraploid durum (Triticum turgidum subspecies durum) (DW) and hexaploid hard and soft bread wheat (T. aestivum subspecies aestivum) (BW) were subjected to ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOF-MS). Discriminant analyses distinguished DW from BW with 100% accuracy due to differences in expression of nonpolar and polar ions, with differences attributed to sterol lipids/fatty acids and phospholipids/glycerolipids, respectively. Hard versus soft BW was distinguished with 100% accuracy by polar ions, with differences attributed to heterocyclic amines and polyketides versus phospholipid ions, respectively. This work provides a foundation for identification of metabolite profiles associated with desirable agronomic and human health traits and for assessing how environmental factors impact these characteristics.

Wolfe, Pamela; Byrne, Patrick F.; Thompson, Henry J.

2012-01-01

320

Similarities of omega gliadins from Triticum urartu to those encoded on chromosome 1A of hexaploid wheat and evidence for their post-translational processing  

Microsoft Academic Search

The ?-gliadins encoded on chromosome 1 of the A genome were purified from Triticum aestivum L . (2 n=6 x=42, AABBDD) cv. Butte86, nullisomic 1D-tetrasomic 1A of cv. Chinese Spring (CS N1DT1A), and the diploid T. urartu (2 n=2 x=14, AA ). Reverse-phase high-performance liquid chromatography combined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis of gliadin extracts from CS nullisomic-tetrasomic (NT)

F. M. DuPont; W. Vensel; T. Encarnacao; R. Chan; D. D. Kasarda

2004-01-01

321

Similarities of omega gliadins from Triticum urartu to those encoded on chromosome 1A of hexaploid wheat and evidence for their post-translational processing.  

PubMed

The omega-gliadins encoded on chromosome 1 of the A genome were purified from Triticum aestivum L. (2n=6 x=42, AABBDD) cv. Butte86, nullisomic 1D-tetrasomic 1A of cv. Chinese Spring (CS N1DT1A), and the diploid T. urartu (2n=2 x=14, AA ). Reverse-phase high-performance liquid chromatography combined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis of gliadin extracts from CS nullisomic-tetrasomic (NT) lines confirmed the assignment to chromosome 1A. The purified omega-gliadins were characterized by mass spectrometry and N-terminal sequencing. The 1A-encoded omega-gliadins were smaller than 1B- or 1D-encoded omega-gliadins. The N-terminal amino acid sequences for 1A omega-gliadin mature peptides were nearly identical to those for the T. urartu omega-gliadins and were more similar to 1D omega-gliadin sequences than to sequences for T. monococum omega-gliadins, barley C-hordeins, or rye omega-secalins. They diverged greatly from the N-terminal sequences for the 1B omega-gliadins. The data suggest that T. urartu is the A-genome donor, and that post-translational cleavage by an asparaginyl endoprotease produces those omega-gliadins with N-terminal sequences beginning with KEL. PMID:14747918

DuPont, F M; Vensel, W; Encarnacao, T; Chan, R; Kasarda, D D

2004-01-28

322

Wheat for Kids! [and] Teacher's Guide.  

ERIC Educational Resources Information Center

"Wheat for Kids" contains information at the elementary school level about: the structure of the wheat kernel; varieties of wheat and their uses; growing wheat; making wheat dough; the U.S. Department of Agriculture Food Guide Pyramid and nutrition; Idaho's part of the international wheat market; recipes; and word games based on the information…

Idaho Wheat Commission, Boise.

323

Wheat for Kids! [and] Teacher's Guide.  

ERIC Educational Resources Information Center

|"Wheat for Kids" contains information at the elementary school level about: the structure of the wheat kernel; varieties of wheat and their uses; growing wheat; making wheat dough; the U.S. Department of Agriculture Food Guide Pyramid and nutrition; Idaho's part of the international wheat market; recipes; and word games based on the information…

Idaho Wheat Commission, Boise.

324

Physical mapping of a large plant genome using global high-information-content-fingerprinting: the distal region of the wheat ancestor Aegilops tauschii chromosome 3DS  

PubMed Central

Background Physical maps employing libraries of bacterial artificial chromosome (BAC) clones are essential for comparative genomics and sequencing of large and repetitive genomes such as those of the hexaploid bread wheat. The diploid ancestor of the D-genome of hexaploid wheat (Triticum aestivum), Aegilops tauschii, is used as a resource for wheat genomics. The barley diploid genome also provides a good model for the Triticeae and T. aestivum since it is only slightly larger than the ancestor wheat D genome. Gene co-linearity between the grasses can be exploited by extrapolating from rice and Brachypodium distachyon to Ae. tauschii or barley, and then to wheat. Results We report the use of Ae. tauschii for the construction of the physical map of a large distal region of chromosome arm 3DS. A physical map of 25.4 Mb was constructed by anchoring BAC clones of Ae. tauschii with 85 EST on the Ae. tauschii and barley genetic maps. The 24 contigs were aligned to the rice and B. distachyon genomic sequences and a high density SNP genetic map of barley. As expected, the mapped region is highly collinear to the orthologous chromosome 1 in rice, chromosome 2 in B. distachyon and chromosome 3H in barley. However, the chromosome scale of the comparative maps presented provides new insights into grass genome organization. The disruptions of the Ae. tauschii-rice and Ae. tauschii-Brachypodium syntenies were identical. We observed chromosomal rearrangements between Ae. tauschii and barley. The comparison of Ae. tauschii physical and genetic maps showed that the recombination rate across the region dropped from 2.19 cM/Mb in the distal region to 0.09 cM/Mb in the proximal region. The size of the gaps between contigs was evaluated by comparing the recombination rate along the map with the local recombination rates calculated on single contigs. Conclusions The physical map reported here is the first physical map using fingerprinting of a complete Triticeae genome. This study demonstrates that global fingerprinting of the large plant genomes is a viable strategy for generating physical maps. Physical maps allow the description of the co-linearity between wheat and grass genomes and provide a powerful tool for positional cloning of new genes.

2010-01-01

325

Genetic Behavior of 2Ai2 Chromosome in Thinopyrum intermedium–Wheat Substitution Lines  

Microsoft Academic Search

The aim of this study was to provide cytogenetical evidence on the behavior of chromosome 2Ai-2 from Thinopyrum intermedium in different wheat (Triticum aestivum L.) chromosome substitution backgrounds. Five wheat-alien disomic or ditelosomic substitution lines were crossed with the common wheat variety Chinese Spring to produce the BC1 and F2 populations, which were tested with expressed sequence target (EST)-PCR markers

Yue ZHANG; Zhi-Shan LIN; Bao-Jiu CAO; Yi-Qiang GUO; Mei-Jiao WANG; Xing-Guo YE; Zhi-Yong XIN; Qiong-Fang XU; Shi-Hua GUO

2009-01-01

326

The wheat chloroplastic proteome.  

PubMed

With the availability of plant genome sequencing, analysis of plant proteins with mass spectrometry has become promising and admired. Determining the proteome of a cell is still a challenging assignment, which is convoluted by proteome dynamics and convolution. Chloroplast is fastidious curiosity for plant biologists due to their intricate biochemical pathways for indispensable metabolite functions. In this review, an overview on proteomic studies conducted in wheat with a special focus on subcellular proteomics of chloroplast, salt and water stress. In recent years, we and other groups have attempted to understand the photosynthesis in wheat and abiotic stress under salt imposed and water deficit during vegetative stage. Those studies provide interesting results leading to better understanding of the photosynthesis and identifying the stress-responsive proteins. Indeed, recent studies aimed at resolving the photosynthesis pathway in wheat. Proteomic analysis combining two complementary approaches such as 2-DE and shotgun methods couple to high through put mass spectrometry (LTQ-FTICR and MALDI-TOF/TOF) in order to better understand the responsible proteins in photosynthesis and abiotic stress (salt and water) in wheat chloroplast will be focused. BIOLOGICAL SIGNIFICANCE: In this review we discussed the identification of the most abundant protein in wheat chloroplast and stress-responsive under salt and water stress in chloroplast of wheat seedlings, thus providing the proteomic view of the events during the development of this seedling under stress conditions. Chloroplast is fastidious curiosity for plant biologists due to their intricate biochemical pathways for indispensable metabolite functions. An overview on proteomic studies conducted in wheat with a special focus on subcellular proteomics of chloroplast, salt and water stress. We have attempted to understand the photosynthesis in wheat and abiotic stress under salt imposed and water deficit during seedling stage. Those studies provide interesting results leading to a better understanding of the photosynthesis and identifying the stress-responsive proteins. In reality, our studies aspired at resolving the photosynthesis pathway in wheat. Proteomic analysis united two complementary approaches such as Tricine SDS-PAGE and 2-DE methods couple to high through put mass spectrometry (LTQ-FTICR and MALDI-TOF/TOF) in order to better understand the responsible proteins in photosynthesis and abiotic stress (salt and water) in wheat chloroplast will be highlighted. This article is part of a Special Issue entitled: Translational Plant Proteomics. PMID:23563086

Kamal, Abu Hena Mostafa; Cho, Kun; Choi, Jong-Soon; Bae, Kwang-Hee; Komatsu, Setsuko; Uozumi, Nobuyuki; Woo, Sun Hee

2013-04-01

327

New Uses for Wheat and Modified Wheat Products  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hard wheat from the Great Plains historically has been used as a source of flour for the production of leavened bakery products. However, potentially applications of wheat in both new markets and new products has necessitated the need to develop wheats with novel processing attributes. The most lo...

328

Russian winter wheat mosaic virus  

Technology Transfer Automated Retrieval System (TEKTRAN)

The chapter contains a description of the Winter wheat (Russian) mosaic disease symptoms, transmission and occurrence. Characteristics of the disease agent, Winter wheat (Russian) mosaic virus are outlined, as are control measures....

329

Recent Advances in Wheat Allelopathy  

Microsoft Academic Search

Wheat (Triticum aestivum), as one of the world’s important crops, has been studied in depth for its allelopathic potential in weed management. Research\\u000a on wheat allelopathy has progressed rapidly from the initial evaluation of allelopathic potential to the identification of\\u000a allelochemicals and genetic markers associated with wheat allelopathy. Allelopathic activity varied among wheat accessions.\\u000a Significant varietal differences in the production

Hanwen Wu; Min An; De Li Liu; Jim Pratley; Deirdre Lemerle

330

Changes of anti-oxidative enzymes and MDA content under soil water deficits among 10 wheat ( Triticum aestivum L.) genotypes at maturation stage  

Microsoft Academic Search

Drought is a world-spread problem seriously influencing grain production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Wheat is the staple food for more than 35% of world population, so wheat anti-drought physiology study is of importance to wheat production and biological breeding for the

Shao HongBo; Liang ZongSuo; Shao MingAn

2005-01-01

331

Occurrence of trichothecin in wheat.  

PubMed

Trichothecin, a toxic metabolite of Trichothecium roseum, was detected in 3 of 13 wheat samples examined at levels of 560, 290, and 270 ng/g. In addition, all the T. roseum isolates from the wheat produced the toxin on wheat. PMID:16347131

Ishii, K; Kobayashi, J; Ueno, Y; Ichinoe, M

1986-08-01

332

Intraspecific sequence comparisons reveal similar rates of non-collinear gene insertion in the B and D genomes of bread wheat  

PubMed Central

Background Polyploidization is considered one of the main mechanisms of plant genome evolution. The presence of multiple copies of the same gene reduces selection pressure and permits sub-functionalization and neo-functionalization leading to plant diversification, adaptation and speciation. In bread wheat, polyploidization and the prevalence of transposable elements resulted in massive gene duplication and movement. As a result, the number of genes which are non-collinear to genomes of related species seems markedly increased in wheat. Results We used new-generation sequencing (NGS) to generate sequence of a Mb-sized region from wheat chromosome arm 3DS. Sequence assembly of 24 BAC clones resulted in two scaffolds of 1,264,820 and 333,768 bases. The sequence was annotated and compared to the homoeologous region on wheat chromosome 3B and orthologous loci of Brachypodium distachyon and rice. Among 39 coding sequences in the 3DS scaffolds, 32 have a homoeolog on chromosome 3B. In contrast, only fifteen and fourteen orthologs were identified in the corresponding regions in rice and Brachypodium, respectively. Interestingly, five pseudogenes were identified among the non-collinear coding sequences at the 3B locus, while none was found at the 3DS locus. Conclusion Direct comparison of two Mb-sized regions of the B and D genomes of bread wheat revealed similar rates of non-collinear gene insertion in both genomes with a majority of gene duplications occurring before their divergence. Relatively low proportion of pseudogenes was identified among non-collinear coding sequences. Our data suggest that the pseudogenes did not originate from insertion of non-functional copies, but were formed later during the evolution of hexaploid wheat. Some evidence was found for gene erosion along the B genome locus.

2012-01-01

333

EFFECTIVE FACTORS INVOLVED IN ADOPTION OF SPRINKLER IRRIGATION: A CASE STUDY IN WHEAT FARMERS IN NAHAVAND TOWNSHIP, IRAN  

Microsoft Academic Search

The purpose of this study was to examine effective factors involved in adoption of sprinkler irrigation about wheat farmers in Nahavand Township from Iran. Wheat farmers (n=15365) in the Nahavand Township from Iran were the target population for this study. The population frame was obtained from Nahavand agricultural organization. The sample obtained through proportional stratified sampling (n=375). The methodological approach

Omid Noruzi; Mohammad Chizari

334

Biolistics Transformation of Wheat  

NASA Astrophysics Data System (ADS)

We present a complete, step-by-step guide to the production of transformed wheat plants using a particle bombardment device to deliver plasmid DNA into immature embryos and the regeneration of transgenic plants via somatic embryogenesis. Currently, this is the most commonly used method for transforming wheat and it offers some advantages. However, it will be interesting to see whether this position is challenged as facile methods are developed for delivering DNA by Agrobacterium tumefaciens or by the production of transformants via a germ-line process (see other chapters in this book).

Sparks, Caroline A.; Jones, Huw D.

335

[Reviewed on wheat genome].  

PubMed

Research development of genetic mapping,physics mapping,genome sequencing and expressed sequence tags in wheat have been reviewed in this paper. RFLP genetic linkage map of wheat recombinant inbred lines derived from W7984 x Opata, was used to study QTL of 33 traits associated with water use efficiency. Compared with QTL map of 7 group homeologues chromosomes, the results were showed as follows: nearby the centromeric region of 1A and 1B chromosome, the gene cluster of controlling photosynthetic and root traits were located. The gene clusters of controlling water use efficiency per plant,root and plant height and growth rate were located on the 2 group chromosomes. The gene clusters of controlling root traits were located on the 6A an 6B chromosome, there was a big gene cluster mad up by 7 QTLs controlling water use efficiency of wheat leaf and per plant nearby the centromeric region of 6D chromosome. It showed that 6th homologous chromosomes play an important role in controlling water use efficiency in wheat. PMID:16126710

Zhang, Zheng-Bin; Xu, Ping

2002-05-01

336

Drought resistance in wheat  

Microsoft Academic Search

Summary 1.The general trend of various factors in the leaves of the wheat varieties Currawa, Federation and Major, respectively, has been followed throughout the season of the year 1933.2.The factors observed included the water content of the leaves, the sap expressed from the leaves under pressure, the water content of the pressed leaves, the total, free and bound water and

J. Calvert

1935-01-01

337

Registration of ‘Shirley’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Shirley’ (Reg. No. CV-, PI) soft red winter (SRW) wheat (Triticum aestivum L.) was developed by the Virginia Agricultural Experiment Station and released in March 2008. Shirley was derived from the three-way cross VA94-52-25 / ‘Coker 9835’ (PI 548846 PVPO) // VA96-54-234. Shirley is widely adapted ...

338

Registration of ‘Jamestown’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Jamestown’ (Reg. No. CV-, PI 653731) soft red winter wheat (Triticum aestivum L.) was developed and released by the Virginia Agricultural Experiment Station in March 2007. Jamestown was derived from the cross ‘Roane’ (PI 612958)/Pioneer Brand ‘2691’ (PI 590941 PVPO) and was tested under the experim...

339

Registration of ‘5205’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The soft red winter (SRW) wheat (Triticum aestivum L.) cultivar ‘5205’ (Reg. No. CV-, PI) was developed by the Virginia Agricultural Experiment Station and released in March 2008. Cultivar 5205 was derived from the three-way cross Pioneer Brand ‘2684’ (PI 566923 PVPO) / VA93-54-185 // ’Pocahontas’ ...

340

Registration of 'Juniper' Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Juniper’ (PI 639951) is a hard red winter wheat (Triticum aestivum L.) developed by the Idaho Agricultural Experimental Station and released in February 2006. Juniper, named for the town of Juniper, Idaho, was released for its superior yield and quality compared with previous full stature hard red...

341

REGISTRATION OF 'DELIVER' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Deliver’ (Reg. No. CV-_______, PI 639232) hard red winter wheat (Triticum aestivum L.) was released to certified seed growers with permission of the Oklahoma Agricultural Experiment Station (AES) and the USDA-ARS in 2004. Deliver, an awnletted cultivar, was named for its unique and competitive abil...

342

Registration of Camelot Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Camelot ' (PI 653832) hard red winter wheat (Triticum aestivum L.) was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in 2008. In addition to researchers at the releasing institutions, USDA-ARS researchers at Manhattan, KS, and St. Paul, MN, ...

343

Modelling Wheat Production  

Technology Transfer Automated Retrieval System (TEKTRAN)

In wheat, a shorter pre-anthesis phase is often associated with increased grain protein content (GPC) but decreased grain yield. Cultivar differences in pre-anthesis development are mainly determined by vernalization requirement, photoperiod sensitivity and earliness per se. This research examines w...

344

REGISTRATION OF 'MACON' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Macon' hard white spring wheat (Triticum aestivum L.) (Reg. no. CV-PI 617072) was developed by the Agricultural Research Center of Washington State University in cooperation with the Agricultural Experiment Stations (AESs) of the University of Idaho and Oregon State University, and the United State...

345

Registration of ‘Endurance’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Endurance’ (Reg. No. CV-994, PI 639233) hard red winter wheat (Triticum aestivum L.) was released to certified seed growers with permission of the Oklahoma Agricultural Experiment Station and the USDA-ARS in 2004. Its name derives from the unique ability to endure and recover from extended and inte...

346

REGISTRATION OF 'EDNURANCE' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Endurance’ is a hard red winter wheat (Triticum aestivum L.) that was released to certified seed growers with permission of the Oklahoma Agricultural Experiment Station and the USDA-ARS in 2004. Its name derives from the unique ability to endure and recover from extended and intensive grazing in a...

347

REGISTRATION OF 'INTRADA' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Intrada' is a hard white winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station, Kansas Agricultural Experiment Station, and the USDA-ARS, and released in September, 2000, in cooperation with the USDA-ARS. Intrada was released for its high yield...

348

[Analysis of storage proteins (prolamines, puroindolines and waxy) in common wheat lines Triticum aestivum L. x (Triticum timopheevii Zhuk. x Triticum tauschii) with complex resistance to fungal infections].  

PubMed

Storage proteins (prolamines, puroindolines, and Waxy) were studied in common wheat introgression lines obtained with the use of the Saratovskaya 29 (S29) cultivar line and synthetic hexaploid wheat (Triticum timopheevii Zhuk. x T. tauschii) (Sintetik, Sin.) and displaying complex resistance to fungal infections. Comparative analysis of storage proteins in the introgression lines of common wheat Triticum aestivum L. and in the parental forms revealed the only line (BC5) having a substitution at the Gli-B2 locus from Sintetik. Hybrid lines subjected to nine back crosses with the recurrent parental form S29 and selections for resistance to pathogens can be considered as nearly isogenic for the selected trait and retaining the allelic composition of (1) prolamines responsible for the bread-making qualitiy, (2) puroindolines associated with grain texture, and (3) Waxy proteins responsible for nutritive qualities. These lines are valuable as donors of immunity in breeding programs without the loss of the quality of flour and grain as compared to the S29 line and are also important in searching for genes determining resistance to leaf and stem rust and to powdery mildew. The amphiploid has a number of characters (silent Glu-A 1 locus and Ha genotype) that can negatively affect the quality of flour and grain and thus should be taken into account when choosing this donor. PMID:20734767

Obukhova, L V; La?kova, L I; Shumny?, V K

2010-06-01

349

Tetraploid Wheat Landraces in the Mediterranean Basin: Taxonomy, Evolution and Genetic Diversity  

PubMed Central

The geographic distribution of genetic diversity and the population structure of tetraploid wheat landraces in the Mediterranean basin has received relatively little attention. This is complicated by the lack of consensus concerning the taxonomy of tetraploid wheats and by unresolved questions regarding the domestication and spread of naked wheats. These knowledge gaps hinder crop diversity conservation efforts and plant breeding programmes. We investigated genetic diversity and population structure in tetraploid wheats (wild emmer, emmer, rivet and durum) using nuclear and chloroplast simple sequence repeats, functional variations and insertion site-based polymorphisms. Emmer and wild emmer constitute a genetically distinct population from durum and rivet, the latter seeming to share a common gene pool. Our population structure and genetic diversity data suggest a dynamic history of introduction and extinction of genotypes in the Mediterranean fields.

Oliveira, Hugo R.; Campana, Michael G.; Jones, Huw; Hunt, Harriet V.; Leigh, Fiona; Redhouse, David I.; Lister, Diane L.; Jones, Martin K.

2012-01-01

350

Tetraploid wheat landraces in the Mediterranean basin: taxonomy, evolution and genetic diversity.  

PubMed

The geographic distribution of genetic diversity and the population structure of tetraploid wheat landraces in the Mediterranean basin has received relatively little attention. This is complicated by the lack of consensus concerning the taxonomy of tetraploid wheats and by unresolved questions regarding the domestication and spread of naked wheats. These knowledge gaps hinder crop diversity conservation efforts and plant breeding programmes. We investigated genetic diversity and population structure in tetraploid wheats (wild emmer, emmer, rivet and durum) using nuclear and chloroplast simple sequence repeats, functional variations and insertion site-based polymorphisms. Emmer and wild emmer constitute a genetically distinct population from durum and rivet, the latter seeming to share a common gene pool. Our population structure and genetic diversity data suggest a dynamic history of introduction and extinction of genotypes in the Mediterranean fields. PMID:22615891

Oliveira, Hugo R; Campana, Michael G; Jones, Huw; Hunt, Harriet V; Leigh, Fiona; Redhouse, David I; Lister, Diane L; Jones, Martin K

2012-05-16

351

Meta-QTL analysis of the genetic control of ear emergence in elite European winter wheat germplasm  

Microsoft Academic Search

Variation in ear emergence time is critical for the adaptation of wheat (Triticum aestivum L.) to specific environments. The aim of this study was to identify genes controlling ear emergence time in elite European\\u000a winter wheat germplasm. Four doubled haploid populations derived from the crosses: Avalon × Cadenza, Savannah × Rialto, Spark × Rialto,\\u000a and Charger × Badger were selected which represent diversity in European winter wheat breeding

Simon Griffiths; James Simmonds; Michelle Leverington; Yingkun Wang; Lesley Fish; Liz Sayers; Leodie Alibert; Simon Orford; Luzie Wingen; Laurence Herry; Sebastien Faure; David Laurie; Lorelei Bilham; John Snape

2009-01-01

352

Delineation of the wheat Tsn1 candidate gene region  

Technology Transfer Automated Retrieval System (TEKTRAN)

The wheat Tsn1 gene confers sensitivity to the host-selective proteinaceous toxins Ptr ToxA and SnToxA produced by the pathogenic fungi Pyrenophora tritici-repentis and Stagonospora nodorum, respectively. A positional cloning strategy is being used to clone this gene. An F2 population consisting of...

353

Genomics of Wheat Domestication  

Microsoft Academic Search

The review covers several issues concerning the state of molecular knowledge of the effects induced by domestication and breeding\\u000a on the wheat crop. Genes at the root of the domestication syndrome are currently the focus of an active research which frequently\\u000a uses comparative genomics approaches. Conclusions drawn on available data indicate that the domestication syndrome is originated\\u000a by “sudden” genetic

Carlo Pozzi; Francesco Salamini

354

Variation to cause host injury between Russian wheat aphid (Homoptera: Aphididae) clones virulent to Dn4 wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Since 2003, many areas of the world (including the USA) has seen the occurrence of Diuraphis noxia (Mordvilko) populations capable of injuring wheat containing the Dn4 resistance gene. These have been termed biotype RWA2, and are identified by observations of plant reaction by D. noxia feeding. Mo...

355

Desarrollo folicular y tasa ovulatoria en cabras criollas después de un periodo corto de consumo de trigo protegido de la degradación ruminal Follicular development and ovulation rate in Creole goats after short- term consumption of wheat protected from ruminal degradation  

Microsoft Academic Search

To determine ovarian effects after consumption of wheat protected from ruminal degradation, 40 Creole female goats received for 11 d before a synchronized estrous, 33.2 g\\/kg.75 of durum wheat treated with 5 % formaldehyde and mixed with 15 % saponified tallow (TW, n=20) or milled durum wheat and separately 15 % saponified tallow (NTW, n=20). Ovarian follicular populations were characterized

Xochitl Pastrana Martínez; Martín Ramírez Sánchez; Juan López; Eugenio Villagómez; Everardo González Padilla; Héctor Raymundo Vera Ávila

356

Aggregation and mortality of Agriotes obscurus (Coleoptera: Elateridae) at insecticide-treated trap crops of wheat.  

PubMed

Agriotes obscurus (L.) wireworms assembled in increasing numbers at rows of treated (Agrox DL Plus seed treatment) and untreated wheat, Triticum aestivum L., planted at increasing densities (0, 0.15, 0.30, and 0.60 seeds/cm). In treated wheat plots at all planting densities, no wireworm damage to seedlings was apparent, and total wireworms taken in core samples in wheat rows increased according to the asymptotic equation y = B0(1 -e(-Blx)), where B0 is the asymptote, B1 is the slope of the initial rise, and x is the seeding density. The number of dead wireworms in treated plots increased linearly and intercepted the asymptotic models (theoretical point at which 100% mortality of assembled population occurs) at 0.95 seeds/cm on 11 June and 1.14 seeds/cm on 18 June 1996. Untreated wheat at all densities planted had severe wireworm damage and significantly reduced stand. Populations that had assembled at the surviving untreated wheat were fewer than in the treated wheat plots, and although increasing with seeding density, did not follow the asymptotic model. The data suggest that A. obscurus populations can be assembled and killed in fallowed fields in large numbers at treated trap crops of wheat over a 19-d period when planted in rows spaced 1 m apart at a linear seeding density of 1.5 seeds/cm. PMID:16539125

Vernon, Robert S

2005-12-01

357

Flooding tolerance of spelt (Triticum spelta L.) compared to wheat (Triticum aestivum L.) – A physiological and genetic approach  

Microsoft Academic Search

In marginal, agroclimatic zones, yield is often affected by flooding, but the effect is much less for winter spelt (Triticum spelta L.) than for winter wheat (Triticum aestivum L.). This study evaluates the reaction of a wheat x spelt population (F5 RILs of Forno x Oberkulmer) to flooding stress in the early phase of germination. Lines with greater tolerance to

M. St. Burgos; M. M. Messmer; P. Stamp; J. E. Schmid

2001-01-01

358

Evolution and Acceleration of No-till Farming in Rice-Wheat Cropping System of the Indo-Gangetic Plains  

Microsoft Academic Search

The major challenge facing the rice-wheat cropping system in India is to sustain its long-term productivity. There are signs that the productivity and economic gains of this cropping system are consistently becoming smaller. For a populous country like India such a slow down amounts to food insecurity. One reason for the slow down in the growth of wheat productivity during

Ram K. Malik; Ashok Yadav; Gurjeet S. Gill; Parveen Sardana; Raj Kumar Gupta; Colin Piggin

359

Combining abilities and heritability of callus formation and plantlet regeneration in wheat ( Triticum aestivum L.) anther cultures  

Microsoft Academic Search

Frequency of callus formation in wheat (Triticum aestivum L. em. Thell) anthers cultured in vitro and the frequency of subsequent plantlet formation from such calli were examined in a diallel population produced from five inbred spring wheat cultivars. Two of the five cultivars were believed to possess relatively high frequencies of response and the other three relatively low response frequencies,

M. D. Lazar; P. S. Baenziger; G. W. Schaeffer

1984-01-01

360

Wheat Stripe Rust in China.  

Technology Transfer Automated Retrieval System (TEKTRAN)

China has the largest epidemic region in the world in terms of wheat acreage affected by stripe rust. Extensive studies on the epidemiology and management were carried out since the widespread occurrence in 1950’s. Based on the factors influencing occurrence of wheat stripe rust, 15 epidemic zones w...

361

A TRANSCRIPTOME MAP OF WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

A transcriptome map of wheat genome with 16,099 EST loci spanning the 21 chromosomes of bread wheat (Triticum aestivum L.) or an average of 766 loci per chromosome, has been developed. Of the 16,099 EST loci, 14,051 were allocated to 159 bins using a set of nullisomic-tetrasomic, ditelosomic, and de...

362

PROTEIN DEMAND IN HARD WHEATS  

Microsoft Academic Search

Wheat protein is one of the most important specifications used in domestic and import purchase contracts. It is used as a proxy for functional quality that is important in domestic markets and to importers. Large differences exist in functional characteristics amongst wheat that vary by protein level and class. The purpose of this paper is to analyze the demand for

William W. Wilson; Wesley W. Wilson; Bruce L. Dahl

2005-01-01

363

Registration of 'Bill Brown' Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Bill Brown’ (Reg. No. CV-133, PI 653260) hard red winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2007 through an exclusive marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorad...

364

Wheat landraces: A mini review  

Technology Transfer Automated Retrieval System (TEKTRAN)

Farmers developed and utilized diverse wheat landraces to meet the complexity of a multitude of spatio-temporal, agro-ecological systems and to provide reliable sustenance and a sustainable food source to local communities. The genetic structure of wheat landraces is an evolutionary approach to surv...

365

Mapping genes affecting flowering time and frost resistance on chromosome 5B of wheat  

Microsoft Academic Search

Two populations of single chromosome recombinant lines were used to map genes controlling flowering time on chromosome 5B of wheat, and one of the populations was also used to map a new frost resistance gene. Genetic maps were developed, mainly using microsatellite markers, and QTL analysis was applied to phenotypic data on the performance of each population collected from growth-room

B. Tóth; G. Galiba; E. Fehér; J. Sutka; J. W. Snape

2003-01-01

366

Wheat-Legume Composite Flour Quality  

Microsoft Academic Search

Wheat-legume composite flours were produced by blending Canada Western Extra Strong (CWES) and Canada Western Red Spring (CWRS) wheat with varying amounts of three legume proteins. Legume protein addition produced breads with lower specific loaf volume, coarser crumb and firmer texture, and cooked white-salted noodles with greater compression stress and less cutting stress than the wheat controls. The CWES wheat

Dora Fenn; Odean M. Lukow; Gavin Humphreys; Paul G. Fields; Joyce I. Boye

2010-01-01

367

Hard Spring Wheat Technical Committee 2006 Crop  

Technology Transfer Automated Retrieval System (TEKTRAN)

Breeders’ experimental lines of wheat are evaluated for overall quality before being released for commercial production. The Hard Spring Wheat Technical Committee provides milling and baking quality data on breeders’ experimental lines of wheat that are annually submitted to the Wheat Quality Counc...

368

BREEDING WHEAT FOR RESISTANCE TO INSECTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Host-plant resistance plays an important role in the management of the insect pests of wheat (Triticum sp.). Five pests, Hessian fly (Mayetiola destructor), Russian wheat aphid (Diuraphis noxia), wheat midge (Sitodiplosis mosellana), greenbug (Schizaphis graminum) and the wheat stem sawfly (Cephus s...

369

Genome size variation in diploid and tetraploid wild wheats  

PubMed Central

Background and aims Intra- and interspecific variations of C-values and the relationship between habitat factors and genome size were studied in natural populations of diploid and tetraploid wild wheats. Methodology The 1C nuclear DNA content of 376 individual plants representing 41 populations of diploid and tetraploid wild wheats was determined by flow cytometry (FCM) and correlated with geographical and bioclimate variables. Principal results Based on analysis of variance, significant differences between diploid and tetraploid Triticum species were found. Differences among populations of T. boeoticum and T. dicoccoides were also statistically significant and argue for isolation between populations, except for T. araraticum. However, the variation among individuals of the same population was not statistically significant. Maximum genome size differences among populations for T. boeoticum (0.143 pg; 2.32 %), T. dicoccoides (0.314 pg; 2.49 %) and T. araraticum (0.116 pg; 0.98 %) argue for genome constancy in these species. There was no significant correlation between intra-population variance and geographical and bioclimate variables for T. boeoticum and T. dicoccoides. In contrast to the limited genome size variation at the intraspecific level, the interspecific variation was large: ?0.5 pg/1C (8 %) at the diploid level (T. boeoticum vs. T. urartu) and ?1 pg/1C (9.7 %) at the tetraploid level (T. dicoccoides vs. T. araraticum). Conclusions Low intraspecific genome size variation occurs in diploid and tetraploid wild wheats, and this limited variation is not correlated with geographical and climate variables. However, interspecific variation is significant at the diploid and tetraploid level. It can be concluded that the genome size of wild self-fertilizing Triticum species is generally stable, despite the presence of many potentially active retroelements. In natural habitats, it is very difficult to distinguish wild wheats from each other. However, all four species can be distinguished easily, quickly and unambiguously by using the FCM technique.

Ozkan, Hakan; Tuna, Metin; Kilian, Benjamin; Mori, Naoki; Ohta, Shoji

2010-01-01

370

Genes encoding 4-Cys antimicrobial peptides in wheat Triticum kiharae Dorof. et Migush.: multimodular structural organization, instraspecific variability, distribution and role in defence.  

PubMed

A novel family of antifungal peptides was discovered in the wheat Triticum kiharae Dorof. et Migusch. Two members of the family, designated Tk-AMP-X1 and Tk-AMP-X2, were completely sequenced and shown to belong to the ?-hairpinin structural family of plant peptides with a characteristic C1XXXC2-X(n)-C3XXXC4 motif. The peptides inhibit the spore germination of several fungal pathogens in vitro. cDNA and gene cloning disclosed unique structure of genes encoding Tk-AMP-X peptides. They code for precursor proteins of unusual multimodular structure, consisting of a signal peptide, several ?-hairpinin (4-Cys) peptide domains with a characteristic cysteine pattern separated by linkers and a C-terminal prodomain. Three types of precursor proteins, with five, six or seven 4-Cys peptide modules, were found in wheat. Among the predicted family members, several peptides previously isolated from T. kiharae seeds were identified. Genes encoding Tk-AMP-X precursors have no introns in the protein-coding regions and are upregulated by fungal pathogens and abiotic stress, providing conclusive evidence for their role in stress response. A combined PCR-based and bioinformatics approach was used to search for related genes in the plant kingdom. Homologous genes differing in the number of peptide modules were discovered in phylogenetically-related Triticum and Aegilops species, including polyploid wheat genome donors. Association of the Tk-AMP-X genes with A, B/G or D genomes of hexaploid wheat was demonstrated. Furthermore, Tk-AMP-X-related sequences were shown to be widespread in the Poaceae family among economically important crops, such as barley, rice and maize. PMID:23702306

Utkina, Lyubov L; Andreev, Yaroslav A; Rogozhin, Eugene A; Korostyleva, Tatyana V; Slavokhotova, Anna A; Oparin, Peter B; Vassilevski, Alexander A; Grishin, Eugene V; Egorov, Tsezi A; Odintsova, Tatyana I

2013-06-18

371

[Demographic pressure and extension of new cultures: difficult adaptation. The case of the wheat-growing culture of highland Byumba].  

PubMed

Results of a 1990 survey are the basis for a discussion of the spread of wheat cultivation in the Byumba highlands of Rwanda. The highlands are among the most densely populated areas of Rwanda, with an estimated 370 persons per sq km compared to the national average of 272. The region offers ideal temperature and rainfall conditions for wheat cultivation. 76% of the cultivable lands of the region are considered suitable for wheat. Wheat is among crops that Rwanda would like to produce internally in greater quantity to reduce import requirements. Population pressure has led to division of plots, so that at present, 57.3% of households have less than 1 hectare of land. Dispersion of plots has also become a problem. A wide variety of crops in addition to wheat are cultivated in the Byumba highlands. The number of hectares devoted to wheat has increased from 140 in 1983 to 2902 in 1990. The increase is due to the growing number of cultivators growing a small amount of wheat rather than to increased size of production units. 68% of wheat cultivators harvested less than 200 kg in 1990. The subsistence nature of most agriculture in the Byumba highlands has limited the spread of wheat cultivation, as households seek to produce an adequate and varied food supply for their own consumption. The small size of holdings has limited the feasibility of technical advances in wheat cultivation for local growers. Many households devote space to crops such as sweet potatoes that do not produce well at their relatively high altitudes. Encouraging greater cultivation of wheat will require an improved marketing system and a sufficiently high price to allow growers to purchase the foodstuffs they forego planting. Steps should be taken to limit the division of land holdings and to improve cultivation techniques. It will be necessary as well to limit population growth through family planning in order to lessen demographic pressure on the limited cultivable lands. PMID:12318252

Rutaganda, T

1993-04-01

372

Endosperm Tolerance of Paternal Aneuploidy Allows Radiation Hybrid Mapping of the Wheat D-Genome and a Measure of ? Ray-Induced Chromosome Breaks  

PubMed Central

Physical mapping and genome sequencing are underway for the ?17 Gb wheat genome. Physical mapping methods independent of meiotic recombination, such as radiation hybrid (RH) mapping, will aid precise anchoring of BAC contigs in the large regions of suppressed recombination in Triticeae genomes. Reports of endosperm development following pollination with irradiated pollen at dosages that cause embryo abortion prompted us to investigate endosperm as a potential source of RH mapping germplasm. Here, we report a novel approach to construct RH based physical maps of all seven D-genome chromosomes of the hexaploid wheat ‘Chinese Spring’, simultaneously. An 81-member subset of endosperm samples derived from 20-Gy irradiated pollen was genotyped for deletions, and 737 markers were mapped on seven D-genome chromosomes. Analysis of well-defined regions of six chromosomes suggested a map resolution of ?830 kb could be achieved; this estimate was validated with assays of markers from a sequenced contig. We estimate that the panel contains ?6,000 deletion bins for D-genome chromosomes and will require ?18,000 markers for high resolution mapping. Map-based deletion estimates revealed a majority of 1–20 Mb interstitial deletions suggesting mutagenic repair of double-strand breaks in pollen provides a useful resource for RH mapping and map based cloning studies.

Tiwari, Vijay K.; Riera-Lizarazu, Oscar; Gunn, Hilary L.; Lopez, KaSandra; Iqbal, M. Javed; Kianian, Shahryar F.; Leonard, Jeffrey M.

2012-01-01

373

Characterization of a Low-Molecular-Weight Glutenin Subunit Gene from Bread Wheat and the Corresponding Protein That Represents a Major Subunit of the Glutenin Polymer1  

PubMed Central

Both high- and low-molecular-weight glutenin subunits (LMW-GS) play the major role in determining the viscoelastic properties of wheat (Triticum aestivum L.) flour. To date there has been no clear correspondence between the amino acid sequences of LMW-GS derived from DNA sequencing and those of actual LMW-GS present in the endosperm. We have characterized a particular LMW-GS from hexaploid bread wheat, a major component of the glutenin polymer, which we call the 42K LMW-GS, and have isolated and sequenced the putative corresponding gene. Extensive amino acid sequences obtained directly for this 42K LMW-GS indicate correspondence between this protein and the putative corresponding gene. This subunit did not show a cysteine (Cys) at position 5, in contrast to what has frequently been reported for nucleotide-based sequences of LMW-GS. This Cys has been replaced by one occurring in the repeated-sequence domain, leaving the total number of Cys residues in the molecule the same as in various other LMW-GS. On the basis of the deduced amino acid sequence and literature-based assignment of disulfide linkages, a computer-generated molecular model of the 42K subunit was constructed.

Masci, Stefania; D'Ovidio, Renato; Lafiandra, Domenico; Kasarda, Donald D.

1998-01-01

374

Should spring wheat breeding for organically managed systems be conducted on organically managed land?  

Microsoft Academic Search

Organic spring wheat (Triticum aestivum L.) producers in the northern Great Plains use cultivars which have been bred for conventional management systems or heritage\\u000a cultivars released before the widespread use of synthetic fertilizers and pesticides. To investigate the feasibility of organic\\u000a wheat breeding and to determine common genetic parameters for each system, we used a random population of 79 F6-derived

Todd A. Reid; Rong-Cai Yang; Donald F. Salmon; D. Spaner

2009-01-01

375

Comparison of the epidemiology of Metopolophium dirhodum and Sitobion avenae on winter wheat  

Microsoft Academic Search

The epidemiology ofMetopolophium dirhodum and its natural enemies on winter wheat was studied from 1975 to 1979 inclusive. AlateM. dirhodum colonize wheat from the middle of May onwards. Immigration occurs until mid-June. Population growth rates ofM. dirhodum can be as high as or occasionally even higher than those ofSitobion avenae. InM. dirhodum alatae are formed in a high proportion throughout

G. W. Ankersmit; N. Carter

1981-01-01

376

Functional gene markers for polyphenol oxidase locus in bread wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Higher polyphenol oxidase (PPO) activity in wheat kernels and flour has been implicated in the time dependent darkening of\\u000a various end-products. Previous study conducted on a bread wheat (Triticum aestivum L.) doubled haploid (DH) mapping population derived from Chara (medium-high PPO) and WW2449 (low PPO) identified a major\\u000a QTL for PPO activity located on the long arm of chromosome 2A.

Rosy Raman; Harsh Raman; Peter Martin

2007-01-01

377

Resistance to the root-lesion nematode Pratylenchus thornei of Iranian landrace wheat  

Microsoft Academic Search

Pratylenchus thornei is widespread throughout the wheat-growing regions in Australia and overseas and can cause yield losses of up to 70% in some\\u000a intolerant cultivars. The most effective forms of management of P. thornei populations are crop rotation and plant breeding. There have been no wheat accessions identified as completely resistant\\u000a to P. thornei, therefore breeding programs have used moderately

J. G. Sheedy; J. P. Thompson

2009-01-01

378

Mapping of resistance to spot blotch disease caused by Bipolaris sorokiniana in spring wheat  

Microsoft Academic Search

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat in warm and humid wheat growing regions of the world. The development of disease resistant\\u000a cultivars is considered as the most effective control strategy for spot blotch. An intervarietal mapping population in the\\u000a form of recombinant inbred lines (RILs) was developed from a cross ‘Yangmai 6’ (a Chinese

Uttam Kumar; Arun K. Joshi; Sundeep Kumar; Ramesh Chand; Marion S. Röder

2009-01-01

379

Effects of starch synthase IIa gene dosage on grain, protein and starch in endosperm of wheat  

Microsoft Academic Search

Starch synthases (SS) are responsible for elongating the ?-1,4 glucan chains of starch. A doubled haploid population was generated\\u000a by crossing a line of wheat, which lacks functional ssIIa genes on each genome (abd), and an Australian wheat cultivar, Sunco, with wild type ssIIa alleles on each genome (ABD). Evidence has been presented previously indicating that the SGP-1 (starch granule

Christine Konik-Rose; Jenny Thistleton; Helene Chanvrier; Ihwa Tan; Peter Halley; Michael Gidley; Behjat Kosar-Hashemi; Hong Wang; Oscar Larroque; Joseph Ikea; Steve McMaugh; Ahmed Regina; Sadequr Rahman; Matthew Morell; Zhongyi Li

2007-01-01

380

Differential gene expression in incompatible interaction between wheat and stripe rust fungus revealed by cDNA-AFLP and comparison to compatible interaction  

PubMed Central

Background Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat worldwide. Due to special features of hexaploid wheat with large and complex genome and difficulties for transformation, and of Pst without sexual reproduction and hard to culture on media, the use of most genetic and molecular techniques in studying genes involved in the wheat-Pst interactions has been largely limited. The objective of this study was to identify transcriptionally regulated genes during an incompatible interaction between wheat and Pst using cDNA-AFLP technique Results A total of 52,992 transcript derived fragments (TDFs) were generated with 64 primer pairs and 2,437 (4.6%) of them displayed altered expression patterns after inoculation with 1,787 up-regulated and 650 down-regulated. We obtained reliable sequences (>100 bp) for 255 selected TDFs, of which 113 (44.3%) had putative functions identified. A large group (17.6%) of these genes shared high homology with genes involved in metabolism and photosynthesis; 13.8% to genes with functions related to disease defense and signal transduction; and those in the remaining groups (12.9%) to genes involved in transcription, transport processes, protein metabolism, and cell structure, respectively. Through comparing TDFs identified in the present study for incompatible interaction and those identified in the previous study for compatible interactions, 161 TDFs were shared by both interactions, 94 were expressed specifically in the incompatible interaction, of which the specificity of 43 selected transcripts were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Based on the analyses of homology to genes known to play a role in defense, signal transduction and protein metabolism, 20 TDFs were chosen and their expression patterns revealed by the cDNA-AFLP technique were confirmed using the qRT-PCR analysis. Conclusion We uncovered a number of new candidate genes possibly involved in the interactions of wheat and Pst, of which 11 TDFs expressed specifically in the incompatible interaction. Resistance to stripe rust in wheat cv. Suwon11 is executed after penetration has occurred. Moreover, we also found that plant responses in compatible and incompatible interactions are qualitatively similar but quantitatively different soon after stripe rust fungus infection.

2010-01-01

381

Spring Wheat in North Kazakhstan.  

National Technical Information Service (NTIS)

This book highlights problems in the biology of spring (soft) and durum (hard) wheat, its place in crop rotation schedules, basic and presowing land preparation, weed control, and varietal trials. It describes various agronomical measures to increase the ...

A. I. Baraev

1983-01-01

382

Dough Rheology and Wet Milling of Hard Waxy Wheat Flours  

Technology Transfer Automated Retrieval System (TEKTRAN)

To realize the full potential of waxy wheat (Triticum aestivum L.), wet milling of waxy wheat flour to produce gluten and waxy wheat starch was investigated. Flours of six advanced lines of waxy hard wheats, one normal hard wheat (‘Karl 92’), and one partial waxy wheat (‘Trego’) were fractionated by...

383

WheatBlog .05b  

NSDL National Science Digital Library

Given the increasing interest in developing personal weblogs and online journals, many users may find the WheatBlog device quite enticing. The application is designed to maintain any number of blog and news pages on personal sites, and will certainly assist users in keeping track of various developments on any variety of such related endeavors. WheatBlog .05b is compatible with all operating systems.

384

Construction of a high-quality yeast two-hybrid (Y2H) library and its application in identification of interacting proteins with key vernalization regulator TaVRN-A1 in wheat  

PubMed Central

Background Low temperature is required for the competence of winter wheat to flowering (vernalization), and several key components in the vernalization-mediated flowering pathway have been isolated. A Y2H library is a very useful platform to further unravel novel regulators in the flowering pathway. Thus, there is a necessity to construct a high-quality Y2H library using vernalized winter wheat plants. Result We described the construction of a high-quality Y2H library using winter wheat plants with cold-treatment for different weeks to maximize pooling interacting proteins during vernalization. The resultant Y2H library contained ~2.5×106 independent clones, with a cell density of ~2.6×108 and an average insert size of ~ 1.5 kb. TaVRN-A1 was used as a “bait” to test the quality of the Y2H library. As a result, several cDNA clones encoding TaSOC1 and TaSVP1 that were known to have a direct binding with TaVRN-A1 were identified, demonstrating that the Y2H screen system constructed in this study was highly efficient. Additional proteins that were discovered but not characterized in previous studies could be novel partners of TaVRN-A1 in wheat. Conclusion We established a high-efficient Y2H screen system using the Matchmaker™ technology with several modifications in the critical steps. Ultimately, we provided a successful example to fast and economically create high-quality Y2H libraries for studies on protein interaction in hexaploid wheat.

2013-01-01

385

Structural and functional properties of Viviparous1 genes in dormant wheat.  

PubMed

Viviparous 1 (Vp1) of maize is known to encode a transcription factor VP1 that controls seed germination. Hexaploid wheat possesses three Vp1 homoeologues (TaVp1): TaVp-A1, TaVp-B1 and TaVp-D1. In this study, we attempted to characterize the molecular properties of TaVp1 in a highly dormant wheat cultivar, Minamino-komugi (Minamino). The seeds of Minamino showed much higher sensitivity to the inhibitory effect of ABA on germination than those of non-dormant cultivars, Sanin-1 and Tozan-18. The sequence analyses of cDNAs also revealed that some of TaVp-A1 transcripts and TaVp-D1 transcripts were spliced incorrectly, presumably resulting in production of truncated or deleted proteins. Most TaVp-B1 transcripts were spliced correctly, but some had an additional 3-bp (AAG) insertion in the B3 domain, which may not affect their function. RT-PCR analyses showed that TaVp1 was highly expressed in Minamino embryos in maturing seeds but much less in roots and leaves of seedlings. The level of TaVp1 mRNA was high when the embryos were treated with ABA but markedly decreased in water-imbibed mature embryos whose dormancy had been broken. Expression analyses of the individual homoeologues showed that the level of TaVp-A1 transcripts was highest in embryos of DAP 20 but much lower in the matured embryos. TaVp-B1 was highly expressed in developing and maturing seed embryos, while TaVp-D1 mRNA existed at lower levels in developing embryos but increased as the seeds were matured. These results suggest that the majority of TaVp1, especially TaVp-B1, are properly spliced and may function as a transcription factor playing an important role on dormancy in Minamino. By employing an efficient transient expression system using diploid wheat seeds, we confirmed the dual function of TaVP-B1: the activation of Em expression and the repression of alpha-amylase expression. PMID:18506099

Utsugi, Shigeko; Nakamura, Shingo; Noda, Kazuhiko; Maekawa, Masahiko

2008-04-01

386

A high-density consensus map of A and B wheat genomes.  

PubMed

A durum wheat consensus linkage map was developed by combining segregation data from six mapping populations. All of the crosses were derived from durum wheat cultivars, except for one accession of T. ssp. dicoccoides. The consensus map was composed of 1,898 loci arranged into 27 linkage groups covering all 14 chromosomes. The length of the integrated map and the average marker distance were 3,058.6 and 1.6 cM, respectively. The order of the loci was generally in agreement with respect to the individual maps and with previously published maps. When the consensus map was aligned to the deletion bin map, 493 markers were assigned to specific bins. Segregation distortion was found across many durum wheat chromosomes, with a higher frequency for the B genome. This high-density consensus map allowed the scanning of the genome for chromosomal rearrangements occurring during the wheat evolution. Translocations and inversions that were already known in literature were confirmed, and new putative rearrangements are proposed. The consensus map herein described provides a more complete coverage of the durum wheat genome compared with previously developed maps. It also represents a step forward in durum wheat genomics and an essential tool for further research and studies on evolution of the wheat genome. PMID:22872151

Marone, Daniela; Laidò, Giovanni; Gadaleta, Agata; Colasuonno, Pasqualina; Ficco, Donatella B M; Giancaspro, Angelica; Giove, Stefania; Panio, Giosué; Russo, Maria A; De Vita, Pasquale; Cattivelli, Luigi; Papa, Roberto; Blanco, Antonio; Mastrangelo, Anna M

2012-08-08

387

Molecular basis of plant gene expression during aphid invasion: wheat Pto- and Pti-like sequences are involved in interactions between wheat and Russian wheat aphid (Homoptera: Aphididae).  

PubMed

The Russian wheat aphid, Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), is a major pest of bread wheat, Triticum aestivum L. (em Thell), in most wheat-growing areas worldwide. Aphid-resistant cultivars are used to combat this pest, but very little is known about the molecular basis of resistance. In this study, differential gene expression in D. noxia biotype 1-resistant wheat plants containing the Dnx gene and D. noxia biotype 1 feeding on Dnx plants was investigated using suppressive subtraction hybridization. The derived subtracted cDNA library includes sequences similar to Pto and Pti1, genes involved in gene-for-gene recognition of and resistance to bacterial speck disease in tomato, Lycopersicon esculentum (L.). Pto- and Pti1-like sequences contain an activation domain with conserved amino acid residues crucial for avr protein recognition and binding by Pto, and avr-Pto phosphorylation of Pti1. Wheat defense signaling is represented by sequences putatively involved in producing sterols, jasmonates, Ca2+, and abscisic and gibberellic acids. We suggest that reductions in populations of D. noxia fed Dnx plants are related to the expression of sequences involved in defensive chemical production, cellular transport, and exocytosis. Dnx plant tolerance of D. noxia feeding is proposed to be based on the expression of sequences putatively involved in self-defense against reactive oxygen species and toxins, and proteolysis; DNA, RNA, and protein synthesis; chloroplast and mitochondrial function; carbohydrate metabolism; and maintenance of cell homeostasis. D. noxia unsuccessfully counter Dnx by expressing sequences putatively involved in detoxification; proteolysis; DNA, RNA, protein, and lipid synthesis; carbohydrate metabolism; and mitochondrial function. PMID:16937702

Boyko, Elena V; Smith, C Michael; Thara, Vankatappa K; Bruno, Jon M; Deng, Youping; Starkey, Sharon R; Klaahsen, Darsey L

2006-08-01

388

21 CFR 137.190 - Cracked wheat.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION CEREAL FLOURS AND RELATED PRODUCTS Requirements for Specific Standardized Cereal Flours and Related Products § 137.190 Cracked wheat. Cracked wheat...

2013-04-01

389

Technological properties of bakers' yeasts in durum wheat semolina dough.  

PubMed

Properties of 13 Saccharomyces cerevisiae strains isolated from different sources (traditional sourdoughs, industrial baking yeasts etc.) were studied in dough produced with durum wheat (Sicilian semolina, variety Mongibello). Durum wheat semolina and durum wheat flour are products prepared from grain of durum wheat (Triticum durum Desf.) by grinding or milling processes in which the bran and germ are essentially removed and the remainder is comminuted to a suitable degree of fineness. Acidification and leavening properties of the dough were evaluated. Strains isolated from traditional sourdoughs (DSM PST18864, DSM PST18865 and DSM PST18866) showed higher leavening power, valuable after the first and second hours of fermentation, than commercial baking yeasts. In particular the strain DSM PST 18865 has also been successfully tested in bakery companies for the improvement of production processes. Baking and staling tests were carried out on five yeast strains to evaluate their fermentation ability directly and their resistance to the staling process. Amplified fragment length polymorphism (fAFLP) was used to investigate genetic variations in the yeast strains. This study showed an appreciable biodiversity in the microbial populations of both wild and commercial yeast strains. PMID:20039189

Giannone, Virgilio; Longo, Chiara; Damigella, Arcangelo; Raspagliesi, Domenico; Spina, Alfio; Palumbo, Massimo

2009-12-29

390

Development of trispecies backcross populations using a 2(ADD) hexaploid bridging line to introgress genes from A-genome diploids into upland cotton  

Technology Transfer Automated Retrieval System (TEKTRAN)

Introgression of genes from A-genome diploid Gossypium species into tetraploid upland cotton is desirable but post-zygotic breeding barriers, in addition to ploidy differences, make the task difficult. G. arboreum L. and G. herbaceum L. accessions that had been previously identified as resistant to ...

391

Growing Wheat. People on the Farm.  

ERIC Educational Resources Information Center

This booklet, one in a series about life on modern farms, describes the daily life of the Don Riffel family, wheat farmers in Kansas. Beginning with early morning, the booklet traces the family's activities through a typical harvesting day in July, while explaining how a wheat farm is run. The booklet also briefly describes the wheat growing…

Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

392

HARD SPRING WHEAT TECHNICAL COMMITTEE 2007 CROP  

Technology Transfer Automated Retrieval System (TEKTRAN)

Twelve experimental lines of hard spring wheat were grown at up to five locations in 2007 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Samples of wheat were submitted through the Wheat Quality Council and processed and milled at the USDA Hard Red Spri...

393

Supplementation of Wheat Gluten Protein1  

Microsoft Academic Search

Male weanling Wistar rats were fed diets containing wheat gluten (group 1), wheat gluten supplemented with lysine monohydrochloride (group 2), wheat gluten plus casein (group 3), casein (group 4), and egg albumin (group 5) as the dietary protein sources, as well as a diet free of protein (group 6). The nitrogen growth index of 8.6 for the group 1 animals

W. L. BANKS; J. B. ALLISON; R. W. WANNEMACHER

2010-01-01

394

Floral Transformation of Wheat  

NASA Astrophysics Data System (ADS)

A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

395

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8?-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition  

PubMed Central

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8?-hydroxyase gene which was highly expressed during seed development (TaABA8?OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8?OH1 on the D genome (TaABA8?OH1-D) was identified in Japanese cultivars including ‘Tamaizumi’. However, a single mutation in TaABA8?OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8?OH1 on the A genome (TaABA8?OH1-A), TM1833, was identified from gamma-ray irradiation lines of ‘Tamaizumi’. TM1833 (a double mutant in TaABA8?OH1-A and TaABA8?OH1-D) showed lower TaABA8?OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in ‘Tamaizumi’ (a single mutant in TaABA8?OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8?OH1 may be effective in germination inhibition in field-grown wheat.

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-01-01

396

Isolation of a wheat (Triticum aestivum L.) mutant in ABA 8'-hydroxylase gene: effect of reduced ABA catabolism on germination inhibition under field condition.  

PubMed

Pre-harvest sprouting, the germination of mature seeds on the mother plant under moist condition, is a serious problem in cereals. To investigate the effect of reduced abscisic acid (ABA) catabolism on germination in hexaploid wheat (Triticum aestivum L.), we cloned the wheat ABA 8'-hydroxyase gene which was highly expressed during seed development (TaABA8'OH1) and screened for mutations that lead to reduced ABA catabolism. In a screen for natural variation, one insertion mutation in exon 5 of TaABA8'OH1 on the D genome (TaABA8'OH1-D) was identified in Japanese cultivars including 'Tamaizumi'. However, a single mutation in TaABA8'OH1-D had no clear effect on germination inhibition in double haploid lines. In a screen for a mutation, one deletion mutant lacking the entire TaABA8'OH1 on the A genome (TaABA8'OH1-A), TM1833, was identified from gamma-ray irradiation lines of 'Tamaizumi'. TM1833 (a double mutant in TaABA8'OH1-A and TaABA8'OH1-D) showed lower TaABA8'OH1 expression, higher ABA content in embryos during seed development under field condition and lower germination than those in 'Tamaizumi' (a single mutant in TaABA8'OH1-D). These results indicate that reduced ABA catabolism through mutations in TaABA8'OH1 may be effective in germination inhibition in field-grown wheat. PMID:23641187

Chono, Makiko; Matsunaka, Hitoshi; Seki, Masako; Fujita, Masaya; Kiribuchi-Otobe, Chikako; Oda, Shunsuke; Kojima, Hisayo; Kobayashi, Daisuke; Kawakami, Naoto

2013-03-01

397

Investigation on dynamic changes of photosynthetic characteristics of 10 wheat (Triticum aestivum L.) genotypes during two vegetative-growth stages at water deficits.  

PubMed

Drought is a worldwide problem, seriously influencing plant (crop) productivity. Wheat is a stable food for 35% of the world population, and moreover, about 60% of land area on the globe belongs to arid and semiarid zone. Wheat drought resistance is a multi-gene controlling quantitative character and wheat final production in field is realized mainly by physiological regulation under the condition of multi-environmental factor interaction. Exploring drought resistance physiological mechanisms for different wheat genotypes is of importance to finding new drought resistance gene resources and conventional breeding, and the basis for wheat drought resistance biotechnological breeding and platform. Photosynthesis is the main component for physiological machinery of wheat assimilates conversion and wheat production. Investigation on photosynthetic characteristics of different wheat genotypes at soil water deficits also has other implications for refine physiological regulation of photosynthesis in fields and field management of crops in arid and semiarid areas. By pot-cultivating experiments, investigation of photosynthesis for 10 wheat genotypes at seedling stage and tillering stage at soil water deficits (75%FC, 55%FC and 45%FC, respectively) was conducted. The main results were as followed: developmental stages influenced wheat photosynthesis greatly and tillering stage played more roles; there were significant difference in the main photosynthetic parameters, photosynthesis rate (Photo), stomatal conductance (Cond) and transpiration rate (Tr), among 10 wheat genotypes; general photosynthesis and drought resistance in different wheat genotypes was related much to their domesticated origin soil water environment and selected generations and there was a photosynthetic threshold effect in terms of different wheat genotypes at soil water deficits. PMID:15975772

Hongbo, Shao; Zongsuo, Liang; Mingan, Shao; Shimeng, Sun; Zanmin, Hu

2005-07-10

398

REGISTRATION OF 'INFINITY CL' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Infinity CL’ (Reg. No. Cv- ) is a hard red winter wheat (Triticum aestivum L.) cultivar developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS, and released in 2005 by the developing institutions. Infinity CL contains a patented gene owned by BASF Corporation. In...

399

Wheat Genetic Resources in Nepal  

Microsoft Academic Search

Genetic diversity must be maintained and utilized for sustainable agriculture development. The amount of genetic diversity in the country depends on the number and diversity of the original ancestors involved in the creation of a germplasm pool, wild relatives and existing landraces. The objective of this research was to study the diversity of wheat gene pool present in the Nepalese

Bal K. Joshi; Ashok Mudwari; Madan R. Bhatta

2009-01-01

400

Iron Absorption from Wheat Bread  

Microsoft Academic Search

Bran is known to reduce iron absorption. There is, however, no information on the relationship between the amount of bran added and the decrease in iron absorption. In the present study a comparison was made of the iron absorption from a white wheat bread and a bread baked with different amounts of bran added (from 10 to 0.3%). There was

Erik Björn-Rasmussen

1974-01-01

401

REGISTRATION OF 'OK102' WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

'Ok102' is a hard red winter (HRW) wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station and the USDA-ARS. Ok102 was released in March 2002, primarily based on its resistance to several foliar diseases, excellent milling quality, and desirable dough st...

402

Registration of ‘Ok101’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Ok101’ (Reg. no. CV-932, PI 631493) is a hard red winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agricultural Experiment Station and the USDA-ARS, and released in March 2001. Ok101 was released for its high tolerance to acidic soil, broad adaptation to both dual-purpose...

403

Registration of ‘Ok102’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘Ok102’ (Reg. no. CV-941, PI 632635) is a hard red winter wheat (Triticum aestivum L.) developed cooperatively by the Oklahoma Agric. Exp. Stn. and the USDA-ARS. Ok102 was released in March 2002, primarily on the basis of its resistance to several foliar diseases, excellent milling quality, and desi...

404

Registration of ‘OK Bullet’ Wheat  

Technology Transfer Automated Retrieval System (TEKTRAN)

‘OK Bullet’ (Reg. No. CV-999, PI 642415) is a hard red winter (HRW) wheat (Triticum aestivum L.) cultivar developed cooperatively by the Oklahoma Agric. Exp. Stn. (AES), USDA-ARS, and the Texas AES and released by the Oklahoma AES and the USDA-ARS in 2005. OK Bullet is recommended for grain-only and...

405

Genetic structure of Tribolium castaneum (Coleptera: Tenebrionidae) populations in mills  

Technology Transfer Automated Retrieval System (TEKTRAN)

The red flour beetle, Tribolium castaneum, is primarily found associated with human structures such as wheat and rice mills, which are spatially isolated resource patches with apparently limited immigration that could produce genetically structured populations. We investigated genetic diversity and...

406

Sex pheromone of orange wheat blossom midge, Sitodiplosis mosellana  

NASA Astrophysics Data System (ADS)

Pheromone extract of the female orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (SM) (Diptera: Cecidomyiidae), was analyzed by coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry (MS), employing fused silica columns coated with DB-5, DB-210, DB-23 or SP-1000. These analyses revealed a single, EAD-active candidate pheromone which was identified as 2,7-nonanediyl dibutyrate. In experiments in wheat fields in Saskatchewan, traps baited with (2S,7S)-2,7-nonanediyl dibutyrate attracted significant numbers of male SM. The presence of other stereoisomers did not adversely affect trap captures. Facile synthesis of stereoisomeric 2,7-nonanediyl dibutyrate will facilitate the development of pheromone-based monitoring or even control of SM populations.

Gries, Regine; Gries, G.; Khaskin, Grigori; King, Skip; Olfert, Owen; Kaminski, Lori-Ann; Lamb, Robert; Bennett, Robb

407

A comparison of marker-assisted and phenotypic selection for high grain protein content in spring wheat  

Microsoft Academic Search

Wheat grain protein content (GPC) is a primary end-use quality determinant for hard spring wheat (Triticum aestivum L.), and marker-assisted selection (MAS) could help plant breeders to develop high GPC cultivars. Two experiments were conducted using two populations developed by crossing low GPC cultivars (Ember) and (McVey) with (Glupro), which contains a high GPC QTL from Triticum dicoccoides (DIC). In

John Davies; William A. Berzonsky; Gene D. Leach

2006-01-01

408

Identification and validation of quantitative trait loci conferring tan spot resistance in the bread wheat variety Ernie  

Microsoft Academic Search

Tan spot, caused by Pyrenophora tritici-repentis, is a foliar disease of wheat, and it can inflict serious reduction in grain yield and quality. The bread wheat variety Ernie\\u000a was found to be immune to this disease in Australia, and its genetic control was investigated by quantitative trait loci (QTL)\\u000a analysis using a doubled haploid population. Eight QTL were identified in

H. B. Li; W. Yan; G. R. Liu; S. M. Wen; C. J. Liu

2011-01-01

409

TaMFT-A1 Is Associated with Seed Germination Sensitive to Temperature in Winter Wheat  

PubMed Central

The ability of seed to germinate under favorable environmental conditions is critical for seedling emergence, plant establishment, subsequent development and growth of adult plants, and it is controlled by internal genetic factors and external environmental factors. Winter wheat in the southern Great Plains is often planted six weeks before the optimal planting date to produce more biomass for cattle grazing during the winter season. A high seed germination rate in this higher soil temperature environment is required for this specific management system. In this study, a major QTL for temperature-sensitive germination was mapped on the short arm of chromosome 3A (QTsg.osu-3A) in a RIL population generated from two winter wheat cultivars. Furthermore, TaMFT-A1, previously reported to regulate seed dormancy and pre-harvest sprouting in spring wheat cultivars, was mapped tightly associated with the peak of QTsg.osu-3A. However, allelic variation in TaMFT-A1 between the two winter wheat cultivars differed from that was observed in spring wheat cultivars. There were 87 SNPs (single nucleotide polymorphisms) and 12 indels (insertions/deletions) in TaMFT-A1 between the Jagger allele for high germination and the 2174 allele for low germination in the after-ripened seeds, in comparison with 2 SNPs between the two alleles for differential pre-harvest sprouting in spring wheat cultivars. The Jagger TaMFT-A1 allele is a novel haplotype and appears extensively in winter wheat cultivars. TaMFT-A1 transcript levels were up-regulated by high temperature but down-regulated by low temperature or seed storage time. These findings suggest that TaMFT-A1 may invoke different mechanisms for controlling seed dormancy/germination among winter wheat cultivars.

Wang, Shuwen; Zhu, Meirong; Carver, Brett F.; Yan, Liuling

2013-01-01

410

Wheat flour fortification is unlikely to benefit the neediest in Guatemala.  

PubMed

The potential impact of wheat flour fortification with iron and folic acid was assessed using data about food purchases from the nationally representative 2000 Guatemalan Living Standards Measurement Survey. Of 7265 households, 35% were indigenous and 57% rural; 11% were extremely poor, 35% were poor, and 54% were nonpoor. The percentage of households that purchased wheat flour, sweet bread, French rolls, and sliced bread in the previous 15 d was 10, 88, 59, and 11%, respectively. The median amount of fortified wheat flour equivalents in purchased foods was 50 g/d per adult equivalent; fortified wheat flour equivalents were 7, 25, and 110 g/d for the poverty groups, 16 g/d in indigenous households and 24 g/d in rural households. Wheat flour fortification contributed 2.3 mg/d of iron and 90 microg/d of folic acid per adult equivalent. Assuming 5% bioavailability, wheat flour fortification provided 2% of the recommended dietary allowance (RDA) and 6% of estimated average requirement (EAR) iron levels for women of reproductive age; values were 1, 3, and 12% of EAR levels for the poverty groups, respectively. Wheat flour fortification met 26% of folic acid RDA and 33% of EAR levels for women; values were 5, 16, and 71% of EAR levels for the poverty groups, respectively. In conclusion, the impact of fortification is likely to be substantial for folate status in nonpoor and urban women but limited in the case of iron status among all social groups. The poorest, rural, indigenous populations who suffer the highest burden of nutritional deficiencies likely benefit least from wheat flour fortification. PMID:17374670

Imhoff-Kunsch, Beth; Flores, Rafael; Dary, Omar; Martorell, Reynaldo

2007-04-01

411

TaMFT-A1 Is Associated with Seed Germination Sensitive to Temperature in Winter Wheat.  

PubMed

The ability of seed to germinate under favorable environmental conditions is critical for seedling emergence, plant establishment, subsequent development and growth of adult plants, and it is controlled by internal genetic factors and external environmental factors. Winter wheat in the southern Great Plains is often planted six weeks before the optimal planting date to produce more biomass for cattle grazing during the winter season. A high seed germination rate in this higher soil temperature environment is required for this specific management system. In this study, a major QTL for temperature-sensitive germination was mapped on the short arm of chromosome 3A (QTsg.osu-3A) in a RIL population generated from two winter wheat cultivars. Furthermore, TaMFT-A1, previously reported to regulate seed dormancy and pre-harvest sprouting in spring wheat cultivars, was mapped tightly associated with the peak of QTsg.osu-3A. However, allelic variation in TaMFT-A1 between the two winter wheat cultivars differed from that was observed in spring wheat cultivars. There were 87 SNPs (single nucleotide polymorphisms) and 12 indels (insertions/deletions) in TaMFT-A1 between the Jagger allele for high germination and the 2174 allele for low germination in the after-ripened seeds, in comparison with 2 SNPs between the two alleles for differential pre-harvest sprouting in spring wheat cultivars. The Jagger TaMFT-A1 allele is a novel haplotype and appears extensively in winter wheat cultivars. TaMFT-A1 transcript levels were up-regulated by high temperature but down-regulated by low temperature or seed storage time. These findings suggest that TaMFT-A1 may invoke different mechanisms for controlling seed dormancy/germination among winter wheat cultivars. PMID:24069187

Lei, Lei; Zhu, Xinkai; Wang, Shuwen; Zhu, Meirong; Carver, Brett F; Yan, Liuling

2013-09-12

412

19 CFR 19.32 - Wheat manipulation; reconditioning.  

Code of Federal Regulations, 2010 CFR

...Duties 1 2009-04-01 2009-04-01 false Wheat manipulation; reconditioning. 19.32 Section...MERCHANDISE THEREIN Space Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The...

2009-04-01

413

19 CFR 19.32 - Wheat manipulation; reconditioning.  

Code of Federal Regulations, 2010 CFR

...Duties 1 2010-04-01 2010-04-01 false Wheat manipulation; reconditioning. 19.32 Section...MERCHANDISE THEREIN Space Bonded for the Storage of Wheat § 19.32 Wheat manipulation; reconditioning. (a) The...

2010-04-01

414

Weight loss and germination failure caused by psocids in different wheat varieties.  

PubMed

We investigated weight loss caused by Liposcelis entomophila (Enderlein) feeding in damaged (cracked) and intact kernels of 'Jagger' variety of hard red winter wheat over a 90-d period at 30 +/- 1 degrees C and 75 +/- 5% relative humidity. L. entomophila caused 8.5% weight loss in damaged wheat kernels, which was significantly greater than the weight loss found in intact wheat kernels (0.2%). We also evaluated the suitability of six wheat varieties commonly grown in Oklahoma, namely, Jagger, 'Endurance,' 'Overley,' 'Jagalene,' 'OK Bullet,' and 'Deliver' to support populations of four psocid species, namely, Liposcelis bostrychophila Badonnel, L. decolor (Pearman), L. entomophila, and L. paeta Pearman over a 30-d period. The greatest population increase was observed in L. bostrychophila followed by L. paeta. Subsequently, weight loss of damaged and intact wheat kernels and germination of intact kernels infested by L. paeta over a 45-d period were assessed in OK Bullet variety. L. paeta caused weight loss of 3.3% in damaged kernels, which was significantly greater than the weight loss found in intact kernels (0.4%). Based on our data, 40% of infested intact kernels failed to germinate after 45 d of infestation by L. paeta, but this decreased to 32% when adjusted using germination failure of uninfested kernels. Our data show that psocid infestations do not only cause considerable loss in weight of wheat, but also result in significant germination failure. These data call for the formulation of effective integrated psocid management strategies for stored wheat to mitigate the negative impacts of psocid pests. PMID:23448066

Gautam, S G; Opit, G P; Giles, K L; Adam, B

2013-02-01

415

Augmentation of beneficial arthropods by strip-management. 3. Artificial introduction of a spider species which preys on wheat pest insects  

Microsoft Academic Search

During a 3-year-experiment on strip-management a population of the spiderDictyna arundinacea (L.) was released in a winter wheat field.D. arundinacea built its webs with high preference at the ears of the wheat and 26–28% of the released spiders were rediscovered at the\\u000a marked first web-sites some weeks later. Enclosure studies and prey samples from several sub-populations showed thatD. arundinacea caught

C. Heidger; W. Nentwig

1989-01-01

416

Aspergillus section Flavi and aflatoxins in Algerian wheat and derived products.  

PubMed

Wheat and its derivatives are a very important staple food for North African populations. The aim of this study was to analyze populations of Aspergillus section Flavi from local wheat based on aflatoxins (AFs), cyclopiazonic acid (CPA) and sclerotia production, and also to evaluate AFs-contaminated wheat collected from two different climatic regions in Algeria. A total of 108 samples of wheat were collected during the following phases: pre-harvest, storage in silos and after processing. The results revealed that among the Aspergillus species isolated, those belonging to section Flavi were predominant. Of the 150 strains of Aspergillus section Flavi isolated, 144 were identified as Aspergillus flavus and 6 as Aspergillus tamarii. We showed that 72% and 10% of the A. flavus strains produced AFs and CPA, respectively. Among the 150 strains tested, 60 produced amounts of AFB1 ranging from 12.1 to 234.6 microg/g of CYA medium. Also, we showed that most strains produced large sclerotia. AFB1was detected by HPLC in 56.6% of the wheat samples and derived products (flour, semolina and bran) with contamination levels ranging from 0.13 to 37.42 microg/kg. PMID:20627118

Riba, Amar; Bouras, Noureddine; Mokrane, Salim; Mathieu, Florence; Lebrihi, Ahmed; Sabaou, Nasserdine

2010-07-27

417

Introgression of a leaf rust resistance gene from Aegilops caudata to bread wheat.  

PubMed

Rusts are the most important biotic constraints limiting wheat productivity worldwide. Deployment of cultivars with broad spectrum rust resistance is the only environmentally viable option to combat these diseases. Identification and introgression of novel sources of resistance is a continuous process to combat the ever evolving pathogens. The germplasm of nonprogenitor Aegilops species with substantial amount of variability has been exploited to a limited extent. In the present investigation introgression, inheritance and molecular mapping of a leaf rust resistance gene of Ae. caudata (CC) acc. pau3556 in cultivated wheat were undertaken. An F(2) population derived from the cross of Triticum aestivum cv. WL711 - Ae. caudata introgression line T291-2 with wheat cultivar PBW343 segregated for a single dominant leaf rust resistance gene at the seedling and adult plant stages. Progeny testing in F(3) confirmed the introgression of a single gene for leaf rust resistance. Bulked segregant analysis using polymorphic D-genome-specific SSR markers and the cosegregation of the 5DS anchored markers (Xcfd18, Xcfd78, Xfd81 and Xcfd189) with the rust resistance in the F(2) population mapped the leaf rust resistance gene (LrAC) on the short arm of wheat chromosome 5D. Genetic complementation and the linked molecular markers revealed that LrAC is a novel homoeoallele of an orthologue Lr57 already introgressed from the 5M chromosome of Ae. geniculata on 5DS of wheat. PMID:22942085

Riar, Amandeep Kaur; Kaur, Satinder; Dhaliwal, H S; Singh, Kuldeep; Chhuneja, Parveen

2012-08-01

418

Spatially discriminating Russian wheat aphid induced plant stress from other wheat stressing factors  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Russian wheat aphid (RWA) Diuraphis noxia (Mordvilko) is a major pest of winter wheat and barley in the United States. RWA induces stress to the wheat crop by damaging plant foliage, lowering the greenness of plants, and affecting productivity. Multispectral remote sensing is effective at dete...

419

Studies on the oxidative cross-linking of feruloylated arabinoxylans from wheat flour and wheat bran  

Microsoft Academic Search

Feruloylated arabinoxylans isolated from wheat flour and wheat bran were compared in their cross-linking behaviour with respect to viscosity properties and cross-linking products formed when various oxidative agents were applied to dilute solutions. Optimal conditions for each oxidative agent were investigated. In case of hydrogen peroxide and peroxidase, similar conditions were found for both types of arabinoxylans but wheat bran

M. E. F. Schooneveld-Bergmans; M. J. W. Dignum; J. H. Grabber; G. Beldman; A. G. J. Voragen

1999-01-01

420

Mapping QTL for resistance to stripe rust in spring wheat PI 192252 and winter wheat Druchamp  

Technology Transfer Automated Retrieval System (TEKTRAN)

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of wheat worldwide. High-temperature adult-plant (HTAP) resistance has proven to be durable, but may not be adequate. Spring wheat PI 192252 and winter wheat Druchamp have high-levels of HTAP resistance. To elucidate...

421

Immunocytochemical localization of wheat germ agglutinin in wheat  

PubMed Central

Immunocytological techniques were developed to localize the plant lectin, wheat germ agglutinin (WGA), in the tissues and cells of wheat plants. In a previous study we demonstrated with a radioimmunoassay that the lectin is present in wheat embryos and adult plants both in the roots and at the base of the stem. We have now found, using rhodamine, peroxidase, and ferritin-labeled secondary antibodies, that WGA is located in cells and tissues that establish direct contact with the soil during germination and growth of the plant In the embryo, WGA is found in the surface layer of the radicle, the first adventitious roots, the coleoptile, and the scutellum. Although found throughout the coleorhiza and epiblast, it is at its highest levels within the cells at the surface of these organs. In adult plants, WGA is located only in the caps and tips of adventitious roots. Reaction product for WGA was not visualized in embryonic or adult leaves or in other tissues of adult plants. At the subcellular level, WGA is located at the periphery of protein bodies, within electron-translucent regions of the cytoplasm, and at the cell wall-protoplast interface. Since WGA is found at potential infection sites and is known to have fungicidal properties, it may function in the defense against fungal pathogens.

1982-01-01

422

A radiation hybrid map of chromosome ID reveals synteny conservation at a wheat speciation locus.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The species cytoplasm specific (scs) genes affect nuclear-cytoplasmic interactions in interspecific hybrids. A radiation hybrid (RH) mapping population of 188 individuals was employed to refine the location of the scsae locus of Tritcum aestivum chromosome 1D. ‘Wheat Zapper’, a comparative genomic...

423

Genetic variation of the durum wheat landrace Haurani from different agro-ecological regions  

Microsoft Academic Search

The durum wheat landrace Haurani (Triticum durum Desf.) is grown under contrasting climatic regions of Syria from Deir Ezzor, in the North-East (230 m altitude, 150 mm mean annual rainfall), to Qunaytra, in the South-West (1060 m altitude, 825 mm mean annual rainfall). In order to assess the genetic variation between and within Haurani populations, samples from eight provinces of

Mario A. Pagnotta; Alfredo Impiglia; Oronzo A. Tanzarella; Miloudi M. Nachit; Enrico Porceddu

2005-01-01

424

Increasing field scale water productivity of rice-wheat systems in the Indo Gangetic Basin  

Microsoft Academic Search

Rice-wheat (RW) systems of the Indo-Gangetic Basin (IGB) are of immense importance for food security and livelihoods in South Asia. However, there are grave concerns about their sustainability, let alone their ability to increase production in pace with population growth. In particular, current levels of groundwater extraction are unsustainable in much of the north west IGB. There is an urgent

E. Humphreys; S. S. Kukal; H. Turral; A. Sikka

425

Races of Puccinia graminis on barley, oat and wheat in Canada in 2006  

Microsoft Academic Search

Stem rust, caused by Puccinia graminis, is a disease of cereal crops worldwide. In Canada, it is primarily controlled using resistant cultivars. Tracking the virulence structure in the pathogen populations is essential to detect new virulent races that may occur. Surveys of barley (Hordeum vulgare), oat (Avena sativa) and wheat (Triticum aestivum) fields and trap nurseries were conducted to provide

T. G. Fetch Jr; J. Mitchell Fetch; A. Xue

2011-01-01

426

Effect of temperature on expression of genes encoding enzymes for starch biosynthesis in developing wheat endosperm  

Microsoft Academic Search

The effect of high temperature on starch accumulation, starch granule populations, and expression of genes encoding key enzymes for starch biosynthesis was examined during grain development in wheat (Triticum aestivum L. cv. Butte 86). High temperature applied from anthesis to maturity reduced the duration of starch accumulation. Starch accumulation ceased approximately 6 days earlier for grain produced under a 37\\/17°C

William J. Hurkman; Kent F. McCue; Susan B. Altenbach; Anna Korn; Charlene K. Tanaka; Kerry M. Kothari; Erika L. Johnson; Donald B. Bechtel; Jeff D. Wilson; Olin D. Anderson; Frances M. DuPont

2003-01-01

427

MAPPING OF A RESISTANCE GENE EFFECTIVE AGAINST KARNAL BUNT PATHOGEN OF WHEAT  

Technology Transfer Automated Retrieval System (TEKTRAN)

A set of 130 wheat recombinant inbred lines (RILs) developed from a cross between parents susceptible (WL711) and resistant (HD29) to Karnal bunt (caused by Tilletia indica), were screened for three years with the pathogen populations prevalent in northern India. When 90 simple sequences repeats (SS...

428

Characterization and molecular mapping of a dwarf mutant in wheat.  

PubMed

A spontaneous dwarf mutant of wheat was found in an F5 generation line derived from a cross between Huamai No. 9 and Een No. 1 in 1998; it was named Huaai 01. We characterized the genetic pattern of Huaai 01 and mapped the gene controlling the dwarf trait. This dwarf mutant was found insensitive to exogenous gibberellic acid treatment, based on the length of the first leaf and the coleoptile at the seedling stage, suggesting that it plays a crucial role in the gibberellin response pathway. Genetic analysis revealed that a single gene that is partially recessive controls the dwarf phenotype in Huaai 01. We named the dwarfing gene Rht-B2. Simple sequence repeats (SSR) were examined as identifying markers linked to the Rht-B2 gene in an F2 population. We screened 904 pairs of primers and identified 5 SSR markers linked to the Rht-B2 gene. Two markers, barc1096 and xgwm495, were located on the flanking region of the Rht-B2 gene at genetic distances of 2.9 and 3.3 cM, respectively. Based on published SSR linkage data for wheat, the Rht-B2 gene was mapped to the long arm of chromosome 4B. This identification and characterization of the Rht-B2 dwarfing gene will facilitate its utilization in wheat breeding. PMID:24065689

Jin, X J; Sun, D F; Li, H Y; Yang, Y; Sun, G L

2013-09-12

429

Achieving yield gains in wheat.  

PubMed

Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks. PMID:22860982

Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

2012-08-20

430

Mapping QTLs for tissue culture response of mature wheat embryos.  

PubMed

The mature wheat embryo is arguably one of the best explants for genetic transformation because of its unlimited availability and lack of growth season restriction. However, an efficient regeneration system using mature wheat embryos (Triticum aestivum L.) is still not available. To identify genes related to the tissue culture response (TCR) of wheat, QTLs for callus induction from mature embryos and callus regeneration were mapped using an RIL population derived from the cross of "Wangshuibai" with "Nanda2419" which has a good TCR. By whole genome scanning we identified five, four and four chromosome regions conditioning, respectively, percent embryos forming a callus (PEFC), percent calli regenerating plantlets (PCRP), and number of plantlets per regenerating callus (NPRC). The major QTLs QPefc.nau-2A and QPcrp.nau-2A were mapped to the long arm of chromosome 2A, explaining up to 22.8% and 17.6% of the respective phenotypic variance. Moreover, two major QTLs for NPRC were detected on chromosomes 2D and 5D; these together explained 51.6% of the phenotypic variance. We found that chromosomes 2A, 2D, 5A, 5B and 5D were associated via different intervals with at least two of the three TCR indexes used. Based on this study and other reports, the TCRs of different explant types of wheat may be under the control of shared or tightly linked genes, while different genes or gene combinations may govern the stages from callus induction to plantlet regeneration. The importance of group 2 and 5 chromosomes in controlling the TCRs of Triticeae crops and the likely conservation of the corresponding genes in cereals are discussed. PMID:17646706

Jia, Haiyan; Yi, Dalong; Yu, Jie; Xue, Shulin; Xiang, Yang; Zhang, Caiqin; Zhang, Zhengzhi; Zhang, Lixia; Ma, Zhengqiang

2007-06-30

431

Two recessive genes controlling thermophotoperiod-sensitive male sterility in wheat  

Microsoft Academic Search

Male sterility of wheat-breeding line 337S (Triticum aestivum L.) is sensitive to both short day-length\\/low temperature and long day-length\\/high temperature. 337S was crossed with the\\u000a common wheat variety, Huamai No. 8 and the F1 was highly fertile. The F2 population segregated in a 15:1 ratio for fertility\\/sterility in 243 individuals under long day-length\\/high-temperature.\\u000a The two thermophotoperiod-responsive male sterile genes were

R. X. Guo; D. F. Sun; Z. B. Tan; D. F. Rong; C. D. Li

2006-01-01

432

Water Deficit as a Driver of the Mutualistic Relationship between the Fungus Trichoderma harzianum and Two Wheat Genotypes?  

PubMed Central

The aim of this study was to assess the occurrence of mutualistic interactions between the fungus Trichoderma harzianum and two wheat genotypes, Triticum aestivum cv. Talhuén and T. turgidum subsp. durum cv. Alifén, and the extent to which water deficit affected these interactions. Two wheat genotypes were cultivated in the presence or absence of T. harzianum and in the presence or absence of water deficit. T. harzianum was in turn cultivated in the presence or absence of wheat plants and in the presence or absence of water deficit. To evaluate the plant-fungus interactions, the root volume, dry biomass, and fecundity of wheat were determined, as was the population growth rate of the fungus. Trichoderma harzianum exerted a positive effect only on plants subjected to water deficit. The population growth rate of T. harzianum was negative in the absence of wheat plants and reached its highest level in the presence of plants under conditions of water deficit. These results confirm the occurrence of a mutualistic interaction between wheat and T. harzianum and show that it is asymmetric and context dependent.

Donoso, Eduardo P.; Bustamante, Ramiro O.; Caru, Margarita; Niemeyer, Hermann M.

2008-01-01

433

The Quantity of Zinc Absorbed from Wheat in Adult Women Is Enhanced by Biofortification1–3  

PubMed Central

Biofortification of crops that provide major food staples to large, poor rural populations offers an appealing strategy for diminishing public health problems attributable to micronutrient deficiencies. The objective of this first-stage human study was to determine the increase in quantity of zinc (Zn) absorbed achieved by biofortifying wheat with Zn. Secondary objectives included evaluating the magnitude of the measured increases in Zn absorption as a function of dietary Zn and phytate. The biofortified and control wheats were extracted at high (95%) and moderate (80%) levels and Zn and phytate concentrations measured. Adult women with habitual diets high in phytate consumed 300 g of 95 or 80% extracted wheat as tortillas for 2 consecutive days using either biofortified (41 mg Zn/g) or control (24 mg Zn/g) wheat. All meals for the 2-d experiment were extrinsically labeled with Zn stable isotopes and fractional absorption of Zn determined by a dual isotope tracer ratio technique. Zn intake from the biofortified wheat diet was 5.7 mg/d (72%) higher at 95% extraction (P < 0.001) and 2.7 mg/d (68%) higher at 80% extraction compared with the corresponding control wheat (P = 0.007). Zn absorption from biofortified wheat meals was (mean ± SD) 2.1 ± 0.7 and 2.0 ± 0.4 mg/d for 95 and 80% extraction, respectively, both of which were 0.5 mg/d higher than for the corresponding control wheat (P < 0.05). Results were consistent with those predicted by a trivariate model of Zn absorption as a function of dietary Zn and phytate. Potentially valuable increases in Zn absorption can be achieved from biofortification of wheat with Zn.

Rosado, Jorge L.; Hambidge, K. Michael; Miller, Leland V.; Garcia, Olga P.; Westcott, Jamie; Gonzalez, Karla; Conde, Jennifer; Hotz, Christine; Pfeiffer, Wolfgang; Ortiz-Monasterio, Ivan; Krebs, Nancy F.

2009-01-01

434

A combined biochemical, biophysical and immunological approach towards the identification of celiac disease-specific wheat antigens.  

PubMed

Celiac disease (CD) is an inflammatory affliction of the small bowel caused by an immunological hypersensitivity to ingested wheat antigens affecting almost 1 % of the population. The gliadin fraction of wheat has been shown to contain the pathogenic antigens which react with antibodies and T cells. However, there is only limited knowledge regarding the precise nature of the wheat antigens recognized by IgA antibodies from CD patients and diagnostic tests based on the gliadin fraction have been demonstrated to give frequently false positive results. The aim of this study was the characterization of wheat an