scholarly journals The Cre1 and Cre3 Nematode Resistance Genes Are Located at Homeologous Loci in the Wheat Genome

2003 ◽  
Vol 16 (12) ◽  
pp. 1129-1134 ◽  
Author(s):  
John de Majnik ◽  
Francis C. Ogbonnaya ◽  
Odile Moullet ◽  
Evans S. Lagudah
Keyword(s):  
Fragment Length Polymorphism ◽  
Diagnostic Marker ◽  
Nematode Resistance ◽  
Near Isogenic Lines ◽  
Leucine Rich Repeat ◽  
Homoeologous Group ◽  
Genes Encoding ◽  
Group 2 ◽  
Conserved Gene ◽  
Wheat Lines

Differential responses in host-nematode pathotype interactions occur in wheat lines carrying different cereal cyst nematode resistance (Cre) genes. Cre1, located on chromosome 2B, confers resistance to most European nematodes and the sole Australian pathotype, while Cre3, present on chromosome 2D, is highly resistant to the Australian patho-type and susceptible to a number of European pathotypes. Genes encoding nucleotide binding site-leucine rich repeat (NBS-LRR) proteins that cosegregate with the Cre3 locus cross hybridize to homologues whose restriction fragment length polymorphism (RFLP) patterns distinguish near-isogenic Cre1 nematode-resistant wheat lines. Genetic mapping showed that the NBS-LRR gene members that distinguished the Cre1 near-isogenic lines were located on chromosome 2BL at a locus, designated Xcsl107, that cosegregates with the Cre1 locus. A haplotype of NBS-LRR genes from the Xcsl107 locus provides a diagnostic marker for the presence of Cre1 nematode resistance in a wide collection of wheat lines and segregating families. Genetic analysis of NBS-LRR haplo-types that cosegregate with Cre1 and Cre3 resistance, together with flanking cDNA markers and other markers from homoeologous group 2 chromosomes, revealed a conserved gene order that suggests Cre1 and Cre3 are homeoloci.

Construction of comparative genetic maps of two 4Bs.4Bl-5Rl translocations in bread wheat (Triticum aestivum L.)

Genome ◽  
2006 ◽  
Vol 49 (7) ◽  
pp. 729-734 ◽  
Author(s):  
R C Leach ◽  
I S Dundas ◽  
A Houben
Keyword(s):  
Triticum Aestivum ◽  
Bread Wheat ◽  
Rflp Analysis ◽  
Triticum Aestivum L ◽  
Genetic Maps ◽  
Homoeologous Group ◽  
Group 4 ◽  
Translocation Breakpoints ◽  
Group 5 ◽  
Wheat Lines

The physical length of the rye segment of a 4BS.4BL–5RL translocation derived from the Cornell Wheat Selection 82a1-2-4-7 in a Triticum aestivum 'Chinese Spring' background was measured using genomic in situ hybridization (GISH) and found to be 16% of the long arm. The size of this translocation was similar to previously published GISH measurements of another 4BS.4BL–5RL translocation in a Triticum aestivum 'Viking' wheat background. Molecular maps of both 4BS.4BL–5RL translocations for 2 different wheat backgrounds were developed using RFLP analysis. The locations of the translocation breakpoints of the 2 4BS.4BL–5RL translocations were similar even though they arose in different populations. This suggests a unique property of the region at or near the translocation breakpoint that could be associated with their similarity and spontaneous formation. These segments of rye chromosome 5 also contain a gene for copper efficiency that improves the wheat's ability to cope with low-copper soils. Genetic markers in these maps can also be used to screen for copper efficiency in bread wheat lines derived from the Cornell Wheat Selection 82a1 2-4-7.Key words: Triticum aestivum, wheat–rye translocation, homoeologous group 4, homoeologous group 5, GISH, comparative map, copper efficiency, hairy peduncle.

Identification of restriction fragment length polymorphism and random amplified polymorphic DNA markers linked to downy mildew resistance genes in lettuce, using near-isogenic lines

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 1021-1027 ◽  
Author(s):  
Ilan Paran ◽  
Richard Kesseli ◽  
Richard Michelmore
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Restriction Fragment ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Rapd Markers ◽  
Fragment Length Polymorphism ◽  
Random Amplified Polymorphic Dna ◽  
Near Isogenic Lines ◽  
Isogenic Lines ◽  
Restriction Fragment Length

Near-isogenic lines were used to identify restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers linked to genes for resistance to downy mildew (Dm) in lettuce. Two pairs of near-isogenic lines that differed for Dm1 plus Dm3 and one pair of near-isogenic lines that differed for Dm11 were used as sources of DNA. Over 500 cDNAs and 212 arbitrary 10-mer oligonucleotide primers were screened for their ability to detect polymorphism between the near-isogenic lines. Four RFLP markers and four RAPD markers were identified as linked to the Dm1 and Dm3 region. Dm1 and Dm3 are members of a cluster of seven Dm genes. Marker CL922 was absolutely linked to Dm15 and Dm16, which are part of this cluster. Six RAPD markers were identified as linked to the Dm11 region. The use of RAPD markers allowed us to increase the density of markers in the two Dm regions in a short time. These regions were previously only sparsely populated with RFLP markers. The rapid screening and identification of tightly linked markers to the target genes demonstrated the potential of RAPD markers for saturating genetic maps.Key words: lettuce, downy mildew, near-isogenic lines, disease resistance, restriction fragment length polymorphism, random amplified polymorphic DNA.

Colour genes (R and Rc) for grain and coleoptile upregulate flavonoid biosynthesis genes in wheat

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 747-754 ◽  
Author(s):  
Eiko Himi ◽  
Ahmed Nisar ◽  
Kazuhiko Noda
Keyword(s):  
Flavonoid Biosynthesis ◽  
R Gene ◽  
Homoeologous Group ◽  
Wheat Grain ◽  
Polyphenol Compounds ◽  
Grain Color ◽  
Group 3 ◽  
Significant Expression ◽  
Wheat Lines ◽  
Flavonoid Biosynthesis Pathway

Pigmentation of wheat grain and coleoptile is controlled by the R gene on chromosomes of the homoeologous group 3 and the Rc gene on chromosomes of the homoeologous group 7, respectively. Each of these genes is inherited monogenically. The pigment of grain has been suggested to be a derivative of catechin-tannin and that of coleoptile to be anthocyanin. These polyphenol compounds are known to be synthesized through the flavonoid biosynthesis pathway. We isolated 4 partial nucleotide sequences of the early flavonoid biosynthesis genes (CHS, CHI, F3H, and DFR) in wheat. The expression of these genes was examined in the developing grain of red-grained and white-grained wheat lines. CHS, CHI, F3H, and DFR were highly upregulated in the grain coat tissue of the red-grained lines, whereas there was no significant expression in the white-grained lines. These results indicate that the R gene is involved in the activation of the early flavonoid biosynthesis genes. As for coleoptile pigmentation, all 4 genes were expressed in the red coleoptile; however, DFR was not activated in the white coleoptile. The Rc gene appears to be involved in DFR expression. The possibility that wheat R and Rc genes might be transcription factors is discussed.Key words: flavonoid biosynthesis genes, R gene for grain color, Rc gene for coleoptile color, wheat.

scholarly journals The Tomato Cf-2 Disease Resistance Locus Comprises Two Functional Genes Encoding Leucine-Rich Repeat Proteins

Cell ◽  
1996 ◽  
Vol 84 (3) ◽  
pp. 451-459 ◽  
Author(s):  
Mark S Dixon ◽  
David A Jones ◽  
James S Keddie ◽  
Colwyn M Thomas ◽  
Kate Harrison ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Functional Genes ◽  
Resistance Locus ◽  
Leucine Rich Repeat ◽  
Repeat Proteins ◽  
Genes Encoding

scholarly journals Mamu-B*17+Rhesus Macaques Vaccinated withenv,vif, andnefManifest Early Control of SIVmac239 Replication

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Mauricio A. Martins ◽  
Damien C. Tully ◽  
Núria Pedreño-Lopez ◽  
Benjamin von Bredow ◽  
Matthias G. Pauthner ◽  
...  
Keyword(s):  
T Cells ◽  
Rhesus Macaques ◽  
Chronic Phase ◽  
Virologic Suppression ◽  
Mhc I ◽  
Immunodeficiency Virus ◽  
Genes Encoding ◽  
Siv Infection ◽  
Group 2 ◽  
Group 1

ABSTRACTCertain major histocompatibility complex class I (MHC-I) alleles are associated with spontaneous control of viral replication in human immunodeficiency virus (HIV)-infected people and simian immunodeficiency virus (SIV)-infected rhesus macaques (RMs). These cases of “elite” control of HIV/SIV replication are often immune-mediated, thereby providing a framework for studying anti-lentiviral immunity. In this study, we examined how vaccination impacts SIV replication in RMs expressing the MHC-I alleleMamu-B*17. Approximately 21% ofMamu-B*17+and 50% ofMamu-B*08+RMs control chronic-phase viremia after SIVmac239 infection. Because CD8+T cells targeting Mamu-B*08-restricted SIV epitopes have been implicated in virologic suppression inMamu-B*08+RMs, we investigated whether this might also be true forMamu-B*17+RMs. Two groups ofMamu-B*17+RMs were vaccinated with genes encoding Mamu-B*17-restricted epitopes in Vif and Nef. These genes were delivered by themselves (group 1) or together withenv(group 2). Group 3 included MHC-I-matched RMs and served as the control group. Surprisingly, the group 1 vaccine regimen had little effect on viral replication compared to group 3, suggesting that unlikeMamu-B*08+RMs, preexisting SIV-specific CD8+T cells alone do not facilitate long-term virologic suppression inMamu-B*17+RMs. Remarkably, however, 5/8 group 2 vaccinees controlled viremia to <15 viral RNA copies/ml soon after infection. No serological neutralizing activity against SIVmac239 was detected in group 2, although vaccine-elicited gp140-binding antibodies correlated inversely with nadir viral loads. Collectively, these data shed new light on the unique mechanism of elite control inMamu-B*17+RMs and implicate vaccine-induced, nonneutralizing anti-Env antibodies in the containment of immunodeficiency virus infection.IMPORTANCEA better understanding of the immune correlates of protection against HIV might facilitate the development of a prophylactic vaccine. Therefore, we investigated simian immunodeficiency virus (SIV) infection outcomes in rhesus macaques expressing the major histocompatibility complex class I alleleMamu-B*17. Approximately 21% ofMamu-B*17+macaques spontaneously controlled chronic phase viremia after SIV infection, an effect that may involve CD8+T cells targeting Mamu-B*17-restricted SIV epitopes. We vaccinatedMamu-B*17+macaques with genes encoding immunodominant epitopes in Vif and Nef alone (group 1) or together withenv(group 2). Although neither vaccine regimen prevented SIV infection, 5/8 group 2 vaccinees controlled viremia to below detection limits shortly after infection. This outcome, which was not observed in group 1, was associated with vaccine-induced, nonneutralizing Env-binding antibodies. Together, these findings suggest a limited contribution of Vif- and Nef-specific CD8+T cells for virologic control inMamu-B*17+macaques and implicate anti-Env antibodies in containment of SIV infection.

scholarly journals A new source of root-knot nematode resistance from Arachis stenosperma incorporated into allotetraploid peanut (Arachis hypogaea)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Carolina Ballén-Taborda ◽  
Ye Chu ◽  
Peggy Ozias-Akins ◽  
Patricia Timper ◽  
C. Corley Holbrook ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Snp Array ◽  
Nematode Resistance ◽  
Major Effect ◽  
Root Knot Nematode ◽  
Breeding Programs ◽  
Genes Encoding ◽  
In The Wild ◽  
Arachis Batizocoi ◽  
Lrr Protein

AbstractRoot-knot nematode is a very destructive pathogen, to which most peanut cultivars are highly susceptible. Strong resistance is present in the wild diploid peanut relatives. Previously, QTLs controlling nematode resistance were identified on chromosomes A02, A04 and A09 of Arachis stenosperma. Here, to study the inheritance of these resistance alleles within the genetic background of tetraploid peanut, an F2 population was developed from a cross between peanut and an induced allotetraploid that incorporated A. stenosperma, [Arachis batizocoi x A. stenosperma]4×. This population was genotyped using a SNP array and phenotyped for nematode resistance. QTL analysis allowed us to verify the major-effect QTL on chromosome A02 and a secondary QTL on A09, each contributing to a percentage reduction in nematode multiplication up to 98.2%. These were validated in selected F2:3 lines. The genome location of the large-effect QTL on A02 is rich in genes encoding TIR-NBS-LRR protein domains that are involved in plant defenses. We conclude that the strong resistance to RKN, derived from the diploid A. stenosperma, is transferrable and expressed in tetraploid peanut. Currently it is being used in breeding programs for introgressing a new source of nematode resistance and to widen the genetic basis of agronomically adapted peanut lines.

Rumen digestibility in dairy cows of starch in near-isogenic lines of wheat

1999 ◽  
Vol 1999 ◽  
pp. 90-90
Author(s):  
P.C. Garnsworthy ◽  
J. Wiseman
Keyword(s):  
Near Isogenic Lines ◽  
Limited Information ◽  
Wheat Varieties ◽  
Isogenic Lines ◽  
Relative Value ◽  
Metabolisable Energy ◽  
Growing Conditions ◽  
The Uk ◽  
Wheat Lines ◽  
Agronomic Conditions

Wheat is a good source of carbohydrates for ruminants, and recent low prices in the UK suggest that usage is likely to increase. However, there is a shortage of information on the digestibility of wheat in the rumen. Such information is vital for predicting the relative value of wheat as a source of fermentable metabolisable energy or by-pass starch. Digestibility is likely to be affected by growing conditions and genetics. Genetic differences are found between wheat varieties, but comparisons of named varieties yield limited information because many characteristics vary simultaneously. This problem can be overcome by using near-isogenic lines of wheat that vary only in a limited number of known characteristics. The objective of this study was to determine the rumen digestion characteristics of different near-isogenic wheat lines grown under the same agronomic conditions.

scholarly journals Mapping Agronomic and Quality Traits in Elite Durum Wheat Lines under Differing Water Regimes

Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 144 ◽  
Author(s):  
Rosa Mérida-García ◽  
Alison R. Bentley ◽  
Sergio Gálvez ◽  
Gabriel Dorado ◽  
Ignacio Solís ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Yellow Rust ◽  
Wheat Breeding ◽  
Kernel Weight ◽  
Quality Traits ◽  
Copper Proteins ◽  
Water Regimes ◽  
Growing Seasons ◽  
Genes Encoding ◽  
Wheat Lines

Final grain production and quality in durum wheat are affected by biotic and abiotic stresses. The association mapping (AM) approach is useful for dissecting the genetic control of quantitative traits, with the aim of increasing final wheat production under stress conditions. In this study, we used AM analyses to detect quantitative trait loci (QTL) underlying agronomic and quality traits in a collection of 294 elite durum wheat lines from CIMMYT (International Maize and Wheat Improvement Center), grown under different water regimes over four growing seasons. Thirty-seven significant marker-trait associations (MTAs) were detected for sedimentation volume (SV) and thousand kernel weight (TKW), located on chromosomes 1B and 2A, respectively. The QTL loci found were then confirmed with several AM analyses, which revealed 12 sedimentation index (SDS) MTAs and two additional loci for SV (4A) and yellow rust (1B). A candidate gene analysis of the identified genomic regions detected a cluster of 25 genes encoding blue copper proteins in chromosome 1B, with homoeologs in the two durum wheat subgenomes, and an ubiquinone biosynthesis O-methyltransferase gene. On chromosome 2A, several genes related to photosynthetic processes and metabolic pathways were found in proximity to the markers associated with TKW. These results are of potential use for subsequent application in marker-assisted durum wheat-breeding programs.

scholarly journals Characterization of inter-varietal chromosome substitution lines of wheat using molecular markers

2008 ◽  
Vol 44 (No. 1) ◽  
pp. 22-29 ◽  
Author(s):  
K. Pánková ◽  
Z. Milec ◽  
M. Leverington-Waite ◽  
S. Chebotar ◽  
J.W. Snape
Keyword(s):  
Molecular Markers ◽  
Flowering Time ◽  
Homoeologous Group ◽  
Chromosome Substitution ◽  
Substitution Lines ◽  
Chromosome Substitution Lines ◽  
Vrn Genes ◽  
Group 5 ◽  
Group 2

Several sets of wheat inter-varietal chromosome substitution lines (SLs) have been produced over the last fifty years at the CRI (formerly RICP) in Prague-Ruzyně, based on cytogenetic manipulations using aneuploids. Lines with defined genes have been obtained which significantly influence growth habit and flowering time and these have been used particularly in the study of the genetics and physiology of flowering. The sets of lines include substitutions of homoeologous group 5 chromosomes carrying Vrn genes that control vernalisation response, homoeologous group 2 chromosomes with Ppd genes controlling photoperiodic sensitivity, and some other substitutions, particularly those with chromosome 3B of the Czech alternative variety Česk&aacute; Přes&iacute;vka where a novel flowering time effect was located. Although the phenotypic and cytological analysis of substitution lines has been continually carried out during backcrossing generations, only the use of molecular markers can allow an unambiguous characterization to verify that substitutions are correct and complete. This analysis has allowed incorrect substitutions or partial substitutions to be identified and discarded. This paper summarizes the results of recent molecular checks of the substitution line collections at CRI.

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