scholarly journals Three previously characterized resistances to yellow rust are encoded by a single locus Wtk1

2020 ◽  
Author(s):  
Valentyna Klymiuk ◽  
Andrii Fatiukha ◽  
Dina Raats ◽  
Valeria Bocharova ◽  
Lin Huang ◽  
...  
Keyword(s):  
Gene Networks ◽  
Genomic Sequence ◽  
Triticum Turgidum ◽  
Yellow Rust ◽  
Natural Populations ◽  
Single Locus ◽  
Stripe Rust Resistance ◽  
Dependent Manner ◽  
Resistance Response ◽  
Yellow Stripe

AbstractThe wild emmer wheat (Triticum turgidum ssp. dicoccoides; WEW) yellow (stripe) rust resistance genes Yr15, YrG303 and YrH52 were discovered in natural populations from different geographic locations. They all localize to chromosome 1B but were thought to be non-allelic based on differences in resistance response. We recently cloned Yr15 as a Wheat Tandem Kinase 1 (WTK1) and showed here that these three resistance loci co-segregate in fine-mapping populations and share identical full-length genomic sequence of functional Wtk1. Independent EMS mutagenized susceptible yrG303 and yrH52 lines carried single nucleotide mutations in Wtk1 that disrupted function. A comparison of the mutations for yr15, yrG303 and yrH52 mutants showed that while key conserved residues were intact, other conserved regions in critical kinase subdomains were frequently affected. Thus, we concluded that Yr15-, YrG303- and YrH52-mediated resistances to yellow rust are encoded by a single locus Wtk1. Introgression of Wtk1 into multiple genetic backgrounds resulted in variable phenotypic responses, confirming that Wtk1-mediated resistance is part of a complex immune response network. WEW natural populations subjected to natural selection and adaptation have potential to serve as a good source for evolutionary studies of different traits and multifaceted gene networks.HighlightWe demonstrate that Yr15, YrG303 and YrH52 resistances are encoded by the Wtk1 locus, but express variable resistance responses to yellow rust in a genetic background dependent manner.

scholarly journals Three previously characterized resistances to yellow rust are encoded by a single locus Wtk1

2020 ◽  
Vol 71 (9) ◽  
pp. 2561-2572 ◽  
Author(s):  
Valentyna Klymiuk ◽  
Andrii Fatiukha ◽  
Dina Raats ◽  
Valeria Bocharova ◽  
Lin Huang ◽  
...  
Keyword(s):  
Gene Networks ◽  
Genomic Sequence ◽  
Triticum Turgidum ◽  
Yellow Rust ◽  
Natural Populations ◽  
Single Locus ◽  
Stripe Rust Resistance ◽  
Resistance Response ◽  
Response Network ◽  
Yellow Stripe

Abstract The wild emmer wheat (Triticum turgidum ssp. dicoccoides; WEW) yellow (stripe) rust resistance genes Yr15, YrG303, and YrH52 were discovered in natural populations from different geographic locations. They all localize to chromosome 1B but were thought to be non-allelic based on differences in resistance response. We recently cloned Yr15 as a Wheat Tandem Kinase 1 (WTK1) and show here that these three resistance loci co-segregate in fine-mapping populations and share an identical full-length genomic sequence of functional Wtk1. Independent ethyl methanesulfonate (EMS)-mutagenized susceptible yrG303 and yrH52 lines carried single nucleotide mutations in Wtk1 that disrupted function. A comparison of the mutations for yr15, yrG303, and yrH52 mutants showed that while key conserved residues were intact, other conserved regions in critical kinase subdomains were frequently affected. Thus, we concluded that Yr15-, YrG303-, and YrH52-mediated resistances to yellow rust are encoded by a single locus, Wtk1. Introgression of Wtk1 into multiple genetic backgrounds resulted in variable phenotypic responses, confirming that Wtk1-mediated resistance is part of a complex immune response network. WEW natural populations subjected to natural selection and adaptation have potential to serve as a good source for evolutionary studies of different traits and multifaceted gene networks.

Distribution of Puccinia striiformis f. sp. tritici races and virulence in wheat growing regions of Kenya from 1970 TO 2014

Plant Disease ◽  
2021 ◽  
Author(s):  
Mercy Wamalwa ◽  
Ruth Wanyera ◽  
Julian Rodriguez-Algaba ◽  
Lesley Boyd ◽  
James Owuoche ◽  
...  
Keyword(s):  
Stripe Rust ◽  
Fungal Pathogen ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Stripe Rust Resistance ◽  
Scar Markers ◽  
Seedling Resistance ◽  
Sequence Characterized Amplified Region ◽  
Triticum Spp ◽  
Virulence Diversity

Stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a major threat to wheat (Triticum spp.) production worldwide. The objective of this study was to determine the virulence of Pst races prevalent in the main wheat growing regions of Kenya, which includes Mt. Kenya, Eastern Kenya, and the Rift Valley (Central, Southern, and Northern Rift). Fifty Pst isolates collected from 1970 to 1992 and from 2009 to 2014 were virulence phenotyped using stripe rust differential sets, and 45 isolates were genotyped with sequence characterized amplified region (SCAR) markers to differentiate among the isolates and identify aggressive strains PstS1 and PstS2. Virulence corresponding to stripe rust resistance genes Yr1, Yr2, Yr3, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27 and the seedling resistance in genotype Avocet S were detected. Ten races were detected in the Pst samples obtained from 1970 to 1992, and three additional races were detected from 2009 to 2014, with a single race being detected in both periods. The SCAR markers detected both Pst1 and Pst2 strains in the collection. Increasing Pst virulence was found in the Kenyan Pst population, and that diverse Pst race groups dominated different wheat growing regions. Moreover, recent Pst races in east Africa indicated possible migration of some race groups into Kenya from other regions. This study is important in understanding Pst evolution and virulence diversity and useful in breeding wheat cultivars with effective resistance to stripe rust. Keywords: pathogenicity, Puccinia f. sp. tritici stripe (yellow) rust, Triticum aestivum

Allelic analysis of stripe rust resistance genes on wheat chromosome 2BS

Genome ◽  
2008 ◽  
Vol 51 (11) ◽  
pp. 922-927 ◽  
Author(s):  
P. G. Luo ◽  
X. Y. Hu ◽  
Z. L. Ren ◽  
H. Y. Zhang ◽  
K. Shu ◽  
...  
Keyword(s):  
Ssr Markers ◽  
Stripe Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Dominant Gene ◽  
Wheat Chromosome ◽  
Stripe Rust Resistance ◽  
Resistance Response ◽  
Rust Resistance Genes ◽  
Yr Genes

Stripe rust, caused by Puccinia striiormis Westend f. sp. tritici, is one of the most important foliar diseases of wheat ( Triticum aestivum L.) worldwide. Stripe rust resistance genes Yr27, Yr31, YrSp, YrV23, and YrCN19 on chromosome 2BS confer resistance to some or all Chinese P. striiormis f. sp. tritici races CYR31, CYR32, SY11-4, and SY11-14 in the greenhouse. To screen microsatellite (SSR) markers linked with YrCN19, F1, F2, and F3 populations derived from cross Ch377/CN19 were screened with race CYR32 and 35 SSR primer pairs. Linkage analysis indicated that the single dominant gene YrCN19 in cultivar CN19 was linked with SSR markers Xgwm410, Xgwm374, Xwmc477, and Xgwm382 on chromosome 2BS with genetic distances of 0.3, 7.9, 12.3, and 21.2 cM, respectively. Crosses of CN19 with wheat lines carrying other genes on chromosome 2B showed that all were located at different loci. YrCN19 is thus different from the other reported Yr genes in chromosomal location and resistance response and was therefore named Yr41. Prospects and strategies of using Yr41 and other Yr genes in wheat improvement for stripe rust resistance are discussed.

Development and identification of new syntheticT. turgidum–T. monococcumamphiploids

2018 ◽  
Vol 16 (6) ◽  
pp. 555-563 ◽  
Author(s):  
Hongyu Li ◽  
Xiaojuan Liu ◽  
Minghu Zhang ◽  
Zhen Feng ◽  
Dengcai Liu ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Stripe Rust ◽  
Triticum Turgidum ◽  
Embryo Rescue ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Colchicine Treatment ◽  
Hormone Treatment ◽  
Stripe Rust Resistance ◽  
Adult Plant

AbstractTriticum monococcumssp.monococcumhas useful traits for bread wheat improvement. The synthesis ofTriticum turgidum–T. monococcumamphiploids is an essential step for transferring genes fromT. monococcuminto bread wheat. In this study, 264 wide hybridization combinations were done by crossing 60T. turgidumlines belonging to five subspecies with 83T. monococcumaccessions. Without embryo rescue and hormone treatment, from the 10,810 florets pollinated, 1983 seeds were obtained, with a mean crossability of 18.34% (range 0–89.29%). Many hybrid seeds (90.73%, 923/1017) could germinate and produce plants. A total of 56 new amphiploids (AABBAmAm) were produced by colchicine treatment ofT. turgidum×T. monococcumF1hybrids. The chromosome constitution of amphiploids was characterized by fluorescencein situhybridization using oligonucleotides probes with different chromosome and sub-chromosome specificities. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis indicated that theGlu-A1m-b,Glu-A1m-c,Glu-A1m-dandGlu-A1m-hproteins ofT. monococcumwere expressed in some amphiploids. Despite resistance reduction in several cases, 45 out of 56 amphiploids exhibited resistance to the current predominant Chinese stripe rust races at both the seedling and adult plant stage. These novel amphiploids provide new germplasm for the potential improvement of bread wheat quality and stripe rust resistance.

Development and characterization of Triticum turgidum – Aegilops comosa and T. turgidum – Ae. markgrafii amphidiploids

Genome ◽  
2020 ◽  
Vol 63 (5) ◽  
pp. 263-273
Author(s):  
Yuanyuan Zuo ◽  
Qin Xiang ◽  
Shoufen Dai ◽  
Zhongping Song ◽  
Tingyu Bao ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Diploid Species ◽  
Unreduced Gametes ◽  
Stripe Rust Resistance ◽  
Aegilops Comosa ◽  
Direct Hybridization

Aegilops comosa and Ae. markgrafii are diploid progenitors of polyploidy species of Aegilops sharing M and C genomes, respectively. Transferring valuable genes/traits from Aegilops into wheat is an alternative strategy for wheat genetic improvement. The amphidiploids between diploid species of Aegilops and tetraploid wheat can act as bridges to overcome obstacles from direct hybridization and can be developed by the union of unreduced gametes. In this study, we developed seven Triticum turgidum – Ae. comosa and two T. turgidum – Ae. markgrafii amphidiploids. The unreduced gametes mechanisms, including first-division restitution (FDR) and single-division meiosis (SDM), were observed in triploid F1 hybrids of T. turgidum – Ae. comosa (STM) and T. turgidum – Ae. markgrafii (STC). Only FDR was observed in STC hybrids, whereas FDR or both FDR and SDM were detected in the STM hybrids. All seven pairs of M chromosomes of Ae. comosa and C chromosomes of Ae. markgrafii were distinguished by fluorescent in situ hybridization (FISH) probes pSc119.2 and pTa71 combinations with pTa-535 and (CTT)12/(ACT)7, respectively. Meanwhile, the chromosomes of tetraploid wheat and diploid Aegilops parents were distinguished by the same FISH probes. The amphidiploids possessed specific valuable traits such as multiple tillers, large seed size related traits, and stripe rust resistance that could be utilized in the genetic improvement of wheat.

Identification and full genomic sequence of nerine yellow stripe virus

2020 ◽  
Vol 165 (12) ◽  
pp. 2967-2971
Author(s):  
Naomi Beddoe ◽  
Ian P. Adams ◽  
Sam McGreig ◽  
Alec Forsyth
Keyword(s):  
Genomic Sequence ◽  
Full Genomic Sequence ◽  
Yellow Stripe

Sensing Iron: Reciprocal Regulation of Hepcidin mRNA by Soluble and Cell-Associated Hemojuvelin.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 512-512
Author(s):  
Lan Lin ◽  
Y. Paul Goldberg ◽  
Tomas Ganz
Keyword(s):  
Iron Homeostasis ◽  
Genomic Sequence ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Human Hepatoma Cell ◽  
Hepcidin Expression ◽  
Juvenile Hemochromatosis ◽  
Hepcidin Mrna

Abstract Human genetic studies identified HJV (also called HFE2) as the major cause for juvenile hemochromatosis (JH). Patients with HJV hemochromatosis have low urinary levels of hepcidin, the principal iron-regulatory hormone secreted by the liver. We attempted to establish the specific roles of HJV in iron metabolism, especially its relationship with hepcidin. Translation of the genomic sequence indicated a C-terminal GPI anchor for the protein product of HJV, hemojuvelin. This suggested that hemojuvelin may have either a soluble or a cell-associated form. In human hepatoma cell line Hep3B, knockdown of cellular HJV by siRNA decreased hepcidin expression, independently of the IL-6 pathway. Intriguingly, the addition of recombinant soluble hemojuvelin (rs-hemojuvelin) also suppressed hepcidin expression in primary human hepatocytes, in a log-linear dose-dependent manner, suggesting competition between soluble and cell-associated forms of hemojuvelin. Soluble hemojuvelin was found in human sera at concentrations similar to those required to suppress hepcidin mRNA in vitro. In cells engineered to express hemojuvelin, soluble hemojuvelin release was progressively inhibited by increasing iron or holotransferrin concentrations. Our study suggests that soluble and cell-associated hemojuvelin reciprocally regulate hepcidin mRNA levels, and that hemojuvelin may serve as a molecular messenger for iron homeostasis. Even in hepatocytes stimulated with IL-6, we observed strong suppression of hepcidin mRNA by rs-hemojuvelin. If rs-hemojuvelin or its active fragments also suppress hepcidin production in vivo, they could be used to alleviate anemia of inflammation.

scholarly journals Some sampling properties of selectively neutral alleles

1979 ◽  
Vol 34 (3) ◽  
pp. 253-267 ◽  
Author(s):  
Ranajit Chakraborty ◽  
Paul A. Fuerst
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Genetic Variability ◽  
Mutation Rate ◽  
Natural Populations ◽  
Single Locus ◽  
Population Parameter ◽  
Mean And Variance ◽  
The Mean

SUMMARYSome sampling properties related with the mean and variance of the number of alleles and single locus heterozygosity are derived to study the effect of variations in mutation rate of selectively neutral alleles. The correlation between single locus heterozygosity and the number of alleles is also derived. Monte Carlo simulation is conducted to examine the effect of stepwise mutations. The relevance of these results in estimating the population parameter, 4Neν, is discussed in connexion with neutralist-selectionist controversy over the maintenance of genetic variability in natural populations.

scholarly journals Empirical verification of heterogeneous DNA fragments generated from wheat genome-specific SSR primers

2008 ◽  
Vol 88 (6) ◽  
pp. 1065-1071 ◽  
Author(s):  
Qijiao Chen ◽  
Lianquan Zhang ◽  
Zhongwei Yuan ◽  
Zehong Yan ◽  
Youliang Zheng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Hexaploid Wheat ◽  
Chinese Spring ◽  
Triticum Turgidum ◽  
Sequence Data ◽  
Aegilops Tauschii ◽  
Single Locus ◽  
Synthetic Hexaploid Wheat ◽  
D Genome ◽  
Synthetic Hexaploid

Due to the high polymorphisms between synthetic hexaploid wheat (SHW) and common wheat, SHW has been widely used in genetic studies. The transferability of simple sequence repeats (SSR) among common wheat and its donor species, Triticum turgidum and Aegilops tauschii, and their SHW suggested the possibility that some SSRs, specific for a single locus in common wheat, might appear in two or more loci in SHWs. This is an important genetic issue when using synthetic hexaploid wheat population and SSR for mapping. However, it is largely ignored and never empirically well verified. The present study addressed this issue by using the well-studied SSR marker Xgwm261 as an example. The Xgwm261 produced a 192 bp fragment specific to chromosome 2D in common wheat Chinese Spring, but generated a 176 bp fragment in the D genome of Ae. tauschii AS60. Chromosomal location and DNA sequence data revealed that the176 bp fragment also donated by 2B chromosome of durum wheat Langdon. These results indicated that although a single 176 bp fragment was appeared in synthetic hexaploid wheat Syn-SAU-5 between Langdon and AS60, the fragment contained two different loci, one from chromosome 2D of AS60 and the other from 2B of Langdon which were confirmed by the segregating analysis of SSR Xgwm261 in 185 plants from a F2 population between Syn-SAU-5 and Chinese Spring. If Xgwm261 in Syn-SAU-5 was considered as a single locus in genetic analysis, distorted segregation or incorrect conclusions would be yielded. A proposed strategy to avoid this problem is to include SHW’s parental T. turgidum and Ae. tauschii in SSR analysis as control for polymorphism detection. Key words: Synthetic hexaploid wheat, microsatellite, segregation distortion, Xgwm261, transferability

Molecular genetic description of the cryptic wheat–Aegilops geniculata introgression carrying rust resistance genes Lr57 and Yr40 using wheat ESTs and synteny with rice

Genome ◽  
2009 ◽  
Vol 52 (12) ◽  
pp. 1025-1036 ◽  
Author(s):  
Vasu Kuraparthy ◽  
Shilpa Sood ◽  
Bikram S. Gill
Keyword(s):  
Resistance Genes ◽  
Rust Resistance ◽  
Genomic Sequence ◽  
Molecular Genetic ◽  
Rice Chromosome ◽  
Stripe Rust Resistance ◽  
Comparative Genomic ◽  
Aegilops Geniculata ◽  
Rice Genomic Sequence ◽  
Rust Resistance Genes

The cryptic wheat–alien translocation T5DL·5DS-5MgS(0.95), with leaf rust and stripe rust resistance genes Lr57 and Yr40 transferred from Aegilops geniculata (UgMg) into common wheat, was further analyzed. Molecular genetic analysis using physically mapped ESTs showed that the alien segment in T5DL·5DS-5MgS(0.95) represented only a fraction of the wheat deletion bin 5DS2-0.78-1.00 and was less than 3.3 cM in length in the diploid wheat genetic map. Comparative genomic analysis indicated a high level of colinearity between the distal region of the long arm of chromosome 12 of rice and the genomic region spanning the Lr57 and Yr40 genes in wheat. The alien segment with genes Lr57 and Yr40 corresponds to fewer than four overlapping BAC or PAC clones of the syntenic rice chromosome arm 12L. The wheat–alien translocation breakpoint in T5DL·5DS-5MgS(0.95) was further localized to a single BAC clone of the syntenic rice genomic sequence. The small size of the terminal wheat–alien translocation, as established precisely with respect to Chinese Spring deletion bins and the syntenic rice genomic sequence, further confirmed the escaping nature of cryptic wheat–alien translocations in introgressive breeding. The molecular genetic resources and information developed in the present study will facilitate further fine-scale physical mapping and map-based cloning of the Lr57 and Yr40 genes.

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