scholarly journals Sources of Resistance to Stem Rust Race Ug99 in Spring Wheat Germplasm

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 762-766 ◽  
Author(s):  
M. N. Rouse ◽  
R. Wanyera ◽  
P. Njau ◽  
Y. Jin
Keyword(s):  
Spring Wheat ◽  
Resistance Genes ◽  
North American ◽  
Stem Rust ◽  
Wheat Breeding ◽  
Field Resistance ◽  
Eastern Africa ◽  
Adult Plant ◽  
Sources Of Resistance ◽  
Wheat Stem Rust

Wheat stem rust (Puccinia graminis f. sp. tritici) race TTKSK (Ug99), with virulence to the majority of the world's wheat (Triticum aestivum) cultivars, has spread from Uganda throughout eastern Africa, Yemen, and Iran. The identification and spread of variants of race TTKSK with virulence to additional stem rust resistance genes has reminded breeders and pathologists of the danger of deploying major resistance genes alone. In order to protect wheat from this rapidly spreading and adapting pathogen, multiple resistance genes are needed, preferably from improved germplasm. Preliminary screening of over 700 spring wheat breeding lines and cultivars developed at least 20 years ago identified 88 accessions with field resistance to Ug99. We included these resistant accessions in the stem rust screening nursery in Njoro, Kenya for two additional seasons. The accessions were also screened with a bulk of North American isolates of P. graminis f. sp. tritici in the field in St. Paul, MN. In order to further characterize the resistance in these accessions, we obtained seedling phenotypes for 10 races of P. graminis f. sp. tritici, including two races from the race TTKSK complex. This phenotyping led to the identification of accessions with either adult-plant or all-stage resistance to race TTKSK, and often North American races of P. graminis f. sp. tritici as well. These Ug99 resistant accessions can be obtained by breeders and introgressed into current breeding germplasm.

scholarly journals Stem Rust Resistance in A-Genome Diploid Relatives of Wheat

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 941-944 ◽  
Author(s):  
M. N. Rouse ◽  
Y. Jin
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Infection Type ◽  
Genetic Resistance ◽  
Wheat Breeding ◽  
Stem Rust Resistance ◽  
Wheat Stem Rust ◽  
A Genome ◽  
Stem Rust Resistance Genes

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, has been effectively controlled through the use of genetic resistance. P. graminis f. sp. tritici race TTKSK (Ug99) possesses virulence to many resistance genes that have been used in wheat breeding worldwide. One strategy to aid breeders in developing resistant cultivars is to utilize resistance genes transferred from wild relatives to wheat. Stem rust resistance genes have previously been introgressed from Triticum monococcum to wheat. In order to identify additional resistance genes, we screened 1,061 accessions of T. monococcum and 205 accessions of T. urartu against race TTKSK and four additional P. graminis f. sp. tritici races: TTTTF, TRTTF, QFCSC, and MCCFC. A high frequency of the accessions (78.7% of T. monococcum and 93.0% of T. urartu) were resistant to P. graminis f. sp. tritici race TTKSK, with infection types ranging from 0 to 2+. Among these resistant accessions, 55 T. monococcum accessions (6.4% of the total) were also resistant to the other four races. Associations of resistance in T. monococcum germplasm to different races indicated the presence of genes conferring resistance to multiple races. Comparing the observed infection type patterns to the expected patterns of known genes indicated that previously uncharacterized genes for resistance to race TTKSK exist in both T. monococcum and T. urartu.

scholarly journals Mapping and Characterization of a Wheat Stem Rust Resistance Gene in Durum Wheat “Kronos”

2021 ◽  
Vol 12 ◽  
Author(s):  
Hongna Li ◽  
Lei Hua ◽  
Matthew N. Rouse ◽  
Tianya Li ◽  
Shuyong Pang ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Wheat Variety ◽  
Wheat Breeding ◽  
Stem Rust Resistance ◽  
Wheat Stem Rust ◽  
Seedling Resistance ◽  
Or Gene

Wheat stem (or black) rust is one of the most devastating fungal diseases, threatening global wheat production. Identification, mapping, and deployment of effective resistance genes are critical to addressing this challenge. In this study, we mapped and characterized one stem rust resistance (Sr) gene from the tetraploid durum wheat variety Kronos (temporary designation SrKN). This gene was mapped on the long arm of chromosome 2B and confers resistance to multiple virulent Pgt races, such as TRTTF and BCCBC. Using a large mapping population (3,366 gametes), we mapped SrKN within a 0.29 cM region flanked by the sequenced-based markers pku4856F2R2 and pku4917F3R3, which corresponds to 5.6- and 7.2-Mb regions in the Svevo and Chinese Spring reference genomes, respectively. Both regions include a cluster of nucleotide binding leucine-repeat (NLR) genes that likely includes the candidate gene. An allelism test failed to detect recombination between SrKN and the previously mapped Sr9e gene. This result, together with the similar seedling resistance responses and resistance profiles, suggested that SrKN and Sr9e may represent the same gene. We introgressed SrKN into common wheat and developed completely linked markers to accelerate its deployment in the wheat breeding programs. SrKN can be a valuable component of transgenic cassettes or gene pyramids that includes multiple resistance genes to control this devastating disease.

DANGEROUS NEW RACES OF OAT STEM RUST AND SOURCES OF RESISTANCE TO THEM

1964 ◽  
Vol 44 (5) ◽  
pp. 418-426 ◽  
Author(s):  
G. J. Green ◽  
R. I. H. McKenzie
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Seedling Stage ◽  
Adult Plant ◽  
Santa Fe ◽  
Sources Of Resistance ◽  
Adult Plant Stage ◽  
Plant Stage ◽  
New Races ◽  
Moderately Resistant

New races of oat stem rust that can attack varieties carrying all identified resistance genes were found in Canada between 1957 and 1963. Varieties moderately resistant to some of these races have been found, but they are susceptible to other less-prevalent races. Some of the sources of resistance are: Ukraine, C.I. 3259; Ark. 674(2)-39-F, C.I. 4529; C.I. 4673; C.I. 5109; Santa Fe Selection, C.I. 5844; C.I. 6792; Silva No. 1729-49-1, C.I. 6849; and Rosen’s Mutant. White Russian (gene D) and Sevnothree (gene E) were resistant in the adult plant stage to one culture of race 6AF, although susceptible in the seedling stage.

Validation of molecular markers for wheat breeding

2001 ◽  
Vol 52 (12) ◽  
pp. 1357 ◽  
Author(s):  
P. J. Sharp ◽  
S. Johnston ◽  
G. Brown ◽  
R. A. McIntosh ◽  
M. Pallotta ◽  
...  
Keyword(s):  
Plant Resistance ◽  
Stem Rust ◽  
Adult Plant Resistance ◽  
Wheat Breeding ◽  
Chromosome Segment ◽  
Adult Plant ◽  
Wheat Stem Rust ◽  
Aegilops Ventricosa ◽  
Flour Colour ◽  
Trait Locus

Five sets of markers were assessed for their usefulness in breeding, two linked to wheat stem rust gene Sr2, several markers linked to a chromosome segment conferring Yr17/Lr37/Sr38 resistance, two reported markers for the linked genes Lr35 andSr39, one for Lr28, and one linked to flour colour. The gene for Sr2 confers adult plant resistance to stem rust (Puccinia graminis f.sp. tritici) and was originally transferred to bread wheat from the tetraploid emmer (‘Yaroslav’) to the cultivars Hope and H-44. The gene is located on the short arm of chromosome 3B and confers a durable adult plant resistance to stem rust usually expressed only in the field. The chromosome segment carrying the Lr37, Sr38, Yr17 resistance genes is located on 2AS and was originally introduced into wheat through an Aegilops ventricosa Triticum persicum cross, followed by a cross to the cultivar Marne (VPM1). The flour colour quantitative trait locus was originally described in a Yarralinka Schomburg cross and is located on chromosome 7A. The primers as originally developed required optimisation for more routine use in a breeding program.

scholarly journals Genetic Analysis of Adult Plant Resistance to Yellow Rust and Leaf Rust in Common Spring Wheat Quaiu 3

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 728-736 ◽  
Author(s):  
B. R. Basnet ◽  
R. P. Singh ◽  
S. A. Herrera-Foessel ◽  
A. M. H. Ibrahim ◽  
J. Huerta-Espino ◽  
...  
Keyword(s):  
Spring Wheat ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Molecular Mapping ◽  
Puccinia Striiformis ◽  
Wheat Breeding ◽  
Adult Plant ◽  
Breeding Programs ◽  
Qualitative Approaches

Identifying and utilizing rust resistance genes in wheat has been hampered by the continuous and rapid emergence of new pathogen races. A major focus of many wheat breeding programs is achieving durable adult plant resistance (APR) to yellow (stripe) rust (YR) and leaf (brown) rust (LR), caused by Puccinia striiformis and P. triticina, respectively. This study aimed to determine the genetic basis of resistance to YR and LR in the common spring wheat ‘Quaiu 3’. To that end, we evaluated 198 F5 recombinant inbred lines (RILs), derived from a cross of susceptible ‘Avocet-YrA’ with Quaiu 3, for APR to LR and YR in artificially inoculated field trials conducted in Mexico during the 2009 and 2010 growing seasons. High narrow-sense heritability (h2) estimates, ranging between 0.91 and 0.95, were obtained for both LR and YR disease severities for both years. The quantitative and qualitative approaches used to estimate gene numbers showed that, in addition to known resistance genes, there are at least two to three APR genes associated with LR and YR resistance in the RIL population. The moderately effective race-specific resistance gene Lr42 and the pleiotropic slow-rusting APR gene Lr46/Yr29 were found to interact with additional unidentified APR genes. The unidentified APR genes should be of particular interest for further characterization through molecular mapping, and for utilization by wheat breeding programs.

scholarly journals Genetics of Stem Rust Resistance in Wheat Cvs. Pasqua and AC Taber

1998 ◽  
Vol 88 (2) ◽  
pp. 171-176 ◽  
Author(s):  
J. Q. Liu ◽  
J. A. Kolmer
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Field Resistance ◽  
Stem Rust Resistance ◽  
Adult Plant ◽  
Leaf Rust Resistance Gene ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes

Canadian wheat cvs. Pasqua and AC Taber were examined genetically to determine the number and identity of stem rust resistance genes in both. The two cultivars were crossed with stem rust susceptible line RL6071, and sets of random F6 lines were developed from each cross. The F6 lines, parents, and tester lines with single stem rust resistance genes were grown in a field rust nursery, inoculated with a mixture of stem and leaf rust races, and evaluated for rust resistance. The same wheat lines were tested by inoculation with specific stem rust races in seedling tests to postulate which Sr genes were segregating in the F6 lines. Segregation of F6 lines indicated that Pasqua had three genes that conditioned field resistance to stem rust and had seedling genes Sr5, Sr6, Sr7a, Sr9b, and Sr12. Leaf rust resistance gene Lr34, which is in Pasqua, was associated with adult-plant stem rust resistance in the segregating F6 lines. Adult-plant gene Sr2 was postulated to condition field resistance in AC Taber, and seedling genes Sr9b, Sr11, and Sr12 also were postulated to be in AC Taber.

scholarly journals Emergence and Spread of New Races of Wheat Stem Rust Fungus: Continued Threat to Food Security and Prospects of Genetic Control

2015 ◽  
Vol 105 (7) ◽  
pp. 872-884 ◽  
Author(s):  
Ravi P. Singh ◽  
David P. Hodson ◽  
Yue Jin ◽  
Evans S. Lagudah ◽  
Michael A. Ayliffe ◽  
...  
Keyword(s):  
Food Security ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Stem Rust ◽  
Large Scale ◽  
Specific Resistance ◽  
Hot Spot ◽  
Adult Plant ◽  
Wheat Stem Rust ◽  
Slow Rusting

Race Ug99 (TTKSK) of Puccinia graminis f. sp. tritici, detected in Uganda in 1998, has been recognized as a serious threat to food security because it possesses combined virulence to a large number of resistance genes found in current widely grown wheat (Triticum aestivum) varieties and germplasm, leading to its potential for rapid spread and evolution. Since its initial detection, variants of the Ug99 lineage of stem rust have been discovered in Eastern and Southern African countries, Yemen, Iran, and Egypt. To date, eight races belonging to the Ug99 lineage are known. Increased pathogen monitoring activities have led to the identification of other races in Africa and Asia with additional virulence to commercially important resistance genes. This has led to localized but severe stem rust epidemics becoming common once again in East Africa due to the breakdown of race-specific resistance gene SrTmp, which was deployed recently in the ‘Digalu’ and ‘Robin’ varieties in Ethiopia and Kenya, respectively. Enhanced research in the last decade under the umbrella of the Borlaug Global Rust Initiative has identified various race-specific resistance genes that can be utilized, preferably in combinations, to develop resistant varieties. Research and development of improved wheat germplasm with complex adult plant resistance (APR) based on multiple slow-rusting genes has also progressed. Once only the Sr2 gene was known to confer slow rusting APR; now, four more genes—Sr55, Sr56, Sr57, and Sr58—have been characterized and additional quantitative trait loci identified. Cloning of some rust resistance genes opens new perspectives on rust control in the future through the development of multiple resistance gene cassettes. However, at present, disease-surveillance-based chemical control, large-scale deployment of new varieties with multiple race-specific genes or adequate levels of APR, and reducing the cultivation of susceptible varieties in rust hot-spot areas remains the best stem rust management strategy.

scholarly journals Virulence and race structure of Puccinia graminis f. sp. tritici in Kazakhstan

2020 ◽  
Vol 56 (No. 4) ◽  
pp. 275-284
Author(s):  
Aralbek Rsaliyev ◽  
Gulbahar Yskakova ◽  
Akerke Maulenbay ◽  
Kunsulu Zakarya ◽  
Shynbolat Rsaliyev
Keyword(s):  
Stem Rust ◽  
Wheat Breeding ◽  
Puccinia Graminis ◽  
Sources Of Resistance ◽  
Wheat Stem Rust ◽  
East Kazakhstan ◽  
Breeding Programmes ◽  
Stem Rust Resistance Genes ◽  
Rust Resistance Genes ◽  
Virulence Diversity

Severe epidemics of wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) have been observed in recent years in major spring wheat producing regions in Kazakhstan. However, information on the virulence structure and race composition of Pgt is currently not available. Stem rust samples were collected in 2015–2018 in three regions of Kazakhstan to determine the virulence diversity and race distribution in the Pgt populations. A total of 203 single-pustule isolates were derived and evaluated on the stem rust differential and supplemental lines and 38 races were identified. Among them, the races QHHSF and THMTF were found in all the regions and in all the years. The races RFRTF, RHMRF, TKRPF and MHCTC were the most common races in the Akmola and Kostanay regions, and the races LHCSF, QKCSF and LKCSF were only widely distributed in East Kazakhstan. The virulence complexity (i.e., number of Sr genes on which the races were virulent) ranged from 5 to 16, with about 40% of the races having 14 or more virulence. The stem rust resistance genes Sr11, Sr13, Sr22, Sr26, Sr31, Sr33 and Sr35 were found to confer resistance to all the races identified during the study period. Hence, these genes can be used as sources of resistance in wheat breeding programmes in Kazakhstan.

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