scholarly journals Principal approaches and achievements in studying race composition of wheat stem rust

2019 ◽  
Vol 22 (8) ◽  
pp. 967-977 ◽  
Author(s):  
A. S. Rsaliyev ◽  
Sh. S. Rsaliyev
Keyword(s):  
Stem Rust ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Differential Set ◽  
Northern Regions ◽  
Disease Agent ◽  
Commercially Important ◽  
New Races ◽  
Intraspecies Structure

 Wheat stem rust caused by the biotrophic fungus Puccinia graminis f. sp. tritici is a dangerous disease that seriously damages the economics in many countries of the world. The review contains information about epidemics of wheat stem rust and causes of their emergence worldwide. Recently wheat stem rust epidemics have been recorded in the northern regions of Kazakhstan and on the territories adjacent to Omsk Region of Russia. It has been shown that severe wheat stem rust epidemics occur mainly due to the emergence of new virulent races of the disease agent and to growing susceptible wheat cultivars. New methods of studying the race composition of the fungus are described as well as the use of the previous and current differential sets for race determination of P. graminis f. sp. tritici. The results of developing molecular markers and assessing their effectiveness in studying stem rust races are presented. Wheat stem rust races dominant in major grain-growing countries of the globe and their typical peculiarities are described. The paper contains information on identifcation of race Ug99 and of its variations including data on areas of their dissemination and on their virulence to Sr-resistance genes. The existence and emergence of other races of the agent potentially dangerous for commercially important genes for stem rust resistance is also described. Currently in nature strongly virulent races of P. graminis f. sp. tritici are circulating with wide geographical coverage and their virulence is absolutely different from the virulence of race Ug99. Historical and modern data on studying the race composition of the pathogen in Kazakhstan are summarized. It is stated that the use of the old standard differential set and an incomplete North American system of race nomenclature in experiments prevents measuring similarity between Kazakhstani races and the worldwide known races of the pathogen. It has been shown that there is a need to continue studies on the intraspecies structure of the disease agent’s population in Kazakhstan with the use of the modern differential set, on determination of race composition and ways of emergence of new races potentially dangerous for commercial wheat varieties.

scholarly journals Determination of the Role of Berberis spp. in Wheat Stem Rust in China

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1113-1117 ◽  
Author(s):  
Jie Zhao ◽  
Shilei Zhao ◽  
Xianming Chen ◽  
Zhiyan Wang ◽  
Long Wang ◽  
...  
Keyword(s):  
Stem Rust ◽  
Rust Fungus ◽  
Wheat Stem Rust ◽  
Wheat Seedlings ◽  
Detectable Rate ◽  
New Races ◽  
Relationship Of ◽  
The Relationship

Previous studies on the relationship of barberry (Berberis spp.) and wheat stem rust suggested that, although some barberry species can serve as alternate hosts for the stem rust fungus Puccinia graminis f. sp. tritici, barberry plants play no role in wheat stem rust development and virulence variation of P. graminis f. sp. tritici in China. In the present study, severe rust infections on Berberis shensiana, B. brachypoda, B. potaninii, B. soulieana, and B. aggregata were observed during field surveys in 2011 and 2012. Through artificial inoculation of wheat seedlings (‘Mingxian 169’) under greenhouse conditions with aeciospores from naturally infected barberry plants, 185 isolates of P. graminis f. sp. tritici were obtained. From the 27 selected isolates that were tested on a set of wheat genotypes used to differentiate P. graminis f. sp. tritici races in China, 18 races were identified, of which 8 races were new and others were of Chinese 21 and 34 race groups. In addition to the information of virulence or avirulence patterns on the Chinese differentials, none of the races were virulent to resistance gene Sr31. The virulence frequencies based on individual Sr genes or differentials ranged from 0 to 96%. Using molecular markers for P. graminis f. sp. tritici, 75 of 4,036 samples of single aecia were identified as P. graminis f. sp. tritici. The low detectable rate of P. graminis f. sp. tritici was verified based on both infection and molecular marker tests. This observation may be correlated with the low levels of wheat stem rust in the surveyed regions. This study shows that P. graminis f. sp. tritici can produce new races through sexual reproduction on Berberis spp. in China.

Stabilizing selection in Puccinia graminis tritici in Canada

1976 ◽  
Vol 54 (19) ◽  
pp. 2204-2214 ◽  
Author(s):  
Mishael Oichoe Osoro ◽  
G. J. Green
Keyword(s):  
Field Experiment ◽  
Stem Rust ◽  
Virulence Genes ◽  
Spore Production ◽  
Stabilizing Selection ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Competitive Abilities ◽  
Field Plots

Experiments were designed to show whether or not virulence genes reduce fitness and bring about stabilizing selection. The competitive abilities of seven related races of Puccinia graminis f. sp. tritici were studied on seedlings of three to five susceptible wheat varieties by growing mixtures of the races in greenhouses, growth cabinets, and field plots. In experiments in which simple races with few virulence genes were mixed with complex races with one, two, or three extra virulence genes, the complex races predominated after 4 to 10 generations in five of the six mixtures, and the simple race predominated in one mixture. A complex race predominated over simple races in the field experiment. It was concluded that virulence genes did not impair the fitness of the wheat stem rust races studied.In one race mixture studied in growth cabinets the complex race predominated at 25 °C, and the simple race, at 15 °C. Temperature did not differentially influence the competitive abilities of the races in three other mixtures.Incubation periods for all races were shorter at higher temperatures, but races C18(15B-1L) and C33(15B-1L) developed faster than races C9(15B-1L), C37(15), C38(15B-1L), C42(15), and C49(15) at all temperatures. In addition, races C18(15B-1L) and C33(15B-1L) produced more urediospores per pustule than races C9(15B-1L), C37(15), and C49(15). The differences in incubation period and spore production are considered to be the most important factors studied and they could cause the differences in aggressiveness of the seven races.

SELFING STUDIES WITH PHYSIOLOGIC RACES OF WHEAT STEM RUST, PUCCINIA GRAMINIS VAR TRITICI

1954 ◽  
Vol 32 (4) ◽  
pp. 506-522 ◽  
Author(s):  
T. Johnson
Keyword(s):  
Stem Rust ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Recessive Character ◽  
Triticum Vulgare ◽  
Pathogenic Variation ◽  
Differential Hosts ◽  
Physiologic Races ◽  
Parent Race

Forty-two cultures of wheat stem rust (Puccinia graminis var. tritici Erikss. and Henn.), comprising 34 physiologic races, were subjected to selfing studies each of which involved the inoculation of barberry plants with the sporidia of a race, and the determination of the races in the uredial cultures derived from the aeciospores. In all of the cultures studied, the pathogenic properties expressed on the differential hosts appeared to be inherited according to the same principles. On the varieties Marquis and Kota (Triticum vulgare), pathogenicity of the races in the progeny tended to resemble that of the parent race. On Reliance (T. vulgare), avirulence was a dominant character, virulence a recessive one. On the durum wheats Arnautka, Mindum, and Spelmar, virulence was a dominant and avirulence a recessive character. On Einkorn (T. monococcum) and on Vernal (T. dicoccum), avirulence was dominant to virulence. In the progenies of some races, pathogenic variation occurred though it did not transgress the circumscribed limits of the parent race; the population therefore consisted chiefly of substrains (biotypes) of the same race.

scholarly journals Physical Mapping of Stem Rust Resistance Gene Sr52 from Dasypyrum villosum Based on ph1b-Induced Homoeologous Recombination

2019 ◽  
Vol 20 (19) ◽  
pp. 4887 ◽  
Author(s):  
Li ◽  
Dong ◽  
Ma ◽  
Tian ◽  
Qi ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Stem Rust ◽  
Rust Resistance ◽  
Distal Segment ◽  
Stem Rust Resistance ◽  
Dasypyrum Villosum ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Stem Rust Resistance Genes ◽  
Chromosome Segments

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) had been a devastating foliar disease worldwide during the 20th century. With the emergence of Ug99 races, which are virulent to most stem rust resistance genes deployed in wheat varieties and advanced lines, stem rust has once again become a disease threatening global wheat production. Sr52, derived from Dasypyrum villosum and mapped to the long arm of 6V#3, is one of the few effective genes against Ug99 races. In this study, the wheat–D. villosum Robertsonian translocation T6AS·6V#3L, the only stock carrying Sr52 released to experimental and breeding programs so far, was crossed with a CS ph1b mutant to induce recombinants with shortened 6V#3L chromosome segments locating Sr52. Six independent homozygous recombinants with different segment sizes and breakpoints were developed and characterized using in situ hybridization and molecular markers analyses. Stem rust resistance evaluation showed that only three terminal recombinants (1381, 1380, and 1392) containing 8%, 22%, and 30% of the distal segment of 6V#3L, respectively, were resistant to stem rust. Thus, the gene Sr52 was mapped into 6V#3L bin FL 0.92–1.00. In addition, three molecular markers in the Sr52-located interval of 6V#3L were confirmed to be diagnostic markers for selection of Sr52 introgressed into common wheat. The newly developed small segment translocation lines with Sr52 and the identified molecular markers closely linked to Sr52 will be valuable for wheat disease breeding.

REPRODUCTIVE POTENTIALS OF RACES 15B AND 56 OF WHEAT STEM RUST

1967 ◽  
Vol 45 (7) ◽  
pp. 1077-1091 ◽  
Author(s):  
K. Katsuya ◽  
G. J. Green
Keyword(s):  
Incubation Period ◽  
Stem Rust ◽  
Selection Pressure ◽  
Field Conditions ◽  
Puccinia Graminis ◽  
Western Canada ◽  
Stages Of Development ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Infection Density

Variations in the prevalence of races 56 and 15B-1 (Can.) of wheat stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. and Henn.) have occurred that cannot be explained by changes in the wheat varieties grown in Western Canada. The reasons for the changes in prevalence were investigated by comparing in growth cabinets the reproductive potentials or aggressiveness of the two races and the factors that might influence them. When a mixture of urediospores of the two races was used to inoculate three susceptible varieties for successive uredial generations, race 56 predominated at 25 and 20 °C, and race 15B-1 (Can.) predominated at 15 °C. Experimentation showed that the urediospores of race 56 were more infective than those of 15B-1 (Can.) and that the incubation period of race 56 was shorter than that of race 15B-1 (Can.). Pustules of race 56 grew faster than those of race 15B-1 (Can.) during early stages of development but those of 15B-1 (Can.) ultimately became larger than those of race 56. Race 56 produced more urediospores per pustule than race 15B-1 (Can.) on the susceptible varieties Little Club, Red Bobs, and Marquis at 15 and 20 °C. Infection density markedly affected competitive abilities. Race 56 tended to predominate in light infections but race 15B-1 (Can.) tended to predominate in heavy infections. Pustule size decreased as infection density increased. The possible significance of these findings under field conditions is discussed. It seems likely that the rise of race 15B-1 (Can.) to predominance in 1950 resulted not only from the selection pressure of the widely grown varieties that were resistant to race 56 and susceptible to 15B-1 (Can.) but from the lower temperatures that prevailed and favored 15B-1 (Can.) over 56. The rise to predominance of race 56 from 1956 to 1961 may have resulted from the greater aggressiveness of that race under the moderate or warm conditions that prevailed.

PHYSIOLOGIC SPECIALIZATION OF WHEAT STEM RUST IN CANADA, 1919 TO 1955

1957 ◽  
Vol 37 (3) ◽  
pp. 275-287 ◽  
Author(s):  
T. Johnson ◽  
G. J. Green
Keyword(s):  
Stem Rust ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Production Methods ◽  
Physiologic Specialization ◽  
New Varieties ◽  
Group 3 ◽  
Differential Hosts

From 1919 until shortly after 1930 the races of wheat stem rust most prevalent in Canada were: race 21, the race group 3-18-36, and the race group 17–29 which again assumed importance from 1940 to 1948. Race 49 was widely prevalent from 1927 to 1932. Race 56, first found in Canada in 1931, was the predominant race from 1934 to 1949. Race 15B, discovered shortly before 1940 and first found in Canada in 1946, was predominant from 1950 to 1955.The influence of changes in the wheat varieties under cultivation on the rust race population is discussed and it is postulated that a north-to-south movement of rust spores late in the summer plays an important part in the perpetuation of races selectively propagated in northern areas.Recently, biotypes of certain races have become important in relation to varieties now in cultivation and new varieties in the course of production. Methods of identification of such biotypes by means of accessory differential hosts are discussed in relation to the breeding or rust-resistant varieties.A brief account is given of races identified from collections of aecia from barberry.

scholarly journals Markers Linked to Wheat Stem Rust Resistance Gene Sr11 Effective to Puccinia graminis f. sp. tritici Race TKTTF

2016 ◽  
Vol 106 (11) ◽  
pp. 1352-1358 ◽  
Author(s):  
Jayaveeramuthu Nirmala ◽  
Shiaoman Chao ◽  
Pablo Olivera ◽  
Ebrahiem M. Babiker ◽  
Bekele Abeyo ◽  
...  
Keyword(s):  
Stem Rust ◽  
Rust Resistance ◽  
Genetic Resistance ◽  
Wheat Breeding ◽  
Snp Markers ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Breeding Lines

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, can cause severe yield losses on susceptible wheat varieties and cultivars. Although stem rust can be controlled by the use of genetic resistance, population dynamics of P. graminis f. sp. tritici can frequently lead to defeat of wheat stem rust resistance genes. P. graminis f. sp. tritici race TKTTF caused a severe epidemic in Ethiopia on Ug99-resistant ‘Digalu’ in 2013 and 2014. The gene Sr11 confers resistance to race TKTTF and is present in ‘Gabo 56’. We identified seven single-nucleotide polymorphism (SNP) markers linked to Sr11 from a cross between Gabo 56 and ‘Chinese Spring’ exploiting a 90K Infinium iSelect Custom beadchip. Five SNP markers were validated on a ‘Berkut’/‘Scalavatis’ population that segregated for Sr11, using KBioscience competitive allele-specific polymerase chain reaction (KASP) assays. Two of the SNP markers, KASP_6BL_IWB10724 and KASP_6BL_IWB72471, were predictive of Sr11 among wheat genetic stocks, cultivars, and breeding lines from North America, Ethiopia, and Pakistan. These markers can be utilized to select for Sr11 in wheat breeding and to detect the presence of Sr11 in uncharacterized germplasm.

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