scholarly journals Race Dynamics, Diversity, and Virulence Evolution in Puccinia striiformis f. sp. tritici, the Causal Agent of Wheat Stripe Rust in China from 2003 to 2007

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1093-1101 ◽  
Author(s):  
W. Q. Chen ◽  
L. R. Wu ◽  
T. G. Liu ◽  
S. C. Xu ◽  
S. L. Jin ◽  
...  
Keyword(s):  
Stripe Rust ◽  
Large Scale ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Rust Fungus ◽  
Long Distance ◽  
Center Of Origin ◽  
Virulence Evolution ◽  
Large Scale Cultivation ◽  
Pathogen Populations

Stripe (or yellow) rust caused by Puccinia striiformis f. sp. tritici is the most destructive foliar disease of wheat in China. The pathogen populations were analyzed for virulence evolution, complexity, phenotypic dynamics, and diversity on temporal and spatial bases. A total of 41 races were identified and characterized from 4,714 stripe rust isolates collected during 2003 through 2007 from wheat growing areas in 15 provinces in China. The races were based on avirulence/virulence patterns to 19 differential host genotypes. Chinese stripe rust population exhibited high diversity with a complex virulence structure. Comparisons using the relative Shannon's index indicated that some differences in the richness and evenness of races were present in pathogen populations within years and between regions despite a national tendency to reduced diversity over time. A noticeably increased frequency of race CYR33 (Chinese yellow rust 33) with virulence for YrSu was the major virulence change recorded in this study compared to the results on an annual basis. Isolates of Puccinia striiformis f. sp. tritici from different regions showed differences in the composition of races, distribution frequency, and diversity. The uneven distribution of major races and comparatively greater diversity in the Northwest and Southwest regions than that in the Huang-Huai-Hai region suggest that long-distance migrations of the pathogen occur from one or more over-summering areas eastward into over-wintering areas. This supports the hypothesis that southern Gansu and northwestern Sichuan comprises a “center of origin for virulence”. Mutation of virulence or avirulence for host resistance in the stripe rust fungus may be the basic cause of the occurrence of new virulent types. The subsequent dominance of certain races will vary with parasitic fitness and the opportunities to be selected through large-scale cultivation of varieties with matching resistance genes. Implications of the center of origin for virulence variation and diversity in the pathogen population and an alternative strategy for limiting virulence evolution are discussed.

scholarly journals Yellow Rust (Puccinia striiformis): a Serious Threat to Wheat Production Worldwide

2018 ◽  
Vol 10 (3) ◽  
pp. 410-423 ◽  
Author(s):  
Siham KHANFRI ◽  
Mohammed BOULIF ◽  
Rachid LAHLALI
Keyword(s):  
Life Cycle ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Wheat Crop ◽  
Long Distance ◽  
Susceptible Host ◽  
Center Of Origin ◽  
Resistant Varieties ◽  
The World

Wheat (Triticum sp. L.), as one of the first domesticated food crops, is the basic staple food for a large segment of population around the world. The crop though is susceptible to many fungal pathogens. Stripe rust is an important airborne disease caused by Puccinia striiformis (Pst) and is widespread wherever wheat is cultivated throughout the world, in temperate-cool and wet environments. The causal fungus of stripe rust or yellow rust is an obligate parasite that requires another living host to complete its life cycle. Pst includes five types of spores in the life cycle on two distinct hosts. Stripe rust is distinguished from other rusts by the dusty yellow lesions that grow systemically in the form of streaks between veins and on leaf sheaths. The importance and occurrence of stripe rust disease varies in cultivated wheat, depending on environmental conditions (moisture, temperature, and wind), inoculum levels and susceptible host varieties. Transcaucasia was previously thought to be the center of origin for the pathogen. However, new findings further underlined Himalayan and near-Himalayan regions as center of diversity and a more tenable center of origin for P. striiformis. Long-distance dispersal of stripe rust pathogen in the air and occasionally by human activities enables Pst to spread to new geographical areas. This disease affects quality and yield of wheat crop. Early seeding, foliar fungicide application and cultivation of resistant varieties are the main strategies for its control. The emergence of new races of Pst with high epidemic potential which can adapt to warmer temperatures has expanded virulence profiles. Subsequently, races are more aggressive than those previously characterized. These findings emphasize the need for more breeding efforts of resistant varieties and reinforcement of other management practices to prevent and overcome stripe rust epidemic around the world.

scholarly journals Virulence Characterization of Puccinia striiformis f. sp. tritici Using a New Set of Yr Single-Gene Line Differentials in the United States in 2010

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1534-1542 ◽  
Author(s):  
Anmin Wan ◽  
Xianming Chen
Keyword(s):  
United States ◽  
Stripe Rust ◽  
Large Scale ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Single Gene ◽  
The United States ◽  
The Past ◽  
History Of

Puccinia striiformis f. sp. tritici causes stripe rust (yellow rust) of wheat and is highly variable in virulence toward wheat with race-specific resistance. During 2010, wheat stripe rust was the most widespread in the recorded history of the United States, resulting in large-scale application of fungicides and substantial yield loss. A new differential set with 18 yellow rust (Yr) single-gene lines was established and used to differentiate races of P. striiformis f. sp. tritici, which were named as race PSTv in distinction from the PST races identified in the past. An octal system was used to describe the virulence and avirulence patterns of the PSTv races. From 348 viable P. striiformis f. sp. tritici isolates recovered from a total of 381 wheat and grass stripe rust samples collected in 24 states, 41 races, named PSTv-1 to PSTv-41, were identified using the new set of 18 Yr single-gene differentials, and their equivalent PST race names were determined on the previous set of 20 wheat cultivar differentials. The frequencies and distributions of the races and their virulences were determined. The five most predominant races were PSTv-37 (34.5%), PSTv-11 (17.5%), PSTv-14 (7.2%), PSTv-36 (5.2%), and PSTv-34 (4.9%). PSTv-37 was distributed throughout the country while PSTv-11 and PSTv-14 were almost restricted to states west of the Rocky Mountains. The races had virulence to 0 to 13 of the 18 Yr genes. Frequencies of virulences toward resistance genes Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr43, Yr44, YrTr1, and YrExp2 were high (67.0 to 93.7%); those to Yr1 (32.8%) and YrTye (31.3%) were moderate; and those to Yr10, Yr24, Yr32, and YrSP were low (3.4 to 5.7%). All of the isolates were avirulent to Yr5 and Yr15.

Appearance of atypical Puccinia striiformis f. sp. tritici phenotypes in north-western Europe

2007 ◽  
Vol 58 (6) ◽  
pp. 518 ◽  
Author(s):  
Mogens S. Hovmøller ◽  
Annemarie F. Justesen
Keyword(s):  
Large Scale ◽  
Western Europe ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Time Period ◽  
Genetic Interpretation ◽  
Wide Range ◽  
Diverse Origin ◽  
Large Scale Cultivation ◽  
Short Time

A combination of large-scale cultivation of highly susceptible cultivars and mild winters caused severe yield losses due to yellow rust in NW Europe in the early 1990s, but in recent years the disease has become less predominant. Several atypical Puccinia striiformis f. sp. tritici pathotypes have been observed in recent years, showing virulence spectra which made them able only to infect cultivars covering less than 5% of the wheat and triticale area in Denmark. Some were even unable to grow on any of the standard ‘European’ and ‘World’ yellow rust differentials. We observed 2 distinct groups of atypical pathotypes, each subdividing into 2 highly divergent AFLP phenotypes. It was striking that AFLP diversity among unusual pathotypes, sampled within a short time period in a small area on very few host cultivars, which induced limited or no selection on the pathogen population, was 3–4 times higher than among isolates sampled from a large number of cultivars with different Yr-genes in 4 different countries during more than 25 years. The repeated occurrence of atypical phenotypes of diverse origin may suggest a more frequent and even more distant dispersal of P. striiformis uredospores than previously anticipated. Finally, the disease reactions conferred by these unusual types on a wide range of differentials were used to discuss the limits for a genetic interpretation in terms of assessment of virulence and avirulence in pathogen isolates.

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

scholarly journals Virulence Characterization of Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici in Ethiopia and Evaluation of Ethiopian Wheat Germplasm for Resistance to Races of the Pathogen from Ethiopia and the United States

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Anmin Wan ◽  
Kebede T. Muleta ◽  
Habtemariam Zegeye ◽  
Bekele Hundie ◽  
Michael O. Pumphrey ◽  
...  
Keyword(s):  
United States ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Rust Fungus ◽  
Single Gene ◽  
The United States ◽  
Wheat Cultivars ◽  
Low Frequencies ◽  
Additional Information

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat in Ethiopia. In total, 97 isolates were recovered from stripe rust samples collected in Ethiopia in 2013 and 2014. These isolates were tested on a set of 18 Yr single-gene differentials for characterization of races and 7 supplementary differentials for additional information of virulence. Of 18 P. striiformis f. sp. tritici races identified, the 5 most predominant races were PSTv-105 (21.7%), PSTv-106 (17.5%), PSTv-107 (11.3%), PSTv-76 (10.3%), and PSTv-41 (6.2%). High frequencies (>40%) were detected for virulence to resistance genes Yr1, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27, Yr28, Yr31, Yr43, Yr44, YrExp2, and YrA. Low frequencies (<40%) were detected for virulence to Yr10, Yr24, Yr32, YrTr1, Hybrid 46, and Vilmorin 23. None of the isolates were virulent to Yr5, Yr15, YrSP, and YrTye. Among the six collection regions, Arsi Robe and Tiyo had the highest virulence diversities, followed by Bekoji, while Bale and Holeta had the lowest. Evaluation of 178 Ethiopian wheat cultivars and landraces with two of the Ethiopian races and three races from the United States indicated that the Ethiopian races were more virulent on the germplasm than the predominant races of the United States. Thirteen wheat cultivars or landraces that were resistant or moderately resistant to all five tested races should be useful for breeding wheat cultivars with resistance to stripe rust in both countries.

scholarly journals High Relative Parasitic Fitness of G22 Derivatives is Associated with the Epidemic Potential of Wheat Stripe Rust in China

Plant Disease ◽  
2018 ◽  
Vol 102 (3) ◽  
pp. 483-487 ◽  
Author(s):  
Bing Bing Bai ◽  
Tai Guo Liu ◽  
Bo Liu ◽  
Li Gao ◽  
Wan Quan Chen
Keyword(s):  
Latent Period ◽  
Stripe Rust ◽  
Large Scale ◽  
Puccinia Striiformis ◽  
Germination Rate ◽  
Durable Resistance ◽  
Wheat Cultivars ◽  
Wheat Stripe Rust ◽  
Expansion Speed ◽  
Parasitic Fitness

In total, 13 commercial wheat cultivars around China and four races of Puccinia striiformis f. sp. tritici (namely, CYR32, CYR33, G22-9, and G22-14) were employed for a test of relative parasitic fitness (RPF) using the drop method. The RPF values were measured, including the urediniospore germination rate, the latent period, the uredinial length, the uredinial density, the infection area, the sporulation intensity, the lesion expansion speed, and the sporulation period. The results indicated that the parameters of relative parasitic fitness of the four P. striiformis f. sp. tritici races on the 13 wheat cultivars were significantly different (P = 0.00) in sporulation intensity, lesion expansion speed, uredinial length, sporulation period, uredinial density, and latent period. The urediniospore germination rates of the four P. striiformis f. sp. tritici races for the test were significantly different (P = 0.00), whereas no correlation with the different cultivars was observed (P = 1.00). The infection areas of the tested races on the different cultivars were significantly different (P = 0.00) but there were no obvious manifestations among the various races (P = 0.20). Principal component analysis (PCA) showed that the sporulation intensity represented sporulation capacity and scalability, the latent period indicated infection ability, and the urediniospore germination rate represented urediniospore vigor, all of which fully contributed to the RPF in the interaction of the four races and 13 wheat cultivars, which was calculated by the following formula: RPF = (sporulation intensity × urediniospore germination rate)/latent period. The sporulation and infection of G22-9 on the 13 large-scale cultivated cultivars were the highest, and the RPF of G22-9 was higher than that of the predominant races, CYR32 and CYR33. This result suggested that G22-9 could become a new predominant race and potentially cause epidemics of wheat stripe rust in China. To prevent potential epidemics, susceptible wheat cultivars should be withdrawn from production and breeding programs should reduce the use of Yr10 and Yr26 and use other more effective resistance genes in combination with nonrace-specific resistance for developing wheat cultivars with durable resistance to stripe rust.

scholarly journals Evidence for Increased Aggressiveness in a Recent Widespread Strain of Puccinia striiformis f. sp. tritici Causing Stripe Rust of Wheat

2009 ◽  
Vol 99 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Eugene A. Milus ◽  
Kristian Kristensen ◽  
Mogens S. Hovmøller
Keyword(s):  
Stripe Rust ◽  
Temperature Regime ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Severe Disease ◽  
Lesion Length ◽  
Eastern United States ◽  
Inoculation Site ◽  
Temperature Regimes ◽  
Higher Temperature

Stripe rust (yellow rust) of wheat, caused by Puccinia striiformis f. sp. tritici, has become more severe in eastern United States, Australia, and elsewhere since 2000. Recent research has shown that this coincided with a global spread of two closely related strains that were similar based on virulence phenotype and amplified fragment length polymorphism. The objective of this research was to quantify differences in aggressiveness among isolates representative of the pre-2000 and post-2000 populations. Representative isolates were evaluated at low (10 to 18°C) and high (12 to 28°C) temperature regimes for latent period, lesion length, lesion width, lesion area, and spore production on adult plants of a susceptible wheat cultivar with no known genes for resistance to stripe rust. “New” isolates (since 2000) were significantly more aggressive than “old” isolates (before 2000) for all variables. At the low temperature regime, new isolates sporulated 2.1 days (16%) sooner, grew 0.3 mm per day (18%) faster, produced 999 (140%) more spores per inoculation site per day, and produced 6.5 (71%) more spores per mm2 of lesion per day compared with old isolates. At the high temperature regime, new isolates sporulated 3 days (26%) sooner, grew 0.2 mm per day (18%) and 2.2 mm2 per day (88%) faster, grew 1.2 mm (50%) wider, produced 774 (370%) more spores per inoculation site per day, and produced 6.2 (159%) more spores per mm2 of lesion per day than old isolates. New isolates showed significant adaptation to the warm temperature regime for all variables. Based on these results and previously published models for stripe rust epidemics, recent severe stripe rust epidemics were most likely enhanced by the pathogen's increased aggressiveness, especially at higher temperature. Furthermore, these results demonstrate that wheat rust fungi can adapt to warmer temperatures and cause severe disease in previously unfavorable environments.

Puccinia striiformis in Australia: a review of the incursion, evolution, and adaptation of stripe rust in the period 1979 - 2006

2007 ◽  
Vol 58 (6) ◽  
pp. 567 ◽  
Author(s):  
C. R. Wellings
Keyword(s):  
Stripe Rust ◽  
Chemical Control ◽  
Puccinia Striiformis ◽  
Cool Temperature ◽  
Pathogen Population ◽  
European Origin ◽  
Yield And Quality ◽  
Eastern Australia ◽  
Major Shift ◽  
Pathogen Populations

The wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici; Pst) was first detected in Australia in 1979. The features of the initial pathotype suggested that it was of European origin, and later work provided evidence that it was most likely transmitted as adherent spores on travellers’ clothing. Despite long-held views that this cool temperature pathogen would not adapt to Australian conditions, Pst became endemic and progressively adapted to commercial wheat production through step-wise mutation. Several of these mutant pathotypes became frequent in the Pst population, causing widespread infection and significant costs to production (yield and quality losses; chemical control expenditure) in certain cultivars and seasons. Pathotype evolution, including adaptation to native barley grass (Hordeum spp.) populations, is described. The occurrence of an exotic pathotype of Pst in Western Australia in 2002, and its subsequent spread to eastern Australia, represented a major shift in the pathogen population. This pathotype dominated pathogen populations throughout Australia from 2003, with chemical control expenditure estimated at AU$40–90 million annually. Another exotic introduction was detected in 1998. Initial data indicated that certain isolates collected from barley grass were highly avirulent to wheat differentials, with the exception of partial virulence to Chinese 166. Further seedling tests revealed that these isolates, tentatively designated barley grass stripe rust (BGYR), were virulent on several Australian barleys, notably those of Skiff parentage. Data, including molecular studies, suggest that BGYR is a new forma specialis of P. striiformis. Field nurseries indicate that BGYR is likely to have little impact on commercial barley, although this may change with further pathotype evolution or the release of susceptible cultivars.

scholarly journals Small RNAs from the wheat stripe rust fungus (Puccinia striiformis f.sp. tritici)

BMC Genomics ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Nicholas A. Mueth ◽  
Sowmya R. Ramachandran ◽  
Scot H. Hulbert
Keyword(s):  
Stripe Rust ◽  
Small Rnas ◽  
Puccinia Striiformis ◽  
Rust Fungus ◽  
Wheat Stripe Rust ◽  
Stripe Rust Fungus

High-temperature adult-plant resistance to stripe rust in facultative winter wheat

2016 ◽  
Vol 67 (10) ◽  
pp. 1064 ◽  
Author(s):  
Beyhan Akin ◽  
Xian Ming Chen ◽  
Alex Morgunov ◽  
Nusret Zencirci ◽  
Anmin Wan ◽  
...  
Keyword(s):  
Molecular Markers ◽  
High Temperature ◽  
Winter Wheat ◽  
Stripe Rust ◽  
Field Experiments ◽  
Puccinia Striiformis ◽  
Yellow Rust ◽  
Stripe Rust Resistance ◽  
Adult Plant ◽  
Improvement Program

Stripe (yellow) rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss., is one of the most damaging diseases in wheat and is especially damaging for winter and facultative wheat. The objective of this study was to understand stripe rust resistance in 100 wheat and facultative wheat entries from the International Winter Wheat Improvement Program by conducting experiments in a greenhouse and in four field environments in Washington State, USA, and by genotyping molecular markers linked to Yr genes. Percentages of entries resistant to the rust races at the seedling stage were: PST-17, 44%; PST-37, 32%; PST-43, 45%; PST-45, 49%; PST-116, 18%; PST-100, 17%; and PST-127, 8%. Molecular markers were positive for genes Yr9, Yr17, and Yr18 and negative for Yr5, Yr10, and Yr15. Yr18 was present in 44 entries (44%). By using the highly virulent races PST-127 and PST-100 under controlled conditions, 16 entries were shown to have high-temperature adult-plant (HTAP) resistance and resistant–moderately resistant field reactions at all four field sites. Resistant entries, especially those with HTAP resistance, were also identified in the field experiments.

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