Sexual recombination within the “Kranich” race of the yellow rust fungus Puccinia striiformis f.sp. tritici on Berberis vulgaris

Puccinia striiformis f.sp. tritici (Pst), which causes yellow (or stripe) rust on wheat, is a macrocyclic and heteroecious fungus. In this study, we investigated whether Berberis vulgaris subsp. seroi and B. vulgaris subsp. australis, which are indigenous in Spain, may serve as alternate hosts for Pst. Wheat leaves bearing telia of an isolate of Pst were harvested and used to inoculate plants of both barberry subspecies. Pycnia were observed on the adaxial side of the leaves from 10 days after inoculation (dai). Following successful fertilisation, aecia were observed on the abaxial side of the leaves from 16 dai. At 27 dai, barberry leaves bearing aecia were detached and used to inoculate susceptible wheat seedlings of cultivar ‘Morocco’. Uredinia were observed on wheat seedlings from 12 days after aeciospore exposure. Eighty-three single lesions were recovered from individual wheat leaves, of which 43 were genotyped using 19 Pst simple sequence repeat markers (SSR). In total, 19 multilocus genotypes (MLGs) were identified among the 43 progeny isolates. The SSR genotyping confirmed that all 43 isolates were derived from the parental isolate. Seven heterozygous SSR markers showed segregation among the progenies, whereas none of the 12 homozygous markers resulted in segregation. These results demonstrated that B. vulgaris subspp. seroi and australis can serve as alternate hosts for the yellow rust fungus, which may result in novel virulence combinations that can have a detrimental impact on wheat production. Although Pst has not been detected on these barberry species in nature, this study highlights the importance of rust surveillance in barberry areas where suitable conditions for completion of the sexual life cycle may be present.

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Sexual structures and recombination of the wheat rust fungus Puccinia striiformis on Berberis vulgaris

Fungal Genetics and Biology ◽

10.1016/j.fgb.2014.07.005 ◽

2014 ◽

Vol 70 ◽

pp. 77-85 ◽

Cited By ~ 45

Author(s):

Julian Rodriguez-Algaba ◽

Stephanie Walter ◽

Chris K. Sørensen ◽

Mogens S. Hovmøller ◽

Annemarie F. Justesen

Keyword(s):

Puccinia Striiformis ◽

Rust Fungus ◽

Berberis Vulgaris ◽

Wheat Rust

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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 ◽

10.1094/pdis-93-11-1093 ◽

2009 ◽

Vol 93 (11) ◽

pp. 1093-1101 ◽

Cited By ~ 133

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.

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Mutations in Wheat Exhibiting Growth-Stage-Specific Resistance to Biotrophic Fungal Pathogens

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2004.17.11.1242 ◽

2004 ◽

Vol 17 (11) ◽

pp. 1242-1249 ◽

Cited By ~ 6

Author(s):

Phil H. Smith ◽

John A. Howie ◽

Anthony J. Worland ◽

Rebecca Stratford ◽

Lesley A. Boyd

Keyword(s):

Fungal Pathogens ◽

Growth Stage ◽

Puccinia Striiformis ◽

Specific Resistance ◽

Yellow Rust ◽

Dominant Mutation ◽

Resistance Phenotype ◽

The Third ◽

Enhanced Resistance ◽

Seedling Leaf

Two mutants were isolated in wheat that showed enhanced resistance towards Puccinia striiformis f. sp. tritici, the fungal causal agent of yellow rust. The altered phenotype of I3-48 is due to a minimum of two mutation events, each showing a partial, additive effect, with one mutation segregating with a deletion on the long arm of chromosome 4D. In the case of I3-54, the enhanced resistance is due to a single, dominant mutation. In both mutants, the expression of the enhanced resistance is growth-stage specific. With I3-54, the full resistance phenotype is apparent from the third seedling leaf onwards, while with I3-48, a full resistance phenotype is only seen on the tenth and subsequent leaves. In addition to the enhanced resistance towards yellow rust, I3-48 also shows enhanced resistance towards brown rust, and I3-54 shows enhanced resistance to powdery mildew.

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Evolution of Physiologic Races and Virulence of Puccinia striiformis on Wheat in Syria and Lebanon

Plant Disease ◽

10.1094/pdis.2002.86.5.499 ◽

2002 ◽

Vol 86 (5) ◽

pp. 499-504 ◽

Cited By ~ 17

Author(s):

A. H. Yahyaoui ◽

M. S. Hakim ◽

M. El Naimi ◽

N. Rbeiz

Keyword(s):

Resistance Genes ◽

Puccinia Striiformis ◽

Yellow Rust ◽

Wheat Breeding ◽

Natural Conditions ◽

Breeding Programs ◽

Land Race ◽

Physiologic Races ◽

Resistant Genotypes

Virulence-avirulence phenotypes of Puccinia striiformis isolates collected in Lebanon and Syria were determined on seedlings of the wheat-yellow rust differential genotypes. We found 25 and 11 physiologic races over 6 years (1994 to 1999) in Syria and Lebanon, respectively. The composition of physiologic races found in Syria and Lebanon differed greatly between 1994 and 1999. Races identified in 1999, such as 230E150 and 230E134, have wider spectra of virulence on resistant genotypes than races collected in 1994. In Lebanon, three races were found in 1994 compared with six races in 1999. Yellow rust differential genotypes were used in a trap nursery to monitor yellow rust populations under natural conditions. Races identified from cultivars in the trap nursery in Syria and Lebanon, and from land race cultivars in Iraq, were recovered among the races identified from farm fields. Yellow rust samples were collected from Yemen, and none of the races identified from Yemen samples were identical to those in Syria and Lebanon. Virulence frequencies in the yellow rust population on the differential genotypes tested in the trap nurseries were above 70% for some resistance genes. Yellow rust populations in Syria and Lebanon have diverse virulence phenotypes. P. striiformis populations appear to be changing over, and this would be an important consideration for wheat breeding programs in the region.

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

Plant Disease ◽

10.1094/pdis-11-20-2341-re ◽

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

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