Genetic Diversity in Australasian Populations of the Crown Rust Pathogen of Ryegrasses (Puccinia coronata f.sp. lolii)

The causative organism of crown rust in ryegrasses (Puccinia coronata f.sp. lolii) is an obligate biotroph that causes significant economic losses within the temperate grazing industries of dairy, meat, and wool production. This study reports on the development, transferability, and utility of gene-associated simple sequence repeat (SSR) molecular markers for crown rust. Analysis of 1100 expressed sequence tag (EST) sequences from a urediniospore-derived cDNA library detected 55 SSR loci. The majority of EST-SSR arrays contained perfect trinucleotide repeats with consistently low repeat numbers, and the motifs (ACC)n and (CAT)n were most commonly represented. DNA extraction from single pustules, in conjunction with multiple displacement amplification, provided the basis for PCR-based screening to evaluate genetic marker performance. An example of the identification of intraspecific genetic diversity was obtained from the analysis of 16 P. coronata isolates originating from the United Kingdom, Australia, New Zealand, and Japan. A subset of 12 robust EST-SSR markers was informative for determination of pathogen diversity within and between these localities. It was also demonstrated that crown rust EST-SSR markers were capable of cross-amplification in closely related fungal taxa (Puccinia spp.) and filamentous fungi within the Ascomycota.Key words: Puccinia coronata, simple sequence repeat, expressed sequence tags, urediniospore, genetic diversity, pathogen.

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Hidden Diversity of Crown Rust Resistance within Genebank Resources of Avena sterilis L.

Agronomy ◽

10.3390/agronomy11020315 ◽

2021 ◽

Vol 11 (2) ◽

pp. 315

Author(s):

Edyta Paczos-Grzęda ◽

Maja Boczkowska ◽

Sylwia Sowa ◽

Aneta Koroluk ◽

Joanna Toporowska

Keyword(s):

Rust Resistance ◽

Crown Rust ◽

Puccinia Coronata ◽

Sources Of Resistance ◽

Avena Sterilis ◽

Seedling Resistance ◽

Susceptibility Data ◽

Infection Pattern ◽

Crown Rust Resistance ◽

Rust Pathogen

The most widespread and damaging fungal disease of the oat plant is crown rust. Resistance to the crown rust pathogen, Puccinia coronata Cda. f. sp. avenae (Pca), at the seedling stage of Avena sterilis accessions from the Polish national genebank was characterised by five North American and Polish pathotypes of Pca of diverse pathogenicity. Pca pathogenicity was determined on a series of 34 differential lines carrying known seedling resistance genes. Seventy-five percent of studied accessions showed a heterogeneous infection pattern, 17% behaved as homogenous susceptibles, and 7% of tested genotypes could be unambiguously described as resistant. This study proved that A. sterilis accessions preserved in a genebank as complex populations could be a very valuable source of resistance to crown rust. The complexity of analysed populations was ascertained by a detailed variance analysis of transformed resistance/susceptibility data. We demonstrate here that hidden sources of resistance may be discovered in accessions with general susceptibility.

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Virulence of Oat Crown Rust in Brazil and Uruguay

Plant Disease ◽

10.1094/pd-89-0802 ◽

2005 ◽

Vol 89 (8) ◽

pp. 802-808 ◽

Cited By ~ 22

Author(s):

K. J. Leonard ◽

J. A. Martinelli

Keyword(s):

Avena Sativa ◽

Western Siberia ◽

Specific Resistance ◽

The United States ◽

Crown Rust ◽

Puccinia Coronata ◽

South American ◽

Oat Crown Rust ◽

High Virulence ◽

Important Disease

Race-specific resistance to crown rust, the most important disease of oat (Avena sativa) in Bra-zil, often fails within a few years of use in Brazilian cultivars. Virulence of 144 isolates of Puccinia coronata from cultivated oat in Brazil in 1997 to 1999 and 36 isolates from Uruguay in 1994-95 and 1998 was tested on a set of 27 oat crown rust differentials lines, each with a different Pc gene for race-specific resistance. Frequencies of virulence and mean virulence complexity were compared among these five collections from Brazil and Uruguay as well as with mean virulence complexity for a collection of 17 isolates from cultivated oat in western Siberia in Russia. Virulence-avirulence for each of the 27 Pc genes was polymorphic in both Brazil and Uruguay. Virulence frequencies were similar for collections from Brazil in 1998 and 1999 and for the collection from Uruguay from 1998, but there were large differences between the 1997 collection and the 1998 and 1999 collections from Brazil. Mean virulence complexity in both Brazil and Uruguay was greater than reported in the United States and much greater than in the Russian collection of P. coronata. A large number of races of P. coronata were found, with no more than five isolates of any race found in a single year in Brazil or Uruguay. The high virulence complexity and great diversity of virulence polymorphisms in Brazil and Uruguay make it unlikely that race-specific resistance can be effective there even though the South American populations of P. coronata are apparently entirely asexual.

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Incidence and Distribution of Puccinia coronata and P. graminis on Turfgrass in the Midwestern United States

Plant Disease ◽

10.1094/pdis-09-17-1353-re ◽

2018 ◽

Vol 102 (5) ◽

pp. 955-963

Author(s):

Brijesh B. Karakkat ◽

Vonte L. Jackson ◽

Paul L. Koch

Keyword(s):

United States ◽

Stem Rust ◽

Kentucky Bluegrass ◽

The United States ◽

Primary Objective ◽

Crown Rust ◽

Puccinia Coronata ◽

Midwestern United States ◽

Fungal Populations ◽

Relationship Of

Crown rust (caused by Puccinia coronata) and stem rust (caused by P. graminis) are two common and destructive diseases of turfgrass in the United States. Crown rust has been associated with perennial ryegrass and stem rust with Kentucky bluegrass when identified based solely on fungal morphology. However, recent studies using molecular identification methods have indicated the host–pathogen relationship of rusts on turf to be more complex. Our primary objective was to quickly and accurately identify P. coronata and P. graminis in symptomatic turfgrass leaves over 3 years on turfgrass samples from across the Midwestern United States. Between 2013 and 2015, 413 samples of symptomatic cool-season turfgrass from Wisconsin and surrounding states were screened using real-time polymerase chain reaction. Of these samples, 396 were Kentucky bluegrass and 17% of them contained P. coronata, 69% contained P. graminis, and 13% contained both P. coronata and P. graminis. In addition, both year and location effects were observed on the distribution of Puccinia spp. collected annually from two locations in southern Wisconsin. This research supports previous conclusions that have identified variability among P. graminis and P. coronata host relationships on turfgrass, and further demonstrates that rust fungal populations on Kentucky bluegrass may not be consistent between locations in the same year or over multiple years at the same location. The increasing evidence of variation in the turfgrass rust populations will likely affect future rust management and turfgrass breeding efforts.

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Genetic diversity of the myrtle rust pathogen (Austropuccinia psidii ) in the Americas and Hawaii: Global implications for invasive threat assessments

Forest Pathology ◽

10.1111/efp.12378 ◽

2017 ◽

Vol 48 (1) ◽

pp. e12378 ◽

Cited By ~ 16

Author(s):

J. E. Stewart ◽

A. L. Ross-Davis ◽

R. N. Graҫa ◽

A. C. Alfenas ◽

T. L. Peever ◽

...

Keyword(s):

Genetic Diversity ◽

Myrtle Rust ◽

Rust Pathogen ◽

Austropuccinia Psidii ◽

Threat Assessments

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CROWN RUST ON PERENNIAL RYEGRASS IN FIELD TRIALS

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1989.50.1867 ◽

1989 ◽

pp. 253-254

Author(s):

H.S. Easton ◽

B.M. Cooper ◽

T.J. Frasers ◽

K.H. Widdup

Keyword(s):

Perennial Ryegrass ◽

Field Trials ◽

Crown Rust ◽

Puccinia Coronata ◽

Rust Infection

Crown rust infection of 11 perennial ryegrass cultivars vaned significantly and consistently over 6 sites. 'Grasslands Ariki,' the new cultivar 'Yatsyn' and Grasslands selections G26 and G33 were less infected than 'Grasslands Nui', 'Ellett' or 'Grasslands Ruanui'. 'Droughtmaster' and 'Marathon' proved more susceptible than most. Keywords: Crown rust, Puccinia coronata. perenmal ryegrass

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Variation and Distribution of the Oat Crown Rust-Fungus, Puccinia Coronata Avenae,in Britain in Relation to Breeding Resistant Oat Cultivars

Proceedings of the Second International Oats Conference ◽

10.1007/978-94-009-4408-4_17 ◽

1986 ◽

pp. 81-82

Author(s):

B. C. Clifford

Keyword(s):

Rust Fungus ◽

Crown Rust ◽

Puccinia Coronata ◽

Oat Crown Rust ◽

Puccinia Coronata Avenae ◽

Oat Cultivars

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Assessment of virulence patterns in crown rust populations

Canadian Journal of Botany ◽

10.1139/b68-089 ◽

1968 ◽

Vol 46 (5) ◽

pp. 613-617 ◽

Cited By ~ 2

Author(s):

George Fleischmann

Keyword(s):

Crown Rust ◽

Puccinia Coronata ◽

Western Canada ◽

Differential Host ◽

Oat Crown Rust ◽

Virulence Pattern ◽

Continued Use ◽

Race Identification

Two methods of determining the virulence pattern of oat crown rust, Puccinia coronata f. sp. avenae, populations collected in 1965, 1966, and 1967, in Eastern and Western Canada were compared. The results with a single-pustule isolate from each of 50 field collections were as accurate as those obtained with two single-pustule isolates from 100 or more field collections. The continued use of Bond and Ukraine as differential host varieties is of little value except for purposes of race identification, because they are attacked by most of the isolates.

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