scholarly journals Diversity of oat crown rust (Puccinia coronata f.sp. avenae) isolates detected by virulence and AFLP analyses

2010 ◽  
Vol 46 (No. 3) ◽  
pp. 98-106 ◽  
Author(s):  
H. Klenová-Jiráková ◽  
L. Leišová-Svobodová ◽  
A. Hanzalová ◽  
L. Kučera
Keyword(s):  
Virulence Genes ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Aflp Analysis ◽  
Avirulence Genes ◽  
Correlation Relationship ◽  
Oat Crown Rust ◽  
Molecular Pattern ◽  
Oat Cultivars ◽  
Relationship Of

Forty Puccinia coronata f.sp. avenae isolates from several European countries and Israel were tested for virulence to 18 differential oat lines. Amplified Fragment Length Polymorphism (AFLP) analysis was used to evaluate diversity among the studied isolates. Twenty-nine different pathotypes were identified. The prevailing occurrence of pathotypes with a limited number of virulence genes may indicate that oat cultivars grown in Europe possess the limited number of resistance genes. A total of 501 AFLP polymorphic fragments were scored in the studied isolates using twelve primer combinations. All isolates had the unique AFLP molecular pattern. The genetic similarity of isolates from Serbia. Austria and from the Czech Republic indicates that oat crown rust urediniospores may often migrate to particular areas. The number of virulence genes in isolates also seems to play an important role in the clustering. Most isolates possessing a lower number of virulence genes (0–4) were grouped into two clusters, whereas another cluster was composed of a majority of isolates with 4–7 virulence genes. A significant correlation relationship of 0.187 (P = 0.007) was found between AFLP and virulence/avirulence genes based on distance matrices.

scholarly journals Crown rust pathotypes determined on oats in the Czech Republic from 2004 to 2006 and reaction to oat cultivars

2008 ◽  
Vol 44 (No. 2) ◽  
pp. 60-65 ◽  
Author(s):  
H. Jiráková ◽  
A. Hanzalová
Keyword(s):  
Czech Republic ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Resistance Breeding ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
The Czech Republic ◽  
Oat Crown Rust ◽  
Oat Cultivars ◽  
High Diversity

The incidence of oat crown rust (Puccinia coronata var. avenae Fraser et Ledingham) pathotypes was recorded in the Czech Republic in 2004–2006. The virulence of collected 79 monopustule oat crown rust isolates was assessed on 23 differentials. High diversity was observed; the isolates possessed from 0 to 8 virulence genes. More than 80% of pathotypes were recorded only once. Pathotypes BLBG and BLBC were the most frequent. None of the tested isolates was virulent to resistance genes Pc39, Pc50, Pc52, Pc59, Pc62 and Pc68. Registered cultivars Avenuda, Dalimil, Auron, Isak were susceptible to the majority of pathotypes, cvs. Abel, Ardo, Atego, Azur, Neklan, Radius and Saul to all used pathotypes. Only the Czech cultivar Vok was resistant to all but four used pathotypes. Acquired data are useful for resistance breeding.

scholarly journals Virulence in Oat Crown Rust (Puccinia coronata f. sp. avenae) in the United States from 2006 through 2009

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1528-1534 ◽  
Author(s):  
M. L. Carson
Keyword(s):  
United States ◽  
Resistance Genes ◽  
The United States ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
The North ◽  
Oat Crown Rust ◽  
Primary Means ◽  
Oat Cultivars ◽  
The U.S

The use of race-specific seedling genes for resistance is the primary means of controlling crown rust of oat (Puccinia coronata f. sp. avenae) in the United States. To better utilize those resistance genes, knowledge of the occurrence and frequency of corresponding virulence in the population of P. coronata f. sp. avenae in the United States is essential. In total, 571 single-pustule isolates of oat crown rust were collected from cultivated and wild oat (Avena sativa and A. fatua, respectively) in the major oat production areas of the United States from 2006 through 2009. They were tested for virulence on seedlings of 31 differential oat lines in the greenhouse. In all, 201 races were found among the 357 isolates from the spring oat region of the north-central United States, and 140 races were found among 214 isolates from the southern winter oat region. The crown rust populations from the winter and spring oat regions were clearly differentiated from one another, differing in the frequency of virulence for 24 of the 31 differentials. Some virulence associations previously reported in the U.S. oat crown rust population were also found in both regions in this survey, even when the dataset was clone corrected. Associations between virulence to the Pc genes were predominately positive in both regions but both positive and negative associations occurred more frequently in the winter oat region, where sexual reproduction does not occur. Some of the virulence diversity in the oat crown rust population in the United States can be related to the deployment of resistance genes in commercial oat cultivars and virulence associations existing in the oat crown rust population. When data from a previous report covering 2001 through 2005 is combined with data reported in this article, the mean virulence of the U.S. populations of crown rust continued to increase from 2001 to 2009. Virulence to Pc38, Pc39, Pc45, Pc48, Pc52, Pc55, Pc56, Pc57, Pc59, Pc62, Pc63, Pc64, Pc68, and Pc96 significantly increased in one or both regions during this time period. No significant declines in virulence frequency were found in either region. Genes for crown rust resistance derived from A. sterilis appear to be as rapidly defeated as has happened to Pc genes from A. sativa. There is an urgent need to find additional sources of effective resistance to P. coronata f. sp. avenae and introgress it into adapted oat cultivars.

scholarly journals Virulence of Oat Crown Rust in Brazil and Uruguay

Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 802-808 ◽  
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.

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

Plant Disease ◽  
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.

Assessment of virulence patterns in crown rust populations

1968 ◽  
Vol 46 (5) ◽  
pp. 613-617 ◽  
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.

scholarly journals Virulence of Oat Crown Rust in Mexico

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 941-948 ◽  
Author(s):  
K. J. Leonard ◽  
J. Huerta-Espino ◽  
J. J. Salmeron
Keyword(s):  
Avena Sativa ◽  
Virulence Genes ◽  
Specific Resistance ◽  
The United States ◽  
Puccinia Coronata ◽  
Central Mexico ◽  
Nuevo Leon ◽  
Oat Crown Rust ◽  
Nuevo León ◽  
Pathogenic Races

Virulence of isolates of Puccinia coronata collected during 1992 to 1998 from Sonora, Chihua-hua, Nuevo Leon, and five states in Central Mexico were compared on a set of 27 differential oat (Avena sativa) lines with different genes for race-specific resistance. Frequencies of virulence and the presence of specific pathogenic races were compared among the four regions of Mexico and between Mexico and the adjoining states of California and Texas in the United States. The P. coronata populations in Mexico were highly diverse even though the sexual stage of the fungus is not known to occur there. Overall virulence frequencies were most similar between Chihuahua and Nuevo Leon, but there were more races in common between Central Mexico and Chihuahua than between any other pair of regions of Mexico. No races found in Sonora were found in other regions of Mexico. More races found in Texas also occurred in Nuevo Leon than in any other region of Mexico. Mean virulence complexity was lowest in isolates from central Mexico; greatest in Sonora, California, and Texas; and intermediate in Chihuahua and Nuevo Leon. Significant (P < 0.05) associations of virulences occurred for 24 pairs of virulence genes in at least three of the four regions of Mexico. Virulences to 19 of the 24 pairs were also significantly associated in Texas; virulences to 13 were also significantly associated in California.

scholarly journals De Novo Assembly and Phasing of Dikaryotic Genomes from Two Isolates of Puccinia coronata f. sp. avenae, the Causal Agent of Oat Crown Rust

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Marisa E. Miller ◽  
Ying Zhang ◽  
Vahid Omidvar ◽  
Jana Sperschneider ◽  
Benjamin Schwessinger ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
De Novo ◽  
Rust Fungus ◽  
Expression Patterns ◽  
Haplotype Diversity ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Small Subset ◽  
Nucleotide Polymorphisms ◽  
Oat Crown Rust

ABSTRACT Oat crown rust, caused by the fungus Pucinnia coronata f. sp. avenae, is a devastating disease that impacts worldwide oat production. For much of its life cycle, P. coronata f. sp. avenae is dikaryotic, with two separate haploid nuclei that may vary in virulence genotype, highlighting the importance of understanding haplotype diversity in this species. We generated highly contiguous de novo genome assemblies of two P. coronata f. sp. avenae isolates, 12SD80 and 12NC29, from long-read sequences. In total, we assembled 603 primary contigs for 12SD80, for a total assembly length of 99.16 Mbp, and 777 primary contigs for 12NC29, for a total length of 105.25 Mbp; approximately 52% of each genome was assembled into alternate haplotypes. This revealed structural variation between haplotypes in each isolate equivalent to more than 2% of the genome size, in addition to about 260,000 and 380,000 heterozygous single-nucleotide polymorphisms in 12SD80 and 12NC29, respectively. Transcript-based annotation identified 26,796 and 28,801 coding sequences for isolates 12SD80 and 12NC29, respectively, including about 7,000 allele pairs in haplotype-phased regions. Furthermore, expression profiling revealed clusters of coexpressed secreted effector candidates, and the majority of orthologous effectors between isolates showed conservation of expression patterns. However, a small subset of orthologs showed divergence in expression, which may contribute to differences in virulence between 12SD80 and 12NC29. This study provides the first haplotype-phased reference genome for a dikaryotic rust fungus as a foundation for future studies into virulence mechanisms in P. coronata f. sp. avenae. IMPORTANCE Disease management strategies for oat crown rust are challenged by the rapid evolution of Puccinia coronata f. sp. avenae, which renders resistance genes in oat varieties ineffective. Despite the economic importance of understanding P. coronata f. sp. avenae, resources to study the molecular mechanisms underpinning pathogenicity and the emergence of new virulence traits are lacking. Such limitations are partly due to the obligate biotrophic lifestyle of P. coronata f. sp. avenae as well as the dikaryotic nature of the genome, features that are also shared with other important rust pathogens. This study reports the first release of a haplotype-phased genome assembly for a dikaryotic fungal species and demonstrates the amenability of using emerging technologies to investigate genetic diversity in populations of P. coronata f. sp. avenae.

scholarly journals Virulence Frequencies in Oat Crown Rust in the United States from 2001 Through 2005

Plant Disease ◽  
2008 ◽  
Vol 92 (3) ◽  
pp. 379-384 ◽  
Author(s):  
M. L. Carson
Keyword(s):  
United States ◽  
The United States ◽  
Crown Rust ◽  
Upper Midwest ◽  
Oat Crown Rust ◽  
Oat Cultivars ◽  
The Mean ◽  
Production Areas ◽  
The U.S ◽  
Virulence Diversity

In all, 680 single-pustule isolates of the oat crown rust pathogen, Puccinia coronata f. sp. avenae, were collected from cultivated and wild oat (Avena sativa and A. fatua, respectively) in the major oat-production areas of the United States from 2001 through 2005. They were tested for virulence on seedlings of differential oat lines in the greenhouse. In all, 171 races were found among the 357 isolates from the winter oat region of the United States, whereas 212 races were found among 323 isolates from the spring oat region. The crown rust population derived from winter oat in the southern United States was distinct from the spring oat population in the upper Midwest, although there was no virulence unique to either population. Virulence to Pc48 and Pc52 increased significantly in both regions during 2001 to 2005. Virulence to Pc59 increased and virulence to Pc53 decreased in the winter oat region during the same period. Many of the virulence associations previously reported in the U.S. oat crown rust population in the early 1990s also were found in both regions in this survey. Associations between virulence to the Pc genes were predominately positive in both regions; however, both positive and negative associations occurred more frequently in the winter oat region. Much of the virulence diversity in the oat crown rust population in the United States can be related to the deployment of resistance genes in commercial oat cultivars and virulence associations existing in the oat crown rust population. The mean virulence of the U.S. populations of crown rust continued to increase from 2001 to 2005. Genes for crown rust resistance derived from A. sterilis appear to be rapidly defeated, as has happened to Pc genes from A. sativa.

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