Detection of race-specific resistance against Puccinia coronata f. sp. avenae in Brachypodium species

AbstractOat crown rust caused by Puccinia coronata f. sp. avenae is the most destructive foliar disease of cultivated oat. Characterization of genetic factors controlling resistance responses to Puccinia coronata f. sp. avenae in non-host species could provide new resources for developing disease protection strategies in oat. We examined symptom development and fungal colonization levels of a collection of Brachypodium distachyon and B. hybridum accessions infected with three North American P. coronata f. sp. avenae isolates. Our results demonstrated that colonization phenotypes are dependent on both host and pathogen genotypes, indicating a role for race-specific responses in these interactions. These responses were independent of the accumulation of reactive oxygen species. Expression analysis of several defense-related genes suggested that salicylic acid and ethylene-mediated signaling, but not jasmonic acid are components of resistance reaction to P. coronata f. sp. avenae. Our findings provide the basis to conduct a genetic inheritance study to examine if effector-triggered immunity contributes to non-host resistance to P. coronata f. sp. avenae in Brachypodium species.

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Detection of Race-Specific Resistance Against Puccinia coronata f. sp. avenae in Brachypodium Species

Phytopathology ◽

10.1094/phyto-03-18-0084-r ◽

2018 ◽

Vol 108 (12) ◽

pp. 1443-1454 ◽

Cited By ~ 1

Author(s):

Vahid Omidvar ◽

Sheshanka Dugyala ◽

Feng Li ◽

Susan M. Rottschaefer ◽

Marisa E. Miller ◽

...

Keyword(s):

Genetic Factors ◽

Specific Resistance ◽

Brachypodium Distachyon ◽

Puccinia Coronata ◽

Fungal Colonization ◽

Oat Crown Rust ◽

Protection Strategies ◽

Effector Triggered Immunity ◽

Resistance Reaction

Oat crown rust caused by Puccinia coronata f. sp. avenae is the most destructive foliar disease of cultivated oat. Characterization of genetic factors controlling resistance responses to Puccinia coronata f. sp. avenae in nonhost species could provide new resources for developing disease protection strategies in oat. We examined symptom development and fungal colonization levels of a collection of Brachypodium distachyon and B. hybridum accessions infected with three North American P. coronata f. sp. avenae isolates. Our results demonstrated that colonization phenotypes are dependent on both host and pathogen genotypes, indicating a role for race-specific responses in these interactions. These responses were independent of the accumulation of reactive oxygen species. Expression analysis of several defense-related genes suggested that salicylic acid and ethylene-mediated signaling but not jasmonic acid are components of resistance reaction to P. coronata f. sp. avenae. Our findings provide the basis to conduct a genetic inheritance study to examine whether effector-triggered immunity contributes to nonhost resistance to P. coronata f. sp. avenae in Brachypodium spp.

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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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Virulence of Oat Crown Rust in Mexico

Plant Disease ◽

10.1094/pd-89-0941 ◽

2005 ◽

Vol 89 (9) ◽

pp. 941-948 ◽

Cited By ~ 11

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.

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Rds and Rih Mediate Hypersensitive Cell Death Independent of Gene-for-Gene Resistance to the Oat Crown Rust Pathogen Puccinia coronata f. sp. avenae

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.12.1376 ◽

2001 ◽

Vol 14 (12) ◽

pp. 1376-1383 ◽

Cited By ~ 14

Author(s):

Gong-Xin Yu ◽

Ed Braun ◽

Roger P. Wise

Keyword(s):

Cell Death ◽

Plant Disease Resistance ◽

Recombination Breakpoint ◽

Crown Rust ◽

Host Cells ◽

Puccinia Coronata ◽

Hypersensitive Cell Death ◽

Oat Crown Rust ◽

Gene For Gene

The Pca crown rust resistance cluster in the diploid Avena genus confers gene-for-gene specificity to numerous isolates of Puccinia coronata f. sp. avenae. Recombination breakpoint analysis indicates that specificities conferred by the Pca cluster are controlled by at least five distinct genes, designated Pc81, Pc82, Pc83, Pc84, and Pc85. Avena plants with the appropriate genotype frequently respond to P. coronata by undergoing hypersensitive cell death at the sites of fungal infection. Autofluorescence of host cells in response to P. coronata occurs in plants that develop visible necrotic lesions but not in plants that lack this phenotype. Two newly described, non-Pc loci were shown to control hypersensitive cell death. Rds (resistance-dependent suppressor of cell death) suppresses the hypersensitive response (HR), but not the resistance, mediated by the Pc82 resistance gene. In contrast, Rih (resistance-independent hypersensitive cell death) confers HR in both resistant and susceptible plants. Linkage analysis indicates that Rds is unlinked to the Pca cluster, whereas Rih is tightly linked to it. These results indicate that multiple synchronous pathways affect the development of hypersensitive cell death and that HR is not essential for resistance to crown rust. Further characterization of these genes will clarify the relationship between plant disease resistance and localized hypersensitive cell death.

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