Virulence Variability of <i>Puccinia coronata</i> f. sp. <i>avenae</i> Isolates Collected in Three Counties from Rio Grande do Sul State, Brazil

Vieira, Eduardo Alano; Carvalho, Fernando Irajâ Félix de; Chaves, Márcia Soares; Oliveira, Antônio Costa de; Benin, Giovani; Hartwig, Irineu; Silva, J A G; Bertan, Ivandro; Martins, Anelise Afonso; Martins, Luís Fernando

doi:10.1094/pd-91-0066

Cited by 13 publications

(9 citation statements)

References 22 publications

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“…However, the frequency of virulence on the gene has been consistently low, particularly in parts of the world such as South America (Leonard and Martinelli 2005;Vieira et al 2007). Therefore, Pc68 shows potential to be introgressed into the germplasm of A. sativa with good agronomic characteristics, especially if this is done in association with other strategies to improve the durability of resistance, such as gene pyramiding, which has been advocated for use in other pathosystems (Rubiales and Niks 2000).…”

Section: Introductionmentioning

confidence: 99%

Molecular mapping of Pc68, a crown rust resistance gene in Avena sativa

et al. 2010

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Crown rust, which is caused by Puccinia coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats (Avena sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F 6 genetic map from Pc68/5*Starter 9 UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in 12 linkage groups. The map covered 409.4 cM of the Avena sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located in the linkage group 4_12 in the Kanota 9 Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes.

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Section: Introductionmentioning

confidence: 99%

Molecular mapping of Pc68, a crown rust resistance gene in Avena sativa

et al. 2010

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“…In southern Brazil, due to the highly complex and diverse pathogen populations (Vieira et al. ), severe epidemics occur every year. Furthermore, when environmental conditions are favourable to the development of the pathogen, the reduction in grain yield may exceed 50% for susceptible cultivars (Martinelli et al.…”

Section: Introductionmentioning

confidence: 99%

Reactive Oxygen Species are not Increased in Resistant Oat Genotypes Challenged by Crown Rust Isolates

Figueiró

Reese

Gonzalez-Hernandez

et al. 2015

Journal of Phytopathology

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Crown rust (Puccinia coronata Corda f.sp. avenae) can devastate oats (Avena sativa). Oxidative stress is part of the resistance mechanism in several pathosystems, but in the oat–crown rust system, it is unclear, especially regarding partial resistance. We evaluated the effects of P. coronata on oxidative stress in oat cultivars: URS 21 (partially resistant), Leggett (race‐specific resistant), URS22 and Clintland 64 (susceptibles). Seedlings and plants were inoculated with P. coronata uredospores. Cultivars were assessed for antioxidant enzyme activity and the reactive oxygen species (ROS) hydrogen peroxide and superoxide. Due to the importance of the partial resistance of URS21, this cultivar and URS 22 were also appraised for total phenolics and the relative expression of oxidative stress genes. Postinoculation, Leggett and URS 21 showed no increased peroxide levels. The susceptible cultivars increased ROS and ascorbate peroxidase activity. Clintland 64 increased also catalase activity, whereas URS 22 increased glutathione reductase and the expression of genes encoding antioxidant enzymes. URS 21 showed almost no antioxidant enzyme induction. Shortly after inoculation, URS 21 showed increased expression of genes encoding lipoxygenase and peroxidase. Cultivars URS 21 and Leggett accumulated cell wall fluorescent compounds, phenolics being detected in the former. Oxidative stress appears not to cause the hypersensitive response in this pathosystem, but late ROS accumulation did occur in the susceptible cultivars. Cultivar URS 21 may, differently from other known mechanism to date, reduce ROS accumulation by increasing the level of phenolics, resulting in later pathogen and cell death, showing non‐specific resistance to races of the pathogen also at seedling stage.

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“…Mesmo não havendo relatos da ocorrência da fase sexual de P. coronata no ambiente do Sul Brasil, a qual seria responsável pelo aumento na variabilidade genética do patógeno, a estrutura da população do patógeno é extremamente diversificada e fundamentalmente constituída por super-raças, as quais possuem de oito a 27 genes de virulência (MARTINELLI et al 1998, VIEIRA et al, 2007. Nesse ambiente, a maioria dos genes Pc de resistência conhecidos tem baixa efetividade, e o espectro de virulência das raças encontradas é tão complexo quanto o observado em outros países, incluindo Israel, considerado o centro de origem do patógeno (LEONARD & MARTINELLI, 2005).…”

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