Gene Action and Linkage of Avirulence Genes to DNA Markers in the Rust Fungus <i>Puccinia graminis</i>

Zambino, Paul J.; Kubelik, Anne R.; Szabo, Les J.

doi:10.1094/phyto.2000.90.8.819

Cited by 59 publications

(53 citation statements)

References 46 publications

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“…The genetic basis for pathogen resistance is not completely understood. Resistance to both rust fungi seems to be under both major gene and polygene control (Rose-Fricker et al 1986, Roelfs 1988, Kimbeng 1999, Zambino et al 2000. However, pathogens may also adapt to host genotypes rapidly, and previously resistant hosts can become highly susceptible (Wilkins 1978).…”

Section: Proportion Of Infested Individualsmentioning

confidence: 99%

Resistance to rust fungi in Lolium perenne depends on within-species variation and performance of the host species in grasslands of different plant diversity

et al. 2007

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The hypothesis that plant species diversity and genetic variation of the host species decrease the severity of plant diseases is supported by studies of agricultural systems, but experimental evidence from more complex systems is scarce. In an experiment with grassland communities of varying species richness (1, 2, 4, 8, 16, and 60 species) and functional group richness (1, 2, 3, and 4 functional groups), we used different cultivars of Lolium perenne (perennial ryegrass) to study effects of biodiversity and cultivar identity on the occurrence and severity of foliar fungal diseases caused by Puccinia coronata (crown rust) and P. graminis (stem rust). Cultivar monocultures of perennial ryegrass revealed strong differences in pathogen susceptibility among these cultivars. Disease intensity caused by both rust fungi decreased significantly with growing species richness of species mixtures. The response to the diversity gradient was related to the decreased density and size of the host individuals with increasing species richness. The occurrence of other grass species known to be possible hosts of the pathogens in the experimental mixtures did not promote disease intensity in L. perenne, indicating that there was a high host specificity of pathogen strains. Differences in pathogen susceptibility among perennial ryegrass cultivars persisted independent of diversity treatment, host density and host individual size, but resulted in a cultivar-specific pattern of changes in pathogen infestation across the species-richness gradient. Our study provided evidence that within-species variation in pathogen susceptibility and competitive interactions of the host species with the environment, as caused by species diversity treatments, are key determinants of the occurrence and severity of fungal diseases.

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Section: Proportion Of Infested Individualsmentioning

confidence: 99%

Resistance to rust fungi in Lolium perenne depends on within-species variation and performance of the host species in grasslands of different plant diversity

et al. 2007

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“…Genetic analysis is not trivial since the cereal rust fungi complete their sexual cycles on alternate hosts, but the life cycle can be completed for several of the Puccinia species and has been used to genetically map avirulence genes in P. graminis (Zambino et al 2000). A breakthrough in understanding the sexual cycle of P. striiformis was recently made when an alternate host was identified (Jin et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Prospects for functional analysis of effectors from cereal rust fungi

Yin

Hulbert

2010

Euphytica

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With the advancement of several Puccinia genome sequencing projects, along with gene expression data and methods for predicting secreted proteins, it is now possible to predict many effector proteins from the cereal rusts. Biological assays that can be conducted in a relatively high throughput fashion are necessary to assign specific functions, such as avirulence. Biolistic delivery of potential effectors is limited by the need to examine individual cells and delivery by Agrobacterium generally also affects small numbers of cells in grasses. An approach that has had some success in dicots is the use of bacterial systems to deliver proteins by their type III secretion systems (TTSS). Several bacterial systems were thus tested for their suitability in delivering effectors to wheat. Pseudomonas syringae DC3000 caused hypersensitive reactions (HR) when infiltrated into all tested wheat lines but only some barley lines. A variant strain with multiple effectors deleted showed a reduced HR on wheat lines. Pseudomonas fluorescens with an engineered TTSS system showed no HR in wheat lines but was able to deliver bacterial effectors AvrRpm1 and AvrRpt2 and the fungal toxin ToxA. Delivery of the effectors by P. fluorescens could be detected by HR or by staining for presence of hydrogen peroxide or callose deposits. The bacterial systems thus showed good potential for their ability to deliver foreign proteins into wheat cells.

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“…NBS-LRR proteins also confer resistance to rusts in maize (Zea mays) (Collins et al, 1999), and similar proteins in Arabidopsis, Lactuca sativa (lettuce), and Hordeum vulgare (barley) confer resistance to downy mildew and powdery mildew pathogens (Noel et al, 1999;Halterman et al, 2001;Zhou et al, 2001;Shen et al, 2002), which are also haustoria-producing obligate biotrophs. Although Avr genes have been described at a genetic level in rusts and mildews (Flor, 1971;Lawrence et al, 1981;Zambino et al, 2000;Pedersen et al, 2002;Rehmany et al, 2003), no Avr products have been identified in these pathogens, so the conundrum of how intracellular R proteins recognize these extracellular pathogens remains unresolved.…”

Section: Introductionmentioning

confidence: 99%

The Melampsora lini AvrL567 Avirulence Genes Are Expressed in Haustoria and Their Products Are Recognized inside Plant Cells

et al. 2004

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The Linum usitatissimum (flax) L gene alleles, which encode nucleotide binding site-Leu rich repeat class intracellular receptor proteins, confer resistance against the Melampsora lini (flax rust) fungus. At least 11 different L resistance specificities are known, and the corresponding avirulence genes in M. lini map to eight independent loci, some of which are complex and encode multiple specificities. We identified an M. lini cDNA marker that cosegregates in an F2 rust family with a complex locus determining avirulence on the L5, L6, and L7 resistance genes. Two related avirulence gene candidates, designated AvrL567-A and AvrL567-B, were identified in a genomic DNA contig from the avirulence allele, whereas the corresponding virulence allele contained a single copy of a related gene, AvrL567-C. Agrobacterium tumefaciens-mediated transient expression of the mature AvrL567-A or AvrL567-B (but not AvrL567-C) proteins as intracellular products in L. usitatissimum and Nicotiana tabacum (tobacco) induced a hypersensitive response-like necrosis that was dependent on coexpression of the L5, L6, or L7 resistance gene. An F1 seedling lethal or stunted growth phenotype also was observed when transgenic L. usitatissimum plants expressing AvrL567-A or AvrL567-B (but not AvrL567-C) were crossed to resistant lines containing L5, L6, or L7. The AvrL567 genes are expressed in rust haustoria and encode 127 amino acid secreted proteins. Intracellular recognition of these rust avirulence proteins implies that they are delivered into host cells across the plant membrane. Differences in the three AvrL567 protein sequences result from diversifying selection, which is consistent with a coevolutionary arms race.

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Gene Action and Linkage of Avirulence Genes to DNA Markers in the Rust Fungus Puccinia graminis

Cited by 59 publications

References 46 publications

Resistance to rust fungi in Lolium perenne depends on within-species variation and performance of the host species in grasslands of different plant diversity

Resistance to rust fungi in Lolium perenne depends on within-species variation and performance of the host species in grasslands of different plant diversity

Prospects for functional analysis of effectors from cereal rust fungi

The Melampsora lini AvrL567 Avirulence Genes Are Expressed in Haustoria and Their Products Are Recognized inside Plant Cells

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