RESISTANCE TO PUCCINIA GRAMINIS AVENAE AND P. CORONATA AVENAE IN THE WILD AND CULTIVATED AVENA POPULATIONS OF IRAN, IRAQ AND TURKEY

Tests of over 1400 Avena accessions, comprising eight species, from Iran, Iraq and Turkey have shown that resistance to oat stem rust caused by Puccinia graminis Pers. f. sp. avenae Eriks and E. Henn. occurs infrequently in the Avena populations of the region and was found only in A. barbata Pott ex Link and A. sterilis L. Resistance to oat crown rust caused by P. coronata Cda f. sp. avenae Eriks, was common in A. barbata from Turkey and in A. sterilis from all three countries. The inheritance of resistance conferred by two genes from the region, Pg-15 and Pc-54 is described. Gene Pg-15, the first stem rust resistance gene found in this region, is partially dominant and independent of the Pg-2, Pg-9, Pg-12 and Pg-13 loci. It conferred resistance to races that are important in North America. Gene Pc-54 was also the first crown rust resistance gene to be identified from this region. It was usually recessive, and allelic or closely linked with gene Pc-35.

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Allele Sequencing of the Barley Stem Rust Resistance Gene Rpg1 Identifies Regions Relevant to Disease Resistance

Phytopathology ◽

10.1094/phyto-98-8-0910 ◽

2008 ◽

Vol 98 (8) ◽

pp. 910-918 ◽

Cited By ~ 14

Author(s):

A. Mirlohi ◽

R. Brueggeman ◽

T. Drader ◽

J. Nirmala ◽

B. J. Steffenson ◽

...

Keyword(s):

Disease Resistance ◽

Resistance Gene ◽

Stem Rust ◽

Rust Resistance ◽

Wild Barley ◽

Stem Rust Resistance ◽

Rust Resistance Gene ◽

Puccinia Graminis ◽

Stem Rust Resistance Gene ◽

Specific Pcr

The stem rust resistance gene Rpg1 has protected North American barley cultivars from significant yield losses for over 65 years. The remarkable durability of this gene warrants further study as to its possible origin and allelic variation. Eight Swiss barley (Hordeum vulgare) landraces and eight wild barley (H. vulgare subsp. spontaneum) accessions from diverse geographic regions were analyzed to uncover new alleles of Rpg1 and learn about its possible origin. The two germplasm groups included accessions that were resistant and susceptible to Puccinia graminis f. sp. tritici pathotype MCCF. Allele-specific primers were utilized to amplify 1 kbp overlapping fragments spanning the Rpg1 gene and sequenced if a polymerase chain reaction (PCR) fragment was generated. Variation among the PCR products revealed significant polymorphisms among these Hordeum accessions. Landraces and wild barley accessions susceptible to pathotype MCCF exhibited the highest degree of Rpg1 polymorphism. One resistant landrace (Hv672) and one resistant wild barley accession (WBDC040) yielded all seven Rpg1-specific PCR fragments, but only landrace Hv672 coded for an apparently functional Rpg1 as determined by comparison to previously characterized resistant and susceptible alleles and also resistance to HKHJ, a stem rust pathotype that can specifically detect Rpg1 in the presence of other resistance genes. Accessions resistant to stem rust pathotype MCCF, but completely lacking Rpg1-specific PCR amplification and hybridization with an Rpg1-specific probe, suggested the presence of stem rust resistant gene(s) different from Rpg1 in the Hordeum germplasm pool. Some Rpg1 alleles that retained the ability to autophosphorylate did not confer resistance to Puccinia graminis f. sp. tritici pathotype MCCF, confirming our previous observations that autophosphorylation is essential, but not sufficient for disease resistance. Thus, the RPG1 protein plays a complex role in the stem rust disease resistance-signaling pathway.

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Identification of the stem rust resistance gene Pg9 and its association with crown rust resistance and endosperm proteins in 'Dumont' oat

Genome ◽

10.1139/g94-062 ◽

1994 ◽

Vol 37 (3) ◽

pp. 440-447 ◽

Cited By ~ 32

Author(s):

J. Chong ◽

N. K. Howes ◽

P. D. Brown ◽

D. E. Harder

Keyword(s):

Resistance Gene ◽

Stem Rust ◽

Rust Resistance ◽

Stem Rust Resistance ◽

Crown Rust ◽

Rust Resistance Gene ◽

Stem Rust Resistance Gene ◽

Crown Rust Resistance ◽

Sds Page ◽

Map Distance

The Canadian oat cultivar 'Dumont' is known to have genes Pc38 and Pc39 for crown rust resistance and genes Pg2 and Pg13 for stem rust resistance. When crossed to a susceptible oat line OT328, 'Dumont' was shown to have an additional dominant gene for crown rust resistance, designated PcX. Tests of segregating progeny indicated that the stem rust resistance gene Pg9 is present and is tightly linked in coupling to PcX. The presence of Pg9 in 'Dumont' was confirmed in crosses involving the cultivar 'Ukraine', which has Pg9 and a crown rust resistance gene tightly linked to it. The association of rust resistance with endosperm proteins in 'Dumont' was investigated. The linkage of gene Pg13 with a 56.6-kDa polypeptide locus (map distance of 10.47 ± 2.70 cM) was demonstrated using sodium dodecylsulfate – polyacrylamide gel electrophoresis (SDS–PAGE). A 27.9-kDa polypeptide was shown to be associated with the linked PcX/Pg9 loci by SDS–PAGE but appeared to be more reliably separated as an avenin band, designated B4, using acid–PAGE. Another avenin band, designated B2, also was shown to be associated with the PcX/Pg9 loci using acid–PAGE. The loci conditioning the B2 and B4 bands appeared to be tightly linked or allelic and are separated from the linked PcX/Pg9 loci by a map distance of 1.03 ± 0.36 cM. The association of Pg13 with a 56.6-kDa polypeptide and the tight linkage between PcX/Pg9 and the B2 (in coupling) and B4 (in repulsion) avenin loci offer a useful tool to breeders to detect the presence of these genes in oat breeding.Key words: avenins, gel electrophoresis, molecular markers.

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