Resistance of genes isolated from Avena sterilis to isolates of oat crown rust prevalent in Canada in 1968

1969 ◽  
Vol 47 (4) ◽  
pp. 623-623
Author(s):  
George Fleischmann

Lines of Pendek each containing a single Avena sterilis gene (Pc-38, Pc-39, Pc-40, Pc-41, and Pc-42) were tested to 116 isolates of Puccinia coronata var. avenae identified in Canada in 1968. None of the isolates attacked gene Pc-39 and only two isolates (races 290 and 326) attacked Pc-38. The other A. sterilis genes were not particularly effective against these crown rust isolates.

1970 ◽  
Vol 48 (12) ◽  
pp. 2117-2121
Author(s):  
George Fleischmann

All isolates of oat crown rust, Puccinia coronata f. sp. avenae, identified in Canada in 1969 were inoculated onto 12 different lines containing resistance from wild oats, Avena sterilis, collected in Europe and the Middle East. Lines that contain resistance genes Pc-38 and Pc-39, and wild oat collections CI 8081 and F158, provide effective resistance to nearly every culture of crown rust. Regional differences in the level of virulence of crown rust cultures isolated from eastern and western Canada were observed on lines that contain A. sterilis resistance, with cultures of crown rust isolated from the east being generally less virulent than those from western Canada.


1976 ◽  
Vol 18 (4) ◽  
pp. 717-726 ◽  
Author(s):  
F. A. Kiehn ◽  
R. I. H. McKenzie ◽  
D. E. Harder

The inheritance of resistance to oat crown rust Puccinia coronata Cda. f. sp. avenae Eriks. was studied in four accessions of Avena sterilis L. Three of the accessions, CAV 4963, CAV 1358 and CAV 1376, originated from Israel, and one, CAV 1964, from Algeria. Seedling rust tests on F2 backcross families indicated that a single recessive gene, Pc-55, in CAV 4963 conditioned seedling resistance to 10 of 12 crown rust isolates tested. In CAV 1964, a single dominant gene Pc-56 conferred resistance in both the adult and seedling stages to all crown rust isolates tested except race 239, while a second dominant gene conditioned resistance to only two of the twelve cultures used. From adult and seedling tests it appeared that the resistance in CAV 1358 and CAV 1376 was conditioned by a number of recessive minor additive genes. The genes Pc-55 and Pc-56 are not allelic with the A. sterilis derived genes Pc-35, Pc-38, Pc-40, Pc-45, Pc-46, Pc-47, Pc-48, and Pc-50. Genes Pc-39 and Pc-55 are either very closely linked or allelic and Pc-56 is not closely linked to either Pc-39 or Pc-55. The usefulness of genes Pc-55 and Pc-56 was demonstrated in tests which showed that both genes were effective against 99.8 and 94.5%, respectively, of all crown rust cultures isolated in Canada in 1974 and 1975. The genes for seed color and awn character did not appear to be linked to the crown rust resistance genes. In CAV 4963, CAV 1358 and CAV 1376 the genes for grey color and wild type awns appeared to be linked with recombination values of about 2, 23 and 18%, respectively.


1971 ◽  
Vol 49 (8) ◽  
pp. 1433-1437 ◽  
Author(s):  
George Fleischmann ◽  
R. J. Baker

A review of the physiologic races of oat crown rust, Puccinia coronata f. sp. avenae, isolated in surveys since 1967 indicated a continuing trend toward increased virulence on the standard differential varieties of oats, Avena sativa. Because of this trend and because the inheritance and interrelationships of resistances in the standard differential set are not completely known, a new set of oat crown rust differentials has been introduced. The new set comprises 10 near-isogenic lines of the common oat variety 'Pendek,' into which single resistance genes from Avena sterilis had been transferred. A system of race nomenclature which reflects the pattern of virulence on the new set is proposed.


Plant Disease ◽  
2005 ◽  
Vol 89 (8) ◽  
pp. 802-808 ◽  
Author(s):  
K. J. Leonard ◽  
J. A. Martinelli

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.


1980 ◽  
Vol 22 (1) ◽  
pp. 27-33 ◽  
Author(s):  
D. E. Harder ◽  
R. I. H. McKenzie ◽  
J. W. Martens

The inheritance of resistance to oat crown rust was studied in three accessions of Avena sterilis L. Accession CAV 4274 originated from Morocco, CAV 4540 from Algeria, and CAV 3695 from Tunisia. Seedling rust tests on F2 backcross families indicated the presence of two dominant genes for crown rust resistance in CAV 4274. One of these, a gene conditioning resistance to most races tested, was linked or allelic to gene Pc-38, and was designated gene Pc-62. The second gene conferred resistance only to one of the six races studied, and was not tested further. In CAV 4540, a single dominant gene, Pc-63 was possibly allelic with Pc-62 and linked or allelic to Pc-38. Genes Pc-62 and 63 are generally similar to Pc-38 in their resistance spectrum, but these three genes are differentiated by races CR 102, CR 103, and CR 107. A single dominant gene in CAV 3695 appeared to be Pc-50.


1968 ◽  
Vol 46 (5) ◽  
pp. 613-617 ◽  
Author(s):  
George Fleischmann

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.


1983 ◽  
Vol 25 (4) ◽  
pp. 329-335 ◽  
Author(s):  
L. S. L. Wong ◽  
R. I. H. McKenzie ◽  
D. E. Harder ◽  
J. W. Martens

The inheritance of resistance to Puccinia coronata, awn development, lemma pubescence, and lemma color were studied in the Avena sterilis accessions CAV 4248, CAV 4656, and CAV 4904. Three independent, partially dominant genes (Pc-64, Pc-65, Pc-66) in CAV 4248, one partially dominant gene (Pc-67) in CAV 4656, and a dominant gene (Pc-68) in CAV 4904 were identified which conferred resistance to P. coronata. Genes Pc-64, Pc-65, Pc-66, Pc-67, and Pc-68 conferred resistance to 13, 8, 6, 12, and 14 races, respectively, of the 14 races of P. coronata tested. Gene Pc-68 conferred resistance to all field isolates of P. coronata collected in Canada in 1981 and was found to be closely linked or allelic to gene Pc-46. Awns and lemma pubescence were inherited monogenically in crosses with all three CAV accessions. Grey lemma color was controlled by one gene in CAV 4248 and by two genes in CAV 4656. Brown lemma color was controlled by one gene, which was closely linked or pleiotropic with the gene for lemma pubescence in CAV 4904. There was no association between crown rust resistance and the three floret characters studied.


mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Marisa E. Miller ◽  
Ying Zhang ◽  
Vahid Omidvar ◽  
Jana Sperschneider ◽  
Benjamin Schwessinger ◽  
...  

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.


1971 ◽  
Vol 13 (2) ◽  
pp. 251-255 ◽  
Author(s):  
G. Fleischmann ◽  
R. I. H. McKenzie ◽  
W. A. Shipton

The inheritance of genes in three collections of Avena sterilis wild oats conferring resistance to races 216, 264, 295, 305, 326, 330, 332, and 446 of crown rust, Puccinia coronata avenae, was investigated. C. I. 8081 from Portugal contained a partially dominant gene, designated Pc47, which conferred resistance to all eight races. CW486 from Tunisia had a dominant gene, designated Pc50, which gave resistance to all races except 295, 326, and 446. F158 from Israel had two dominant genes; one, designated Pc48, conferred resistance to all the races but 305, while the second, designated Pc49, conferred resistance to races 216, 326, 330, 332, and 446. Genes Pc47, Pc48, Pc49, and Pc50 were inherited independently of each other and of those genes previously isolated from A. sterilis.


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