scholarly journals Accumulations of genes for durable resistance to wheat leaf rust pathogen

2008 ◽  
Vol 53 (3) ◽  
pp. 163-172 ◽  
Author(s):  
Jelena Boskovic ◽  
M. Boskovic ◽  
Zeljana Prijic
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Puccinia Recondita ◽  
Recurrent Parent ◽  
Considerable Influence ◽  
Wheat Leaf Rust ◽  
Resistant Genes ◽  
Rust Pathogen ◽  
Wheat Leaf ◽  
Puccinia Recondita Tritici

The individual use of single race-specific resistance genes with major phenotypic effects has rarely provided lasting resistance. However, breeding and combining or pyramiding of resistance genes into individual cultivars has had considerable success, particularly in situation where the pathogen does not reproduce sexually, as in the case of wheat leaf rust pathogen. Within international leaf rust of wheat investigations it was necessary, to create by breeding new resistant wheat lines to Puccinia recondita tritici for differentiation of pathogen population, as well as for sources of resistance in European-Mediterranean regions. In the beginning 18 donors of resistance had been selected after an extensive screening test of several International Rust Nurseries, to be crosses with recur- rent parents varieties Princ and Starke. These tests proved that in those lines were present new resistant genes. Eighth genetically different hybrids of the first back-cross had been selected and tested in the seedling stage with three international pathogen cultures (YU-13-19-1; H-13-9-1 and C2-13-Ar-3). Considerable influence of recurrent parent to the number of resistant genes in donors used was demonstrated. On the other side, it was established considerable influence of the pathogen culture to the number of resistant genes in donors used. The same crossing combinations tested with one pathogen culture results in presence of two resistance genes, but with another culture three or one resistant gene. In order to enhancement resistance and pyramiding genes in these hybrids, eight selected the most interesting lines have been crossed with only effective isogenic containing the strong genes Lr9, Lr19 and Lr24.The genetic analysis of twenty two crossing combinations have been realized by testing with three pathotypes of Puccinia recondita tritici ( Bg.s. 12/89; Is.w 8/89 and Chl.w. 14/89). On the base of different segregation ratios of all crossing combinations it was proved that no one of the resistant donors contained the strong resistant genes used. It means that our hybrid lines contained resistant genes from the donors and in addition three strong resistant genes Lr9, Lr19 and Lr24.

scholarly journals Durable resistance to Puccinia triticina by accumulation of resistance genes

Genetika ◽  
2009 ◽  
Vol 41 (3) ◽  
pp. 353-378 ◽  
Author(s):  
Jelena Boskovic ◽  
Momcilo Boskovic
Keyword(s):  
Leaf Rust ◽  
Resistance Genes ◽  
Durable Resistance ◽  
Puccinia Triticina ◽  
Recurrent Parent ◽  
Considerable Influence ◽  
Wheat Leaf Rust ◽  
Resistant Genes ◽  
Wheat Leaf ◽  
Hybrid Lines

The individual use of single race-specific resistance genes with major phenotypic effects has rarely provided lasting resistance. However, breeding and combining or pyramiding of resistance genes into individual cultivars has had considerable success, particularly in situations in which the pathogen does not reproduce sexually, as in the case of wheat leaf rust pathogen. In European-Mediterranean region perfomed international investigations of wheat leaf rust proved that breeding of new lines of wheat resistant to Puccinia triticina Eriks. for differentiation of pathogen population, as well as for sources of durable resistance is necessary. Breeding of such resistant lines has proved necessary due to the unsatisfatory survey results of these regions on standard isogenic Lr lines. It has become clear that these regions needed new, more efficient differential resistance genes, as well as sources of resistance. In the beginning, after extensive screening tests of several International Rust Nurseries, 18 donors of resistance had been selected as crosses with recurrent parents' varieties Princ and Starke. These hybrid lines had been comparatively tested with twenty six Lr single gene lines using twenty especially virulent cultures of P. triticina in order to check the presence of these known Lr genes in our hybrid lines. Considerable influence of recurrent parent to the number of resistant genes in used donors was demonstrated. On the other hand, considerable influence of the pathogen culture was established to the number of resistance genes in used donors. In order to enhance resistance and pyramiding genes in these hybrids, the most interesting selected eight lines have been crossed with only effective isogenic ones, containing the strong genes Lr9, Lr19 and Lr24. On the basis of different segregation rations of all crossing combinations it was proved that no one of resistant donors contained the applied strong resistant genes. It means that our hybrid lines contained resistant genes from the donors, as well as three strong resistant genes Lr9, Lr19 and Lr24.

Control of wheat leaf rust with 4-n-butyl-1,2,4-triazole

1975 ◽  
Vol 15 (73) ◽  
pp. 276 ◽  
Author(s):  
RG Rees ◽  
GJ Platz
Keyword(s):  
Leaf Rust ◽  
Field Experiments ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
Yield Increase ◽  
Boot Stage ◽  
Crop Development ◽  
Wheat Leaf ◽  
Puccinia Recondita Tritici ◽  
Excellent Control

The control of wheat leaf rust (Puccinia recondita tritici) by seed or foliar applications of 4-n-butyl-l,2,4-triazole (RH-124) has been examined in field experiments over three years at Gatton, Queensland. Single foliar sprays of RH-124 at rates as low as 100 g a.i, ha-1 have given excellent control of leaf rust. One such spray resulted in a yield increase of 30 per cent. A spray at 400 g a.i. ha-1 increased yield by 46 per cent compared with an increase of 61 per cent in the rust-free reference. Applications around the early boot stage of crop development were the most effective. Treatment of seed with RH-124 resulted in some control of leaf rust in one season with an associated yield increase of 22 per cent. Although RH-124 appears promising, additional studies are required before use of the fungicide on commercial wheat crops would be accepted.

THE INHERITANCE OF RESISTANCE IN RYE TO Puccinia recondita f. sp. secalis and f. sp. tritici

1984 ◽  
Vol 64 (3) ◽  
pp. 511-519 ◽  
Author(s):  
G. L. C. MUSA ◽  
P. L. DYCK ◽  
D. J. SAMBORSKI
Keyword(s):  
Disease Resistance ◽  
Leaf Rust ◽  
Secale Cereale ◽  
Single Gene ◽  
Inbred Lines ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
Susceptible Parent ◽  
Seedling Resistance ◽  
Wheat Leaf

The inheritance of seedling resistance to isolate RLR 213/78 of rye leaf rust (Puccinia recondita f. sp. secalis) and race 30 of wheat leaf rust (P. recondita f. sp. tritici Rob.) was investigated in six inbred lines of rye (Secale cereale). Inbred line UM8116 was used as the susceptible parent in crosses. Inbred lines UM8003, UM8071 and UM8301 each have a single gene and UM8336 and UM8340 each have two genes for resistance to rye leaf rust. For resistance to wheat leaf rust UM8071 has a single gene, UM8003 and UM8340 each have two genes and UM8301 and UM8336 each have three genes. UM8295 is heterogeneous for reaction to both rusts. One of the genes in UM8340 may condition resistance to both rusts. The genes for resistance to RLR 213/78 appear to be independently inherited while some of the genes conferring resistance to race 30 may be identical or very closely linked. The potential of rye as a source of disease resistance for wheat and triticale improvement is discussed.Key words: Secale cereale, disease resistance, wheat leaf rust

Molecular and virulence diversity and linkage disequilibria in asexual and sexual populations of the wheat leaf rust fungus, Puccinia recondita

Genome ◽  
1998 ◽  
Vol 41 (6) ◽  
pp. 832-840 ◽  
Author(s):  
J Q Liu ◽  
J A Kolmer
Keyword(s):  
Leaf Rust ◽  
Rust Fungus ◽  
Field Population ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
Asexual Population ◽  
Sexual Population ◽  
Linkage Disequilibria ◽  
Wheat Leaf ◽  
Virulence Diversity

An asexual field population and a sexually derived population of the wheat leaf rust fungus, Puccinia recondita, were examined and compared for diversity and linkage disequilibria between virulence and molecular phenotypes. Isolates in both populations were tested for virulence to 20 Thatcher wheat lines near-isogenic for leaf rust resistance genes, and for random amplified polymorphic DNA (RAPD) variation using 10 DNA primers. In the asexual field population, 36 virulence phenotypes and 14 RAPD phenotypes were identified in 43 isolates. In the sexual population, 87 virulence phenotypes and 79 RAPD phenotypes were identified in 104 isolates. Linkage disequilibria was less in the sexual population compared to the asexual field population. Virulence-RAPD phenotype pairs (110 in total) were directly compared between the two populations for association. In the asexual population, 39 virulence-RAPD phenotype pairs were associated (P < 0.05), compared with 18 pairs in the sexual population. Linkage was not evident, as some residual disequilibria remained between virulence and RAPD phenotypes. In the asexual population 18 RAPD phenotype pairs were associated, compared with 9 pairs in the sexual population. The sexual population was also tested for RAPD variation with an additional six primers. In the sexual population, amplification sites of four different primers were tightly linked which indicated a chromosomal segment in P. recondita may not readily undergo recombination. Disequilibria between virulence and RAPD phenotypes in field populations of P. recondita in Canada is maintained by asexual reproduction.Key words: Puccinia recondita, molecular diversity, virulence diversity, linkage disequilibria, wheat leaf rust.

COMPUTER ANALYSIS OF DISEASE DATA TO DERIVE HYPOTHETICAL GENOTYPES FOR REACTION OF HOST VARIETIES TO PATHOGENS

1971 ◽  
Vol 13 (4) ◽  
pp. 742-748 ◽  
Author(s):  
W. Q. Loegering ◽  
R. A. McIntosh ◽  
Coleman H. Burton
Keyword(s):  
Boolean Algebra ◽  
Computer Program ◽  
Leaf Rust ◽  
Visual Inspection ◽  
Puccinia Recondita ◽  
Wheat Leaf Rust ◽  
High Infection ◽  
Wheat Leaf ◽  
Infection Types ◽  
Genotype A

A method is described for deriving genotypes for low reaction in varieties of a host from data resulting from inoculating many host varieties with many cultures of a pathogen. A computer program utilizing Boolean algebra was used to compare and group patterns of low and high infection types produced by host variety: pathogen culture combinations. Visual inspection within each group allows derivation of the genotype. A successful trial of the system was made with data on wheat leaf rust involving 60 varieties of wheat and nine cultures of Puccinia recondita.

scholarly journals Virulence and Molecular Polymorphism in International Collections of the Wheat Leaf Rust Fungus Puccinia triticina

2000 ◽  
Vol 90 (4) ◽  
pp. 427-436 ◽  
Author(s):  
J. A. Kolmer ◽  
J. Q. Liu
Keyword(s):  
New Zealand ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Fungus ◽  
Puccinia Triticina ◽  
Western Canada ◽  
Wheat Leaf Rust ◽  
Wheat Leaf ◽  
Rapd Variation ◽  
Wheat Lines

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from Great Britain, Slovakia, Israel, Germany, Australia, Italy, Spain, Hungary, South Africa, Uruguay, New Zealand, Brazil, Pakistan, Nepal, and eastern and western Canada. All single-uredinial isolates derived from the collections were tested for virulence polymorphism on 22 Thatcher wheat lines that are near-isogenic for leaf rust resistance genes. Based on virulence phenotype, selected isolates were also tested for randomly amplified polymorphic DNA (RAPD) using 11 primers. The national collections were placed into 11 groups based on previously established epidemiological zones. Among the 131 single-uredinial isolates, 105 virulence phenotypes and 82 RAPD phenotypes were described. In a modified analysis of variance, 26% of the virulence variation was due to differences in isolates between groups, with the remainder attributable to differences within groups. Of the RAPD variation, 36% was due to differences in isolates between groups. Clustering based on the average virulence distance (simple distance coefficient) within and between groups resulted in eight groups that differed significantly. Collections from Australia-New Zealand, Spain, Italy, and Britain did not differ significantly for virulence. Clustering of RAPD marker differences (1 - Dice coefficient) distinguished nine groups that differed significantly. Collections from Spain and Italy did not differ significantly for RAPD variation, neither did collections from western Canada and South America. Groups of isolates distinguished by avirulent/virulent infection types to wheat lines with resistance genes Lr1, Lr2a, Lr2c, and Lr3 also differed significantly for RAPD distance, showing a general relationship between virulence and RAPD phenotype. The results indicated that on a worldwide level collections of P. triticina differ for virulence and molecular backgrounds.

scholarly journals Dissecting the first phased dikaryotic genomes of the wheat rust pathogen Puccinia triticina reveals the mechanisms of somatic exchange in nature

2019 ◽  
Author(s):  
Jing Qin Wu ◽  
Chongmei Dong ◽  
Long Song ◽  
Christina A. Cuomo ◽  
Robert F. Park
Keyword(s):  
Leaf Rust ◽  
Somatic Hybridization ◽  
Puccinia Triticina ◽  
Genomic Variation ◽  
Hybrid Wheat ◽  
Wheat Cultivars ◽  
Wheat Leaf Rust ◽  
Virulence Evolution ◽  
Rust Pathogen ◽  
Wheat Leaf

AbstractAlthough somatic hybridization (SH) has been proposed as a means of accelerating rust pathogen virulence evolution in the absence of sexual recombination, previous studies are limited to the laboratory and none have revealed how this process happens. Using long-read sequencing, we generated dikaryotic phased genomes and annotations for three Australian field-collected isolates of the wheat leaf rust pathogen (Puccinia triticina; Pt), including a putative asexual hybrid (Pt64) and two putative parental isolates (Pt104 and Pt53; 132-141 Mb,155-176 contigs, N50 of 1.9-2.1 Mb). The genetic dissection based on the high-quality phased genomes including whole-genome alignments, phylogenetic and syntenic analyses along with short-read sequencing of 27 additional Pt isolates convergently demonstrated that Pt64, which rendered several commercial hybrid wheat cultivars susceptible to leaf rust, arose from SH between isolates within the Pt53 and Pt104 lineages. Parentage analysis demonstrated the role of mitotic crossover in the derivation of both nuclei of Pt64. Within HD mating type genes, the distinct specificity regions in Pt64 and the distinct phylogenetic pattern of the remaining admixed isolates suggested high genetic variation in specificity-related regions on the b locus intrinsically associated with the SH. This study not only provided a fundamental platform for investigating genomic variation underlying virulence evolution in one of the most devastating wheat pathogens, but also offered an in-depth understanding of the mechanisms of naturally occurring SH. This asexual mechanism can be broadly exploited by any dikaryotic pathogen to accelerate virulence evolution, and understanding this process is both urgent and crucial for sustainable pathogen control.ImportanceStrategies to manage plant rust pathogens are challenged by the constant emergence of new virulence. Although somatic hybridization has been proposed as a means by which rusts could overcome host resistance rapidly and cause crop loss, there is very little evidence of this process in nature and the mechanisms underlying it are not known. This study generated and analysed the first dikaryotic phased genomes of the wheat leaf rust pathogen, identifying an isolate as a hybrid and for the first time unveiling parasexuality via mitotic crossover in a rust pathogen. The erosion of the resistance of several hybrid wheat cultivars in agriculture by the hybrid rust has important implications for breeding efforts targeting durable resistance and sustained rust control.

scholarly journals Comparative Analysis of Indices in the Study of Virulence Diversity Between and Within Populations of Puccinia recondita f. sp. tritici in Israel

2000 ◽  
Vol 90 (6) ◽  
pp. 601-607 ◽  
Author(s):  
J. Manisterski ◽  
Z. Eyal ◽  
P. Ben-Yehuda ◽  
E. Kosman
Keyword(s):  
Comparative Analysis ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Phenotypic Diversity ◽  
Rank Order ◽  
Wild Emmer ◽  
Puccinia Recondita ◽  
Pathogen Population ◽  
Wheat Leaf ◽  
Virulence Diversity

Isolates of Puccinia recondita f. sp. tritici (n = 260) obtained from bread, durum, and wild emmer wheat leaf collections throughout Israel during 1993 to 1997 were analyzed for virulence on a set of wheat differentials. The overall frequency of virulence increased on differentials possessing resistance genes Lr1, Lr2a, Lr3, and Lr26 and decreased on Lr17, Lr21, and Lr30. Genes Lr9 and Lr24 were resistant, while Lr18 was susceptible (98% in 1996) to all tested leaf rust isolates and Lr10 and Lr23 were susceptible to more than 78% of the isolates. Diversity between populations (years) was assessed using Kosman's HKB (based on degrees of similarity among distinct phenotypes) and HKDis (based on frequencies of individual virulences) and Nei's and Rogers' distances. The greatest difference occurred between the 1993 and 1994 populations. Phenotypic diversity within each population (year) was analyzed using the Shannon's, Simpson's, and Kosman's indices. The highest diversity within years was recorded in 1994 and significantly increased from 1993 to 1994 for all indices. The variance in the diversity between populations can be only partially explained by differences between corresponding diversities within population. The comparative analysis of diversity between and within populations over the 5 years enabled a detailed study of changes in the pathogen population. The results show that the different measures do not yield the same rank order of diversity.

scholarly journals Virulence surveys of wheat leaf rust in the Czech Republic and resistance genes in registered cultivars

2014 ◽  
Vol 50 (No. 3) ◽  
pp. 241-246 ◽  
Author(s):  
A. Hanzalová ◽  
P. Bartoš
Keyword(s):  
Czech Republic ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Wheat Cultivars ◽  
Wheat Leaf Rust ◽  
The Czech Republic ◽  
Technical Report ◽  
Wheat Leaf ◽  
Physiologic Races ◽  
The Given

The technical report presents a summary of results obtained in the leaf rust race surveys carried out in Czechoslovakia/Czech Republic in the years 1966&ndash;2001. The physiologic races were determined using the standard differentials Malakoff (Lr1), Carina (Lr2b), Brevit (Lr2c), Webster (Lr2a), Loros (Lr2c), Mediterranean (Lr3), Hussar (Lr11), Democrat (Lr3) and the additional differential Salzm&uuml;nder Bartweizen (Lr26). Races 14, 77, 61, 53 and&nbsp;2&nbsp; successively dominated in the given period. They mostly appeared in two variants, avirulent and virulent to Lr26. Genes for virulence in the leaf rust races were compared with genes for resistance in the registered wheat cultivars listed in the report. Most frequent were the genes Lr3 and Lr26.

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