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.

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

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.

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.

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 Fusion Body Formation, Germ Tube Anastomosis, and Nuclear Migration During the Germination of Urediniospores of the Wheat Leaf Rust Fungus, Puccinia triticina

2009 ◽  
Vol 99 (12) ◽  
pp. 1355-1364 ◽  
Author(s):  
Xiben Wang ◽  
Brent McCallum
Keyword(s):  
Leaf Rust ◽  
Germ Tube ◽  
Rust Fungus ◽  
Puccinia Triticina ◽  
Rust Fungi ◽  
Wheat Leaf Rust ◽  
Virulence Phenotype ◽  
Close Proximity ◽  
Wheat Leaf ◽  
Germ Tubes

Vegetative or parasexual recombination is thought to be a key mechanism for the genetic diversity of cereal rust fungi. The process of germ tube fusion leading to hyphal anastomosis and nuclear recombination was analyzed in wheat leaf rust fungus, Puccinia triticina. Germ tube anastomosis was observed in 27 P. triticina isolates, each representing a different virulence phenotype. Germ tube fusion bodies (GFBs), which appeared as viscid globules formed at tips of germ tubes, were essential for germ tube anastomosis. The formation of GFBs was affected by the urediniospore density and the length of illumination during germination. GFBs were formed at the highest frequency when urediniospores were spread to a concentration of 1 × 106 urediniospores/ml and incubated in dark for 12 to 24 h during germination. GFB attached to either the side of another germ tube (“tip to side”) or to another GFB formed at the tip of a second germ tube (“tip to tip”). In “tip to side” anastomosis, two nuclei in the germ tube bearing the GFB migrated into the second germ tube through the GFB which resulted in four nuclei within this germ tube. In “tip to tip” anastomosis, nuclei in both germ tubes migrated into the fused GFB and all four nuclei came into close proximity. Urediniospores of isolates MBDS-3-115 and TBBJ-5-11 were stained with DAPI (4′,6′diamine-2-phenylindole) and Nuclear Yellow (Hoechst S769121), respectively, and then mixed and germinated on water agar. Some fused GFBs contained nuclei stained with DAPI and nuclei stained with Nuclear Yellow in close proximity, demonstrating the fusion between genetically different P. triticina isolates. In some fused GFBs, “bridge-like” structures connecting different nuclei were observed.

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.

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