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

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.

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

Phytopathology ◽

10.1094/phyto.2000.90.4.427 ◽

2000 ◽

Vol 90 (4) ◽

pp. 427-436 ◽

Cited By ~ 43

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.

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

Phytopathology ◽

10.1094/phyto-99-12-1355 ◽

2009 ◽

Vol 99 (12) ◽

pp. 1355-1364 ◽

Cited By ~ 24

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.

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Effect of theLr9Resistance Gene on Pathogenesis of the Wheat Leaf Rust Fungus

Plant Disease ◽

10.1094/pd-80-0014 ◽

1996 ◽

Vol 80 (1) ◽

pp. 14 ◽

Cited By ~ 3

Author(s):

S. Ortelli

Keyword(s):

Leaf Rust ◽

Rust Fungus ◽

Wheat Leaf Rust ◽

Wheat Leaf

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Virulence and molecular polymorphisms of the wheat leaf rust fungus Puccinia triticina in Canada from 1997 to 2007

Botany ◽

10.1139/b10-034 ◽

2010 ◽

Vol 88 (6) ◽

pp. 575-589 ◽

Cited By ~ 16

Author(s):

Xiben Wang ◽

Guus Bakkeren ◽

Brent McCallum

Keyword(s):

Leaf Rust ◽

Expressed Sequence Tag ◽

Rust Fungus ◽

Puccinia Triticina ◽

Leaf Rust Resistance ◽

Significant Shift ◽

Wheat Leaf Rust ◽

Rust Disease ◽

The Pacific ◽

Wheat Leaf

Populations of Puccinia triticina , one of the casual agents of wheat leaf rust disease, in the pacific (British Columbia and Alberta), prairie (Manitoba and Saskatchewan), and eastern regions (Quebec and Ontario) of Canada from 1997 to 2007 were analyzed for virulence and genetic diversity by revealing expressed sequence tag derived simple sequence repeat (EST-SSR) polymorphisms. Since 1997, a significant shift in the virulence of P. triticina occurred across Canada. The diversity of P. triticina virulence phenotypes in Manitoba and Saskatchewan, as measured by Shannon and Simpson indexes, decreased due to the directional selection toward predominant virulence phenotypes, whereas it remained relatively constant in Quebec and Ontario. The clustering of P. triticina virulence phenotypes from 1997 to 2007 was similar to that found in previous years, and was correlated with virulence to leaf rust resistance genes Lr2a, Lr2c, and Lr17a. Distinct EST-SSR profiles were found in different groups of P. triticina virulence phenotypes based on virulence to Lr2a, Lr2c, and Lr17a. In addition, the population of P. triticina in Manitoba and Saskatchewan was different from that in Quebec and Ontario from 1997 to 2007, based on both virulence characteristics and EST-SSR genotypes.

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Population Differentiation of Wheat Leaf Rust Fungus Puccinia triticina in South Asia

Current Science ◽

10.18520/cs/v112/i10/2073-2084 ◽

2017 ◽

Vol 112 (10) ◽

pp. 2073 ◽

Cited By ~ 9

Author(s):

Pramod Prasad ◽

S. C. Bhardwaj ◽

O. P. Gangwar ◽

Subodh Kumar ◽

Hanif Khan ◽

...

Keyword(s):

South Asia ◽

Leaf Rust ◽

Population Differentiation ◽

Rust Fungus ◽

Puccinia Triticina ◽

Wheat Leaf Rust ◽

Wheat Leaf

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Effect of Intracellular Calcium Stores on Hypersensitive Reaction Induced by Wheat Leaf Rust Fungus

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2010.00833 ◽

2010 ◽

Vol 36 (5) ◽

pp. 833-839 ◽

Cited By ~ 1

Author(s):

Bei ZHANG ◽

Ai-Hua YAN ◽

Gang LIU ◽

Meng LIU ◽

Chun-Yan HOU ◽

...

Keyword(s):

Intracellular Calcium ◽

Leaf Rust ◽

Rust Fungus ◽

Hypersensitive Reaction ◽

Calcium Stores ◽

Wheat Leaf Rust ◽

Intracellular Calcium Stores ◽

Wheat Leaf

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Molecular polymorphism and virulence phenotypes of the wheat leaf rust fungus Puccinia triticina in Canada

Canadian Journal of Botany ◽

10.1139/cjb-79-8-917 ◽

2001 ◽

Vol 79 (8) ◽

pp. 917-926 ◽

Cited By ~ 25

Author(s):

J.A. Kolmer

Keyword(s):

Leaf Rust ◽

Rust Fungus ◽

Puccinia Triticina ◽

Wheat Leaf Rust ◽

Molecular Polymorphism ◽

Wheat Leaf

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Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2000

Plant Disease ◽

10.1094/pdis.2002.86.9.981 ◽

2002 ◽

Vol 86 (9) ◽

pp. 981-986 ◽

Cited By ~ 15

Author(s):

D. L. Long ◽

J. A. Kolmer ◽

K. J. Leonard ◽

M. E. Hughes

Keyword(s):

United States ◽

Leaf Rust ◽

Great Plains ◽

Gulf Coast ◽

Rust Fungus ◽

Puccinia Triticina ◽

The United States ◽

Wheat Leaf Rust ◽

Ohio Valley ◽

Wheat Leaf

Collections of Puccinia triticina were obtained from rust infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio Valley, Gulf Coast, and Atlantic Coast States in order to determine the virulence of the wheat leaf rust fungus in 2000. Single uredinial isolates (1,120 in total) were derived from the wheat leaf rust collections and tested for virulence phenotype on 16 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In the United States in 2000, 54 virulence phenotypes of P. triticina were found. Virulence phenotypes MBDS and MCDS, which are virulent to resistance gene Lr17, were the first and third most common phenotypes in the United States and were found in the Great Plains and the Ohio Valley regions. MCRK, which is virulent to Lr26, was the second most common phenotype and was found primarily in the Southeast, Ohio Valley, and Northeast regions. In the northern area of the Great Plains, phenotypes with virulence to Lr16 increased in frequency from 1998 and 1999. The Southeast and Great Plains regions had different predominant virulence phenotypes, which indicates that populations of P. triticina in those areas are not closely connected. The northern and southern areas of the Great Plains region had the same predominant virulence phenotypes, indicating movement of virulence phenotypes of P. triticina within this region.

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