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 Genetic Differentiation of the Wheat Leaf Rust Fungus Puccinia triticina in Pakistan and Genetic Relationship to Other Worldwide Populations

2017 ◽  
Vol 107 (6) ◽  
pp. 786-790 ◽  
Author(s):  
J. A. Kolmer ◽  
J. I. Mirza ◽  
M. Imtiaz ◽  
S. J. A. Shah
Keyword(s):  
Leaf Rust ◽  
Rust Fungus ◽  
Principal Component ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Wheat Leaf Rust ◽  
Single Leaf ◽  
Virulence Phenotype ◽  
Ssr Primers ◽  
Wheat Leaf

Collections of Puccinia triticina, the wheat leaf rust pathogen, were obtained from Pakistan in 2008, 2010, 2011, 2013, and 2014. Collections were also obtained from Bhutan in 2013. Single uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes, and for molecular genotype with 23 simple-sequence repeat (SSR) primers. Twenty-four virulence phenotypes were described among the 89 isolates tested for virulence. None of the isolates had virulence to Thatcher lines with Lr9, Lr24, or Lr18. Virulence to most of the other Thatcher lines was over 50%. The two most common virulence phenotypes, FHPSQ and KHPQQ, had virulence to Lr16, Lr17, and Lr26. Twenty-seven SSR genotypes were found among the 38 isolates tested for molecular variation. The SSR genotypes had high levels of observed heterozygosity and significant correlation with virulence phenotype, which indicated clonal reproduction. Cluster analysis and principal component plots indicated three groups of SSR genotypes that also varied significantly for virulence. Isolates with MBDSS and MCDSS virulence phenotypes from Pakistan and Bhutan were highly related for SSR genotype and virulence to isolates from Turkey, Europe, Central Asia, the Middle East, North America and South America, indicating the possible migration of the rust fungus between continental regions.

scholarly journals Genetically Divergent Types of the Wheat Leaf Fungus Puccinia triticina in Ethiopia, a Center of Tetraploid Wheat Diversity

2016 ◽  
Vol 106 (4) ◽  
pp. 380-385 ◽  
Author(s):  
J. A. Kolmer ◽  
M. A. Acevedo
Keyword(s):  
Leaf Rust ◽  
Common Wheat ◽  
Hexaploid Wheat ◽  
Rust Fungus ◽  
Tetraploid Wheat ◽  
Low Frequency ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Virulence Phenotype ◽  
Wheat Leaf

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya, from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. Single-uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes and for molecular genotypes with 10 simple sequence repeat (SSR) primers. Nine virulence phenotypes were described among the 193 isolates tested for virulence. Phenotype BBBQJ, found only in Ethiopia, was predominantly collected from tetraploid wheat. Phenotype EEEEE, also found only in Ethiopia, was exclusively collected from tetraploid wheat and was avirulent to the susceptible hexaploid wheat ‘Thatcher’. Phenotypes MBDSS and MCDSS, found in both Ethiopia and Kenya, were predominantly collected from common wheat. Phenotypes CCMSS, CCPSS, and CBMSS were found in Ethiopia from common wheat at low frequency. Phenotypes TCBSS and TCBSQ were found on durum wheat and common wheat in Kenya. Four groups of distinct SSR genotypes were described among the 48 isolates genotyped. Isolates with phenotypes BBBQJ and EEEEE were in two distinct SSR groups, and isolates with phenotypes MBDSS and MCDSS were in a third group. Isolates with CCMSS, CCPSS, CBMSS, TCBSS, and TCBSQ phenotypes were in a fourth SSR genotype group. The diverse host environment of Ethiopia has selected and maintained a genetically divergent population of P. triticina.

scholarly journals Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2002

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1079-1084 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Leaf Rust ◽  
Great Plains ◽  
Puccinia Triticina ◽  
The United States ◽  
Wheat Leaf Rust ◽  
Ohio Valley ◽  
Virulence Phenotype ◽  
Common Phenotype ◽  
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, Southeast, California, and the Pacific Northwest, in order to determine the virulence of the wheat leaf rust fungus in 2002. Single uredinial isolates (785 in total) were derived from the wheat leaf rust collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, Lr30, LrB, Lr10, Lr14a, and Lr18. In the United States in 2002, 52 virulence phenotypes of P. triticina were found. Virulence phenotype MBDS, which is virulent to resistance gene Lr17, was the most common phenotype in the United States. MBDS was found in the Southeast, Great Plains, and the Ohio Valley regions, and also in California. Phenotype MCDS, virulent to Lr17 and Lr26, was the second most common phenotype and occurred in the same regions as MBDS. Virulence phenotype THBJ, which is virulent to Lr16 and Lr26, was the third most common phenotype, and was found in the southern and northern central Great Plains region. Phenotype TLGJ, with virulence to Lr2a, Lr9, and Lr11, was the fourth most common phenotype and was found primarily in the Southeast and Ohio Valley regions. The Southeast and Ohio Valley regions differed from the Great Plains regions for predominant virulence phenotypes, which indicate that populations of P. triticina in those areas are not closely connected. The northern and southern areas of the Great Plains were similar for frequencies of predominant phenotypes, indicating a strong south to north migration of urediniospores.

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.

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

Botany ◽  
2010 ◽  
Vol 88 (6) ◽  
pp. 575-589 ◽  
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.

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

2017 ◽  
Vol 112 (10) ◽  
pp. 2073 ◽  
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

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

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 981-986 ◽  
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.

scholarly journals The role of reactive oxygen species in the virulence of wheat leaf rust fungus Puccinia triticina

2020 ◽  
Vol 22 (7) ◽  
pp. 2956-2967
Author(s):  
Xiben Wang ◽  
Mingzhe Z. Che ◽  
Hala B. Khalil ◽  
Brent D. McCallum ◽  
Guus Bakkeren ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Leaf Rust ◽  
Rust Fungus ◽  
Reactive Oxygen ◽  
Puccinia Triticina ◽  
Oxygen Species ◽  
Wheat Leaf Rust ◽  
Wheat Leaf

scholarly journals Multilocus Genotypes of the Wheat Leaf Rust Fungus Puccinia triticina in Worldwide Regions Indicate Past and Current Long-Distance Migration

2019 ◽  
Vol 109 (8) ◽  
pp. 1453-1463 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Ordoñez ◽  
S. German ◽  
A. Morgounov ◽  
Z. Pretorius ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Genetic Relatedness ◽  
Rust Fungus ◽  
Puccinia Triticina ◽  
Pathogenic Fungi ◽  
Multilocus Genotype ◽  
Wheat Leaf Rust ◽  
Long Distance ◽  
Multilocus Genotypes ◽  
Wheat Leaf

Many plant pathogenic fungi have a global distribution across diverse ecological zones and agricultural production systems. Puccinia triticina, the wheat leaf rust fungus, is a major pathogen in many wheat production areas of the world. The objective of this research was to determine the genetic relatedness of P. triticina in different worldwide regions. A total of 831 single-uredinial isolates collected from 11 regions were characterized for multilocus genotype at 23 simple sequence repeat loci and for virulence to 20 lines of wheat with single genes for leaf rust resistance. A total of 424 multilocus genotypes and 497 virulence phenotypes were found. All populations had high heterozygosity and significant correlation between virulence and molecular variation, which indicated clonal reproduction. The populations from North America and South America, Central Asia and Russia, and the Middle East and Europe were closely related for multilocus genotypes and many individual isolates from other continental regions were closely related. Twenty-seven multilocus genotypes were found in more than one continental region, and 13 of these had isolates with identical virulence phenotypes. The wide geographic distribution of identical and highly related multilocus genotypes of P. triticina indicated past and more recent migration events facilitated by the spread of clonally produced urediniospores.

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