Early abortion of colonies of leaf rust, Puccinia hordei, in partially resistant barley seedlings

1982 ◽  
Vol 60 (5) ◽  
pp. 714-723 ◽  
Author(s):  
R. E. Niks
Keyword(s):  
Leaf Rust ◽  
Infection Type ◽  
Durable Resistance ◽  
Infection Process ◽  
Host Cells ◽  
Puccinia Hordei ◽  
Pr Genes ◽  
Mother Cells ◽  
Early Abortion ◽  
Barley Genotypes

Partial resistance (PR) in barley to leaf rust is assumedly a case of durable resistance. PR is characterized by a reduced rate of epidemic development in spite of a susceptible infection type. One of the components of PR, low infectibility, was studied histologically by means of fluorescence microscopy. Quantitative analyses of the phases of the infection process beyond appressorium formation showed that the reduced infectibility of partially resistant barley seedlings rests on a significant "early abortion" of colonies. This type of abortion occurs at about the moment of the formation of the first haustoria, when the young colonies have formed up to five or six haustorial mother cells. Early abortion is only incidentally associated with the collapse of host cells. Not only the variation in infectibility among barley genotypes but also the variation in infectivity among leaf rust isolates is based mainly on differences in the degree of early abortion. The occurrence of a high degree of early abortion in several unrelated barley genotypes indicates that the PR genes are part of a generally occurring system.

Ultrastructure of eastern cottonwood clones susceptible or resistant to leaf rust

1987 ◽  
Vol 65 (8) ◽  
pp. 1586-1598 ◽  
Author(s):  
L. Shain ◽  
U. Järlfors
Keyword(s):  
Electron Microscopy ◽  
Leaf Rust ◽  
Light And Electron Microscopy ◽  
Infection Process ◽  
The Other ◽  
Host Cells ◽  
Eastern Cottonwood ◽  
Melampsora Medusae ◽  
Wall Appositions ◽  
Infected Cells

The infection process in four clones of eastern cottonwood susceptible or resistant to leaf rust caused by Melampsora medusae was studied by light and electron microscopy. Infection was initiated by stomatal rather than direct entry. Typical dikaryotic haustoria were observed in all clones within 1 day of inoculation. Some healthy-appearing haustoria were observed in susceptible clones throughout the duration of the study, which was terminated during the initiation of uredial production. Incompatibility was expressed differently in the two resistant clones. In clone St 75, most haustoria and invaded host cells that were observed appeared necrotic within 2 days of inoculation. Cell wall appositions appeared during this time in cells adjoining necrotic host cells. Some infected cells disintegrated within 4 days of inoculation. Affected host cells of clone St 92, on the other hand, plasmolyzed during the first 2 to 3 days after inoculation. Necrotic host cells were not observed in this clone until the 4th day after inoculation. Hyphal ramification and host plasmolysis were extensive at 6 days after inoculation.

scholarly journals Priming Is a Suitable Strategy to Enhance Resistance Towards Leaf Rust in Barley

2019 ◽  
Vol 3 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Gwendolin Wehner ◽  
Doris Kopahnke ◽  
Klaus Richter ◽  
Steffen Kecke ◽  
Adam Schikora ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Infection Type ◽  
Homoserine Lactone ◽  
Negative Control ◽  
Puccinia Hordei ◽  
Resistance Level ◽  
Biotic Stresses ◽  
First Results ◽  
Meliloti Strain ◽  
Open Access Article

Priming allows plants to respond faster and stronger to abiotic or biotic stresses. Leaf rust (Puccinia hordei) is an important pathogen of barley (Hordeum vulgare), for which resistance genes are known, but mostly overcome. Therefore, the aims of this study were (i) to establish a priming system in barley, based on bacterial N-acyl homoserine lactone (AHL), and (ii) to get information on the effect of priming on the reaction to leaf rust. Plants were inoculated with bacteria, i.e., Ensifer meliloti with repaired expR copy, producing the oxo-C14-homoserine lactone (AHL) and an E. meliloti strain carrying the attM lactonase gene from Agrobacterium tumefaciens, which cleaves the AHL and acts here as negative control. After three bacterial inoculations, plants were challenged with P. hordei strain I-80 at the three leaves stage. Twelve days after infection, scoring of the leaf area diseased and the infection type was conducted followed by the calculation of the relative susceptibility. First results indicate a significantly (P < 0.001) higher resistance level to P. hordei after inoculation with E. meliloti. Furthermore, significant (P < 0.001) differences were detected between the accessions tested for priming efficiency, which can be the basis to screen a larger set of barley accessions to detect quantitative trait loci or candidate genes involved in priming. [Formula: see text] Copyright © 2019 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

scholarly journals Genes for Adult-Plant Resistance to Leaf Rust in Soft Red Winter Wheat

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Yeshi A. Wamishe ◽  
Eugene A. Milus
Keyword(s):  
Winter Wheat ◽  
Leaf Rust ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Infection Type ◽  
Durable Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Soft Red Winter Wheat ◽  
Red Winter Wheat

Host plant resistance in wheat (Triticum aestivum) has been the principal means of managing leaf rust caused by Puccinia triticina. The need for durable resistance has changed the focus from the use of seedling resistance to adult-plant resistance. The objectives of this study were to determine the genetic basis for adult-plant resistance and to determine the most effective method to identify adult-plant resistance genes Lr12, 13, and 34 among 116 contemporary soft red winter wheat cultivars and breeding lines. Adult-plant resistance was detected by inoculating flag leaves with a race that was virulent on seedlings. Approximately 90% of the lines expressed resistance under controlled conditions. It was postulated that the adult-plant resistance in 67 lines was due in part to either Lr12, 13, or 34; the adult-plant resistance detected in 17 lines was attributed to Lr12 based on a distinctive low infection type very similar to that on the isoline TcLr12; the adult-plant resistance in 27 lines was attributed to Lr34, as all of these lines expressed a “leaf tip necrosis” in the field (a phenotype controlled by a gene known to be tightly linked with Lr34); and the adult-plant resistance in 23 lines was attributed to Lr13 based on a high infection type at 18.1°C and low infection type at 25.5°C with one or more pathogen isolates that were virulent on Lr13 at 18.1°C and avirulent on Lr13 at 25.5°C. The adult-plant resistance detected in the remaining 40% of the lines was due to one or more unidentified genes for adult-plant resistance. In a 4-year field study at several locations, nearly 29% of the lines were resistant at all locations, no line was susceptible at all locations, and only 30% of the lines were susceptible at one or more locations. Given that many of the lines in this study were resistant to all known races of P. triticina before being released as cultivars, the high frequency of adult-plant resistance in this study demonstrates that adult-plant resistance can be incorporated even in the presence of highly effective seedling resistance.

scholarly journals Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2005

Plant Disease ◽  
2007 ◽  
Vol 91 (8) ◽  
pp. 979-984 ◽  
Author(s):  
J. A. Kolmer ◽  
D. L. Long ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Leaf Rust ◽  
Great Plains ◽  
Durable Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
The United States ◽  
Ohio River ◽  
Virulence Phenotype ◽  
Common Phenotype

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 River Valley, southeast, California, and Washington State, in order to determine the virulence of the wheat leaf rust population in 2005. Single uredinial isolates (797 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr21, Lr28, and winter wheat lines with genes Lr41 and Lr42. In the United States in 2005, 72 virulence phenotypes of P. triticina were found. Virulence phenotype TDBGH, selected by virulence to resistance gene Lr24, was the most common phenotype in the United States, and was found throughout the Great Plains region. Virulence phenotype MCDSB with virulence to Lr17a and Lr26 was the second most common phenotype and was found widely in the wheat growing regions of the United States. Virulence phenotype MFPSC, which has virulence to Lr17a, Lr24, and Lr26, was the third most common phenotype, and was found in the Ohio Valley region, the Great Plains, and California. The highly diverse population of P. triticina in the United States will continue to present a challenge for the development of wheat cultivars with effective durable resistance to leaf rust.

The illustrated life cycle of Microbotryum on the host plant Silene latifolia

Botany ◽  
2010 ◽  
Vol 88 (10) ◽  
pp. 875-885 ◽  
Author(s):  
Angela Maria Schäfer ◽  
Martin Kemler ◽  
Robert Bauer ◽  
Dominik Begerow
Keyword(s):  
Life Cycle ◽  
Light And Electron Microscopy ◽  
Laboratory Data ◽  
Infection Process ◽  
Host Cells ◽  
Silene Latifolia ◽  
Long Distance ◽  
Biological Studies ◽  
Plant Parasitic

The plant-parasitic genus Microbotryum (Pucciniomycotina) has been used as a model for various biological studies, but fundamental aspects of its life history have not been documented in detail. The smut fungus is characterized by a dimorphic life cycle with a haploid saprophytic yeast-like stage and a dikaryotic plant-parasitic stage, which bears the teliospores as dispersal agents. In this study, seedlings and flowers of Silene latifolia Poir. (Caryophyllaceae) were inoculated with teliospores or sporidial cells of Microbotryum lychnidis-dioicae (DC. ex Liro) G. Deml & Oberw. and the germination of teliospores, the infection process, and the proliferation in the host tissue were documented in vivo using light and electron microscopy. Although germination of the teliospore is crucial for the establishment of Microbotryum, basidium development is variable under natural conditions. In flowers, where the amount of nutrients is thought to be high, the fungus propagates as sporidia, and mating of compatible cells takes place only when flowers are withering and nutrients are decreasing. On cotyledons (i.e., nutrient-depleted conditions), conjugation occurs shortly after teliospore germination, often via intrapromycelial mating. After formation of an infectious hypha with an appressorium, the invasion of the host occurs by direct penetration of the epidermis. While the growth in the plant is typically intercellular, long distance proliferation seems mediated through xylem tracheary elements. At the beginning of the vegetation period, fungal cells were found between meristematic shoot host cells, indicating a dormant phase inside the plant. By using different microscopy techniques, many life stages of Microbotryum are illustrated for the first time, thereby allowing new interpretations of laboratory data.

scholarly journals Genetic Analysis of Leaf Rust Resistance in Six Durum Wheat Genotypes

2014 ◽  
Vol 104 (12) ◽  
pp. 1322-1328 ◽  
Author(s):  
Alexander Loladze ◽  
Dhouha Kthiri ◽  
Curtis Pozniak ◽  
Karim Ammar
Keyword(s):  
Durum Wheat ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Rust Resistance ◽  
Durable Resistance ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Allelism Tests

Leaf rust, caused by Puccinia triticina, is one of the main fungal diseases limiting durum wheat production. This study aimed to characterize previously undescribed genes for leaf rust resistance in durum wheat. Six different resistant durum genotypes were crossed to two susceptible International Maize and Wheat Improvement Center (CIMMYT) lines and the resulting F1, F2, and F3 progenies were evaluated for leaf rust reactions in the field and under greenhouse conditions. In addition, allelism tests were conducted. The results of the study indicated that most genotypes carried single effective dominant or recessive seedling resistance genes; the only exception to this was genotype Gaza, which carried one adult plant and one seedling resistance gene. In addition, it was concluded that the resistance genes identified in the current study were neither allelic to LrCamayo or Lr61, nor were they related to Lr3 or Lr14a, the genes that already are either ineffective or are considered to be vulnerable for breeding purposes. A complicated allelic or linkage relationship between the identified genes is discussed. The results of the study will be useful for breeding for durable resistance by creating polygenic complexes.

scholarly journals An endometrial organoid model of Chlamydia-epithelial and immune cell interactions

2020 ◽  
Author(s):  
Lee Dolat ◽  
Raphael H. Valdivia
Keyword(s):  
Epithelial Cell ◽  
Cell Biology ◽  
Immune Cell ◽  
Three Dimensional ◽  
Time Lapse ◽  
Cell Types ◽  
Infection Process ◽  
Host Cells ◽  
Cell Diversity ◽  
Intracellular Organelles

ABSTRACTOur understanding of how the obligate intracellular bacterium Chlamydia trachomatis reprograms the cell biology of host cells in the upper genital tract is largely based on observations made in cell culture with transformed epithelial cell lines. Here we describe a primary spherical organoid system derived from endometrial tissue to recapitulate epithelial cell diversity, polarity, and ensuing responses to Chlamydia infection. Using high-resolution and time-lapse microscopy, we catalogue the infection process in organoids from invasion to egress, including the reorganization of the cytoskeleton and positioning of intracellular organelles. We show this model is amenable to screening C. trachomatis mutants for defects in the fusion of pathogenic vacuoles, the recruitment of intracellular organelles, and inhibition of cell death. Moreover, we reconstructed a primary immune cell response by co-culturing infected organoids with neutrophils, and determined that the effector TepP limits the recruitment of neutrophils to infected organoids. Collectively, our model details a system to study the cell biology of Chlamydia infections in three dimensional structures that better reflect the diversity of cell types and polarity encountered by Chlamydia upon infection of their animal hosts.Summary statement3D endometrial organoids to model Chlamydia infection and the role of secreted virulence factors in reprogramming host epithelial cells and immune cell recruitment

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