Host species specificity of the goldenrod rust fungus and the existence of rust resistance within some goldenrod species

1992 ◽  
Vol 70 (12) ◽  
pp. 2461-2466 ◽  
Author(s):  
Michèle C. Heath
Keyword(s):  
British Columbia ◽  
Rust Resistance ◽  
Selective Pressure ◽  
Specific Resistance ◽  
Rust Fungus ◽  
Single Gene ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Low Levels ◽  
Coleosporium Asterum

Five out of six species of goldenrod at a study site in Ontario had rust pustules in the field and also developed pustules after laboratory inoculation with urediospores of a single-pustule isolate of the rust fungus (Coleosporium asterum) obtained from Solidago canadensis. This isolate also successfully infected seedlings of S. canadensis and an additional goldenrod species from British Columbia. Light microscopy revealed low levels of spore germination and high levels of failed infection attempts even on susceptible plants; in S. canadensis, infection commonly failed before the formation of the first haustorium, a phenomenon typical of nonhost resistance and indicative of a degree of nonspecific incompatibility between fungus and host. Only 2 out of over 200 S. canadensis seedlings from Ontario or British Columbia lacked pustules after repeated inoculations compared with 7 out of 36 for Solidago rugosa seedlings from the study site. Microscopically, infection sites in most of these resistant plants resembled those in crop plants with parasite-specific, single-gene resistance. The data raise the possibility that the fungus has exerted a stronger selective pressure for parasite-specific resistance on S. rugosa than on S. canadensis. Key words: Coleosporium asterum, goldenrod, rust fungi, Solidago, specificity.

scholarly journals An Investigation into the Involvement of Defense Signaling Pathways in Components of the Nonhost Resistance of Arabidopsis thaliana to Rust Fungi Also Reveals a Model System for Studying Rust Fungal Compatibility

2003 ◽  
Vol 16 (5) ◽  
pp. 398-404 ◽  
Author(s):  
Denny G. Mellersh ◽  
Michèle C. Heath
Keyword(s):  
Arabidopsis Thaliana ◽  
Rust Fungus ◽  
Fungal Growth ◽  
Rust Fungi ◽  
Nonhost Resistance ◽  
Wild Type ◽  
Pr Genes ◽  
Hypersensitive Cell Death ◽  
Defense Signaling ◽  
Infection Hypha

Seventeen accessions of Arabidopsis thaliana inoculated with the cowpea rust fungus Uromyces vignae exhibited a variety of expressions of nonhost resistance, although infection hypha growth typically ceased before the formation of the first haustorium, except in Ws-0. Compared with wild-type plants, there was no increased fungal growth in ndr1 or eds1 mutants defective in two of the signal cascades regulated by the major class of Arabidopsis host resistance genes. However, in the Col-0 background, infection hyphae of U. vignae and two other rust fungi were longer in sid2 mutants defective in an enzyme that synthesizes salicylic acid (SA), in npr1 mutants deficient in a regulator of the expression of SA-dependent pathogenesis related (PR) genes, and in NahG plants containing a bacterial salicylate hydroxylase. Infection hyphae of U. vignae and U. appendiculatus but not of Puccinia helianthi were also longer in jar1 mutants, which are defective in the jasmonic acid defense signaling pathway. Nevertheless, haustorium formation increased only for the Uromyces spp. and only in sid2 mutants or NahG plants. Rather than the hypersensitive cell death that usually accompanies haustorium formation in nonhost plants, Arabidopsis typically encased haustoria in calloselike material. Growing fungal colonies of both Uromyces spp., indicative of a successful biotrophic relationship between plant and fungus, formed in NahG plants, but only U. vignae formed growing colonies in the sid2 mutants and cycloheximide-treated wild-type plants. Growing colonies did not develop in NahG tobacco or tomato plants. These data suggest that nonhost resistance of Arabidopsis to rust fungi primarily involves the restriction of infection hypha growth as a result of defense gene expression. However, there is a subsequent involvement of SA but not SA-dependent PR genes in preventing the Uromyces spp. from forming the first haustorium and establishing a sufficient biotrophic relationship to support further fungal growth. The U. vignae-Arabidopsis combination could allow the application of the powerful genetic capabilities of this model plant to the study of compatibility as well as nonhost resistance to rust fungi.

The mechanism and inheritance of adult plant leaf rust resistance in 12 wheat lines

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 877-883 ◽  
Author(s):  
D. R. Knott ◽  
B. Yadav
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Flag Leaf ◽  
Rust Fungus ◽  
Single Gene ◽  
Field Resistance ◽  
Growth Chamber ◽  
Adult Plant ◽  
Progress Curve ◽  
Field Nursery

Twelve lines of wheat (Triticum aestivum L.) were developed that had susceptible infection types to leaf rust (Puccinia recondita Rob. ex Desm. f.sp. tritici) race UN 15 in the seedling stage but were resistant in the adult plant stage in the field. The lines were developed from four crosses, each involving four parents (eight in total) that had originally been selected for adult plant or field resistance to stem rust (Puccinia graminis Pers. f.sp. tritici Eriks, and Henn.). The objectives of the present study were to determine the mechanism of resistance to leaf rust and its inheritance in the 12 lines. The 12 lines were grown in an artificially inoculated field nursery in Saskatoon, coefficients of infection (CI) were determined at four dates, and the areas under the disease progress curve (AUDPC) were calculated. Four representative lines were grown in a growth chamber to measure the latent period and pustule size at the two-leaf and flag-leaf stages. Eight lines were crossed and backcrossed to a susceptible check and the parents, F1, F2, F3, and BC1F2 generations were grown in a field nursery. The 12 lines showed wide ranges in CI and AUDPC but all were significantly more resistant than the susceptible check. The four lines studied in the growth chamber had longer latent periods and smaller pustules than the susceptible check at both stages. The differences tended to be greater at the flag-leaf stage. The inheritance studied showed that resistance was recessive or partially recessive and was controlled by two or more genes in each line of the eight lines. In three of the eight lines, Lr34 may be one of the genes and in the other five both Lr13 and Lr34 could be present. However, additional genes are clearly involved. A single gene by itself had only a small effect, but in two and three gene combinations the effects appeared to be greater. This type of resistance appears to occur frequently and may be durable because its complex inheritance may make it more difficult for the rust fungus to overcome. It should be used in breeding wheat for areas where leaf rust is a major problem.Key words: wheat, adult plant rust resistance.

Interactions of the bean rust and cowpea rust fungi with species of the Phaseolus–Vigna plant complex. II. Histological responses to infection in heat-treated and untreated leaves

1989 ◽  
Vol 67 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Janice F. Elmhirst ◽  
Michèle C. Heath
Keyword(s):  
Heat Treatment ◽  
Related Species ◽  
High Frequency ◽  
Colony Formation ◽  
Specific Resistance ◽  
Rust Fungus ◽  
Rust Fungi ◽  
Taxonomic Group ◽  
Bean Rust ◽  
Heat Treated

A comparison of the histological responses of species within the Phaseolus–Vigna plant complex to single isolates of the bean and cowpea rust fungi revealed that no particular response was restricted to any plant taxonomic group, although species differed in the proportion of infection sites at which a particular response was exhibited. Related species did not always show similar frequencies of responses and sometimes there were differences between different genotypes within a nonhost species. In host and nonhost species, preinoculation heat treatment commonly inhibited prehaustorial defenses and delayed the death of the invaded cell. Growing fungal colonies subsequently developed in many species, even those considered nonhosts, particularly if they exhibited a high frequency of prehaustorial defenses in untreated leaves. It is argued that a lack of heat-induced colony formation is a sign of parasite-specific resistance, which most likely evolved only in originally susceptible plants. Consequently, the data suggest that the bean rust fungus has had a long association with American species of the complex and that extant nonhost species may have evolved from susceptible ancestors. In contrast, the cowpea rust fungus appears to have had little evolutionary contact with these American species and may not be as closely related to the bean rust fungus as originally thought.

THE INHERITANCE OF PATHOGENICITY IN RACES 111 AND 29 OF WHEAT STEM RUST

1969 ◽  
Vol 11 (2) ◽  
pp. 266-274 ◽  
Author(s):  
K. N. Kao ◽  
D. R. Knott
Keyword(s):  
Stem Rust ◽  
Rust Resistance ◽  
Single Gene ◽  
Stem Rust Resistance ◽  
Wheat Stem Rust ◽  
Complementary Genes

The inheritance of pathogenicity in wheat stem rust was studied in selfed cultures of races 29 and 111, F1 and F2 cultures of a cross between the two races and cultures from a backcross to race 29. The various cultures were tested on Marquis and Prelude and on a series of lines of these varieties carrying single genes for stem rust resistance. Virulence on Sr 5, Sr 6, Sr 8, Sr 9a, Sr 14 and a gene in Marquis was recessive and in each case there was a single gene for virulence corresponding to each gene for resistance. Virulence on Sr 1 was possibly controlled by two dominant complementary genes. There appeared to be two alleles for virulence on Prelude, one dominant and one recessive.

Linkage and expression of genes for resistance to leaf rust and stem rust in triticale

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 115-118 ◽  
Author(s):  
S. J. Singh ◽  
R. A. McIntosh
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Genetic Linkage ◽  
Rust Resistance ◽  
Single Gene ◽  
Leaf Rust Resistance ◽  
Stem Rust Resistance ◽  
Stem Rust Resistance Gene ◽  
Expression Of Genes ◽  
Triticosecale Wittmack

Leaf rust resistance in five triticale cultivars was controlled by a single gene designated LrSatu. This gene was closely linked in coupling with the stem rust resistance gene SrSatu believed to be located on chromosome 3R. Approximately 50% of lines in the 17th International Triticale Screening Nursery possessed SrSatu and LrSatu. Lines carrying SrSatu and LrSatu occurred more frequently among complete than in substituted triticale lines.Key words: × Triticosecale Wittmack, P. graminis f.sp. tritici, P. recondita f.sp. tritici, leaf rust, stem rust, rust resistnace, genetic linkage.

scholarly journals Virulence Characterization of Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici in Ethiopia and Evaluation of Ethiopian Wheat Germplasm for Resistance to Races of the Pathogen from Ethiopia and the United States

Plant Disease ◽  
2017 ◽  
Vol 101 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Anmin Wan ◽  
Kebede T. Muleta ◽  
Habtemariam Zegeye ◽  
Bekele Hundie ◽  
Michael O. Pumphrey ◽  
...  
Keyword(s):  
United States ◽  
Stripe Rust ◽  
Puccinia Striiformis ◽  
Rust Fungus ◽  
Single Gene ◽  
The United States ◽  
Wheat Cultivars ◽  
Low Frequencies ◽  
Additional Information

Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most important diseases of wheat in Ethiopia. In total, 97 isolates were recovered from stripe rust samples collected in Ethiopia in 2013 and 2014. These isolates were tested on a set of 18 Yr single-gene differentials for characterization of races and 7 supplementary differentials for additional information of virulence. Of 18 P. striiformis f. sp. tritici races identified, the 5 most predominant races were PSTv-105 (21.7%), PSTv-106 (17.5%), PSTv-107 (11.3%), PSTv-76 (10.3%), and PSTv-41 (6.2%). High frequencies (>40%) were detected for virulence to resistance genes Yr1, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27, Yr28, Yr31, Yr43, Yr44, YrExp2, and YrA. Low frequencies (<40%) were detected for virulence to Yr10, Yr24, Yr32, YrTr1, Hybrid 46, and Vilmorin 23. None of the isolates were virulent to Yr5, Yr15, YrSP, and YrTye. Among the six collection regions, Arsi Robe and Tiyo had the highest virulence diversities, followed by Bekoji, while Bale and Holeta had the lowest. Evaluation of 178 Ethiopian wheat cultivars and landraces with two of the Ethiopian races and three races from the United States indicated that the Ethiopian races were more virulent on the germplasm than the predominant races of the United States. Thirteen wheat cultivars or landraces that were resistant or moderately resistant to all five tested races should be useful for breeding wheat cultivars with resistance to stripe rust in both countries.

High Levels of Genetic Variability in an Isolated Colony of Rock-wallabies (Petrogale assimilis): Evidence from Three Classes of Molecular Markers

1997 ◽  
Vol 45 (2) ◽  
pp. 199 ◽  
Author(s):  
Peter B. S. Spencer ◽  
Mark Adams ◽  
Helene Marsh ◽  
David J. Miller ◽  
Mark D. B. Eldridge
Keyword(s):  
Genetic Variation ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Mating Systems ◽  
Selective Pressure ◽  
Multiple Mating ◽  
Dna Fingerprints ◽  
Average Heterozygosity ◽  
Low Levels ◽  
High Level

Estimates of genetic variation for a small (Ne = 39) colony of allied rock-wallabies (Petrogale assimilis) were calculated with three different categories of molecular marker. Average heterozygosity was estimated at 3·8% for allozymes, 47·3% for multilocus ‘DNA fingerprints’ and 85·5% for microsatellite markers. Overall these values indicate that this small isolated colony of rock-wallabies maintains a high level of genetic variation despite its relative isolation and the apparently low levels of migration between colonies. It is likely that mechanisms exist (such as kin avoidance, multiple mating systems, high and variable selective pressure in extreme and fluctuating environmental conditions) that promote the maintenance of high levels of genetic variation in isolated colonies of P. assimilis. These mechanisms are discussed in the context of the results obtained from the molecular markers.

scholarly journals Leaf Cuticle Can Contribute to Non-Host Resistance to Poplar Leaf Rust

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 870 ◽  
Author(s):  
Yu ◽  
Shen ◽  
Newcombe ◽  
Fan ◽  
Chen
Keyword(s):  
Host Resistance ◽  
Populus Deltoides ◽  
Rust Fungus ◽  
Trimethylsilyl Ether ◽  
Populus Tomentosa ◽  
Rust Fungi ◽  
Mesophyll Cells ◽  
Defense Compounds ◽  
Leaf Cuticle ◽  
Poplar Leaf

The plant leaf cuticle is a chemically complex but largely waxy outer shell that limits water loss and also prevents some pathogens from gaining access to internal mesophyll. Rust fungi are obligate parasites, and most bypass the cuticle by thigmotropically locating stomata, growing through the stomatal openings, and then parasitizing mesophyll cells with haustoria. It is thought that even non-hosts of a given rust fungus do not resist until their mesophyll cells are contacted in this way. In other words, it is thought that the cuticle plays no role in non-host resistance. Here, we tested the hypothesis that poplar leaf cuticles might contribute to non-host resistance to rust fungi by chemically impeding the germination and growth of urediniosporelings of Melampsora larici-populina. Following an initial survey in China of the resistance of 36 genotypes of various species and interspecific hybrids of Populus to M. larici-populina, we selected three genotypes for the initial test of hypothesis: (1) A Populus purdomii genotype that is fully susceptible; (2) a Populus deltoides cv. ‘I-69′ that is incompletely resistant (i.e., a resistant host); and (3) a Populus tomentosa genotype that is a non-host to M. larici-populina. Urediniospores were assayed for germination in extracts of the cuticles of the three genotypes. Germination was most reduced by the P. tomentosa non-host cuticular extracts that also reduced the growth of germ tubes to 36 times less than that in controls or in the extract of the susceptible P. purdomii. Four cuticular components were identified as putative defense compounds given greater concentrations in P. tomentosa than in P. purdomii: Aucubin, hexakis(trimethylsilyl) ether, catechol, 7,9-Di-tert-buty l-1-oxaspiro (4,5) deca-6, 9-diene-2,8-dione and trifluoroacetamide. These four compounds were then tested, and they reduced urediniospore germination and uredinial density in inoculations of normally susceptible P. purdomii with Melampsora larici-populina. Thus, the cuticle of P. tomentosa can contribute to pre-haustorial, non-host resistance to M. larici-populina.

scholarly journals Putative Rust Fungal Effector Proteins in Infected Bean and Soybean Leaves

2016 ◽  
Vol 106 (5) ◽  
pp. 491-499 ◽  
Author(s):  
Bret Cooper ◽  
Kimberly B. Campbell ◽  
Hunter S. Beard ◽  
Wesley M. Garrett ◽  
Nazrul Islam
Keyword(s):  
Plant Cell ◽  
Crop Production ◽  
Rust Fungus ◽  
Fungal Spores ◽  
Pathogenic Fungi ◽  
Rust Fungi ◽  
Effector Proteins ◽  
Glycoside Hydrolases ◽  
Data Set ◽  
Soybean Leaves

The plant-pathogenic fungi Uromyces appendiculatus and Phakopsora pachyrhizi cause debilitating rust diseases on common bean and soybean. These rust fungi secrete effector proteins that allow them to infect plants, but their effector repertoires are not understood. The discovery of rust fungus effectors may eventually help guide decisions and actions that mitigate crop production loss. Therefore, we used mass spectrometry to identify thousands of proteins in infected beans and soybeans and in germinated fungal spores. The comparative analysis between the two helped differentiate a set of 24 U. appendiculatus proteins targeted for secretion that were specifically found in infected beans and a set of 34 U. appendiculatus proteins targeted for secretion that were found in germinated spores and infected beans. The proteins specific to infected beans included family 26 and family 76 glycoside hydrolases that may contribute to degrading plant cell walls. There were also several types of proteins with structural motifs that may aid in stabilizing the specialized fungal haustorium cell that interfaces the plant cell membrane during infection. There were 16 P. pachyrhizi proteins targeted for secretion that were found in infected soybeans, and many of these proteins resembled the U. appendiculatus proteins found in infected beans, which implies that these proteins are important to rust fungal pathology in general. This data set provides insight to the biochemical mechanisms that rust fungi use to overcome plant immune systems and to parasitize cells.

Notes on rust fungi in China 8. Pucciniastrum tiliae life cycle and new host plants inferred from phylogenetic evidence

Mycotaxon ◽  
2020 ◽  
Vol 135 (3) ◽  
pp. 490-499
Author(s):  
Jing-Xin Ji ◽  
Zhuang Li ◽  
Yu Li ◽  
Makoto Kakishima
Keyword(s):  
Life Cycle ◽  
Northeast China ◽  
Host Plants ◽  
Phylogenetic Analyses ◽  
Rust Fungus ◽  
Rust Fungi ◽  
New Host ◽  
First Time

The life cycle connection between spermogonial and aecial stages of a rust fungus found on Abies holophylla and uredinial and telial stages on Tilia mongolica and T. mandshurica collected in northeast China were confirmed by phylogenetic analyses. The rust, identified as Pucciniastrum tiliae, was confirmed by morphological observations. The life cycle of this rust fungus is reported for the first time in China, and A. holophylla and T. mongolica represent new host plants for the species.

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