GENETIC CONTROL OF VIRULENCE IN USTILAGO HORDEI. II. SEGREGATIONS FOR HIGHER LEVELS OF VIRULENCE

1971 ◽  
Vol 13 (2) ◽  
pp. 173-178 ◽  
Author(s):  
Gurmel Sidhu ◽  
Clayton Person
Keyword(s):  
Genetic Control ◽  
Virulence Genes ◽  
Barley Cultivars ◽  
Ustilago Hordei

Genetics of virulence of Ustilago hordei towards five barley cultivars (Excelsior, Vantage, Hannchen, Trebi and Lion) was investigated. Two genes, Uhv-1 and Uhv-2, were identified; Uhv-2 was effective on Excelsior, and Uhv-1 on both Hannchen and Vantage. The virulence genes were both recessive.

IDENTICAL GENES FOR VIRULENCE IN THE SMUTS USTILAGO HORDEI AND U. NIGRA, AND INHERITANCE OF VIRULENCE ON THE BARLEY CULTIVARS KEYSTONE AND CONQUEST

1974 ◽  
Vol 54 (2) ◽  
pp. 253-257 ◽  
Author(s):  
R. A. FULLERTON ◽  
J. NIELSEN
Keyword(s):  
Hordeum Vulgare ◽  
Virulence Genes ◽  
Recessive Gene ◽  
Breeding Program ◽  
Hordeum Vulgare L ◽  
Barley Cultivars ◽  
Ustilago Hordei

Virulence of Ustilago hordei (Pers.) Lagerh. and U. nigra Tapke on the barley (Hordeum vulgare L.) cultivars Keystone and Conquest was studied. One recessive gene or linked genes, the same in both smut species, appeared to confer virulence on both cultivars. Earlier investigators had found identical virulence genes in both species of smut for the cultivars Excelsior, Lion, Pannier and Trebi. Therefore, testing for resistance or susceptibility in a breeding program could be done with a strain of only one of the species.

GENETIC CONTROL OF VIRULENCE IN USTILAGO HORDEI III. IDENTIFICATION OF GENES FOR HOST RESISTANCE AND DEMONSTRATION OF GENE-FOR-GENE RELATIONS

1972 ◽  
Vol 14 (2) ◽  
pp. 209-213 ◽  
Author(s):  
Gurmel Sidhu ◽  
Clayton Person
Keyword(s):  
Hordeum Vulgare ◽  
Genetic Control ◽  
Host Resistance ◽  
Virulence Genes ◽  
Genetics Of Resistance ◽  
Ustilago Hordei ◽  
Dominant Characteristic ◽  
Test Cultures ◽  
Gene For Gene

The genetics of resistance of three barley varieties, Excelsior (E), Hannchen (H) and Vantage (V), was investigated against two known virulence genes (Uhv-1 and Uhv-2) present in two test cultures of Ustilago hordei. Segregations obtained from F3 progenies derived from crosses EXH and EXV revealed that resistance and susceptibility to the two test cultures were inherited independently of one another; the resistance was expressed as a dominant characteristic at both loci. The host alleles discovered through the interactions with culture UhV1UhV1Uhv2Uhv2 were designated as UhR1 and Uhr1; those revealed by interactions with culture Uhv1Uhv1UhV2UhV2 were designated as UhR2 and Uhr2. The genotype UhR1UhR1Uhr2UhV2 was thus assigned to varieties Hannchen and Vantage and UhR1Uhr1UhR2UhR2 to variety Excelsior. The interrelationships between two loci for resistance in the host and the two corresponding loci for virulence in the pathogen thus lead us to conclude that a gene-for-gene relationship also exists in the Hordeum vulgare: Ustilago hordei system.

Quantitative genetics of disease incidence in Ustilago hordei controlled by virulence and aggressiveness genes

1991 ◽  
Vol 69 (2) ◽  
pp. 420-427 ◽  
Author(s):  
David D. Pope ◽  
Conrad F. Wehrhahn
Keyword(s):  
Disease Incidence ◽  
Additive Genetic Variance ◽  
Virulence Gene ◽  
Supporting Evidence ◽  
Gene Effects ◽  
Barley Cultivars ◽  
Weak Evidence ◽  
Ustilago Hordei ◽  
Selection For ◽  
Maximal Expression

Biometric analyses of variability in the disease incidence phenotype were performed using three F2 dikaryotic populations of the smut fungus Ustilago hordei (Pers.) Lagerh. on barley cultivars 'Trebi' (partially resistant) and 'Odessa' (universal suscept). The variance component involving interactions between segregating genes of U. hordei and environmental factors made the largest contribution towards the disease incidence on both cultivars. Additive and nonadditive (dominant and epistatic) gene effects contributed significantly to total disease incidence variation on both 'Trebi' and 'Odessa'. Heritability (additive genetic variance) was 2.5 times higher on 'Trebi' than on 'Odessa', and nonadditive variance effects were higher on 'Odessa' than on 'Trebi' by a factor of 1.5. Five effective factors were estimated to be segregating in the F2 populations; the virulence gene and four agressiveness factors. It is hypothesized that certain aggressiveness polygenes interact either with at least one other aggressiveness polygene or with the virulence gene. Analysis of variance–covariance provided supporting evidence for the epistatic activity of some genes and weak evidence for possible previous selection for intermediate optimal rather than maximal expression of the disease incidence phenotype. Key words: Ustilago hordei, aggressiveness, polygenes, disease incidence, smut.

scholarly journals Resistance To Powdery Mildew In Selected Czech Winter Barley Breeding Lines

2011 ◽  
Vol 41 (No. 2) ◽  
pp. 45-50 ◽  
Author(s):  
A. Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Virulence Genes ◽  
Spring Barley ◽  
Practical Importance ◽  
Farming Systems ◽  
Winter Barley ◽  
Substantial Part ◽  
Breeding Lines ◽  
Barley Cultivars ◽  
Barley Breeding

Powdery mildew resistances in Czech winter barley breeding lines were postulated on the basis of their reaction types to 32 pathotypes of the pathogen with different combinations of virulence genes. The results from testing 38 lines represent a substantial part of found variability in the examined trait with 13 found resistances. The resistances typical of winter barley cultivars dominated in six-row lines whereas the resistances typical of spring barley cultivars were more frequent in two-row lines. None of these resistances was effective enough to all used pathotypes. Desired effectiveness is present neither in the lines with a combination of corresponding resistances nor in the cases when their resistance is controlled by more (up to six) postulated genes. Resistances “Ch” (detected in the line CH 669) and “Lu” (detected in the line LU 1258/A/02) are novel, the former without any practical importance. A need of breeding winter barley cultivars resistant to powdery mildew is discussed since they are required for both conventional and particularly low-input farming systems.

scholarly journals UhAVR1, an HR-triggering avirulence effector of Ustilago hordei, is secreted via the ER-Golgi pathway to the cytosol of barley coleoptile cells and contributes to virulence early in infection

2020 ◽  
Author(s):  
Ana Priscilla Montenegro Alonso ◽  
Shawkat Ali ◽  
Xiao Song ◽  
Rob Linning ◽  
Guus Bakkeren
Keyword(s):  
Natural Infection ◽  
Resistance Breeding ◽  
Infection Process ◽  
Molecular Function ◽  
Avirulence Genes ◽  
Heterologous Host ◽  
Common Component ◽  
Barley Cultivars ◽  
Ustilago Hordei ◽  
Virulence Effectors

AbstractThe basidiomycete Ustilago hordei (Uh) causes covered smut disease of barley and oats. Virulence effectors that aid the infection process and support the pathogen’s lifestyle have been described for this fungus. Genetically, six avirulence genes are known and one codes for UhAVR1, the only proven avirulence effector identified in smut pathogens to date that triggers complete immunity in barley cultivars carrying the resistance gene Ruh1. A prerequisite for resistance breeding is understanding the host targets and molecular function of UhAVR1. Analysis of this effector upon natural infection of barley coleoptiles using teliospores showed that UhAVR1 is expressed during the early stages of fungal infection where it leads to HR triggering in resistant cultivars or performs its virulence function in susceptible cultivars. Fungal secretion of UhAVR1 is directed by its signal peptide and occurs via the BrefeldinA-sensitive ER-Golgi pathway, both in cell culture away from its host, and during barley interaction. Transient expression of this effector in barley and a heterologous host, Nicotiana benthamiana (Nb), supports a cytosolic localization. Delivery of UhAVR1 via foxtail mosaic virus, Pseudomonas species or Agrobacterium-mediated suppression of cell inducers in barley and Nb support a role in the suppression of a common component(s) of ETI and PTI which is conserved in both plant systems.

scholarly journals UhAVR1, an HR-Triggering Avirulence Effector of Ustilago hordei, Is Secreted via the ER–Golgi Pathway, Localizes to the Cytosol of Barley Cells during in Planta-Expression, and Contributes to Virulence Early in Infection

2020 ◽  
Vol 6 (3) ◽  
pp. 178 ◽  
Author(s):  
Ana Priscilla Montenegro Alonso ◽  
Shawkat Ali ◽  
Xiao Song ◽  
Rob Linning ◽  
Guus Bakkeren
Keyword(s):  
Nicotiana Benthamiana ◽  
Natural Infection ◽  
Resistance Breeding ◽  
Molecular Function ◽  
Avirulence Genes ◽  
In Planta ◽  
Barley Cultivars ◽  
Ustilago Hordei ◽  
Pseudomonas Species ◽  
Virulence Effectors

The basidiomycete Ustilago hordei causes covered smut disease of barley and oats. Virulence effectors promoting infection and supporting pathogen lifestyle have been described for this fungus. Genetically, six avirulence genes are known and one codes for UhAVR1, the only proven avirulence effector identified in smuts to date that triggers complete immunity in barley cultivars carrying resistance gene Ruh1. A prerequisite for resistance breeding is understanding the host targets and molecular function of UhAVR1. Analysis of this effector upon natural infection of barley coleoptiles using teliospores showed that UhAVR1 is expressed during the early stages of fungal infection where it leads to HR triggering in resistant cultivars or performs its virulence function in susceptible cultivars. Fungal secretion of UhAVR1 is directed by its signal peptide and occurs via the BrefeldinA-sensitive ER–Golgi pathway in cell culture away from its host. Transient in planta expression of UhAVR1 in barley and a nonhost, Nicotiana benthamiana, supports a cytosolic localization. Delivery of UhAVR1 via foxtail mosaic virus or Pseudomonas species in both barley and N. benthamiana reveals a role in suppressing components common to both plant systems of Effector- and Pattern-Triggered Immunity, including necrosis triggered by Agrobacterium-delivered cell death inducers.

INTERACTION OF VIRULENCE GENES IN USTILAGO HORDEI

1976 ◽  
Vol 18 (1) ◽  
pp. 141-149 ◽  
Author(s):  
P. L. Thomas
Keyword(s):  
Virulence Genes ◽  
Single Gene ◽  
Virulence Gene ◽  
Ustilago Hordei ◽  
Genotype V

The genetic cause of virulence of Ustilago hordei on the cultivars Lion and Plush was attributed to a single gene, designated v6. This gene was recessive and unlinked to either v1 or v2. Dikaryons with the genotype v1v1V6v6 were virulent on Hannchen while those with v2v2V6v6 were virulent on Excelsior. However, the the combination v1v1v6v6 was required for virulence on Vantage. The resistance of other cultivars of the host was overcome by combinations of more than one virulence gene in the pathogen, indicating that some cultivars possess more than one gene for resistance.

Ultrastructural characteristics of sporidia of Ustilago

1989 ◽  
Vol 47 ◽  
pp. 786-787
Author(s):  
Patricia N. Hackney
Keyword(s):  
Electron Microscope ◽  
Type System ◽  
Tube Formation ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
University Of Wisconsin ◽  
Transmission Electron ◽  
Ustilago Hordei ◽  
Silene Alba ◽  
The University

Ustilago hordei and Ustilago violacea are yeast-like basidiomycete pathogens ofHordeum vulgare and Silene alba respectively. The mating type system in both species of Ustilago is bipolar, with alleles, A,a, (U.hordei) and a1, a2 (U.violacea) at a single locus. Haploid sporidia maintain the asexual phase by budding, while the sexual phase is initiated by conjugation tube formation between the mating types during budding and conjugation.For observation of budding, sporidia were prepared by culturing the four types on YEG (yeast extract glucose) broth for 24 hours. After centrifugation at 5000g cells were either left unmated or mated in a1/a2,A/a combinations. The sporidia were then mixed 1:1 with 4% agar and the resulting 1mm cubes fixed in 8% gluteraldehyde and post fixed in osmium tetroxide. After dehydration and embedding cubes were thin sectioned with a LKB ultratome and photographed in a Zeiss 9s transmission electron microscope or in an AE1 electron microscope of MK11 1MEV at the High Voltage Electron Microscopy Center of the University of Wisconsin-Madison.

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

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