Occurrence of Tapesia yallundae apothecia on field and laboratory-inoculated material and evidence for recombination between isolates

1991 ◽  
Vol 40 (4) ◽  
pp. 626-634 ◽  
Author(s):  
P. NICHOLSON ◽  
H N. REZANOOR ◽  
T. W. HOLLINS
Keyword(s):  
Tapesia Yallundae

scholarly journals Distinguishing isolates of cereal stem disease pathogens of the genus Tapesia from isolates of Fusarium and Rhizoctonia using the RAPD method

2000 ◽  
Vol 36 (No. 4) ◽  
pp. 132-140
Author(s):  
P. Vejl ◽  
S. Skupinová ◽  
I. Polišenská ◽  
M. Váňová
Keyword(s):  
Triticum Aestivum ◽  
Triticum Aestivum L ◽  
Fusarium Avenaceum ◽  
The Czech Republic ◽  
Tapesia Yallundae ◽  
Random Amplification ◽  
High Degree ◽  
Rhizoctonia Cerealis ◽  
Species Variability ◽  
Rapd Method

The RAPD method (Random Amplification of Polymorphous DNA) was used to distinguish Tapesia acufonnis and T. yallundae isolates from other pathogens of wheat stem base diseases (Fusarium avenaceum, F. culmorum, F. nivale, Rhizoctonia cerealis and R. so/ani).Isolates of the fungi originated from infected wheat plants (Triticum aestivum L.) collected at various locations in the Czech Republic. Three decameric oligonucleotide-primers were selected as producing genotype-specific RAPD products. These markers distinguish all isolates of the above taxons. The intra-species genetic variability of these species also was studied. The values of Dice's coefficients of similarity suggest that isolates of Tapesia yallundae showed a higher degree of intra-species variability than those ofT acufonnis. A high degree of intra-species variability was identified also in Fusarium avenaceum.

Diversité morphologique en culture, sensibilité au carbendazime et pouvoir pathogène du Tapesia yallundae (anamorphe : Pseudocercosporella herpotrichoides)

1995 ◽  
Vol 73 (9) ◽  
pp. 1379-1384 ◽  
Author(s):  
Peter Frei ◽  
Daniel Gindrat
Keyword(s):  
Growth Rate ◽  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Rapid Growth ◽  
Slow Growth ◽  
Colony Growth ◽  
Sexual Stage ◽  
Pseudocercosporella Herpotrichoides ◽  
Tapesia Yallundae ◽  
Irregular Margin

Three types of colonies (WH, WA, and RA) have been characterized among 2245 isolates of Pseudocercosporella herpotrichoides on the basis of colony growth rate and appearance (W, rapid growth and regular margin; R, slow growth and irregular margin) and of the shape of the majority of conidia (H, coiled; A, straight). Apothecia of Tapesia yallundae (anamorph : P. herpotrichoides) were produced on naturally infected stems of winter wheat and barley. Apothecia of an undetermined discomycete were occasionally observed. The progeny of more than 1700 ascospores from 72 apothecia of T. yallundae was distributed among the three types of colonies. These types remained stable through successive conidial and mycelial subcultures. All three colony types were sometimes obtained from a single apothecium. WH and WA were the most common, while RH was never observed. WA isolates were more often resistant than WH isolates to carbendazim. Inoculations of wheat and barley stems with ascospores of T. yallundae were unsuccessful, while inoculations with conidia or mycelium resulted in eyespot lesions. During equivalent periods, RA isolates were less virulent than WH and WA. Key words: cereals, eyespot, Deuteromycetes, sexual stage, Hordeum vulgare, Triticum aestivum.

scholarly journals Changes in populations of the eyespot fungi Tapesia yallundae and T. acuformis under different fungicide regimes in successive crops of winter wheat, 1984-2000

2002 ◽  
Vol 51 (2) ◽  
pp. 191-201 ◽  
Author(s):  
S. M. Bierman ◽  
B. D. L. Fitt ◽  
F. Van Den Bosch ◽  
G. L. Bateman ◽  
J. F. Jenkyn ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Tapesia Yallundae

scholarly journals Ornithine Decarboxylase Knockout in Tapesia yallundae Abolishes Infection Plaque Formation In Vitro but Does Not Reduce Virulence Toward Wheat

2001 ◽  
Vol 14 (11) ◽  
pp. 1303-1311 ◽  
Author(s):  
E. Mueller ◽  
A. Bailey ◽  
A. Corran ◽  
A. J. Michael ◽  
P. Bowyer
Keyword(s):  
Ornithine Decarboxylase ◽  
Genomic Library ◽  
Normal Growth ◽  
Gene Replacement ◽  
Tapesia Yallundae ◽  
Suitable Target ◽  
Targeted Gene Replacement ◽  
Polymerase Chain ◽  
In Vitro Induction

A knockout strain of Tapesia yallundae lacking the single ornithine decarboxylase (ODC) allele has been created by targeted gene replacement. A central region of the ODC gene was isolated by polymerase chain reaction with degenerate oligonucleotides and used to probe a lambda genomic library. The gene was sequenced, and the encoded ODC protein sequence was shown to be similar to those from other fungi. The functionality of the T. yallundae ODC was confirmed by complementation of an Aspergillus nidulans mutant (puA) strain devoid of ODC activity, restoring growth in the absence of exogenous polyamines. Transformation-mediated gene replacement was used to create strains that were auxotrophic for putrescine and lack ODC coding sequences. ODC knockout strains were unable to differentiate infection structures after in vitro induction and showed an abnormal hyphal branching phenotype. Pathogenicity studies on these mutants showed that, surprisingly, they are not reduced in virulence compared with nondisrupted transformants. This suggests that the strains carrying an ODC disruption can obtain sufficient polyamines from the host plant for normal growth and differentiation and, therefore, that fungal ODC may not be a suitable target for fungicides.

scholarly journals Tapesia yallundae collected from wheat stubble in South Africa

1994 ◽  
Vol 125 (1) ◽  
pp. 23-28 ◽  
Author(s):  
B. Robbertse ◽  
P. W. Crous ◽  
G. Holz
Keyword(s):  
South Africa ◽  
Tapesia Yallundae ◽  
Wheat Stubble

scholarly journals Genetic Control of Resistance to the Sterol 14α-Demethylase Inhibitor Fungicide Prochloraz in the Cereal Eyespot PathogenTapesia yallundae

2000 ◽  
Vol 66 (11) ◽  
pp. 4599-4604 ◽  
Author(s):  
Paul S. Dyer ◽  
Jacqueline Hansen ◽  
Andrew Delaney ◽  
John A. Lucas
Keyword(s):  
New Zealand ◽  
Genetic Basis ◽  
Major Gene ◽  
Bimodal Distribution ◽  
Genetic Components ◽  
Quantitative Genetic ◽  
Tapesia Yallundae ◽  
And Control ◽  
Resistant Progeny ◽  
Sexual Crosses

ABSTRACT Sexual crosses were used to determine the genetic basis of resistance to the sterol 14 α-demethylase inhibitor fungicide prochloraz in the cereal eyespot pathogen Tapesia yallundae. Three different crosses between sensitive parental strains (22-432 and 22-433 [the concentration required to inhibit growth by 50% {IG50} for each was ≤0.03 mg/liter]) and field isolates from France and New Zealand with differing levels of resistance (PR11 [IG50 = 0.5 mg/liter], PR1 [IG50 = 1.0 mg/liter], and 11-3-18 [IG50 = 2.4 mg/liter]) yielded progeny showing a bimodal distribution, with an even number of sensitive and resistant progeny. This indicated the segregation of a single major gene for resistance in each cross, which was confirmed by the use of backcrosses, crosses between F1 progeny, and control crosses between sensitive parents. However, there was also evidence of additional quantitative genetic components responsible for the increased IG50s of the more resistant isolates. A further cross was made between isolate PR11 and an F1 progeny arising from isolate 11-3-18, and this also yielded progeny which were entirely prochloraz resistant. This suggested that resistance genes were allelic in these two isolates, with resistance conferred by a gene at the same locus (or closely linked loci), despite the fact that the isolates (PR11 and 11-3-18) originated from different continents.

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