Role of Host Sensitivity to Ptr ToxA in Development of Tan Spot of Wheat

Friesen, Timothy L.; Ali, Shaukat; Kianian, Shahryar F.; Francl, L. J.; Rasmussen, J. B.

doi:10.1094/phyto.2003.93.4.397

Cited by 69 publications

(67 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The evaluation was conducted individually with each isolate. Preparation of fungal cultures and inoculum and fungal inoculations were done as described by Friesen et al (2003). The fungus was cultured on V8-potato dextrose agar (PDA) in the dark for 5 days at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Evaluation and Association Mapping of Resistance to Tan Spot and Stagonospora Nodorum Blotch in Adapted Winter Wheat Germplasm

et al. 2015

View full text Add to dashboard Cite

Tan spot and Stagonospora nodorum blotch (SNB), often occurring together, are two economically significant diseases of wheat in the Northern Great Plains of the United States. They are caused by the fungi Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, both of which produce multiple necrotrophic effectors (NE) to cause disease. In this work, 120 hard red winter wheat (HRWW) cultivars or elite lines, mostly from the United States, were evaluated in the greenhouse for their reactions to the two diseases as well as NE produced by the two pathogens. One P. nodorum isolate (Sn4) and four Pyrenophora tritici-repentis isolates (Pti2, 331-9, DW5, and AR CrossB10) were used separately in the disease evaluations. NE sensitivity evaluation included ToxA, Ptr ToxB, SnTox1, and SnTox3. The numbers of lines that were rated highly resistant to individual isolates ranged from 11 (9%) to 30 (25%) but only six lines (5%) were highly resistant to all isolates, indicating limited sources of resistance to both diseases in the U.S. adapted HRWW germplasm. Sensitivity to ToxA was identified in 83 (69%) of the lines and significantly correlated with disease caused by Sn4 and Pti2, whereas sensitivity to other NE was present at much lower frequency and had no significant association with disease. As expected, association mapping located ToxA and SnTox3 sensitivity to chromosome arm 5BL and 5BS, respectively. A total of 24 potential quantitative trait loci was identified with −log (P value) > 3.0 on 12 chromosomes, some of which are novel. This work provides valuable information and tools for HRWW production and breeding in the Northern Great Plains.

show abstract

Section: Methodsmentioning

confidence: 99%

Evaluation and Association Mapping of Resistance to Tan Spot and Stagonospora Nodorum Blotch in Adapted Winter Wheat Germplasm

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Anderson et al (1999) further reported that the same insensitivity gene, Tsn1, controls insensitivity in both durum and common wheat and this gene is located on chromosome arm 5BL. However, Friesen et al (2003) observed that segregation of insensitivity to necrosis induced by Ptr ToxA was controlled by a single gene, while the disease reaction of the recombinant inbred lines to spore inoculation by race 2 revealed that four to five genes may control resistance in the population. They observed that insensitivity to Ptr ToxA accounted for only 24% of the resistance to race 2 and concluded that Ptr ToxA was a virulence factor and not a pathogenicity factor.…”

Section: Pathogenic Variabilitymentioning

confidence: 99%

Genetics of wheat–Pyrenophora tritici-repentis interactions

Singh

Duveiller

et al. 2009

Euphytica

View full text Add to dashboard Cite

Tan spot, caused by an ascomycete fungus Pyrenophora tritici-repentis, is one of the most devastating foliar diseases of wheat. This fungus induces two distinct symptoms, tan necrosis and extensive chlorosis, on susceptible wheat cultivars. Besides causing average yield losses of 5-10%, tan spot also causes significant losses in grain quality by grain shriveling, red smudge, and black point. Conservation agriculture in combination with wheat monoculture involving cultivation of susceptible cultivars has resulted in frequent onset of tan spot epidemics worldwide. Development of new resistant wheat cultivars, in conjunction with crop rotation, will provide an effective, economical, and environmentally safe means of controlling tan spot. Presently, eight races of P. tritici-repentis have been identified worldwide based on the ability to induce necrosis and chlorosis symptoms on a set of differential wheat cultivars. P. tritici-repentis is a homothallic fungus having both sexual and asexual reproduction resulting in high genetic diversity worldwide. Both quantitative and qualitative mode of inheritance for resistance to tan spot of wheat has been reported. The tan spot fungus produces multiple host-specific toxins and host resistance is highly correlated to insensitivity to toxins. Genetic studies have further confirmed that wheat-P. tritici-repentis follows the toxin model of gene-for-gene hypothesis although other mechanism of host-pathogen interaction may exist and exploitation of all resistance phenomenon is to be adopted to develop durable resistant cultivars.

show abstract

“…Friesen et al (2002), however, observed that wheat lines harboring mutations for insensitivity to Ptr ToxA induced by ethylmethane sulfonate were not necessarily resistant to race 1 (Ptr ToxA + or Ptr ToxC + ) of the fungus. In a recent study, Friesen et al (2003) reported that insensitivity to Ptr ToxA in F 2 -derived F 6 recombinant inbred lines did not result in complete resistance to race 2 (Ptr ToxA). The authors found that insensitivity to Ptr ToxA accounted for only 24% of the resistance to race 2 The solid line indicates the region coding for a putative signal peptide.…”

Section: Like Most Reported Host-specific Toxins the Toxins Of Pyrenmentioning

confidence: 99%

Host–parasite interactions in tan spot [Pyrenophora tritici-repentis] of wheat

Strelkov

Lamari

2003

Canadian Journal of Plant Pathology

151

View full text Add to dashboard Cite

Tan spot of wheat, caused by the ascomycete Pyrenophora tritici-repentis, is an economically important disease in all the major wheat growing areas worldwide. Even though the pathogen was known to occur on grasses and episodically on wheat for more than eight decades, large-scale epidemics of tan spot were first recorded in the early 1970s. The increased incidence was associated with stubble retention, a practice implemented in the context of soil conservation. The present review highlights some of the recent developments that have occurred in studies of the wheat -P. tritici-repentis interaction and discusses the implications for our understanding of host-parasite relations in general. Races of P. tritici-repentis produce at least three host-specific toxins, effective on particular host lines or cultivars. Single dominant and independently inherited genes control host reaction to these toxins, with one gene for each toxin. Eight races of the pathogen have now been identified from collections made in several parts of the world, accounting for all virulence patterns expected from three toxins matching three "susceptibility" genes in the host. Genetic analyses of host and pathogen suggested that a one-to-one relationship existed in the wheat -P. tritici-repentis interaction. The model described for tan spot of wheat appears to be a mirror image of the classical gene-for-gene in that it is based on compatibility. Thus, it is proposed that the gene-for-gene model can be extended, as previously predicted by others, to pathosystems involving multiple host-specific toxins. The relationship between toxin production and the evolution of new races is also discussed.Résumé : La tache auréolée du blé, causée par l'ascomycète Pyrenophora tritici-repentis, est une maladie économiquement importante dans toutes les principales zones de culture du blé du monde. Même si l'agent pathogène était connu sur les graminées et, à l'occasion, sur le blé depuis huit décennies, des épidémies de tache auréolée à grande échelle ne furent signalées pour la première fois qu'en début des années 1970. La fréquence accrue fut associée à la culture sous déchaumage superficiel, une mesure mise en place pour la conservation du sol. La présente revue met en lumière de récents développements qui sont survenus dans des études sur l'interaction blé -P. tritici-repentis et discute des implications quant à notre compréhension des relations hôte-parasite en général. Les races de P. triticirepentis produisent au moins trois toxines spécifiques à l'hôte, actives sur des lignées ou cultivars hôtes précis. Un seul gène dominant et indépendamment hérité détermine la réaction de l'hôte à ces toxines, avec un gène pour chaque toxine. Huit races de l'agent pathogène ont jusqu'à maintenant été identifiées à partir de collections faites dans plusieurs parties du monde, représentant tous les patrons de virulence prévus des trois toxines correspondant à trois gènes de « sensibilité de l'hôte ». Les analyses génétiques de l'hôte et de l'agent pathogène suggèrent qu'une ...

show abstract

Role of Host Sensitivity to Ptr ToxA in Development of Tan Spot of Wheat

Cited by 69 publications

References 15 publications

Evaluation and Association Mapping of Resistance to Tan Spot and Stagonospora Nodorum Blotch in Adapted Winter Wheat Germplasm

Evaluation and Association Mapping of Resistance to Tan Spot and Stagonospora Nodorum Blotch in Adapted Winter Wheat Germplasm

Genetics of wheat–Pyrenophora tritici-repentis interactions

Host–parasite interactions in tan spot [Pyrenophora tritici-repentis] of wheat

Contact Info

Product

Resources

About