Pathogenic and molecular variability among isolates of Pyrenophora tritici-repentis, causal agent of tan spot of wheat in Argentina

Moreno, María Virginia; Stenglein, Sebastián Alberto; Balatti, Pedro Alberto; Perelló, A. E.

doi:10.1007/s10658-008-9277-2

Cited by 36 publications

(34 citation statements)

References 34 publications

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“…Thereafter, the mycelia were ground into a fine powder using a first prep machine Retsch MM 301 (Retsch., Clifton, NJ). DNA from all the isolates was recovered by following the method of Moreno et al [25]. The DNA concentration was adjusted to 25 ng/µl using a Nano drop (Counterpane Inc. Tacoma, WA) and run on a 0.8% agarose gel to verify the DNA quality.…”

Section: Genotypic Characterization Of P Tritici-repentis Isolates Fmentioning

confidence: 99%

Race Diversity of Pyrenophora tritici-repentis in South Dakota and Response of Predominant Wheat Cultivars to Tan Spot

Abdullah¹,

Sk²,

Ali³

2017

J Plant Pathol Microbiol

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The fungus Pyrenophora tritici-repentis (Ptr) causing tan spot (TS) is an important pathogen of wheat in the US Northern-Great-Plains. Knowledge of physiological variation in the pathogen population is essential in the development of durable TS resistant cultivars. Eight Ptr races have been identified based on three host selective toxins (Ptr ToxA/Ptr ToxB/Ptr ToxC), which are associated with necrosis and chlorosis symptoms. The information about Ptr race structure and reaction of wheat cultivars grown in SD to tan spot is scarcely available. In this study, 569 isolates of Ptr collected from wheat were genotyped for Ptr ToxA and Ptr ToxB genes and a subset of 134 isolates were evaluated for their race identity on a wheat differential set. Ptr ToxA and Ptr ToxB genes were amplified in 89.6% and 0.4% isolates, respectively. The remaining 57 (10%) isolates lacked both toxins genes. The characterization of 134 isolates exhibited diverse race structure with 74.6%, 18.7%, 1.49% , and <1% isolates categorized as race 1, 4, 5, and 2, respectively. Another six (4.5%) isolates behaved like race 2 but lacked Ptr ToxA gene, hence could not fit under the currently known eight races. Our results determine the diversity of Ptr population that exists in SD and establish the presence of race 5 in SD for the first time. Since races 1 and 5 are most prevalent in the region, we screened 45 most predominant wheat cultivars against these races and Ptr ToxA. We observed eleven cultivars resistant or moderately resistant to both races, however, seven spring wheat cultivars showed susceptibility to both races 1 and 5. Continued cultivation of wheat cultivars susceptible to both races could play a role in the establishment and development of new races. Continuous germplasm enhancement and periodically monitoring Ptr population can help in better TS management.

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Section: Genotypic Characterization Of P Tritici-repentis Isolates Fmentioning

confidence: 99%

Race Diversity of Pyrenophora tritici-repentis in South Dakota and Response of Predominant Wheat Cultivars to Tan Spot

Abdullah¹,

Sk²,

Ali³

2017

J Plant Pathol Microbiol

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“…Recently, Moreno et al (2008) observed isolates that induced chlorosis on the cultivar Glenlea which previously was only necrotic susceptible. Hence, novel races, beyond the presently designated eight races, are being observed in the phenotypic classification of P. tritici-repentis.…”

Section: Pathogenic Variabilitymentioning

confidence: 99%

Genetics of wheat–Pyrenophora tritici-repentis interactions

Singh

Duveiller

et al. 2009

Euphytica

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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.

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“…However, clustering of isolates was independent of their race designation or geographical origin (10). Moreno et al (12) identified intraspecific variability within P. tritici-repentis isolates, but they could not establish a relationship between this variability and the geographical regions and/or wheat cultivars from where P. tritici-repentis isolates were obtained (12). They proposed that the occurrence of the sexual state and long distance dispersal of inoculums could have contributed to pathogenic and genetic variability independent of geographic region (12).…”

Section: Discussionmentioning

confidence: 97%

“…The pathogen is reported in many wheat growing regions around the world, but so far genetic diversity of limited populations have been studied. These populations consisted of the isolates from North America including Canada and the USA (2, 7, 10), South America including Argentina and Brazil (2,11,12), and Europe including Czech Republic, Germany, Slovak Republic and Russia (2,7,13). Although the Fertile Crescent is considered to be the center of origin of wheat and most of its fungal pathogens (14,15), to date no information is available on the genetic structure of natural populations of the pathogen in Iran.…”

mentioning

confidence: 99%

Genetic Diversity of Pyrenophera tritici-repentis Isolates, the Causal Agent of Wheat Tan Spot Disease from Northern Iran

2015

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Background:The tan spot disease of wheat caused by Pyrenophera tritici-repentis has become a major disease in most wheat growing areas worldwide. Objectives: Here we used ISSR and RAPD markers to study the genetic diversity of 34 P. tritici-repentis isolates collected from North of Iran. Materials and Methods:The leaves having the typical symptoms of tan spot disease were collected and after fungal isolation, purification and identification, DNAs were extracted. After PCR amplification using each primer, PCR products were run in agarose gels, and the resulting bands were scored. Cluster analysis was performed using Un-Wighted Nighbor Joining method. Results: A total of 178 reproducible bands were scored. Out of which 115 (65%) were polymorphic corresponding to an average of 8 polymorphic bands per primer. The average PIC values for ISSR and RAPD markers were 0.38 and 0.43, respectively. A high degree of genetic variability among Iranian P. tritici-repentis isolates was identified. Cluster analysis based on un-weighted neighbor-joining method using the combined molecular data revealed five distinct clusters. The results from the cluster analysis indicated that the genetic similarity among the Iranian P. tritici-repentis isolates could be partly explained by geographic origins where the isolates were collected. Conclusions: Genetic variability of P. tritici-repentis along with relatively high level of geographic diversity observed in this study may suggest longer evolutionary period for the isolates from the Middle East, wheat center of origin, as opposed to other places.

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Pathogenic and molecular variability among isolates of Pyrenophora tritici-repentis, causal agent of tan spot of wheat in Argentina

Cited by 36 publications

References 34 publications

Race Diversity of Pyrenophora tritici-repentis in South Dakota and Response of Predominant Wheat Cultivars to Tan Spot

Race Diversity of Pyrenophora tritici-repentis in South Dakota and Response of Predominant Wheat Cultivars to Tan Spot

Genetics of wheat–Pyrenophora tritici-repentis interactions

Genetic Diversity of Pyrenophera tritici-repentis Isolates, the Causal Agent of Wheat Tan Spot Disease from Northern Iran

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