scholarly journals Phytopathological screening and molecular marker analysis of wheat germplasm from Kazakhstan and CIMMYT for resistance to tan spot

2019 ◽  
Vol 23 (7) ◽  
pp. 879-886 ◽  
Author(s):  
A. M. Kokhmetova ◽  
M. N. Atishova ◽  
M. T. Kumarbayeva ◽  
I. N. Leonova

Tan spot caused by the fungus Pyrenophora tritici-repentis is an important leaf spot disease in wheat growing areas throughout the world. The study aims to identify wheat germplasm resistant to tan spot based on phytopathological screening and molecular marker analysis. A collection of 64 common wheat germplasms, including cultivars and breeding lines from Kazakhstan and CIMMYT, was assessed for tan spot resistance in greenhouse conditions and characterized using the Xfcp623 molecular marker, diagnostic for the Tsn1 gene. All wheat cultivars/lines varied in their reaction to tan spot isolate race 1, ranging from susceptible to resistant. Most accessions studied (53 %) were susceptible to Ptr race 1. Spring wheat cultivars were more susceptible to race 1 than winter wheat cultivars. As a result of genotyping, an insensitive reaction to Ptr ToxA was predicted in 41 wheat cultivars (64 %). The tsn1 gene carriers identified included 27 Kazakhstani and 14 CIMMYT cultivars/lines, demonstrating insensitivity to Ptr ToxA. The majority of the Tsn1 genotype were sensitive to race 1 and showed susceptibility to the pathogen in the field. Disease scores from seedling stage positively correlated with field disease ratings. Of particular interest are 27 wheat accessions that demonstrated resistance to spore inoculation by Ptr race 1, were characterized by insensitivity to ToxA and showed field resistance to the pathogen. The results of this study will contribute to wheat breeding programs for tan spot resistance with Marker Assisted Selection using the closely flanking markers.

2019 ◽  
Vol 22 (8) ◽  
pp. 978-986 ◽  
Author(s):  
A. М. Kokhmetova ◽  
Sh. Ali ◽  
Z. Sapakhova ◽  
M. N. Atishova

Pyrenophora tritici-repentis(Ptr) is the causative agent of tan spot, one of the yield limiting diseases of wheat, rapidly increasing in wheat growing countries including Kazakhstan. The aim of this study was the identifcation of wheat genotypes with resistance to Ptr race 1 and race 5 and their host­selective effectors (toxins) Ptr ToxA and Ptr ToxB. A common wheat collection of 41 accessions (38 experimental and 3 controls) was characterized using the molecular markersXfcp623andXBE444541, diagnostic for theTsn1andTsc2genes conferring sensitivity to fungal toxins. The coincidence of the markerXBE444541with resistance to race 5 was 92.11 %, and with Ptr ToxB, 97.37 %. Genotyping results using the markerXfcp623confrmed the expected response to Ptr ToxA; the presence/absence of the markerXfcp623completely (100 %) coincided with sensitivity/resistance to race 1 and Ptr ToxA. This demonstrates the reliability of the diagnostic markerXfcp623for identifying wheat genotypes with resistance to the fungus and insensitivity to Ptr ToxA. The study of the reaction of wheat germplasm to the fungal inoculation and toxin infltration showed that out of 38 genotypes analyzed 30 (78 %) exhibited resistance to both race 1 and race 5, and insensitivity to toxins Ptr ToxA and ToxB. Of most signifcant interest are eight wheat genotypes that showed resistance/insensitivity both to the two races and two toxins. The results of phenotyping were reconfrmed by the molecular markers used in this study. Sensitivity to Ptr ToxB is not always correlated with susceptibility to race 5 and is dependent on the host’s genetic background of the wheat genotype, i. e. on a specifc wheat genotype. The results of the study are of interest for increasing the efciency of breeding based on the elimination of the genotypes with the dominant allelesTsn1andTsc2sensitive to the toxins Ptr ToxA and ToxB. The genotypes identifed will be used in wheat breeding for resistance to tan spot.


PLoS ONE ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. e0165640 ◽  
Author(s):  
Tian Ya Li ◽  
Yuan Yin Cao ◽  
Xian Xin Wu ◽  
Xiao Feng Xu ◽  
Wan Lin Wang

2020 ◽  
Vol 24 (7) ◽  
pp. 722-729
Author(s):  
A. M. Kokhmetova ◽  
N. M. Kovalenko ◽  
M. T. Kumarbaeva

Pyrenophora tritici-repentis is a causative agent of tan spot in wheat. In recent years, there has been an increasing spread and harmfulness of wheat tan spot. The aim of the research was to study the racial composition of the P. tritici-repentis population in the Republic of Kazakhstan. A collection of 30 common wheat accessions, including promising lines and cultivars from Kazakhstan and CIMMYT–ICARDA, was assessed for resistance to P. triticirepentis in a greenhouse and characterized using the Xfcp623 molecular marker, diagnostic for the Tsn1 gene. Monosporic isolates of P. tritici-repentis isolated from the southeastern region were assigned to certain races based on the manifestation of symptoms of necrosis/chlorosis on standard differentials (Glenlea, 6B662, 6B365). Five races of P. tritici-repentis have been identified, including races 1, 2, 3, 7 and 8. It has been shown that races 1 and 8 of P. tritici-repentis are dominant. As a result of the analysis of the frequency of occurrence of the P. tritici-repentis races, it was found that race 1 (50 %) producing Ptr ToxA and Ptr ToxB and race 8 (35 %) producing Ptr ToxA, Ptr ToxB and Ptr ToxC turned out to be dominant. From a practical point of view, of greatest interest are 16 wheat samples, which demonstrated resistance to race 1 and confirmed insensitivity to Ptr ToxA in a molecular screening. These include eight Kazakhstani (4_PSI, 10204_2_KSI, 10204_3_KSI, 10205_2_KSI, 10205_3_KSI, 605_SP2, 632_SP2, Dana) and seven foreign lines (KR11-20, KR11-03, KR11-9014, 11KR-13, KR12-9025, KR12-07, GN-68/2003). The results of this study are of interest in wheat breeding programs for tan spot resistance.


2010 ◽  
Vol 100 (5) ◽  
pp. 468-473 ◽  
Author(s):  
Xiao-Chun Sun ◽  
William Bockus ◽  
Guihua Bai

Tan spot, caused by Pyrenophora tritici-repentis, is an economically important foliar disease of wheat worldwide. Eight races of the pathogen have been characterized on the basis of their ability to cause necrosis or chlorosis in a set of differential wheat lines. Race 1 produces two host-selective toxins, Ptr ToxA and Ptr ToxC, that induce necrosis and chlorosis, respectively, on leaves of sensitive wheat genotypes. A population of recombinant inbred lines was developed from a cross between Chinese landrace Wangshuibai (resistant) and Chinese breeding line Ning7840 (highly susceptible) to identify chromosome regions harboring quantitative trait loci (QTL) or genes for tan spot resistance. Plants were inoculated at the four-leaf stage in a greenhouse and percent leaf area diseased was scored 7 days after inoculation. Two QTL for resistance to race 1 were mapped to the short arms of chromosomes 1A and 2B in the population. The QTL on 1AS, designated as QTs.ksu-1AS, showed a major effect and accounted for 39% of the phenotypic variation; the QTL on 2BS, designated as QTs.ksu-2BS, explained 4% of the phenotypic variation for resistance. A toxin infiltration experiment demonstrated that both parents were insensitive to Ptr ToxA, suggesting that the population was most likely segregating for reaction to chlorosis, not necrosis. The markers closely linked to the QTL should be useful for marker-assisted selection in wheat-breeding programs.


Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 513
Author(s):  
Pao Theen See ◽  
Caroline S. Moffat

After nearly 40 years of DNA molecular marker development in plant breeding, the wheat research community has amassed an extensive collection of molecular markers which have been widely and successfully used for selection of agronomic, physiological and disease resistance traits in wheat breeding programs. Tan spot is a major fungal disease of wheat and a significant global economic challenge and is caused by the necrotrophic fungal pathogen Pyrenophora tritici-repentis (Ptr). Here, the potential for using a PCR-based marker (Ta1AS3422) present on the short arm of wheat chromosome 1A, was evaluated for effectiveness in distinguishing tan spot disease susceptibility. The marker was initially screened against 40 commercial Australian hexaploid wheat varieties, and those that amplified the marker had an overall lower disease score (2.8 ± 0.7 for seedlings and 2.4 ± 0.4 for plants at the tillering stage), compared to those lacking the marker which exhibited a higher disease score (3.6 ± 0.8 for both growth stages). The potential of Ta1AS3422 as a marker for the tan spot disease response was further assessed against a panel of 100 commercial Australian hexaploid wheat varieties. A significant association was observed between marker absence/presence and tan spot disease rating (Pearson’s chi-squared test, χ2 (6) = 20.53, p = 0.002), with absence of Ta1AS3422 associated with susceptibility. This simple and cost-effective PCR-based marker may be useful for varietal improvement against tan spot, although further work is required to validate its effectiveness.


2014 ◽  
Vol 13 (40) ◽  
pp. 3999-4007 ◽  
Author(s):  
D. N. Njoku, ◽  
V. E Gracen, ◽  
S. K. Offei, ◽  
I. K. Asante, ◽  
E. Y. Danquah, ◽  
...  

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