scholarly journals Deriving isolates of powdery mildew (Blumeria graminis DC. f.sp. avenae Em. Marchal.) in common oat (Avena sativa L.) and using them to identify selected resistance genes

2012 ◽  
Vol 65 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Sylwia Okoń ◽  
Krzysztof Kowalczyk
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Avena Sativa ◽  
Blumeria Graminis ◽  
Matching Model ◽  
F2 Population ◽  
Host Pathogen ◽  
Dominant Genes

Powdery mildew in common oat is caused by <i>Blumeria graminis</i> DC. f.sp. <i>avenae</i> Em. Marchal. Host-pathogen tests are commonly used to identify and locate resistance genes to powdery mildew in cereals. The aim of the study was to determine the virulence of powdery mildew isolates obtained from powdery mildew populations harvested in Poland and to identify OMR1, OMR2 and OMR3 resistance genes to powdery mildew in F<sub>2</sub> populations of inter-cultivar hybrids of common oat: Bruno × Fuchs, Jumbo × Fuchs and Mostyn × Fuchs. On the basis of the analysis conducted, isolates enabling division of the studied populations into groups of resistant and susceptible plants were selected. M10 and M14 isolates were chosen for the population which was obtained from crossbreeding of ‘Bruno’ with ‘Fuchs’; these isolates demonstrated avirulence to Bruno cultivar containing OMR1 gene. In order to divide population obtained from crossbreeding of ‘Jumbo’ with ‘Fuchs’, M13 and M16 isolates were chosen; they demonstrated avirulence to the cultivar Jumbo containing the OMR2 gene. On the basis of the tests conducted, it was impossible to select isolates characterised by avirulence to the OMR3 gene. In the F2 population of Bruno × Fuchs and Jumbo × Fuchs hybrids, a division was made into resistant and susceptible plants. The obtained results were verified by the <sup>2</sup> test; the proportion in the dispersion matching model was found to be 3 resistant plants: 1 sensitive plant both in the Bruno × Fuchs and Jumbo × Fuchs populations. Such dispersion indicated that the resistance to powdery mildew in the studied cultivars Bruno and Jumbo was conditioned by single dominant genes.

scholarly journals Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars

2020 ◽  
Author(s):  
Xian Xin Wu ◽  
Yue Gao ◽  
Qiang Bian ◽  
Qian Sun ◽  
Xin Yu Ni ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Large Scale ◽  
Durable Resistance ◽  
Cost Effective ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Initial Inoculum ◽  
Wheat Powdery Mildew

Abstract Background: Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici ( Bgt ), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and alos in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3 , Pm8 , Pm13 , Pm16 , and Pm21 in these cultivars using gene specific DNA markers. Results: Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3 , 18 likely to have Pm8 , 5 likely to have Pm16 , and 3 likely to have Pm21 . No cultivar was found to carry Pm13 . Conclusion: The information on the presence of the Pm resistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21 , which is effective against all Bgt races in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew. Keywords: Blumeria graminis f. sp. tritici , Pm gene, molecular markers, wheat

scholarly journals Identification of powdery mildew resistance genes in Polish common oat (Avena sativa L.) cultivars using host-pathogen tests

2012 ◽  
Vol 65 (3) ◽  
pp. 63-68 ◽  
Author(s):  
Sylwia Okoń
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Resistance Pattern ◽  
Mildew Resistance ◽  
Differential Set ◽  
Host Pathogen ◽  
Resistance Patterns ◽  
Breeding Programmes ◽  
New Gene

The aim of the present study was to characterize and identify powdery mildew resistance genes in Polish common oat cultivars using host-pathogen tests. A differential set of six <em>Blumeria graminis </em>f.sp<em>. avenae </em>isolates virulent or avirulent to four cultivars and one line that has known resistance to powdery mildew were used. Among the investigated cultivars, only four of them (13.3%) had resistance patterns similar to genotypes belonging to the differential set. The resistance of OMR group 1 was found in the cultivar &lsquo;Dragon&rsquo;, while that of OMR2 in the cultivar &lsquo;Skrzat&rsquo;. The cultivars &lsquo;Deresz&rsquo; and &lsquo;Hetman&rsquo; showed a resistance pattern that corresponded with OMR group 3. The resistance corresponding to OMR4 was not found, which suggests that until now this gene has not been used in Polish oat breeding programmes. The cultivar &lsquo;Canyon&rsquo; had a different pat- tern of resistance than the genotypes that have already known OMR genes, which indicates that the resistance of this cultivar is determined by a new gene or a combination of known genes.

scholarly journals A novel way to identify specific powdery mildew resistance genes in hybrid barley cultivars

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Antonín Dreiseitl
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Specific Resistance ◽  
Genetic Resistance ◽  
Limiting Factor ◽  
Response Type ◽  
Barley Cultivars ◽  
Dominant Genes ◽  
Cereal Disease

Abstract Powdery mildew, a common cereal disease caused by the fungus Blumeria graminis, is a major limiting factor of barley production and genetic resistance is the most appropriate protection against it. To aid the breeding of new cultivars and their marketing, resistance genes can be postulated in homogeneous accessions. Although hybrid cultivars (F1) should be homogeneous, they are often not genetically uniform, especially if more than two genotypes are involved in their seed production or due to undesirable self-pollination, out-crossing and mechanical admixtures. To overcome these problems the accepted method of postulating specific resistance genes based on comparing response type arrays (RTAs) of genetically homogeneous cultivars with RTAs of standard genotypes was substituted by analysing the frequency of response types to clusters of pathogen isolates in segregating F2 generations. This method combines a genetic and phytopathological approach for identifying resistance genes. To assess its applicability six hybrid cultivars were screened and from three to seven with a total of 14 resistance genes were found. Two genes were newly located at the Mla locus and their heritability determined. In addition, three unknown dominant genes were detected. This novel, comprehensive and efficient method to identifying resistance genes in hybrid cultivars can also be applied in other cereals and crops.

scholarly journals PmLX66 and PmW14: New Alleles of Pm2 for Resistance to Powdery Mildew in the Chinese Winter Wheat Cultivars Liangxing 66 and Wennong 14

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1118-1124 ◽  
Author(s):  
Yanling Sun ◽  
Jingwei Zou ◽  
Huigai Sun ◽  
Wei Song ◽  
Xiaoming Wang ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Northern China ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Winter Wheat Cultivars ◽  
Allelism Tests ◽  
The Relationship ◽  
Dominant Genes ◽  
New Alleles

Wheat powdery mildew (caused by Blumeria graminis f. sp. tritici) can be effectively managed by growing resistant cultivars. ‘Liangxing 66’ and ‘Wennong 14’ are the current winter wheat cultivars grown in northern China where powdery mildew is epidemic. Both cultivars have been demonstrated to carry single dominant genes for resistance to powdery mildew, tentatively designated PmLX66 and PmW14, on chromosome 5DS and share common linked markers with Pm2. Allelism tests were performed using a total of 15,657 plants of F2 segregating populations to determine the relationship between PmLX66, PmW14, and Pm2. All progeny from the crosses Liangxing 66 × ‘Ulka/8*Chancellor’ (Ulka/8*Cc), Wennong 14 × Ulka/8*Cc, and Liangxing 66 × Wennong 14 were resistant when tested with B. graminis f. sp. tritici isolate E20, indicating that PmLX66 and PmW14 are allelic to Pm2 and to each other. Liangxing 66 was resistant to 76.7% of the 60 B. graminis f. sp. tritici isolates from northern China, a slightly smaller proportion than Ulka/8*Cc (78.3%). However, Wennong 14 (85.0%) was more resistant against this set of B. graminis f. sp. tritici isolates than Ulka/8*Cc and Liangxing 66. Liangxing 66 and Wennong 14 differed from Ulka/8*Cc in respect to a number of B. graminis f. sp. tritici isolates. Based on these findings, PmLX66 and PmW14 are new alleles at the Pm2 locus.

scholarly journals Variability of the wheat powdery mildew pathogen Blumeria graminis f. sp. tritici in the 2003 crop season

2005 ◽  
Vol 30 (4) ◽  
pp. 420-422 ◽  
Author(s):  
Leila M. Costamilan
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Genetic Resistance ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Crop Season ◽  
Grain Yields ◽  
Wheat Powdery Mildew ◽  
Powdery Mildew Pathogen

Wheat (Triticum aestivum) powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici, is one of the most severe foliar diseases attacking this crop, reducing grain yields by 10% to 62% in Brazil. The disease can be controlled by genetic resistance of the host, but the pathogen has physiological specialization, which enables it to infect wheat cultivars that have remained resistant for years. The objective of this work was to evaluate the variability of pathogenic strains of B. graminis f. sp. tritici collected in Brazil and the effectiveness of wheat resistance genes to powdery mildew in the 2003 crop season. Plants of a differential series were inoculated with each monopustular isolate. Thirty-one combinations of effective and ineffective resistance genes were identified. Only the gene Pm4a+... remained totally effective to all isolates, and gene Pm6 was highly effective (below 10% of susceptibility), whereas genes Pm3a and Pm8 were totally ineffective (susceptible to all isolates). Genes Pm3c, D1, and D2 showed low effectiveness (above 50% of susceptibility), and genes Pm1, 2, 4a, 1+?, and 2+Mld had mean effective results to most strains (susceptibility between 10% and 49%). The virulence formula Pm1, 3c, 4a, 6, 1+?, 2+Mld, 4a+..., D2 (effective genes) / 2, 3a, 8, D1 (ineffective genes) was most frequently found, accounting for 15% of the occurrences. The most frequent number of ineffective genes was seven, ranging from three to ten.

RFLP markers linked to powdery mildew resistance genes Pm1, Pm2, Pm3, and Pm4 in wheat

Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 871-875 ◽  
Author(s):  
Z. Q. Ma ◽  
M. E. Sorrells ◽  
S. D. Tanksley
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Polymorphic Locus ◽  
Triticum Aestivum L ◽  
Blumeria Graminis ◽  
Rflp Markers ◽  
Recurrent Parent ◽  
Polymorphic Markers ◽  
Restriction Fragment Length Polymorphic

Near-isogenic lines (NILs) and their recurrent parent Chancellor (Cc) were used to identify restriction fragment length polymorphic markers linked to powdery mildew (Blumeria graminis (DC.) E.O. Speer f.sp. tritici) resistance genes Pm1, Pm2, Pm3, and Pm4 in wheat (Triticum aestivum L. em. Thell). By mapping these polymorphic markers in F2 progenies from crosses of the NILs with Cc, it was found that Pm1 cosegregated with a polymorphic locus detected by DNA probe CDO347; Pm2 was linked to a locus detected by probe BCD1871 with a distance of 3.5 cM; Pm3b was linked to a locus detected by probe BCD1434 with a distance of 1.3 cM; Pm4a cosegregated with Xbcd1231-2A(2) and Xcdo678-2A, and was closely flanked by Xbcd1231-2A(1) and Xbcd292-2A both with a distance of 1.5 cM. Aneuploid mapping of these markers indicated that locus Xcdo347-7A is on 7AL, Xbcd1871-5D on 5DS, Xbcd1434-1A on 1AS, and loci Xbcd292-2A and Xcdo678-2A are on 2AL. The same polymorphic fragments detected in the Pm3b NIL by Xbcd1434-1A were found in Pm3a NIL using several enzyme digestions.Key words: RFLP markers, Pm1, Pm2, Pm3, Pm4, Blumeria graminis (DC.) E.O. Speer f.sp. tritici (Erysiphe graminis f.sp. tritici), wheat (Triticum aestivum L. em. Thell), gene tagging.

scholarly journals Virulence of Blumeria graminis f. sp. tritici Populations in Morocco

Plant Disease ◽  
2002 ◽  
Vol 86 (4) ◽  
pp. 383-388 ◽  
Author(s):  
Yasmina Imani ◽  
Abdallah Ouassou ◽  
Carl A. Griffey
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Triticum Turgidum ◽  
Blumeria Graminis ◽  
Nitrogen Fertilizers ◽  
Pathogen Population ◽  
High Frequencies ◽  
Cultivar Development ◽  
Production Areas

The incidence and severity of powdery mildew, caused by Blumeria graminis f. sp. tritici, have increased in Morocco during the past decade as a result of the introduction and intensive production of a few semidwarf cultivars of bread wheat (Triticum aestivum) and durum wheat (Triticum turgidum) that are genetically uniform, and the increased utilization of nitrogen fertilizers and irrigation. The virulence of the pathogen population has not been characterized in Morocco, and little is known about the spectra and distribution of virulence in B. graminis populations. Such knowledge will facilitate the identification and utilization of effective resistance genes in cultivar development and deployment. Isolates of B. graminis collected in 1999 and 2000 from three Moroccan wheat production areas were analyzed for virulence using a host differential series comprised of 13 known genes conferring resistance to powdery mildew. Segments of primary leaves from 12-day-old seedlings of the wheat differentials were inoculated with isolates of B. graminis derived from a single pustule. Powdery mildew reactions were assessed on a 0 to 9 scale 12 days after inoculation. Virulence frequencies, complexity, and racial composition of the pathogen population were determined. Data were analyzed for associations among pairs and triplets of virulence genes and for distribution of virulence genes among pathotypes. High frequencies of virulence to genes Pm1, Pm3c, Pm3f, Pm4a, pm5, and Pm7 were found over both years and across all three regions. Frequencies of virulence for Pm17 and Pm2 were intermediate, while virulence frequencies for Pm3a, Pm3b, Pm3d, and Pm4b were low. Virulence to Pm8 increased to high levels, while virulence to Pm4a decreased across the area surveyed from 1999 to 2000. The random distribution of virulence genes among patho-types indicates that sexual reproduction contributes to the variability of the pathogen. The Moroccan population of Blumeria graminis f. sp. tritici is composed of complex and highly variable pathotypes (87% of the isolates had five or more virulence genes), and strategies for deployment of resistance genes should take into account this complexity.

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