scholarly journals Identification of genes for resistanceto wheat powdery mildew in Hungarian, Polish and Slovak wheat cultivars

2012 ◽  
Vol 38 (No. 2) ◽  
pp. 64-72 ◽  
Author(s):  
M. Švec ◽  
L. Szunics ◽  
T. Slováková ◽  
M. Miklovičová ◽  
V. Tisová ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Gene ◽  
Common Wheat ◽  
Resistance Genes ◽  
Wheat Cultivars ◽  
Breeding For Resistance ◽  
Land Races ◽  
Wheat Powdery Mildew ◽  
Significant Difference ◽  
Two Populations

The objective of the study was to identify genes for resistance to powdery mildew in wheat cultivars and land races from Poland, Slovakia and Hungary. The presence and distribution of resistance genes was compared to powdery mildew virulence structure in these countries. The different strategies in breeding for resistance were expressed in a different distribution of resistance genes, especially among Polish and Hungarian cultivars. In 20 of the 29 Hungarian common wheat cultivars the resistance gene Pm8 was found. Of the 32 Polish cultivars investigated, 16 possess a combination of genes Pm2+6. Resistance gene Pm4b did not occur in any Hungarian cultivar tested, and resistance gene pm5 was not detected in any Polish cultivar. Virulence in wheat powdery mildew populations was influenced by differences in distribution of resistance genes in host genotypes. The most significant difference was found between Polish and Hungarian powdery mildew populations. The two populations differed mainly in virulence against Pm2. Resistance gene MlAr was detected in three old Slovak cultivars.

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

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10425
Author(s):  
Xianxin Wu ◽  
Qiang Bian ◽  
Yue Gao ◽  
Xinyu Ni ◽  
Yanqiu Sun ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Large Scale ◽  
Durable Resistance ◽  
Cost Effective ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Initial Inoculum ◽  
Wheat Powdery Mildew ◽  
Serious Disease

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 also 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 Pm21in these cultivars using gene specific DNA markers. 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. The information on the presence of the Pmresistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21, which is effective against all Bgtraces in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew.

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.

scholarly journals Standing genetic variation of the AvrPm17 avirulence gene in powdery mildew limits the effectiveness of an introgressed rye resistance gene in wheat

2021 ◽  
Author(s):  
Marion C. Mueller ◽  
Lukas Kunz ◽  
Seraina Schudel ◽  
Sandrine Kammerecker ◽  
Jonatan Isaksson ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Powdery Mildew ◽  
Qtl Mapping ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Resistance Breeding ◽  
Avirulence Gene ◽  
Avirulence Genes ◽  
Immune Receptor ◽  
Wheat Powdery Mildew

AbstractIntrogressions of chromosomal segments from related species into wheat are important sources of resistance against fungal diseases. The durability and effectiveness of introgressed resistance genes upon agricultural deployment is highly variable - a phenomenon that remains poorly understood as the corresponding fungal avirulence genes are largely unknown. Until its breakdown, the Pm17 resistance gene introgressed from rye to wheat provided broad resistance against powdery mildew (Blumeria graminis). Here, we used QTL mapping to identify the corresponding wheat mildew avirulence effector AvrPm17. It is encoded by two paralogous genes that exhibit signatures of re-occurring gene conversion events and are members of a mildew sub-lineage specific effector cluster. Extensive haplovariant mining in wheat mildew and related sub-lineages identified several ancient virulent AvrPm17 variants that were present as standing genetic variation in wheat powdery mildew prior to the Pm17 introgression, thereby paving the way for the rapid breakdown of the Pm17 resistance. QTL mapping in mildew identified a second genetic component likely corresponding to an additional resistance gene present on the 1AL.1RS translocation carrying Pm17. This gene remained previously undetected due to suppressed recombination within the introgressed rye chromosomal segment. We conclude that the initial effectiveness of 1AL.1RS was based on simultaneous introgression of two genetically linked resistance genes. Our results demonstrate the relevance of pathogen-based genetic approaches to disentangle complex resistance loci in wheat. We propose that identification and monitoring of avirulence gene diversity in pathogen populations becomes an integral part of introgression breeding to ensure effective and durable resistance in wheat.Significance StatementDomesticated and wild wheat relatives provide an important source of new immune receptors for wheat resistance breeding against fungal pathogens. The durability of these resistance genes is variable and difficult to predict, yet it is crucial for effective resistance breeding. We identified a fungal effector protein recognised by an immune receptor introgressed from rye to wheat. We found that variants of the effector allowing the fungus to overcome the resistance are ancient. They were already present in the wheat powdery mildew gene pool before the introgression of the immune receptor and are therefore responsible for the rapid resistance breakdown. Our study demonstrates that the effort to identify new resistance genes should be accompanied by studies of avirulence genes on the pathogen side.

Microsatellite markers linked to 2 powdery mildew resistance genes introgressed from Triticum carthlicum accession PS5 into common wheat

Genome ◽  
2005 ◽  
Vol 48 (4) ◽  
pp. 585-590 ◽  
Author(s):  
Zhendong Zhu ◽  
Ronghua Zhou ◽  
Xiuying Kong ◽  
Yuchen Dong ◽  
Jizeng Jia
Keyword(s):  
Powdery Mildew ◽  
Microsatellite Markers ◽  
Resistance Gene ◽  
Common Wheat ◽  
Resistance Genes ◽  
Powdery Mildew Resistance ◽  
Wheat Chromosome ◽  
The Other ◽  
Powdery Mildew Resistance Gene ◽  
Mildew Resistance

Two dominant powdery mildew resistance genes introduced from Triticum carthlicum accession PS5 to common wheat were identified and tagged using microsatellite markers. The gene designated PmPS5A was placed on wheat chromosome 2AL and linked to the microsatellite marker Xgwm356 at a genetic distance of 10.2 cM. Based on the information of its origin, chromosome location, and reactions to 5 powdery mildew isolates, this gene could be a member of the complex Pm4 locus. The 2nd gene designated PmPS5B was located on wheat chromosome 2BL with 3 microsatellite markers mapping proximally to the gene: Xwmc317 at 1.1 cM; Xgwm111 at 2.2 cM; and Xgwm382 at 4.0 cM; and 1 marker, Xgwm526, mapping distally to the gene at a distance of 18.1 cM. Since this gene showed no linkage to the other 2 known powdery mildew resistance genes on wheat chromosome 2B, Pm6 and Pm26, we believe it is a novel powdery mildew resistance gene and propose to designate this gene as Pm33.Key words: powdery mildew, resistance gene, microsatellite, Triticum carthlicum, wheat.

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