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 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.

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 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 Virulence Analysis of Wheat Powdery Mildew (Blumeria graminis f. sp. tritici) and Effective Genes in Middle Delta, Egypt

Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1927-1930 ◽  
Author(s):  
Moustafa M. El-Shamy ◽  
Hassan M. Emara ◽  
Mona E. Mohamed
Keyword(s):  
Powdery Mildew ◽  
Adult Stage ◽  
Resistance Breeding ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Natural Field ◽  
Wheat Powdery Mildew ◽  
Virulence Analysis ◽  
High Virulence ◽  
First Time

Wheat powdery mildew (Blumeria graminis f. sp. tritici) has increased in Delta Egypt in recent years as a result of growing susceptible cultivars of bread wheat. Fifty-two isolates of B. graminis f. sp. tritici collected in 2013 and 2014 from commercial fields in five provinces were analyzed for virulence, using 21 genes conferring resistance to powdery mildew (Pm genes) as well as 12 local wheat cultivars. First true leaves of 10-day-old wheat differentials were inoculated with isolates derived from a single pustule of B. graminis f. sp. tritici. No virulence to the resistance genes Pm3d, Pm12, Pm16, Pm24, Pm35, Pm36, and Pm37 was detected, indicating that these genes could be used for resistance breeding. Virulence to Pm2, Pm4a, and Pm6 was low, while high virulence to genes Pm1a, Pm3a, Pm3c, Pm3f, Pm5a, Pm7, Pm8, Pm9, and Pm17 was found, indicating that breeders should be very cautious in using these genes. At the adult stage, genes Pm2, Pm3d, Pm3f, Pm4a, Pm6, Pm12, Pm16, Pm17, Pm24, Pm35, Pm36, and Pm37 were completely effective in both years. All the tested Egyptian wheat cultivars were susceptible under natural field conditions. The virulence of B. graminis f. sp. tritici population and resistance Pm genes have been assessed for the first time in Egypt.

Changes in sterol composition with ontogeny of Blumeria graminis conidia

2000 ◽  
Vol 78 (10) ◽  
pp. 1288-1293 ◽  
Author(s):  
Jérôme Muchembled ◽  
Anissa Lounès-Hadj Sahraoui ◽  
Anne Grandmougin-Ferjani ◽  
Michel Sancholle
Keyword(s):  
Powdery Mildew ◽  
Plant Pathogen ◽  
Total Sterol ◽  
Sterol Composition ◽  
Blumeria Graminis ◽  
Erysiphe Graminis ◽  
Qualitative And Quantitative ◽  
Wheat Powdery Mildew

The total sterol composition of conidia of the obligate plant pathogen Blumeria (= Erysiphe) graminis f.sp. tritici has been analysed as a function of their ontogeny during sporulation. Two main classes of sterols were characterized: 24-ethylsterols (24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol) and 24-methylsterols (24-methylenecholesterol and episterol). Our results show that sterol composition is greatly modified during ontogeny of B. graminis conidia both at the qualitative and quantitative levels. In particular, 24-methylsterols, e.g., 24-methylenecholesterol and episterol, are the major sterols in old conidia whereas 24-ethylsterols, e.g., 24-ethylcholesta-5,22-dienol, 24-ethylcholesterol, and Δ5-avenasterol, are the main sterols in young conidia.Key words: Erysiphe, wheat powdery mildew, sterols, ontogeny.

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