scholarly journals Mapping Powdery Mildew (Blumeria graminis f. sp. tritici) Resistance in Wild and Cultivated Tetraploid Wheats

2020 ◽  
Vol 21 (21) ◽  
pp. 7910
Author(s):  
Rosanna Simeone ◽  
Luciana Piarulli ◽  
Domenica Nigro ◽  
Massimo Antonio Signorile ◽  
Emanuela Blanco ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Triticum Turgidum ◽  
Snp Array ◽  
Blumeria Graminis ◽  
Adult Plant ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Nucleotide Binding Sites ◽  
Tetraploid Wheats ◽  
Environmentally Safe

Wheat is the most widely grown crop and represents the staple food for one third of the world’s population. Wheat is attacked by a large variety of pathogens and the use of resistant cultivars is an effective and environmentally safe strategy for controlling diseases and eliminating the use of fungicides. In this study, a collection of wild and cultivated tetraploid wheats (Triticum turgidum) were evaluated for seedling resistance (SR) and adult plant resistance (APR) to powdery mildew (Blumeria graminis) and genotyped with a 90K single nucleotide polymorphism (SNP) array to identify new sources of resistance genes. The genome-wide association mapping detected 18 quantitative trait loci (QTL) for APR and 8 QTL for SR, four of which were identical or at least closely linked to four QTL for APR. Thirteen candidate genes, containing nucleotide binding sites and leucine-rich repeats, were localized in the confidence intervals of the QTL-tagging SNPs. The marker IWB6155, associated to QPm.mgb-1AS, was located within the gene TRITD1Av1G004560 coding for a disease resistance protein. While most of the identified QTL were described previously, five QTL for APR (QPm.mgb-1AS, QPm.mgb-2BS, QPm.mgb-3BL.1, QPm.mgb-4BL, QPm.mgb-7BS.1) and three QTL for SR (QPm.mgb-3BL.3, QPm.mgb-5AL.2, QPm.mgb-7BS.2) were mapped on chromosome regions where no resistance gene was reported before. The novel QTL/genes can contribute to enriching the resistance sources available to breeders.

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

Sources of oat crown rust resistance in hexaploid and tetraploid wild oats in Israel

1970 ◽  
Vol 48 (1) ◽  
pp. 153-161 ◽  
Author(s):  
A. Dinoor
Keyword(s):  
Small Samples ◽  
Adult Plant ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Efficient Procedure ◽  
Seed Collection ◽  
Distribution Maps ◽  
Wild Oats ◽  
Oat Crown Rust ◽  
Intensive Search

A wealth of resistant plants was found in the tetraploid wild oat Avena barbata Pott, as well as in the hexaploid A. sterilis L. The appreciably high frequency of resistance found in A. sterilis (about 7.5%) reveals an abundant and useful source of resistance, for direct crosses with cultivated varieties. The most efficient procedure of seed collection and screening for obtaining sources of resistance, was (1) random sampling of small samples in the entire region (method A); (2) seedling tests in the greenhouse; (3) construction of distribution maps of resistance; (4) more intensive search in promising locations according to distribution maps (methods B and D). The use of seedling resistance as an indication of adult resistance may result in overlooking the adult plant resistance in up to 40% of the locations where adult resistance could have been found by direct adult tests. Nevertheless, the frequency of locations where plants were found to be resistant in both seedling and adult stages allows for the more convenient use of seedling tests in initial screening.

scholarly journals Sources and Genetics of Spot Blotch Resistance to a New Pathotype of Cochliobolus sativus in the USDA National Small Grains Collection

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 1988-1993 ◽  
Author(s):  
Yueqiang Leng ◽  
Rui Wang ◽  
Shaukat Ali ◽  
Mingxia Zhao ◽  
Shaobin Zhong
Keyword(s):  
United States ◽  
Dominant Gene ◽  
The United States ◽  
Spot Blotch ◽  
Cochliobolus Sativus ◽  
Adult Plant ◽  
United States Department ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Small Grains

Spot blotch, caused by Cochliobolus sativus, is one of the important barley diseases in the northern Great Plains of the United States and the Prairie Provinces of Canada. The disease has been under control for almost five decades due to the use of durable spot blotch resistance derived from the barley line ND B112. However, the emergence of isolate ND4008 with virulence on ND B112 prompted us to identify new sources of resistance to this new pathotype. In this study, we screened 2,062 barley accessions from the United States Department of Agriculture National Small Grains Collection for spot blotch resistance, and identified 40 barley accessions exhibiting a high level of resistance to isolate ND4008 at the seedling stage. In all, 24 of the barley accessions with seedling resistance also exhibited moderate to high adult plant resistance to ND4008 in greenhouse tests. Seven of the ND4008-resistant barley accessions showed seedling resistance to two other pathotypes (1 and 2) of the pathogen. Genetic study of resistant barley accessions PI 235186, PI 592275, and PI 643242 indicated that a single major dominant gene controls spot blotch resistance to ND4008 in each of these three accessions. These resistant sources are useful for developing barley cultivars with spot blotch resistance to all pathotypes of C. sativus.

scholarly journals Seedling and Adult Plant Resistance to Powdery Mildew in Chinese Bread Wheat Cultivars and Lines

Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 457-463 ◽  
Author(s):  
Z. L. Wang ◽  
L. H. Li ◽  
Z. H. He ◽  
X. Y. Duan ◽  
Y. L. Zhou ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Bread Wheat ◽  
Resistance Genes ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
The United States ◽  
Adult Plant ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Progress Curve

Powdery mildew, caused by Blumeria graminis f. sp. tritici, is a widespread wheat disease in China. Identification of race-specific genes and adult plant resistance (APR) is of major importance in breeding for an efficient genetic control strategy. The objectives of this study were to (i) identify genes that confer seedling resistance to powdery mildew in Chinese bread wheat cultivars and introductions used by breeding programs in China and (ii) evaluate their APR in the field. The results showed that (i) 98 of 192 tested wheat cultivars and lines appear to have one or more resistance genes to powdery mildew; (ii) Pm8 and Pm4b are the most common resistance genes in Chinese wheat cultivars, whereas Pm8 and Pm3d are present most frequently in wheat cultivars introduced from CIMMYT, the United States, and European countries; (iii) genotypes carrying Pm1, Pm3e, Pm5, and Pm7 were susceptible, whereas those carrying Pm12, Pm16, and Pm20 were highly resistant to almost all isolates of B. graminis f. sp. tritici tested; and (iv) 22 genotypes expressed APR. Our data showed that the area under the disease progress curve, maximum disease severity on the penultimate leaf, and the disease index are good indicators of the degree of APR in the field. It may be a good choice to combine major resistance genes and APR genes in wheat breeding to obtain effective resistance to powdery mildew.

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.

scholarly journals New Pathotype Nomenclature for Better Characterisation the Virulence and Diversity of Blumeria graminis f.sp. avenae Populations

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1852
Author(s):  
Sylwia Okoń ◽  
Magdalena Cieplak ◽  
Adam Kuzdraliński ◽  
Tomasz Ociepa
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Host Resistance ◽  
Powdery Mildew Resistance ◽  
Blumeria Graminis ◽  
Sources Of Resistance ◽  
Mildew Resistance ◽  
Differential Set ◽  
Letter Code ◽  
First Time

Fungal cereal pathogens, including Blumeria graminis f.sp. avenae, have the ability to adapt to specific conditions, which in turn leads to overcoming host resistance. An important aspect is the standardized way of characterizing the races and pathotypes of the pathogen. In the presented work, for the first time it was proposed to use a unified letter code that allows describing the pathotypes of B. graminis f.sp. avenae. The set of 14 oat genotypes were used as a differential set. This set included genotypes having so far described powdery mildew resistance genes Pm1–Pm11, and two genotypes (A. sterilis and A. strigosa) with effective sources of resistance to Bga. Based on the analysis of 160 Bga isolates collected in 2016–2019 from 4 locations in Poland, the most numerous was the TBBB pathotype, represented by 30% of the tested isolates. It was present in all analyzed populations. Subsequently, 8.1% and 6.3% of the isolates represented the TBCB and RBBB pathotypes, respectively.

scholarly journals Phenotypic and Marker-assisted Breeding of Capsicum for Cucumber Mosaic Virus Resistance

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 595c-595 ◽  
Author(s):  
R.C. Grube ◽  
Y. Zhang ◽  
B. Huang ◽  
M.M. Kyle
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Adult Plant ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Disease Symptoms ◽  
Screening Protocol ◽  
Cmv Resistance ◽  
Selection For ◽  
Different Sources

Resistance to cucumber mosaic virus (CMV) in Capsicum from two sources is being transferred into three commercial types (bell, jalapeno, and Anaheim) using a backcross breeding scheme. We have optimized our CMV seedling screening protocol, which involves multiple inoculations beginning at the cotyledon stage with a severe CMV serogroup I isolate. Both sources of resistance, C. annuum `French Perennial' and a C. frutescens accession (BG2814-6), exhibit oligogenic recessive inheritance and share some but not all resistance alleles. Selection for type in the BCF1 generation had no effect on the frequency of resistant individuals in the BCF2 generation. We have determined that it is necessary to self-pollinate every other backcross generation to screen for resistance. Occasionally disease symptoms appear in adult plants that were initially resistant to multiple inoculations at the seedling stage, and we are investigating the correlation between seedling resistance and adult plant resistance. We are also exploring the extent to which the different sources of resistance behave differently as a function of genetic background. Additionally, we are mapping quantitative trait loci (QTLs) for CMV resistance in pepper with the goal of converting RFLP and/or RAPD markers into PCR-based markers to facilitate molecular marker-assisted selection for CMV resistance.

Identification and expression of adult plant resistance in barley to powdery mildew (Blumeria graminis f. sp. hordei) in Australia

Euphytica ◽  
2014 ◽  
Vol 203 (3) ◽  
pp. 595-605 ◽  
Author(s):  
Sanjiv Gupta ◽  
Mario D’Antuono ◽  
Jason Bradley ◽  
Chengdao Li ◽  
Robert Loughman
Keyword(s):  
Powdery Mildew ◽  
Plant Resistance ◽  
Adult Plant Resistance ◽  
Blumeria Graminis ◽  
Adult Plant

scholarly journals Emergence of Virulence to Sr25 of Puccinia graminis f. sp. tritici on Wheat in India

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 840-840 ◽  
Author(s):  
S. K. Jain ◽  
M. Prashar ◽  
S. C. Bhardwaj ◽  
S. B. Singh ◽  
Y. P. Sharma
Keyword(s):  
Resistance Genes ◽  
Stem Rust ◽  
Infection Type ◽  
Adult Plant ◽  
Puccinia Graminis ◽  
Wheat Cultivars ◽  
Sources Of Resistance ◽  
Seedling Resistance ◽  
Additional Gene ◽  
Adult Plants

Stem (black) rust, caused by Puccinia graminis Pers. f. sp. tritici Eriks. & Henn., is one of the most destructive diseases of wheat. It could be controlled through introgression of race-specific resistance genes. However, such kind of resistance is mostly short lived due to emergence of new virulences. For example, resistance genes Sr11, Sr24, Sr30, and Sr31 are no longer effective (2,4). Detection of new virulences has remained vital in the evaluation and identification of new sources of resistance. We report here the detection of virulence to Sr25, a gene from Thinopyrum elongatum (4), which had been effective or partially effective against stem rust worldwide, including race Ug99 (TTKSK) (4). A stem rust isolate collected in 2006 from Karnataka (southern India) produced susceptible reactions (infection type [IT] 3+ to 4) on the primary leaves of differential genotype ‘Agatha’ carrying Sr25 and susceptible check ‘Agra Local’ at 22 ± 2°C. To verify virulence to Sr25, single-pustule isolates from this sample were inoculated onto seedlings of ‘Agrus’, ‘Agatha’, ‘RL6040’ (‘Thatcher’ + Sr25), ‘Superseri#1’, ‘Wheatear’, and ‘Morocco’ + Sr25 (obtained from CIMMYT), which all carry Sr25. All these accessions were found susceptible (IT 3+ to 4) to this isolate, except Wheatear which expressed resistance (IT ;1), indicating the presence of additional gene(s). These genotypes are resistant (ITs ;1 to 2+) to Sr25-avirulent pathotypes. The new pathotype is avirulent to Sr11, 13, 14, 21, 22, 23, 24, 26, 27, 29, 31, 32, 33, 35, 37, 38, 39, 40, 43, and Tmp and virulent to Sr5, 6, 7a, 7b, 8a, 9a, 9b, 9d, 9e, 9f, 9g, 10, 12, 15, 16, 17, 18, 19, 20, 25, 28, 30, 34, 36, 42, Wld-1, and Gt at 22 ± 2°C. This pathotype has been designated as 58G13-3 and PKTSC according to the Indian nomenclature (1) and the North American system (3), respectively. It represents race 40 based on Stakman's differentials. It may have arisen from race 40 through mutation. The type culture of the pathotype has been added to the culture collection at Flowerdale, Shimla. Interestingly, ‘Festiguay’ (Sr30) was found resistant to this pathotype, indicating the presence of additional gene(s), whereas ‘Webster’ (Sr30) was susceptible. Adult plants of Agrus, Agatha, RL6040, Superseri#1, and Morocco+Sr25 also were susceptible, producing 20S to 60S responses. Sr25-avirulent pathotype 62G29 produced a TR (flecking in traces) response on these lines except Morocco + Sr25 that showed 20 to 40MR (moderately resistant) responses. In the same study however, adult plants of Thatcher showed a resistant reaction (10R to MR) at low (16 ± 2°C) and susceptible (20S) at high (22 ± 2°C) temperatures. Agatha and RL6040, having Thatcher as one of the parents, had similar responses. The detection of Sr25 virulence is significant since Sr25 is an important gene to be targeted for breeding wheat cultivars resistant to Ug99. We should use either adult plant resistance and/or pyramiding two or more genes for seedling resistance to enhance the field life of wheat cultivars. References: (1) P. Bahadur et al. Proc. Indian Acad. Sci. 95:29, 1985. (2) S. C. Bhardwaj et al. J. Wheat Res. 1:51, 2007. (3) Y. Jin et al. Plant Dis. 92:923, 2008. (4) R. P. Singh et al. CAB Rev. No. 054:1, 2006.

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