The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Ravi P Singh - One of the best experts on this subject based on the ideXlab platform.
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Data_Sheet_1_High-Density Mapping of Triple Rust Resistance in Barley Using DArT-Seq Markers.zip
2019Co-Authors: Peter M. Dracatos, Ravi P Singh, Kerrie Forrest, Rouja Haghdoust, Julio Huerta Espino, Charles W. Barnes, Matthew Hayden, Rients E. Niks, Robert F. Park, Davinder SinghAbstract:The recent availability of an assembled and annotated genome reference sequence for the diploid crop barley (Hordeum vulgare L.) provides new opportunities to study the genetic basis of agronomically important traits such as resistance to stripe [Puccinia striiformis f. sp. hordei (Psh)], leaf [P. hordei (Ph)], and stem [P. graminis f. sp. tritici (Pgt)] Rust Diseases. The European barley cultivar Pompadour is known to possess high levels of resistance to leaf Rust, predominantly due to adult plant resistance (APR) gene Rph20. We developed a barley recombinant inbred line (RIL) population from a cross between Pompadour and the leaf Rust and stripe Rust susceptible selection Biosaline-19 (B-19), and genotyped this population using DArT-Seq genotyping by sequencing (GBS) markers. In the current study, we produced a high-density linkage map comprising 8,610 (SNP and in silico) markers spanning 5957.6 cM, with the aim of mapping loci for resistance to leaf Rust, stem Rust, and stripe Rust. The RIL population was phenotyped in the field with Psh (Mexico and Ecuador) and Ph (Australia) and in the greenhouse at the seedling stage with Australian Ph and Pgt races, and at Wageningen University with a European variant of Psh race 24 (PshWUR). For Psh, we identified a consistent field QTL on chromosome 2H across all South American field sites and years. Two complementary resistance genes were mapped to chromosomes 1H and 4H at the seedling stage in response to PshWUR, likely to be the loci rpsEm1 and rpsEm2 previously reported from the cultivar Emir from which Pompadour was bred. For leaf Rust, we determined that Rph20 in addition to two minor-effect QTL on 1H and 3H were effective at the seedling stage, whilst seedling resistance to stem Rust was due to QTL on chromosomes 3H and 7H conferred by Pompadour and B-19, respectively.
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Table_1_High-Density Mapping of Triple Rust Resistance in Barley Using DArT-Seq Markers.xlsx
2019Co-Authors: Peter M. Dracatos, Ravi P Singh, Kerrie Forrest, Rouja Haghdoust, Julio Huerta Espino, Charles W. Barnes, Matthew Hayden, Rients E. Niks, Robert F. Park, Davinder SinghAbstract:The recent availability of an assembled and annotated genome reference sequence for the diploid crop barley (Hordeum vulgare L.) provides new opportunities to study the genetic basis of agronomically important traits such as resistance to stripe [Puccinia striiformis f. sp. hordei (Psh)], leaf [P. hordei (Ph)], and stem [P. graminis f. sp. tritici (Pgt)] Rust Diseases. The European barley cultivar Pompadour is known to possess high levels of resistance to leaf Rust, predominantly due to adult plant resistance (APR) gene Rph20. We developed a barley recombinant inbred line (RIL) population from a cross between Pompadour and the leaf Rust and stripe Rust susceptible selection Biosaline-19 (B-19), and genotyped this population using DArT-Seq genotyping by sequencing (GBS) markers. In the current study, we produced a high-density linkage map comprising 8,610 (SNP and in silico) markers spanning 5957.6 cM, with the aim of mapping loci for resistance to leaf Rust, stem Rust, and stripe Rust. The RIL population was phenotyped in the field with Psh (Mexico and Ecuador) and Ph (Australia) and in the greenhouse at the seedling stage with Australian Ph and Pgt races, and at Wageningen University with a European variant of Psh race 24 (PshWUR). For Psh, we identified a consistent field QTL on chromosome 2H across all South American field sites and years. Two complementary resistance genes were mapped to chromosomes 1H and 4H at the seedling stage in response to PshWUR, likely to be the loci rpsEm1 and rpsEm2 previously reported from the cultivar Emir from which Pompadour was bred. For leaf Rust, we determined that Rph20 in addition to two minor-effect QTL on 1H and 3H were effective at the seedling stage, whilst seedling resistance to stem Rust was due to QTL on chromosomes 3H and 7H conferred by Pompadour and B-19, respectively.
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Rust Diseases of wheat
2016Co-Authors: Ravi P Singh, E Saari Cimmyt Reviewrs E L H M BroersAbstract:Rust Diseases of wheat , Rust Diseases of wheat , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
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race non specific resistance to Rust Diseases in cimmyt spring wheats
Euphytica, 2011Co-Authors: Ravi P Singh, Julio Huertaespino, Sridhar Bhavani, S A Herrerafoessel, Davinder Singh, Pawan Singh, Govindan Velu, R E Mason, Yue Jin, P NjauAbstract:Rust Diseases continue to cause significant losses to wheat production worldwide. Although the life of effective race-specific resistance genes can be prolonged by using gene combinations, an alternative approach is to deploy varieties that posses adult plant resistance (APR) based on combinations of minor, slow Rusting genes. When present alone, APR genes do not confer adequate resistance especially under high disease pressure; however, combinations of 4–5 such genes usually result in “near-immunity” or a high level of resistance. Although high diversity for APR occurs for all three Rusts in improved germplasm, relatively few genes are characterized in detail. Breeding for APR to leaf Rust and stripe Rust in CIMMYT spring wheats was initiated in the early 1970s by crossing slow Rusting parents that lacked effective race-specific resistance genes to prevalent pathogen populations and selecting plants in segregating populations under high disease pressure in field nurseries. Consequently most of the wheat germplasm distributed worldwide now possesses near-immunity or adequate levels of resistance. Some semidwarf wheats such as Kingbird, Pavon 76, Kiritati and Parula show high levels of APR to stem Rust race Ug99 and its derivatives based on the Sr2-complex, or a combination of Sr2 with other uncharacterized slow Rusting genes. These parents are being utilized in our crossing program and a Mexico-Kenya shuttle breeding scheme is used for selecting resistance to Ug99. High frequencies of lines with near-immunity to moderate levels of resistance are now emerging from these activities. After further yield trials and quality assessments these lines will be distributed internationally through the CIMMYT nursery system.
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quantitative trait loci for slow Rusting resistance in wheat to leaf Rust and stripe Rust identified with multi environment analysis
Theoretical and Applied Genetics, 2008Co-Authors: Garry M Rosewarne, Ravi P Singh, J Huertaespino, G J RebetzkeAbstract:Rust Diseases are a major cause of yield loss in wheat worldwide, and are often controlled through the incorporation of resistance genes using conventional phenotypic selection methods. Slow-Rusting resistance genes are expressed quantitatively and are typically small in genetic effect thereby requiring multiple genes to provide adequate protection against pathogens. These effects are valuable and are generally considered to confer durable resistance. Therefore an understanding of the chromosomal locations of such genes and their biological effects are important in order to ensure they are suitably deployed in elite germplasm. Attila is an important wheat grown throughout the world and is used as a slow-Rusting donor in international spring wheat breeding programs. This study identified chromosomal regions associated with leaf Rust and stripe Rust resistances in a cross between Attila and a susceptible parent, Avocet-S, evaluated over 3 years in the field. Genotypic variation for both Rusts was large and repeatable with line-mean heritabilities of 94% for leaf Rust resistance and 87% for stripe Rust. Three loci, including Lr46/Yr29 on chromosome 1BL, were shown to provide resistance to leaf Rust whereas six loci with small effects conferred stripe Rust resistance, with a seventh locus having an effect only by epistasis. Disease scoring over three different years enabled inferences to be made relating to stripe Rust pathogen strains that predominated in different years.
James W. Buck - One of the best experts on this subject based on the ideXlab platform.
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fusarium head blight and Rust Diseases in soft red winter wheat in the southeast united states state of the art challenges and future perspective for breeding
Frontiers in Plant Science, 2020Co-Authors: Bikash Ghimire, James W. Buck, Suraj Sapkota, Bochra A Bahri, Alfredo D Martinezespinoza, Mohamed MergoumAbstract:Among the biotic constraints to wheat (Triticum aestivum L.) production, fusarium head blight (FHB), caused by Fusarium graminearum, leaf Rust (LR), caused by Puccinia triticina, and stripe Rust (SR) caused by Puccinia striiformis are problematic fungal Diseases worldwide. Each can significantly reduce grain yield while FHB causes additional food and feed safety concerns due to mycotoxin contamination of grain. Genetic resistance is the most effective and sustainable approach for managing wheat Diseases. In the past 20 years, over 500 quantitative trait loci (QTLs) conferring small to moderate effects for the different FHB resistance types have been reported in wheat. Similarly, 79 Lr-genes and more than 200 QTLs and 82 Yr-genes and 140 QTLs have been reported for seedling and adult plant LR and SR resistance, respectively. Most QTLs conferring Rust resistance are race-specific generally conforming to a classical gene-for-gene interaction while resistance to FHB exhibits complex polygenic inheritance with several genetic loci contributing to one resistance type. Identification and deployment of additional genes/QTLs associated with FHB and Rust resistance can expedite wheat breeding through marker-assisted and/or genomic selection to combine small-effect QTL in the gene pool. LR disease has been present in the southeast United States for decades while SR and FHB have become increasingly problematic in the past 20 years, with FHB arguably due to increased corn acreage in the region. Currently, QTLs on chromosome 1B from Jamestown, 1A, 1B, 2A, 2B, 2D, 4A, 5A, and 6A from W14, Ning7840, Ernie, Bess, Massey, NC-Neuse, and Truman, and 3B (Fhb1) from Sumai 3 for FHB resistance, Lr9, Lr10, Lr18, Lr24, Lr37, LrA2K, and Lr2K38 genes for LR resistance, and Yr17 and YrR61 for SR resistance have been extensively deployed in southeast wheat breeding programs. This review aims to disclose the current status of FHB, LR, and SR Diseases, summarize the genetics of resistance and breeding efforts for the deployment of FHB and Rust resistance QTL on soft red winter wheat cultivars, and present breeding strategies to achieve sustainable management of these Diseases in the southeast US.
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effect of light on in vivo urediniospore germination lesion development and sporulation of puccinia hemerocallidis on daylily and puccinia pelargoniizonalis on geranium
Mycologia, 2011Co-Authors: Weibo Dong, James W. BuckAbstract:The presence of Rusts of daylily and geranium caused respectively by Puccinia hemerocalli- dis and P. pelargonii-zonalis can result in reduced value of these ornamental crops. Experiments were conducted to determine the effects of fluorescent light and sunlight on urediniospore germination, germ tube elongation, lesion development and sporulation of the two fungal pathogens on detached leaves and whole plants. Exposure of dry or hydrated urediniospores of P. hemerocallidis to cool white fluorescent light (600 mmol s 21 m 22 ) or to sunlight (950-1910 mmol s 21 m 22 ) for 2 h or 4 h significantly reduced germination and germ tube elongation on detached daylily leaves. Germination but not germ tube elongation of hydrated urediniospores of P. pelargonii-zonalis on detached geranium leaves was significantly reduced when exposed to fluorescent light for 2 h or 4 h. A 4 h exposure to either light source significantly reduced lesion development of P. hemerocallidis on detached daylily leaves with fewer lesions developing from hydrated compared to dry urediniospores. Sunlight exposures of 1 h and 2 h of hydrated and dry urediniospores respectively signifi- cantly reduced lesion development by either fungus on whole plants. Increasing exposure to fluorescent light negatively affected sporulation of P. hemerocalli- dis and P. pelargonii-zonalis. Complete suppression of sporulation was not observed for either fungus with up to a 24 h exposure to fluorescent light. Light exposure negatively affected disease development by P. hemerocallidis and P. pelargonii-zonalis. Exposure to high light intensities may affect spread of Rust Diseases on ornamental plants.
Garry M Rosewarne - One of the best experts on this subject based on the ideXlab platform.
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quantitative trait loci for slow Rusting resistance in wheat to leaf Rust and stripe Rust identified with multi environment analysis
Theoretical and Applied Genetics, 2008Co-Authors: Garry M Rosewarne, Ravi P Singh, J Huertaespino, G J RebetzkeAbstract:Rust Diseases are a major cause of yield loss in wheat worldwide, and are often controlled through the incorporation of resistance genes using conventional phenotypic selection methods. Slow-Rusting resistance genes are expressed quantitatively and are typically small in genetic effect thereby requiring multiple genes to provide adequate protection against pathogens. These effects are valuable and are generally considered to confer durable resistance. Therefore an understanding of the chromosomal locations of such genes and their biological effects are important in order to ensure they are suitably deployed in elite germplasm. Attila is an important wheat grown throughout the world and is used as a slow-Rusting donor in international spring wheat breeding programs. This study identified chromosomal regions associated with leaf Rust and stripe Rust resistances in a cross between Attila and a susceptible parent, Avocet-S, evaluated over 3 years in the field. Genotypic variation for both Rusts was large and repeatable with line-mean heritabilities of 94% for leaf Rust resistance and 87% for stripe Rust. Three loci, including Lr46/Yr29 on chromosome 1BL, were shown to provide resistance to leaf Rust whereas six loci with small effects conferred stripe Rust resistance, with a seventh locus having an effect only by epistasis. Disease scoring over three different years enabled inferences to be made relating to stripe Rust pathogen strains that predominated in different years.
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lr68 a new gene conferring slow Rusting resistance to leaf Rust in wheat
Theoretical and Applied Genetics, 1998Co-Authors: S A Herrerafoessel, Ravi P Singh, Julio Huertaespino, Garry M Rosewarne, Sambasivam Periyannan, Libby Viccars, V Calvosalazar, Caixia Lan, E S LagudahAbstract:The common wheat cultivar Parula possesses a high level of slow Rusting, adult plant resistance (APR) to all three Rust Diseases of wheat. Previous mapping studies using an Avocet-YrA/Parula recombinant inbred line (RIL) population showed that APR to leaf Rust (Puccinia triticina) in Parula is governed by at least three independent slow Rusting resistance genes: Lr34 on 7DS, Lr46 on 1BL, and a previously unknown gene on 7BL. The use of field Rust reaction and flanking markers identified two F6 RILs, Arula1 and Arula2, from the above population that lacked Lr34 and Lr46 but carried the leaf Rust resistance gene in 7BL, hereby designated Lr68. Arula1 and Arula2 were crossed with Apav, a highly susceptible line from the cross Avocet-YrA/Pavon 76, and 396 F4-derived F5 RILs were developed for mapping Lr68. The RILs were phenotyped for leaf Rust resistance for over 2 years in Ciudad Obregon, Mexico, with a mixture of P. triticina races MBJ/SP and MCJ/SP. Close genetic linkages with several DNA markers on 7BL were established using 367 RILs; Psy1-1 and gwm146 flanked Lr68 and were estimated at 0.5 and 0.6 cM, respectively. The relationship between Lr68 and the race-specific seedling resistance gene Lr14b, located in the same region and present in Parula, Arula1 and Arula2, was investigated by evaluating the RILs with Lr14b-avirulent P. triticina race TCT/QB in the greenhouse. Although Lr14b and Lr68 homozygous recombinants in repulsion were not identified in RILs, γ-irradiation-induced deletion stocks that lacked Lr68 but possessed Lr14b showed that Lr68 and Lr14b are different loci. Flanking DNA markers that are tightly linked to Lr68 in a wide array of genotypes can be utilized for selection of APR to leaf Rust.
Michael O Pumphrey - One of the best experts on this subject based on the ideXlab platform.
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characterization of molecular diversity and genome wide mapping of loci associated with resistance to stripe Rust and stem Rust in ethiopian bread wheat accessions
BMC Plant Biology, 2017Co-Authors: Kebede T Muleta, Matthew N Rouse, Sheri Rynearson, Xianming Chen, Bedada G Buta, Michael O PumphreyAbstract:The narrow genetic basis of resistance in modern wheat cultivars and the strong selection response of pathogen populations have been responsible for periodic and devastating epidemics of the wheat Rust Diseases. Characterizing new sources of resistance and incorporating multiple genes into elite cultivars is the most widely accepted current mechanism to achieve durable varietal performance against changes in pathogen virulence. Here, we report a high-density molecular characterization and genome-wide association study (GWAS) of stripe Rust and stem Rust resistance in 190 Ethiopian bread wheat lines based on phenotypic data from multi-environment field trials and seedling resistance screening experiments. A total of 24,281 single nucleotide polymorphism (SNP) markers filtered from the wheat 90 K iSelect genotyping assay was used to survey Ethiopian germplasm for population structure, genetic diversity and marker-trait associations. Upon screening for field resistance to stripe Rust in the Pacific Northwest of the United States and Ethiopia over multiple growing seasons, and against multiple races of stripe Rust and stem Rust at seedling stage, eight accessions displayed resistance to all tested races of stem Rust and field resistance to stripe Rust in all environments. Our GWAS results show 15 loci were significantly associated with seedling and adult plant resistance to stripe Rust at false discovery rate (FDR)-adjusted probability (P) <0.10. GWAS also detected 9 additional genomic regions significantly associated (FDR-adjusted P < 0.10) with seedling resistance to stem Rust in the Ethiopian wheat accessions. Many of the identified resistance loci were mapped close to previously identified Rust resistance genes; however, three loci on the short arms of chromosomes 5A and 7B for stripe Rust resistance and two on chromosomes 3B and 7B for stem Rust resistance may be novel. Our results demonstrate that considerable genetic variation resides within the landrace accessions that can be utilized to broaden the genetic base of Rust resistance in wheat breeding germplasm. The molecular markers identified in this study should be useful in efficiently targeting the associated resistance loci in marker-assisted breeding for Rust resistance in Ethiopia and other countries.
Pawel Muzyka - One of the best experts on this subject based on the ideXlab platform.
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novel pcr assays for the detection of biological agents responsible for wheat Rust Diseases puccinia triticina and puccinia striiformis f sp tritici
Journal of Molecular Microbiology and Biotechnology, 2017Co-Authors: Adam Kuzdralinski, Anna Kot, Hubert Szczerba, Agnieszka Ostrowska, Michal Nowak, Marta Muszynska, Michal Lechowski, Pawel MuzykaAbstract:The species Puccinia triticina (Pt) and Puccinia striiformis f. sp. tritici (Pst) are devastating cereal pathogens that cause leaf and stripe Rust Diseases. We developed PCR assays for the species-specific detection of Pt and Pst, 2 biological agents that cause wheat Rust disease. For each pathogen, we validated 3 primer sets that target the second largest subunits of the RNA polymerase II (rpb2) and β-tubulin 1 (tub1) genes. The specificities of the primers were verified using naturally infected plant materials with visual symptoms of disease. All primer sets amplified a single DNA fragment of the expected length. The primer sets LidPr15/16, LidPr1/2, and LidPs13/14 were able to detect small amounts of pure fungal DNA with sensitivities of 0.1, 1, and 10 pg/μL, respectively. A sufficient detection limit (1 pg/μL to 5 ng/μL) was observed for all assays when the sensitivity test was performed with host plant DNA. The study also evaluated the simultaneous detection of both Rust pathogens, and the multiplex PCR assay generated amplicons of 240 and 144 bp in length for Pts (LidPs9/10) and Pt (LidPr1/2), respectively.
