Download or read book Identification Characterization and Mapping of LrCen a New Leaf Rust Puccinia Triticina Resistance Gene in Spring Wheat Triticum Aestivum written by Marley Boyce and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat leaf rust, caused by Puccinia triticina Eriks. (= P. recondita Rob. Ex Desmaz. f. sp. tritici), is the most widespread disease of wheat worldwide and causes average annual yield losses of 5 to 25%. The emergence of a new predominant race of leaf rust, TDBG, in the 2004 Canadian virulence survey led to the identification of a second leaf rust resistance gene segregating in the Thatcher-Lr1 near-isogenic differential line, RL6003, which produced an unusual mesothetic infection type. This gene was subsequently isolated in a Thatcher background and temporarily designated as LrCen (Tc-LrCen). A cross was made with a susceptible parent (Tc-LrCen/ Sumai3-lr34) and a doubled haploid (DH) mapping population was generated from the hybrids. Parental lines and 180 double haploid (DH) individuals were phenotyped with race TDBG and a 1:1 ratio was observed in the DH population. Parental lines and 94 DH individuals were genotyped with the Illumina Infinium assay using a custom iSelect 90K wheat SNP array. Two-point linkage between the phenotype and polymorphic SNP markers identified linked markers. A BLAST search of linked SNP sequences was performed against the Wheat Survey Sequence providing a putative chromosomal location of 7AL. Subsequent mapping with microsatellite markers confirmed LrCen was located on the long arm of chromosome 7A flanked by gwm344 (9.5 cM) and cfa2240 (0.6 cM) as well as a group of co-segregating SNPs also at a genetic distance of 0.6 cM. When the SNP sequences were converted to the kompetitive allele specific PCR (KASP) markers they were found to be dominant, making them less useful for marker assisted selection in populations with heterozygotes. LrCen mapped distal to Lr20; the only other Lr gene previously identified on chromosome 7AL.

Download or read book Characterization and Genetic Mapping of Leaf Rust Puccinia Triticina Resistance Genes Lr2a and Lr46 in Canadian Spring Wheat Triticum Aestivum Germplasm written by Mallorie Lewarne and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of the fungal diseases that can infect bread wheat (Triticum aestivum L.), leaf rust, caused by Puccinia triticina Eriks. is the most common and widespread. Pyramiding multiple resistance genes in a cultivar using conventional breeding techniques is often expensive and time consuming. Alternatively, marker assisted selection (MAS) allows for accelerated and accurate selection of resistance gene combinations. The objectives of this study were to characterize two leaf rust resistance genes: an adult plant resistance (APR) gene, hypothesized to be Lr46, from wheat line BW278, and a seedling resistance gene, Lr2a, from wheat cultivar Superb. To characterize the APR, two mapping populations derived from BW278 were genotyped with the iSelect 90K wheat SNP array. Both populations were evaluated for leaf rust in inoculated field nurseries for five years. Quantitative trait locus (QTL) analysis revealed two QTL controlling resistance in the BW278/AC Foremost population, one in the region of interest, chromosome 1B and another on chromosome 5A. Two QTL were detected in Superb/BW278, on chromosomes 4B and 5B, however no QTL were detected in the region of interest on 1B. The QTL on 1B in BW278/AC Foremost, designated QLr.mrdc-1B, was tightly linked to both csLV46G22 and DK0900, two markers previously described as tightly linked to the Lr46 locus. Ten SNPs in the QLr.mrdc-1B region were selected for kompetitive allele-specific PCR (KASP) assay design. To characterize Lr2a, two mapping populations derived from Superb (Superb/BW278 & Superb/86ISMN 2137) were genotyped with the iSelect 90 K wheat SNP array, and evaluated with a single race of P. triticina under greenhouse conditions. Two-point linkage analysis between the marker data and phenotypic infection type ratings revealed that the gene mapped to chromosome 2DS in both mapping populations. The linkage maps generated for the two mapping populations had 11 SNP markers in common and displayed collinearity. Seven SNPs that either flanked or co-segregated with Lr2a in Superb/BW278 were selected for KASP assay design. Of the seven markers, kwh740 (Excalibur_c1944_1017) was polymorphic in both populations and displayed clear clusters, making it the most applicable for use in MAS.

Download or read book Genetic Mapping of Leaf Rust Puccinia Triticina Eriks Resistance in Durum Wheat Triticum Turgidum Var Durum L written by Xiangyu (Bruce) Pei and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leaf rust, caused by Puccinia triticina Eriks. (Pt = P. recondita Rob. Ex Desmaz. F. sp. tritici), is an economically significant pathogen affecting durum wheat (Triticum turgidum var. durum L.) crops worldwide. Genetic resistance is one of the most effective and environmentally friendly methods to control leaf rust in wheat. New sources of resistance genes need to be identified due to the threat of new Pt races to durum wheat production. Marker assisted selection (MAS) is a highly efficient method to select resistance genes in breeding programs particularly to pyramid multiple resistance genes in new varieties. The objective of this study was to characterize and map leaf rust resistance genes in a Canadian durum wheat Strongfield. A double haploid (DH) mapping population of 87 DH lines was developed from the cross Strongfield/Blackbird. Seedling rust tests with Pt isolates 12-3 MBDS, 06-1-1 TDBG, 128-1 MBRJ, 74-2 MGBJ, and 77-2 TJBJ revealed a single hypersensitive leaf rust resistance gene. Three genes segregated for resistance to isolate 1-1 BBBD at the seedling stage, one of which controlled resistance to the other five Pt isolates. Blackbird contributed one of the seedling resistance genes effective against isolate 1-1 BBBD. Parental lines and 87 DH lines were genotyped using the Illumina Infinium assay with the iSelect 90K wheat SNP array. A database search using the DNA sequences of linked markers provided a putative location in the Chinese Spring reference genome sequence. The gene conferring resistance to the six isolates used in the study mapped to the long arm of chromosome 3A and was temporarily designated as LrStr_3A. No leaf rust resistance gene has been detected in this region previously. Quantitative trait locus (QTL) analysis identified eight QTL controlling leaf rust resistance in field leaf rust nurseries. One of these QTL mapped to chromosome 3AL as the same region of LrStr_3A. Another QTL mapped to the expected location of the adult plant resistance (APR) gene Lr46 based upon the marker csLV46G22. Kompetitive allele-specific PCR (KASP) markers were developed for LrStr_3A that will be useful for MAS.

Download or read book Genetics and Molecular Breeding in Cereal Crops written by Hongwei Wang and published by Frontiers Media SA. This book was released on 2023-11-09 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of a Gene from Breeding Line WX93D180 Conferring Resistance to Leaf Rust Puccinia Triticina in Wheat written by Hsiao-Yi Hung and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat (Triticum aestivum L. em. Thell, 2n=6x=42, AABBDD) is subjected to significant yield losses by the endemic leaf rust pathogen, Puccinia triticina (Roberge ex Desmaz. F. sp. tritici). Breeding for resistance to this disease is a more appropriate option both environmentally and economically over fungicidal application. More than 57 leaf rust resistance genes in wheat have been identified and many of the resistance genes have been successfully introgressed into resistant cultivars, yet the continuous shifting of predominant races of P. triticina continues to be a challenge to breeders. Pyramiding multiple resistance genes into a single resistant cultivar is one of the preferred strategies to develop superior disease resistant cultivars. Efficient pyramiding requires the utilization of markers closely linked to the resistance genes. The objectives of this study were to characterize a novel source of resistance to leaf rust introgressed into the breeding line WX93D180-R-8-1, to determine its inheritance, map position, and linkage with molecular markers suitable for marker assisted selection. According to the pedigree of WX93D180, TX86D1310*3/TTCC417, the resistance in this breeding line should be derived from TTCC417 (Turkey tritici cereal collection), which was thought to be Triticum monococcum, which is a diploid species made up of only the A genome. However, our marker analyzes results indicated the resistance gene is located in the D genome and has the same location as the cloned leaf rust resistance gene Lr21. We verified the result in our population using primers from Lr21 and found the same segregation pattern with the phenotypic data (disease response). Therefore the pedigree is incorrect, TTCC417 was misidentified, or the resistance was not from TTCC417.

Download or read book Characterization and Mapping of Four New Leaf Rust Resistance Genes Transferred to Common Wheat from Triticum Tauschii and T Monococcum written by Temam Hussien and published by . This book was released on 1996 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of the Leaf Rust Puccinia Recondita F sp Tritici Resistance Genes Lr24 and Lr26 and the Stem Rust Puccinia Graminis F sp Tritici Resistance Genes Sr24 and Sr31 in Wheat Triticum Aestivum written by Heather M. Norquay and published by . This book was released on 1992 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification of Leaf Rust Susceptibility Genes in Wheat written by Joseph Fenoglio and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leaf Rust, caused by Puccinia triticina, is a major disease of wheat. Leaf rust has proven to be a resilient pathogen, overcoming resistance genes multiple times. Plants have factors, known as susceptibility genes, that facilitate the ability of pathogens to cause disease. Altering susceptibility genes may provide a more durable defense against infection than resistance genes but have yet to be identified for susceptibility to leaf rust in wheat. By characterizing random mutants created through chemical mutagenesis, mechanisms determining wheat susceptibility to leaf rust can be determined. The susceptible wheat variety Thatcher was mutagenized using ethyl methanesulfonate (EMS). Surviving plants were scored for a reduction in pustule size or quantity when challenged with leaf rust. From these plants, three mutant lines (1995, 2048, and 2348) have been obtained. Mutant lines 1995 and 2048 exhibit a constitutive hypersensitive-like response (HR-like). Mutant line 2348 exhibits no evidence of a HR. Microscopic analysis of the initial 5 days of the infection process revealed the ability of P. triticina to form appressoria, early colonization, and pustule development was altered in 1995 and 2048. In 2348, P. triticina was less able to progress beyond appressoria formation and intercellular hyphae than in Thatcher. Bulked segregant RNAseq analysis of F[subscript 2:3] pools of tissue originating from a backcross to the wild type parent revealed an induction of the plant defense response in 1995 and 2048. Genotypic studies were conducted to identify regions that may contain the causative mutation. A F4 mapping population was generated by crossing each mutant line with the hard red winter wheat variety KS061705M11 and utilizing single seed descent. Association mapping identified SNPs within each population that associated with the mutant phenotype. Confidence intervals surrounding each identified SNP were created through haplotype blocking. A second genotyping method, exome capture, identified SNPs in M8 lines for each mutant. Using the confidence intervals from association mapping, the list of SNPs from exome capture was narrowed. Mutant line 1995 mapped to a 3.89Mb window on 2D, a 7Mb window on 3A, and a 4.85Mb window on 4B. Mutant line 2048 mapped to a 3.89Mb window on 3B and a 4.52Mb window on 4B. These intervals narrow the region of interest for future fine mapping studies that seek to identify the causative mutation.

Download or read book Molecular Characterization of Durable Yellow and Leaf Rust Resistance in Two Wheat Populations written by Bhoja Basnet and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wheat (Triticum aestivum L.) is one of the most important food crops, comprising the largest source of daily calorie and protein intake of human beings worldwide. Among the several diseases of wheat, Yellow Rust (YR; caused by Puccinia striiformis Westend. f. sp. tritici) and Leaf Rust (LR; caused by Puccinia triticina Erikss. & Henn.) have always been major production constraints since the domestication of wheat. For the last few decades, scientists have invested large efforts to identify, characterize and utilize Adult Plant Resistance (APR), a.k.a. slow rusting resistance, in wheat germplasm to promote durability of resistance against rust. The objectives of this study were to 1) understand the genetics of APR to YR and/or LR present in two potential wheat lines 'Quaiu 3' and 'TAM 111', and 2) map the putative Quantitative Trait Loci (QTL) associated with YR and LR resistance using DNA-based molecular markers. Two Recombinant Inbred Line (RIL) populations were subjected to YR and LR disease evaluation experiments in multiple years and locations. Visual evaluation of Disease severity (DS) and Infection Type (IT) score in both RIL populations showed that APR to YR and LR were highly heritable quantitative traits with significant correlation among experiments. In spring wheat population, composite interval mapping consistently detected four and three large effect QTL for YR and LR resistance, respectively. Among those QTLs, 1B, 3B and 1D QTL were found to be associated with previously characterized genes Lr46/Yr29, Sr2/Yr30 and Lr42, respectively. However, QTLs QYr.tam-3D and QYr.tam-2D were potentially novel. The largest YR QTL QYr.tam-2D was located on long arm of chromosome 2D explaining about 48 to 61% of the total phenotypic variation. Similarly, in winter wheat population, apart from three environment-specific QTL on chromosomes 1A, 2A and 7D, the QTL on chromosome 2B (QYr.tam-2B) was found to express consistently in multiple environments explaining about 23 to 63% of total phenotypic variation. This study has further elucidated the inheritance mechanism of APR to YR and LR present in two different wheat lines, Quaiu 3 and TAM 111, and resulted in the successful mapping and characterization of the genetic loci associated with corresponding disease resistance traits. These findings should be very useful to isolate the novel APR genes and/or directly use in wheat breeding programs to enhance durable rust resistance in diverse wheat germplasm and cultivars in the future.

Download or read book Mapping High Temperature Adult Plant Resistance to Stripe Rust Puccinia Striiformis in Spring Wheat Triticum Aestivum and Characterization of Their Interaction on a Molecular Level written by Taras Nazarov and published by . This book was released on 2017 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here we report the discovery of precise molecular marker for HTAP resistance locus in wheat cultivar Louise. Using Louise x Penawawa mapping population, coupled with data from survey sequences of wheat genome, linkage mapping and synteny analysis, we developed expressed, cleaved amplified polymorphic sequence (CAPS) marker LPHTAP2B on the short arm of wheat chromosome 2B. It perfectly segregates with the resistant phenotype and explains 62% of phenotypic variance based on disease severity, and 58% based on infection type.

Download or read book Molecular Mapping of a Gene for Resistance to Stripe Rust in Spring Wheat Cultivar IDO377s and Identification of a New Race of Puccinia Striiformis F Sp Tritici Virulent on IDO377s written by Peng Cheng and published by . This book was released on 2008 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary Record of the 7th Meeting closed Held at Headquarters New York on Friday 26 August 2005 written by and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Next generation Sequencing Technologies to Develop New Molecular Markers for the Leaf Rust Resistance Gene Lr16 written by Nicole Rezac Harrison and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Leaf rust is caused by Puccinia triticina and is one of the most widespread diseases of wheat worldwide. Breeding for resistance is one of the most effective methods of control. Lr16 is a leaf rust resistance gene that provides partial resistance at the seedling stage. One objective of this study was to use RNA-seq and in silico subtraction to develop new resistance gene analog (RGA) markers linked to Lr16. RNA was isolated from the susceptible wheat cultivar Thatcher (Tc) and the resistant Thatcher isolines TcLr10, TcLr16, and TcLr21. Using in silico subtraction, Tc isoline ESTs that did not align to the Tc reference were assembled into contigs and analyzed using BLAST. Primers were designed from 137 resistance gene analog sequences not found in Tc. A population of 260 F2 lines derived from a cross between the rust-susceptible cultivar Chinese Spring (CS) and a Thatcher isoline containing Lr16 (TcLr16) was developed for mapping these markers. Two RGA markers XRGA266585 and XRGA22128 were identified that mapped 1.1 cM and 23.8 cM from Lr16, respectively. Three SSR markers Xwmc764, Xwmc661, and Xbarc35 mapped between these two RGA markers at distances of 4.1 cM, 10.7 cM, and 16.1 cM from Lr16, respectively. Another objective of this study was to use genotyping-by-sequencing (GBS) to develop single nucleotide polymorphism (SNP) markers closely linked to Lr16. DNA from 22 resistant and 22 susceptible F2 plants from a cross between CS and TcLr16 was used for GBS analysis. A total of 39 Kompetitive Allele Specific PCR (KASP) markers were designed from SNPs identified using the UNEAK and Tassel pipelines. The KASP marker XSNP16_TP1456 mapped 0.7 cM proximal to Lr16 in a TcxTcLr16 population consisting of 129 F2 plants. These results indicate that both techniques are viable methods to develop new molecular markers. RNA-seq and in silico subtraction were successfully used to develop two new RGA markers linked to Lr16, one of which was more closely linked than known SSR markers. GBS was also successfully used on an F2 population to develop a KASP marker that is the most closely linked marker to Lr16 to date.

Download or read book The Genetics of Leaf Rust Resistance in the Durably Resistant Wheat Cultivar Toropi written by Silvia Barcellos Rosa and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic Characterization of Virulence in a Pacific Northwest Stem Rust Population and Mapping of New Sources of Resistance in Barley written by Arjun Upadhaya and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stem rust caused by the biotrophic fungal pathogen Puccinia graminis f. sp. tritici (Pgt) is an important disease of barley and wheat globally. In the last decade, the Pacific Northwest (PNW) region of the United States has experienced an increase in the incidence and severity of stem rust disease. This may be attributed to various factors, including increase in summer temperatures, lack of effective resistance, and early inoculum from sexual hosts. The PNW region's conducive environment and the presence of the sexual hosts, Mahonia and barberry, present an opportunity for the stem rust pathogen to complete its sexual cycle, leading to the emergence of genotypes with novel virulence gene combinations. A total of 100 Pgt isolates collected from barley in eastern Washington during the 2019 growing season were tested for virulence on the two major barley stem rust resistance genes/loci, Rpg1 and the rpg4/5-mediated resistance locus (RMRL) at the seedling stage. Of these isolates, 99% were virulent on cultivar Morex containing the Rpg1 gene, 62% were virulent on Golden Promise transgenic line (H228.2c) carrying a single copy of the Rpg1 gene from Morex, 16% were virulent on the near isogenic line, HQ-1 containing RMRL, and 10% were virulent on barley line Q21861 carrying both Rpg1 and RMRL. This was the first report of Pgt isolates containing virulence on both Rpg1 and RMRL when stacked together, representing the most virulent Pgt population reported on barley worldwide. To identify and map effective resistances against the local virulent isolates, a genome wide association study (GWAS) was conducted on 440 accessions from the World Barley Core Collection (WBCC), genotyped with the 9K Illumina barley iSelect chip and phenotyped with two PNW Pgt isolates at the seedling stage. A total of 10 resistance loci were identified including four novel loci on chromosomes 1H, 2H, 5H, and 6H. On the pathogen side, GWAS was performed using 113 diverse Pgt isolates, collected from the PNW and the Midwest region of the US, to identify virulence and avirulence loci corresponding to the barley stem rust resistance gene Rpg1 and the six wheat stem rust R-genes, Sr5, Sr21, Sr8a, Sr17, Sr9a, and Sr9d. The genotype data for 96 isolates were generated by whole genome shotgun sequencing and for 17 isolates by RNA sequencing. The phenotype data for the Pgt isolates were collected by seedling disease assays on two barley lines, H228.2c and Morex (Rpg1+) and the six wheat stem rust differential lines, Sr5, Sr21, Sr8a, Sr17, Sr9a, and Sr9d. A total of five effector gene candidates were identified at two loci corresponding to the Rpg1 gene. Similarly, 24 putative effector genes were identified at 15 loci corresponding to the six wheat R-genes. Further characterization of these genes will be done to enhance our understanding of host pathogen interactions in both the barley-Pgt and wheat-Pgt pathosystems.

Download or read book Rust Diseases of Wheat written by Alan P. Roelfs and published by CIMMYT. This book was released on 1992 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accelerated Breeding of Cereal Crops written by Andriy Bilichak and published by Humana. This book was released on 2022-10-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a comprehensive collection of methods for plant breeders and researchers working in functional genomics of cereal crops. Chapters detail advances in sequencing of cereal genomes, methods of traditional plant breeding, use of machine learning for genomic selection, random and targeted mutagenesis with CRISPR/Cas9, quantitative proteomics and phenotyping in cereals. Authoritative and cutting-edge, Accelerated Breeding of Cereal Crops aims to be of interest to plant breeders, researchers, postdoctoral fellows, and students working in functional genomics for the development of the next generation of crop plants.