scholarly journals Development of white-grain pre-harvest sprouting tolerant and pyramided protein-rich leaf rust resistant wheats using molecular breeding

2021 ◽  
Author(s):  
Tinku Gautam ◽  
Kuldeep Kumar ◽  
Priyanka Agarwal ◽  
Sandhya Tyagi ◽  
Vandana Jaiswal ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Leaf Rust Resistance ◽  
Grain Protein Content ◽  
Kasp Assay ◽  
Simulated Rain ◽  
White Grain ◽  
High Level ◽  
Protein Rich ◽  
Marker Assisted Backcross Breeding ◽  
Yield Penalty

Abstract The present study was undertaken for developing pre-harvest sprouting tolerant (PHST) wheat genotypes using marker-assisted backcross breeding (MABB). A major QTL for PHST was introgressed into an elite Indian wheat cv. Lok1 that is PHS susceptible. These PHST lines were also pyramided with one gene each for high grain protein content (Gpc-B1) and leaf rust resistance (Lr24). For introgression of PHST QTL, initially Lok1 was separately crossed with each of the two donors (PHS tolerant white-grained AUS1408 and CN19055). Backcrossing in each generation was followed by foreground and background selections using SSR markers. In advanced lines, KASP assay was also carried out for the candidate gene TaMKK3-A underlying the PHST QTL. The MAS derived lines homozygous for PHST QTL were screened for PHS using simulated rain chambers resulting in the selection of 10 PHST lines. For pyramiding of three QTL/genes (PHST QTL, Gpc-B1, and Lr24), MABB derived BC4F2 plants (from the cross Lok1/CN19055) were crossed with a MAS derived BC2F5 line [Lok1 (Gpc-B1 + Lr24)] developed earlier by us in the same background of Lok1. After foreground MAS followed by PHS screening, four advanced lines carrying all the three QTL/genes in homozygous condition were selected. These lines exhibited high level of PHST (PHS score 2–3) associated with significant improvement in GPC with no yield penalty and resistance against leaf rust under artificial epiphytotic conditions.

Genotype groups of the wheat leaf rust fungus Puccinia triticina in the United States as determined by genotyping by sequencing

2021 ◽  
Author(s):  
James Kolmer ◽  
Adam Herman ◽  
John Fellers
Keyword(s):  
United States ◽  
Leaf Rust ◽  
Resistance Genes ◽  
Puccinia Triticina ◽  
Genotyping By Sequencing ◽  
Leaf Rust Resistance ◽  
The United States ◽  
Wheat Leaf ◽  
High Level ◽  
Leaf Rust Resistance Genes

Wheat leaf rust caused by Puccinia triticina, is a widespread disease of wheat in the United States and worldwide. Populations of P. triticina are characterized by virulence phenotypes that change rapidly due to selection by wheat cultivars with leaf rust resistance genes. The objective of this study was to genotype collections of P. triticina from 2011-2018 in the United States, using restriction site associated genotyping by sequencing (GBS), to determine if recently identified new virulence phenotypes belong to established genotype groups or belong to groups previously not detected. A total of 158 isolates were phenotyped for virulence on 20 lines of Thatcher wheat that are isogenic for leaf rust resistance genes and were also genotyped for single nucleotide polymorphism. Eight distinct groups of P. triticina genotypes from common wheat were described based on coancestry, nucleotide divergence, and principal coordinate plots. A separate genotype group had isolates with virulence to durum wheat. Isolates within groups had similar virulence phenotype, and the overall population had high level of heterozygosity and a high level of linkage disequilibria, which were all indicators of clonality. Two new genotype groups were described, raising the possibility of new introductions of P. triticina, although genotypes in these groups may have also originated from somatic nuclear exchange and recombination. A genome wide association study detected 19 SNPs that were highly associated with virulence to 11 resistance genes in the Thatcher near isogenic lines.

scholarly journals Leaf rust resistance in barley accessions from Ethiopia

2020 ◽  
Vol 103 (4) ◽  
pp. 262-264
Author(s):  
R. A. Abdullayev* ◽  
E. Е. Radchenko ◽  
B. A. Batasheva
Keyword(s):  
Leaf Rust ◽  
Leaf Rust Resistance ◽  
Puccinia Hordei ◽  
Point Scale ◽  
Pathogen Population ◽  
Breeding Lines ◽  
Low Diversity ◽  
Cultivated Barley ◽  
High Level ◽  
Damage Symptoms

Currently, the problem of broadening the diversity of cultivated barley varieties based on the effective genes for resistance to the leaf rust causal agent Puccinia hordei has become relevant. In 2018–2019 the resistance of 925 barley accessions from Ethiopia to the northwestern (St. Petersburg, Pushkin) pathogen population was evaluated. The accessions were sown at a later date, favoring to severe plant damage. The resistance was assessed during the heading period and over the milk ripening stage using a point scale. The results of the experiments have indicated a low diversity of Ethiopian barley according to the studied trait. Only 4 accessions have been resistant to P. hordei, and 3 breeding lines (k-30810, k-30811 and k-30812) have been protected by the previously identified Rph7 gene, which efficiency has been decreasing in recent years. The accession k-21919 has possessed a high level of resistance to the pathogen (i.e. lack of damage symptoms) and therefore it can be recommended for utilization in barley breeding.

Genetics of leaf-rust resistance in three spelt wheats

1994 ◽  
Vol 74 (2) ◽  
pp. 231-233 ◽  
Author(s):  
P. L. Dyck ◽  
E. E. Sykes
Keyword(s):  
Leaf Rust ◽  
Plant Resistance ◽  
Rust Resistance ◽  
Adult Plant Resistance ◽  
Leaf Rust Resistance ◽  
Field Resistance ◽  
Adult Plant ◽  
Seedling Resistance ◽  
Field Reaction ◽  
High Level

The inheritance of leaf-rust resistance was studied in three accessions of spelt wheat (Triticum aestivum ssp. spelta L.). Accession 7831 has a gene for seedling resistance to leaf rust that is linked with Lr33 (5.4 ± 1.05%), which is known to he on the long arm of chromosome 1B. This gene, which was either recessive or partially dominant, is designated Lr44, and because of its field reaction, should be useful in breeding rust-resistant wheats. Accession 7839 may also have this gene and an additional gene that in the seedling stage conditioned a type 2 infection to many races but little field resistance. Accessions 7831, 7839 and 7825 also have possibly in common a gene for adult-plant resistance. This gene, which did not give a high level of field resistance, was independent of Lr12, Lr13, Lr22, Lr34 and Lr35, other genes for adult-plant resistance. Key words:Triticum, wheat, leaf-rust resistance

Lr80: A new and widely effective source of leaf rust resistance of wheat for enhancing diversity of resistance among modern cultivars

2021 ◽  
Author(s):  
Subodh Kumar ◽  
Subhash C. Bhardwaj ◽  
Om P. Gangwar ◽  
Akanksha Sharma ◽  
Naeela Qureshi ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Effective Source

scholarly journals Map-Based Cloning of Leaf Rust Resistance Gene Lr21 From the Large and Polyploid Genome of Bread Wheat

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 655-664 ◽  
Author(s):  
Li Huang ◽  
Steven A Brooks ◽  
Wanlong Li ◽  
John P Fellers ◽  
Harold N Trick ◽  
...  
Keyword(s):  
Amino Acid ◽  
Leaf Rust ◽  
Resistance Gene ◽  
Bread Wheat ◽  
Rust Resistance ◽  
Agronomic Traits ◽  
Leaf Rust Resistance ◽  
Triticum Aestivum L ◽  
Rust Resistance Gene ◽  
Leaf Rust Resistance Gene

Abstract We report the map-based cloning of the leaf rust resistance gene Lr21, previously mapped to a generich region at the distal end of chromosome arm 1DS of bread wheat (Triticum aestivum L.). Molecular cloning of Lr21 was facilitated by diploid/polyploid shuttle mapping strategy. Cloning of Lr21 was confirmed by genetic transformation and by a stably inherited resistance phenotype in transgenic plants. Lr21 spans 4318 bp and encodes a 1080-amino-acid protein containing a conserved nucleotide-binding site (NBS) domain, 13 imperfect leucine-rich repeats (LRRs), and a unique 151-amino-acid sequence missing from known NBS-LRR proteins at the N terminus. Fine-structure genetic analysis at the Lr21 locus detected a noncrossover (recombination without exchange of flanking markers) within a 1415-bp region resulting from either a gene conversion tract of at least 191 bp or a double crossover. The successful map-based cloning approach as demonstrated here now opens the door for cloning of many crop-specific agronomic traits located in the gene-rich regions of bread wheat.

scholarly journals Identification of leaf rust resistance genes Lr34 and Lr46 in common wheat (Triticum aestivum L. ssp. aestivum) lines of different origin using multiplex PCR

2021 ◽  
Vol 16 (1) ◽  
pp. 172-183
Author(s):  
Agnieszka Tomkowiak ◽  
Roksana Skowrońska ◽  
Michał Kwiatek ◽  
Julia Spychała ◽  
Dorota Weigt ◽  
...  
Keyword(s):  
Multiplex Pcr ◽  
Leaf Rust ◽  
Common Wheat ◽  
Fungal Pathogens ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Field Conditions ◽  
Pcr Marker ◽  
Specific Sequence ◽  
Cereal Species

Abstract Leaf rust caused by the fungus Puccinia recondita f. sp. tritici is one of the most dangerous diseases of common wheat. Infections caused by fungal pathogens reduce the quantity and quality of yields of many cereal species. The most effective method to limit plant infection is to use cultivars that show rust resistance. Genetically conditioned horizontal-type resistance (racial-nonspecific) is a desirable trait because it is characterized by more stable expression compared to major (R) genes that induce racially specific resistance, often overcome by pathogens. Horizontal resistance is conditioned by the presence of slow rust genes, which include genes Lr34 and Lr46. This study aimed to identify markers linked to both genes in 64 common wheat lines and to develop multiplex PCR reaction conditions that were applied to identify both genes simultaneously. The degree of infestation of the analyzed lines was also assessed in field conditions during the growing season of 2017 and 2018. Simple sequence repeat anchored-polymerase chain reaction (SSR-PCR) marker csLV was identified during analysis in line PHR 4947. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. In addition to gene Lr34, gene Lr46 was identified in this genotype. Lines PHR 4947 and PHR 4819 were characterized by the highest leaf rust resistance in field conditions. During STS-PCR analyses, the marker wmc44 of gene Lr46 was identified in most of the analyzed lines. This marker was not present in the following genotypes: PHR 4670, PHR 4800, PHR 4859, PHR 4907, PHR 4922, PHR 4949, PHR 4957, PHR 4995, and PHR 4997. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. Genotypes carrying the markers of the analyzed gene showed good resistance to leaf rust in field conditions in both 2017 and 2018. Research has demonstrated that marker assisted selection (MAS) and multiplex PCR techniques are excellent tools for selecting genotypes resistant to leaf rust.

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