Publications by authors named "Guillermo Fuentes-Dávila"

6 Publications

  • Page 1 of 1

Genome Wide Association Study of Karnal Bunt Resistance in a Wheat Germplasm Collection from Afghanistan.

Int J Mol Sci 2019 Jun 26;20(13). Epub 2019 Jun 26.

International Maize and Wheat Improvement Center (CIMMYT), Carretera México-Veracruz Km. 45, El Batán, Texcoco, CP 56237, Mexico.

Karnal bunt disease of wheat, caused by the fungus , is one of the most important challenges to the grain industry as it affects the grain quality and also restricts the international movement of infected grain. It is a seed-, soil- and airborne disease with limited effect of chemical control. Currently, this disease is contained through the deployment of host resistance but further improvement is limited as only a few genotypes have been found to carry partial resistance. To identify genomic regions responsible for resistance in a set of 339 wheat accessions, genome-wide association study (GWAS) was undertaken using the DArTSeq technology, in which 18 genomic regions for Karnal bunt resistance were identified, explaining 5-20% of the phenotypic variation. The identified quantitative trait loci (QTL) on chromosome 2BL showed consistently significant effects across all four experiments, whereas another QTL on 5BL was significant in three experiments. Additional QTLs were mapped on chromosomes 1DL, 2DL, 4AL, 5AS, 6BL, 6BS, 7BS and 7DL that have not been mapped previously, and on chromosomes 4B, 5AL, 5BL and 6BS, which have been reported in previous studies. Germplasm with less than 1% Karnal bunt infection have been identified and can be used for resistance breeding. The SNP markers linked to the genomic regions conferring resistance to Karnal bunt could be used to improve Karnal bunt resistance through marker-assisted selection.
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http://dx.doi.org/10.3390/ijms20133124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6651844PMC
June 2019

Unravelling the Complex Genetics of Karnal Bunt () Resistance in Common Wheat () by Genetic Linkage and Genome-Wide Association Analyses.

G3 (Bethesda) 2019 05 7;9(5):1437-1447. Epub 2019 May 7.

Grains Research and Development Corporation, P.O. Box 5367, Kingston, ACT 2604, Australia.

Karnal bunt caused by Mitra [syn. (Mitra) Mundkur] is a significant biosecurity concern for wheat-exporting countries that are free of the disease. It is a seed-, soil-and air-borne disease with no effective chemical control measures. The current study used data from multi-year field experiments of two bi-parental populations and a genome-wide association (GWA) mapping panel to unravel the genetic basis for resistance in common wheat. Broad-sense heritability for Karnal bunt resistance in the populations varied from 0.52 in the WH542×HD29 population, to 0.61 in the WH542×W485 cross and 0.71 in a GWAS panel. Quantitative trait locus (QTL) analysis with seven years of phenotypic data identified a major locus on chromosome 3B (R = 27.8%) and a minor locus on chromosome 1A (R = 12.2%), in the WH542×HD29 population, with both parents contributing the high-value alleles. A major locus (R = 27.8%) and seven minor loci (R = 4.4-15.8%) were detected in the WH542×W485 population. GWA mapping validated QTL regions in the bi-parent populations, but also identified novel loci not previously associated with Karnal bunt resistance. Meta-QTL analysis aligned the results from this study with those reported in wheat over the last two decades. Two major clusters were detected, the first on chromosome 4B, which clustered with , , , and the second on chromosome 3B, which clustered with , and The results provide definitive chromosomal assignments for QTL/genes controlling Karnal bunt resistance in common wheat, and will be useful in pre-emptive breeding against the pathogen in wheat-producing areas that are free of the disease.
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http://dx.doi.org/10.1534/g3.119.400103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6505162PMC
May 2019

Genetic Mapping of Resistance in Hexaploid Wheat for a Quarantine Disease: Karnal Bunt.

Front Plant Sci 2018 16;9:1497. Epub 2018 Oct 16.

International Maize and Wheat Improvement Centre (CIMMYT), Texcoco, Mexico.

Karnal bunt (KB) of wheat, caused by , is one of the greatest challenges to grain industry, not because of yield loss, but quarantine regulations that restrict international movement and trade of affected stocks. Genetic resistance is the best way to manage this disease. Although several different sources of resistance have been identified to date, very few of those have been subjected to genetic analyses. Understanding the genetics of resistance, characterization and mapping of new resistance loci can help in development of improved germplasm. The objective of this study was to identify and characterize resistance loci (QTL) in two independent recombinant inbred lines (RILs) populations utilizing different wheat lines as resistance donors. Elite CIMMYT wheat lines Blouk#1 and Huirivis#1 were used as susceptible female parents and WHEAR/KUKUNA/3/C80.1/3BATAVIA//2WBLL1 (WKCBW) and Mutus as moderately resistant male parents in Pop1 and Pop2 populations, respectively. Populations were evaluated for KB resistance in 2015-16 and 2016-17 cropping seasons at two seeding dates (total four environments) in Cd. Obregon, Mexico. Two stable QTL from each population were identified in each environment: and (Pop1), and (Pop2). Other than those four QTL, other QTL were detected in each population which were specific to environments: , and (Pop1), , and (Pop2). Among the four stable QTL, all but were derived from the resistant parent. and in Pop1 and and in Pop2 explained 5.0-11.4% and 3.3-7.1% phenotypic variance, respectively. A combination of two stable QTL in each population reduced KB infection by 24-33%, respectively. Transgressive resistant segregants lines derived with resistance alleles from both parents in each population were identified. Single nucleotide polymorphism (SNP) markers flanking these QTL regions may be amenable to marker-assisted selection. The best lines from both populations (in agronomy, end-use quality and KB resistance) carrying resistance alleles at all identified loci, may be used for inter-crossing and selection of improved germplasm in future. Markers flanking these QTL may assist in selection of such lines.
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http://dx.doi.org/10.3389/fpls.2018.01497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198147PMC
October 2018

Harnessing genetic potential of wheat germplasm banks through impact-oriented-prebreeding for future food and nutritional security.

Sci Rep 2018 08 21;8(1):12527. Epub 2018 Aug 21.

ICAR-Indian Agricultural Research Institute, Regional Station, Shimla, 171004, India.

The value of exotic wheat genetic resources for accelerating grain yield gains is largely unproven and unrealized. We used next-generation sequencing, together with multi-environment phenotyping, to study the contribution of exotic genomes to 984 three-way-cross-derived (exotic/elite1//elite2) pre-breeding lines (PBLs). Genomic characterization of these lines with haplotype map-based and SNP marker approaches revealed exotic specific imprints of 16.1 to 25.1%, which compares to theoretical expectation of 25%. A rare and favorable haplotype (GT) with 0.4% frequency in gene bank identified on chromosome 6D minimized grain yield (GY) loss under heat stress without GY penalty under irrigated conditions. More specifically, the 'T' allele of the haplotype GT originated in Aegilops tauschii and was absent in all elite lines used in study. In silico analysis of the SNP showed hits with a candidate gene coding for isoflavone reductase IRL-like protein in Ae. tauschii. Rare haplotypes were also identified on chromosomes 1A, 6A and 2B effective against abiotic/biotic stresses. Results demonstrate positive contributions of exotic germplasm to PBLs derived from crosses of exotics with CIMMYT's best elite lines. This is a major impact-oriented pre-breeding effort at CIMMYT, resulting in large-scale development of PBLs for deployment in breeding programs addressing food security under climate change scenarios.
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http://dx.doi.org/10.1038/s41598-018-30667-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6104032PMC
August 2018

Unlocking the genetic diversity of Creole wheats.

Sci Rep 2016 03 15;6:23092. Epub 2016 Mar 15.

International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico DF, Mexico.

Climate change and slow yield gains pose a major threat to global wheat production. Underutilized genetic resources including landraces and wild relatives are key elements for developing high-yielding and climate-resilient wheat varieties. Landraces introduced into Mexico from Europe, also known as Creole wheats, are adapted to a wide range of climatic regimes and represent a unique genetic resource. Eight thousand four hundred and sixteen wheat landraces representing all dimensions of Mexico were characterized through genotyping-by-sequencing technology. Results revealed sub-groups adapted to specific environments of Mexico. Broadly, accessions from north and south of Mexico showed considerable genetic differentiation. However, a large percentage of landrace accessions were genetically very close, although belonged to different regions most likely due to the recent (nearly five centuries before) introduction of wheat in Mexico. Some of the groups adapted to extreme environments and accumulated high number of rare alleles. Core reference sets were assembled simultaneously using multiple variables, capturing 89% of the rare alleles present in the complete set. Genetic information about Mexican wheat landraces and core reference set can be effectively utilized in next generation wheat varietal improvement.
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http://dx.doi.org/10.1038/srep23092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4791556PMC
March 2016