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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 Biol. 2017 08 04; 17(1):134.BP

Abstract

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

Authors+Show Affiliations

Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6420, USA.USDA-ARS Cereal Disease Laboratory, Department of Plant Pathology, University of Minnesota, St. Paul, MN, 55108, USA.Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6420, USA.USDA-ARS, Wheat Health, Genetics, and Quality Research Unit, and Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, Pullman, WA, 99164-6430, USA.Ethiopian Institute of Agricultural Research, Kulumsa Agricultural Research Center, P. O. Box 489, Assela, Ethiopia.Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6420, USA. m.pumphrey@wsu.edu.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

28778144

Citation

Muleta, Kebede T., et al. "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, vol. 17, no. 1, 2017, p. 134.
Muleta KT, Rouse MN, Rynearson S, et al. 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 Biol. 2017;17(1):134.
Muleta, K. T., Rouse, M. N., Rynearson, S., Chen, X., Buta, B. G., & Pumphrey, M. O. (2017). 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, 17(1), 134. https://doi.org/10.1186/s12870-017-1082-7
Muleta KT, et al. 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 Biol. 2017 08 4;17(1):134. PubMed PMID: 28778144.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization of molecular diversity and genome-wide mapping of loci associated with resistance to stripe rust and stem rust in Ethiopian bread wheat accessions. AU - Muleta,Kebede T, AU - Rouse,Matthew N, AU - Rynearson,Sheri, AU - Chen,Xianming, AU - Buta,Bedada G, AU - Pumphrey,Michael O, Y1 - 2017/08/04/ PY - 2016/12/15/received PY - 2017/07/21/accepted PY - 2017/8/6/entrez PY - 2017/8/6/pubmed PY - 2018/1/13/medline KW - Association mapping KW - Bread wheat KW - Genetic diversity KW - Genetic resistance KW - Stem rust KW - Stripe rust SP - 134 EP - 134 JF - BMC plant biology JO - BMC Plant Biol VL - 17 IS - 1 N2 - BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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. SN - 1471-2229 UR - https://www.unboundmedicine.com/medline/citation/28778144/Characterization_of_molecular_diversity_and_genome_wide_mapping_of_loci_associated_with_resistance_to_stripe_rust_and_stem_rust_in_Ethiopian_bread_wheat_accessions_ DB - PRIME DP - Unbound Medicine ER -