Identification and GWAS mapping of genes for resistance to multiple rusts in an eastern European barley collection

Authors: ARIFUZZAMAN, MD - Hajee Mohammad Danesh Science Technology University; JOST, M - Commonwealth Scientific And Industrial Research Organisation (CSIRO); WANG, M - Washington State University; Chen, Xianming; ALI, M - Bangladesh Rice Research Institute; PARK, R - University Of Sydney; Rouse, Matthew; FORREST, K - Agriculture Victoria; HAYDEN, M - Agriculture Victoria; KHAN, G - La Trobe University; DRACATOS, P - University Of Sydney

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2023
Publication Date: 6/29/2023
Citation: Arifuzzaman, M., Jost, M., Wang, M., Chen, X., Ali, M.P., Park, R.F., Rouse, M.N., Forrest, K., Hayden, M., Khan, G.A., Dracatos, P.M. 2023. Identification and GWAS mapping of genes for resistance to multiple rusts in an eastern European barley collection. International Journal of Molecular Sciences. 24. Article 10860. https://doi.org/10.3390/ijms241310860.
DOI: https://doi.org/10.3390/ijms241310860

Interpretive Summary: Barley production in the world is threatened by plant pathogens, especially rusts. In this study, we used the genome-wide association study (GWAS) approach combining targeted genotype-by-sequencing with quantitative phenotyping assessment at the seedling stage to identify exotic rust resistance genes in a collection of 287 genetically distinct diverse barley landraces and historical cultivars sourced from Eastern Europe. The accessions were tested with nine exotic US-derived pathogen isolates including: two barley leaf rust isolates, one crown rust isolate, five stripe rust isolates, and one stem rust Ug99 isolate. Novel resistance factors were identified on chromosomes 1H and 5H in response crown rust, whereas a race-specific gene on chromosome 7HS was identified only effective to stripe rust isolates PSH-72 and PSH-100. A major effect gene on chromosome 5HL conferred resistance to all stripe rust isolates including race PSH-72 which is widely virulent on all 12 stripe rust differential lines. The same major effect gene was also identified in response to both leaf rust pathogen isolates suggesting that this locus contains several pathogen specific rust resistance genes or the same gene is responsible for both leaf and stripe rust resistance. Although no significance was identified using GWAS, several accessions were identified in the panel with resistance to Ug99 suggesting that they contain valuable resistance for further genetic studies.

Technical Abstract: Barley production in the world is threatened by plant pathogens, especially rusts. In this study we used GWAS combining targeted genotype-by-sequencing (GBS) with quantitative phenotyping assessment at the seedling stage to identify exotic rust resistance alleles in a collection of 287 genetically distinct diverse barley landraces and historical cultivars sourced from Eastern Europe. The accessions were challenged with nine exotic US-derived pathogen isolates including: Puccinia hordei (Ph-leaf rust) isolates 17WA26B and 17VA12C, P. coronata var. hordei (Pch-crown rust) isolate 91NE9305 and five pathogenically diverse isolates of P. striiformis f. sp. hordei (Psh-stripe rust) (PSH-33, PSH-48, PSH-54, PSH-72 and PSH-100) and P. graminis f. sp. tritici isolate Ug99 (TTKSK). Novel resistance factors were identified on chromosomes 1H and 5H in response to Pch, whereas a race-specific QTL on 7HS was identified only effective to Psh isolates PSH-72 and PSH-100. A major effect QTL on chromosome 5HL conferred resistance to all Psh isolates including PSH-72 which is widely virulent on all 12 stripe rust differential tester lines. The same major effect QTL was also identified in response to both leaf rust pathogen isolates suggesting that this locus contains several pathogen specific rust resistance genes or the same gene is responsible for both leaf and stripe rust resistance. Although no significance was identified using GWAS, several accessions were identified in the panel with resistance to Ug99 suggesting that they contain valuable resistance for further genetic studies.