Identification of sources of resistance to scald (Rhynchosporium commune) and of related genomic regions using genome-wide association in a mapping panel of spring barley

Houda Hiddar; Sajid Rehman; Bouchra Belkadi; Abdelkarim Filali-Maltouf; Muamar Al-Jaboobi; Ramesh Pal Singh Verma; Sanjaya Gyawali; Zakaria Kehel; Ahmed Amri

doi:10.3389/fpls.2023.1133404

Identification of sources of resistance to scald (Rhynchosporium commune) and of related genomic regions using genome-wide association in a mapping panel of spring barley

Front Plant Sci. 2023 Nov 28:14:1133404. doi: 10.3389/fpls.2023.1133404. eCollection 2023.

Authors

Affiliations

¹ Laboratory of Microbiology and Molecular Biology, Faculty of Sciences, BioBio Research Center, University Mohammed V in Rabat, Rabat, Morocco.
² Biodiversity and Crop Improvement Program, International Center for Agricultural Research in the Dry Areas (ICARDA), Rabat, Morocco.
³ Olds College, Field Crop Development Center, Lacombe, AB, Canada.
⁴ Indian Institute of Wheat and Barley Research (IIWBR), Karnal, Haryana, India.
⁵ Mount Vernon North-Western Washington Research & Extension Center, Washington State University, Mount Vernon, WA, United States.

Abstract

Barley is an important crop worldwide known for its adaptation to harsh environments and used in multiple forms as feed, food and beverages. Its productivity is affected by major abiotic and biotic stresses. Scald caused by hemibiotrophic fungus Rhynchosporium commune is a major foliar disease in many parts of the world. Host plant resistance is targeted by breeders to efficiently control this disease. An association mapping panel of 316 spring barley genotypes (AM2017) was screened for seedling resistance in greenhouse against three R. commune isolates and for adult plant resistance in three field locations in Morocco. The phenotyping results showed different numbers of entries with resistant and moderately resistant reactions at both seedling and adult plant stages. The reactions differed between the isolates with the highest percentage of resistant genotypes observed for isolate SC-S611 (49.4%) and highest percentage of susceptible genotypes (73.8%) for isolate SC-1122. At adult plant stage, the highest percentage of scald resistant genotypes (64.5%) was observed at Rommani site compared to 56% at Guich site and only 28.8% at Marchouch site. Seven genotypes were resistant at the seedling and adult plant stages. Genome wide association study (GWAS) revealed 102 MTA (15 QTL) at the seedling stage, and 25 MTA (12 QTL) associated with scald resistance at the adult plant stage. In addition, the sequences of 92 out of 102 at SRT, and 24 out of 25 significant SNP markers at APR were located in genomic regions enriched with functional proteins involved in diverse cellular processes including disease resistance. These markers span over all chromosomes with the majority of SNPs located on 3H and 7H. This study has verified 18 QTL reported in previous studies. In addition, it was successful in identifying new sources of resistance and novel genomic regions which could help in enhancing scald resistance in barley breeding programs.

Keywords: GWAS; Rhynchosporium commune; SNP; barley; quantitative trait loci; resistance.

Grants and funding

This study is supported financially through GIZ-attributed funding to ICARDA genebank, the CAIGE-GRDCICA00010 project and the CGIAR-Genebank Platform.