Genome-wide association and biparental mapping revealed a major quantitative trait locus associated with seedling resistance to bacterial leaf streak in durum

Authors: MANAN, FAZAL - North Dakota State University; LI, XUEHUL - North Dakota State University; SZABO-HEVER, AGNES - North Dakota State University; SHI, GONGJUN - North Dakota State University; ELIAS, ELIAS - North Dakota State University; Faris, Justin; Xu, Steven; LIU, ZHAOHUI - North Dakota State University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2025
Publication Date: 12/19/2025
Citation: Manan, F., Li, X., Szabo-Hever, A., Shi, G., Elias, E., Faris, J.D., Xu, S.S., Liu, Z. 2025. Genome-wide association and biparental mapping revealed a major quantitative trait locus associated with seedling resistance to bacterial leaf streak in durum. Theoretical and Applied Genetics. 125:259-265. https://doi.org/10.1007/.
DOI: https://doi.org/10.1007/

Interpretive Summary: Durum wheat is used to make macaroni, pasta, and other semolina-based products, making it an economically important crop. The disease known as bacterial leaf streak (BLS) is an emerging threat for durum wheat in the Northern Great Plains region of the United States where most of the country's durum is grown. Genetic resistance is the only method suitable to combat BLS infection in durum, but very few durum lines having acceptable levels of resistance have been identified up until now. Here, researchers evaluated over 500 durum lines collected from around the world as well as locally bred North Dakota varieties for their reactions to BSL and identified several lines with high levels of BLS resistance. Genetic analysis of the lines showed that BLS resistance was controlled by a single genetic factor on durum chromosome 6A, and they identified several DNA markers associated with the factor. The BLS-resistant durum lines and the DNA markers identified in this research will be useful for durum breeders and geneticists in the development of new BLS-resistant durum wheat varieties.

Technical Abstract: Bacterial leaf streak (BLS), caused by Xanthomonas translucens pv. undulosa, has reemerged as a significant disease impacting bread wheat and durum production worldwide. The lack of resistance sources and limited understanding of the genetics behind host resistance have made breeding for BLS resistance challenging, especially in durum wheat. In this study, we first evaluated the reaction of a set of durum cultivars, mainly from North Dakota State University (NDSU). Our results indicated that most cultivars were susceptible, with only a few exceptions. Next, we utilized a subset of the Global Durum Panel (GDP) to identify sources of resistance and conduct a genome-wide association study (GWAS) to identify BLS resistance loci. Additionally, we performed disease evaluations and quantitative trait locus (QTL) analysis on two durum recombinant inbred line (RIL) populations: one was derived from the resistant NDSU cultivar 'Ben' and the other from the resistant Ethiopian landrace PI 387336. Our findings revealed that several modern durum cultivars from different countries within the GDP exhibited a high level of resistance. Both GWAS and biparental mapping identified a major QTL located at the distal end of chromosome arm 6AS. The physical positions of the single nucleotide polymorphism (SNP) markers obtained from both experiments strongly suggest that the same locus is responsible for BLS resistance in the tested durum materials. The resistant accessions and SNP markers identified in this study will be valuable for transferring this major QTL into elite durum and common wheat cultivars.