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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Crop Improvement and Genetics Research » Research » Publications at this Location » Publication #409470
Research Project: New Genetic and Genomics Resources to Improve Wheat Quality and Resilience to Biotic and Abiotic Stresses

Location: Crop Improvement and Genetics Research

Title: Identification of Sr67, a new gene for stem rust resistance in KU168-2 located close to the Sr13 locus in wheat

Author
item SHARMA, JYOTI - Agriculture And Agri-Food Canada
item CHE, MINGZHE - Agriculture And Agri-Food Canada
item FETCH, THOMAS - Agriculture And Agri-Food Canada
item MCCALLUM, BRENT - Agriculture And Agri-Food Canada
item Xu, Steven
item HIEBERT, COLIN - Agriculture And Agri-Food Canada

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2023
Publication Date: 1/24/2024
Citation: Sharma, J.S., Che, M., Fetch, T., McCallum, B.D., Xu, S.S., Hiebert, C.W. 2024. Identification of Sr67, a new gene for stem rust resistance in KU168-2 located close to the Sr13 locus in wheat. Theoretical and Applied Genetics. 137. Article 30. https://doi.org/10.1007/s00122-023-04530-8.
DOI: https://doi.org/10.1007/s00122-023-04530-8

Interpretive Summary: Re-appearance of stem rust disease, caused by the fungal pathogen Puccinia graminis f. sp. tritici (Pgt), in different parts of Europe emphasized the need to develop wheat varieties with genes for effective resistance to local Pgt populations and exotic threats. A bread wheat line KU168-2 was previously reported to carry good resistance to stem rust. In this study, we discovered that the resistance in KU168-2 was controlled by a new gene, designated Sr67, located close to Sr13. Although Sr13 is a major resistance gene effective against local and exotic Pgt populations in durum wheat, it is less effective in bread wheat background. Therefore, Sr67 will be a good source of stem rust resistance in bread wheat breeding programs. The molecular markers linked to Sr67 developed in this study will facilitate deployment of this novel gene into modern wheat varieties.

Technical Abstract: Re-appearance of stem rust disease, caused by the fungal pathogen Puccinia graminis f. sp. tritici (Pgt), in different parts of Europe emphasized the need to develop wheat varieties with effective resistance to local Pgt populations and exotic threats. A Kyoto University wheat (Triticum aestivum L.) accession KU168-2 was reported to carry good resistance to leaf and stem rust. To identify the genomic region associated with the KU168-2 stem rust resistance, a genetic study was conducted using a double haploid (DH) population from the cross RL6071 × KU168-2. The DH population was phenotyped with three Pgt races (TTKSK, TPMKC, and QTHSF) and genotyped using the Illumina 90K wheat SNP array. Linkage mapping showed the resistance to all three Pgt races was conferred by a single stem rust resistance (Sr) gene on chromosome arm 6AL, associated with Sr13. Presently, four Sr13 resistance alleles have been reported. Sr13 allele-specific KASP and STARP markers, and sequencing markers all showed null alleles in KU168-2. KU168-2 showed a unique combination of seedling infection types for five Pgt races (TTKSK, QTHJF, RCRSF, TMRTF, and TPMKC) compared to Sr13 alleles. The phenotypic uniqueness of the stem rust resistance gene in KU168-2 and null alleles for Sr13 allele-specific markers showed the resistance was conferred by a new gene, designated Sr67. Since Sr13 is less effective in hexaploid background, Sr67 will be a good source of stem rust resistance in bread wheat breeding programs.