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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #402862
Research Project: Surveillance, Pathogen Biology, and Host Resistance of Cereal Rusts

Location: Cereal Disease Lab

Title: High-resolution mapping of SrTm4, a recessive resistance gene to wheat stem rust

Author
item LI, HONGNA - Peking University
item LUO, JING - Peking University
item ZHANG, WENJUN - University Of California, Davis
item HUA, LEI - Peking University
item LI, KUN - University Of California, Davis
item WANG, JIAN - Peking University
item XU, BINYANG - Peking University
item YANG, CHEN - Peking University
item WANG, GUIPING - Peking University
item Rouse, Matthew
item DUBCOVSKY, JORGE - University Of California, Davis
item CHEN, SHISHENG - Peking University

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2022
Publication Date: 4/27/2023
Citation: Li, H., Luo, J., Zhang, W., Hua, L., Li, K., Wang, J., Xu, B., Yang, C., Wang, G., Rouse, M.N., Dubcovsky, J., Chen, S. 2023. High-resolution mapping of SrTm4, a recessive resistance gene to wheat stem rust. Theoretical and Applied Genetics. 136. Article 120. https://doi.org/10.1007/s00122-023-04369-z.
DOI: https://doi.org/10.1007/s00122-023-04369-z

Interpretive Summary: Wheat is grown on over 37 million acres in the United States. Stem rust disease of wheat can cause devastating yield losses. Emerging strains of the wheat stem rust pathogen such as Ug99 threaten global and United States wheat production. The identification, mapping, and deployment of effective stem rust resistance genes are critical to reduce this threat. In this study, found that stem rust resistance gene SrTm4 confers resistance to diverse global Pgt races. We mapped SrTm4 within a narrow genetic interval. We developed two diagnostic dominant markers to detect the SrTm4 gene. The tightly linked molecular markers developed in this study are useful tools to accelerate the deployment of SrTm4-mediated resistance in wheat breeding programs to protect United States wheat from stem rust yield losses.

Technical Abstract: Race Ug99 of Puccinia graminis f. sp. tritici (Pgt), the causal agent of wheat stem (or black) rust is one of the most serious threats to global wheat production. The identification, mapping, and deployment of effective stem rust resistance (Sr) genes are critical to reduce this threat. In this study, we generated SrTm4 monogenic lines and found that this gene confers resistance to North American and Chinse Pgt races. Using a large mapping population (9,522 gametes), we mapped SrTm4 within a 0.06 cM interval flanked by marker loci CS4211 and 130K1519, which corresponds to a 1.0-Mb region in the Chinese Spring reference genome v2.1. Physical map of the SrTm4 region was constructed with 11 overlapping BACs from the resistant T. monococcum PI 306540. The comparison of the 754-kb physical map with the genomic sequence of Chinese Spring and the discontinuous BAC sequence of DV92 revealed a 593-kb chromosomal inversion in PI 306540. Within the candidate region, we identified an L-type lectin-domain containing receptor kinase (LLK1), which was disrupted by the proximal inversion breakpoint, as a potential candidate gene. Two diagnostic dominant markers were developed to detect the inversion breakpoints. In a survey of T. monococcum accessions, we identified only 10 domesticated T. monococcum subsp. monococcum genotypes, mainly from the Balkans, carrying the inversion and showing similar mesothetic resistant infection types against Pgt races. The high-density map and the tightly linked molecular markers developed in this study are useful tools to accelerate the deployment of SrTm4-mediated resistance in wheat breeding programs.