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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #334919

Research Project: Biology and Biological Control of Root Diseases of Wheat, Barley and Biofuel Brassicas

Location: Wheat Health, Genetics, and Quality Research

Title: Validation and characterization of a QTL for adult plant resistance to stripe rust on wheat chromosome arm 6BS (Yr78)

Author
item Dong, Zhenzhen - University Of California
item Hegarty, Joshua - University Of California
item Zhang, Junli - University Of California
item Zhang, Wenjun - University Of California
item Chao, Shiaoman
item Chen, Xianming
item Zhou, Yonghong - Sichuan Agricultural University
item Dubcovsky, Jorge - University Of California

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2017
Publication Date: 10/20/2017
Citation: Dong, Z., Hegarty, J.M., Zhang, J., Zhang, W., Chao, S., Chen, X., Zhou, Y., Dubcovsky, J. 2017. Validation and characterization of a QTL for adult plant resistance to stripe rust on wheat chromosome arm 6BS (Yr78). Journal of Theoretical and Applied Genetics. 130(10):2127-2137.

Interpretive Summary: The spread of more virulent and aggressive races of the pathogen of stripe rust after the year 2000 has caused substantial yield losses worldwide. To find new sources of resistance, we previously performed a genome-wide association study and identified two strong quantitative trait loci (QTL) for adult plant resistance on the wheat short arms of chromosomes 6D and 6B . In this study, we validated the 6D QTL in six biparental populations and mapped the peak of the QTL closely linked to single-nucleotide polymorphism (SNP) marker IWA167, between simple sequence repeat (SSR) markers barc54 and cfd188. Since no named stripe rust resistance gene has been mapped before to this region, The 6D QTL was assigned the Yr77 name. We also validated the 6B QTL in ten biparental populations, and mapped it 0.6 cM proximal to SNP marker IWA7257 and 3.9 cM distal to SNP marker IWA4408. We showed that the 6B QTL is located more than 15 cM proximal to the seedling resistance gene Yr35, and that none of the resistant lines carry the previously cloned Yr36 gene. Based on these results, the 6B QTL was assigned the name Yr78. Neither Yr77 nor Yr78 was effective against stripe rust at the seedling stage, indicating that they are adult plant resistance genes. Yr77 can be a useful gene to diversify the sources of stripe rust resistance in Western wheat breeding programs, where this gene is present at very low frequencies. Conversely, Yr78 might be useful in Asia as it is predicted to be present in few wheat varieties from this region.

Technical Abstract: The spread of more virulent and aggressive races of Puccinia tritici f. sp. tritici (Pst, causal pathogen of stripe rust) after the year 2000 has caused substantial yield losses worldwide. To find new sources of resistance, we previously performed a genome-wide association study and identified two strong QTL for adult plant resistance on the short arms of chromosomes 6D (QYr.ucw-6D) and 6B (QYr.ucw-6B). In this study, we validated QYr.ucw-6D in six biparental populations and mapped the peak of the QTL closely linked to IWA167, between barc54 and cfd188. Since no named Pst resistance gene has been mapped before to this region, QYr.ucw-6D was assigned the Yr77 name. We also validated QYr.ucw-6B in ten biparental populations, and mapped it 0.6 cM proximal to IWA7257 and 3.9 cM distal to IWA4408. We showed that QYr.ucw-6B is located >15 cM proximal to the seedling resistance gene Yr35, and that none of the resistant lines carry the previously cloned Yr36 gene. Based on these results, QYr.ucw-6B was assigned the name Yr78. Neither Yr77 nor Yr78 was effective against Pst at the seedling stage, indicating that they are adult plant resistance genes. Yr77 can be a useful tool to diversify the sources of Pst resistance in Western wheat breeding programs, where this gene is present at very low frequencies. Conversely, Yr78 is predicted to be present in few wheat varieties from Asia, where it might be useful if it proves to be effective against Pst races from this region.