Mapping and characterization of wheat stem rust resistance genes SrTm5 and Sr60 from Triticum monococcum

Shisheng Chen, Yan Guo, Jordan Briggs, Felix Dubach, Shiaoman Chao, Wenjun Zhang, Matthew N. Rouse, Jorge Dubcovsky

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Key message: The new stem rust resistance gene Sr60 was fine-mapped to the distal region of chromosome arm 5AmS, and the TTKSK-effective gene SrTm5 could be a new allele of Sr22. Abstract: The emergence and spread of new virulent races of the wheat stem rust pathogen (Puccinia graminis f. sp. tritici; Pgt), including the Ug99 race group, is a serious threat to global wheat production. In this study, we mapped and characterized two stem rust resistance genes from diploid wheat Triticum monococcum accession PI 306540. We mapped SrTm5, a previously postulated gene effective to Ug99, on chromosome arm 7AmL, completely linked to Sr22. SrTm5 displayed a different race specificity compared to Sr22 indicating that they are distinct. Sequencing of the Sr22 homolog in PI 306540 revealed a novel haplotype. Characterization of the segregating populations with Pgt race QFCSC revealed an additional resistance gene on chromosome arm 5AmS that was assigned the official name Sr60. This gene was also effective against races QTHJC and SCCSC but not against TTKSK (a Ug99 group race). Using two large mapping populations (4046 gametes), we mapped Sr60 within a 0.44 cM interval flanked by sequenced-based markers GH724575 and CJ942731. These two markers delimit a 54.6-kb region in Brachypodium distachyon chromosome 4 and a 430-kb region in the Chinese Spring reference genome. Both regions include a leucine-rich repeat protein kinase (LRRK123.1) that represents a potential candidate gene. Three CC–NBS–LRR genes were found in the colinear Brachypodium region but not in the wheat genome. We are currently developing a Bacterial Artificial Chromosome library of PI 306540 to determine which of these candidate genes are present in the T. monococcum genome and to complete the cloning of Sr60.

Original languageEnglish (US)
Pages (from-to)625-635
Number of pages11
JournalTheoretical and Applied Genetics
Volume131
Issue number3
DOIs
StatePublished - Mar 1 2018

Bibliographical note

Funding Information:
Acknowledgements Work at JD laboratory was supported by the Howard Hughes Medical Institute and by the Agriculture and Food Research Initiative Competitive Grant 2017-67007-25939 from the USDA National Institute of Food and Agriculture (NIFA). Work at MNR laboratory was supported by USDA-ARS appropriated Project 5062-21220-021-00-D, the USDA-ARS National Plant Disease Recovery System, and NRI Competitive Grant 2017-67007-25939 from the USDA National Institute of Food and Agriculture (NIFA).

Funding Information:
Work at JD laboratory was supported by the Howard Hughes Medical Institute and by the Agriculture and Food Research Initiative Competitive Grant 2017-67007-25939 from the USDA National Institute of Food and Agriculture (NIFA). Work at MNR laboratory was supported by USDA-ARS appropriated Project 5062-21220-021-00-D, the USDA-ARS National Plant Disease Recovery System, and NRI Competitive Grant 2017-67007-25939 from the USDA National Institute of Food and Agriculture (NIFA). The authors declare that there are no conflicts of interest.

Publisher Copyright:
© 2017, The Author(s).

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