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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETICS, POPULATION BIOLOGY, AND HOST-PARASITE INTERACTIONS OF CEREAL RUST FUNGI AND THEIR DISEASES Title: Development and characterization of wheat-Ae. searsii Robertsonian translocations and a recombinant chromosome conferring resistance to stem rust

Authors
item Liu, W -
item Jin, Yue
item Rouse, Matthew
item Friebe, B -
item Gill, B -
item Pumphrey, M -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2011
Publication Date: February 24, 2011
Citation: Liu, W., Pumphrey, M., Jin, Y., Rouse, M.N., Friebe, B., Gill, B. 2011. Development and characterization of wheat-Ae. searsii Robertsonian translocations and a recombinant chromosome conferring resistance to stem rust. Theoretical and Applied Genetics. 122:1537-1545.

Interpretive Summary: Stem rust, caused by Puccinia graminis tritici, is one of the most damaging diseases of the wheat crop. The emergence of a new highly virulent race of stem rust, Ug99 and related variants, can overcome resistance of widely deployed genes. This stem rust race has spread towards important wheat-growing areas. Exploiting novel genes effective against Ug99 from wild relatives of wheat is one of the most promising strategies for the protection of the wheat crop. A new source of resistance to Ug99 was identified in a wild wheat, Aegilops searsii. For transferring this resistance gene into common wheat, we produced three double-monosomic chromosome populations and then applied integrated stem rust screening, molecular marker analysis, and cytogenetic analysis to identify resistant wheat-Ae. searsii Robertsonian translocation. Three Robertsonian translocations and one recombinant with stem rust resistance were identified and confirmed to be genetically compensating on the basis of genomic in situ hybridization, analysis of DNA markers, and C-banding. In addition, nine DNA markers were developed for marker-assisted selection of the resistant gene. Efforts to reduce potential linkage drag associated with chromosome of Ae. searsii are currently under way.

Technical Abstract: Stem rust, caused by Puccinia graminis tritici, is one of the most damaging diseases of the wheat crop. The emergence of a new highly virulent race of stem rust, Ug99, rapid evolution of new Ug99 derivative races overcoming resistance of widely deployed genes, and spread towards important wheat-growing areas now potentially threaten world food security. Exploiting novel genes effective against Ug99 from wild relatives of wheat is one of the most promising strategies for the protection of the wheat crop. A new source of resistance to Ug99 was identified in the short arm of the Aegilops searsii chromosome 3Ss by screening wheat-Ae. searsii introgression libraries available as individual chromosome and chromosome arm additions to the wheat genome. For transferring this resistance gene into common wheat, we produced three double-monosomic chromosome populations (3A/3Ss, 3B/3Ss, and 3D/3Ss) and then applied integrated stem rust screening, molecular marker analysis, and cytogenetic analysis to identify resistant wheat-Ae. searsii Robertsonian translocation. Three Robertsonian translocations (T3AL/3SsS, T3BL/3SsS, and T3DL/3SsS) and one recombinant (T3DS-3SsS/3SsL) with stem rust resistance were identified and confirmed to be genetically compensating on the basis of genomic in situ hybridization, analysis of 3A, 3B, 3D, and 3SsS-specific SSR/STS-PCR markers, and C-banding. In addition, nine SSR/STS-PCR markers of 3SsS-specific were developed for marker-assisted selection of the resistant gene. Efforts to reduce potential linkage drag associated with 3SsS of Ae. searsii are currently under way.

Last Modified: 10/20/2014
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