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United States Department of Agriculture

Agricultural Research Service

Title: Gene expression patterns of wheat rust resistance gene Lr34/Yr18 indicate novel mode of action

Authors
item Hulbert, Scott - KANSAS STATE UNIVERSITY
item Bai, Jianfa - KANSAS STATE UNIVERSITY
item Fellers, John
item M. G., Pacheco - KANSAS STATE UNIVERSITY
item Bowden, Robert

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 10, 2007
Publication Date: March 1, 2007
Citation: Hulbert, S.H., Bai, J., Fellers, J.P., M. G., P., Bowden, R.L. 2007. Gene expression patterns of wheat rust resistance gene Lr34/Yr18 indicate novel mode of action. Phytopathology 97:1083-1093.

Interpretive Summary: The Lr34/Yr18 resistance gene provides durable, adult-plant, slow-rusting resistance to leaf rust and yellow rust of wheat. Patterns of gene expression were examined by microarray analysis in inoculated and non-inoculated flag leaves of two pairs of wheat lines containing Lr34/Yr18. Many genes with altered expression in Lr34/Yr18 lines have been previously associated with osmotic stress, cold stress, or seed maturation. These results support the hypothesis that Lr34/Yr18 has a novel mode of action involving a set of abiotic stress or seed maturation genes not usually associated with pathogen defense reactions.

Technical Abstract: The Lr34/Yr18 resistance gene provides durable, adult-plant, slow-rusting resistance to leaf rust and yellow rust of wheat. Patterns of gene expression were examined by microarray analysis in inoculated and mock-inoculated flag leaves of two pairs of near isogenic lines for Lr34/Yr18 (Thatcher/Thatcher-Lr34 and Jupateco 73S/Jupateco 73R). Fifty-seven genes were consistently up-regulated and six were down-regulated in mock-inoculated leaf tips or leaf bases of isolines carrying Lr34/Yr18. Five genes were consistently up-regulated in both mock-inoculated tips and bases of leaves of both isolines, including genes homologous to the Arabidopsis Di19 (drought induced 19), a cold regulated protein, a lipid transfer protein, and two with unknown function. Most of the genes with altered pre-challenge expression in Lr34/Yr18 isolines have been previously associated with osmotic stress, cold stress, or seed maturation. These results support the hypothesis that Lr34/Yr18 has a novel mode of action involving pre-challenge ectopic expression of a set of abiotic stress or seed maturation genes not usually associated with pathogen defense reactions. Leaf rust infection up-regulated many known pathogen defense genes, such as the PR proteins, in both resistant and susceptible plants 48 hr after inoculation. Many of these were more highly expressed in resistant than susceptible plants.

Last Modified: 10/19/2014
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