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Lr34-Mediated Leaf Rust Resistance in Wheat: Transcript Profiling Reveals a High Energetic Demand Supported by Transient Recruitment of Multiple Metabolic Pathways

Permanent URL:
http://handle.nal.usda.gov/10113/21414
File:
Download [PDF File]
Abstract:
The wheat gene Lr34 confers partial resistance to all races of Puccinia triticina, the causal agent of wheat leaf rust. However, the biological basis for the exceptional durability of Lr34 is unclear. We used the Affymetrix GeneChip Wheat Genome Array to compare transcriptional changes of near-isogenic lines of Thatcher wheat in a compatible interaction, an incompatible interaction conferred by the resistance gene Lr1, and the race-nonspecific response conditioned by Lr34 3 and 7 days postinoculation (dpi) with P. triticina. No differentially expressed genes were detected in Lr1 plants at either timepoint whereas, in the compatible Thatcher interaction, differentially expressed genes were detected only at 7 dpi. In contrast, differentially expressed genes were identified at both timepoints in P. triticina-inoculated Lr34 plants. At 3 dpi, upregulated genes associated with Lr34-mediated resistance encoded various defense and stress-related proteins, secondary metabolism enzymes, and transcriptional regulation and cellular-signaling proteins. Further, coordinated upregulation of key genes in several metabolic pathways that can contribute to increased carbon flux through the tricarboxylic cycle was detected. This indicates that Lr34-mediated resistance imposes a high energetic demand that leads to the induction of multiple metabolic responses to support cellular energy requirements. These metabolic responses were not sustained through 7 dpi, and may explain why Lr34 fails to inhibit the pathogen fully but does increase the latent period.
Author(s):
Bolton, Melvin D. , Kolmer, James A. , Xu, Wayne W. , Garvin, David F.
Subject(s):
Triticum aestivum , wheat , disease resistance , rust diseases , plant proteins , gene expression regulation , biochemical pathways , Puccinia recondita , plant pathogenic fungi
Format:
p. 1515-1527.
Note:
Includes references
Source:
Molecular plant-microbe interactions : MPMI 2008 Dec., v. 21, no. 12
Language:
English
Year:
2008
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.