Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: January 11, 2008
Publication Date: January 11, 2008
Citation: Garvin, D.F., Bolton, M.D., Kolmer, J.A. 2008. Comparative transcript profiling of race-specific and non-race specific leaf rust resistance in wheat [abstract]. Plant and Animal Genome Conference XVI, January 12-16, 2008, San Diego, California. p. 321. Technical Abstract: Leaf rust caused by the fungal pathogen Puccinia triticina is a widespread disease of wheat. Race-specific leaf rust resistance genes have been used extensively to control leaf rust, but high levels of genetic variation in P. triticina often lead to rapid collapse in the effectiveness of these genes. In contrast, the leaf rust resistance gene Lr34 is unusual because it confers non-race specific resistance to P. triticina. This study sought to compare changes in gene expression associated with 1) a compatible interaction between wheat and P. triticina, 2) leaf rust resistance encoded by a typical race-specific resistance gene, and 3) race non-specific resistance. Thatcher wheat and near-isolines harboring either Lr1 or Lr34 were inoculated with P. triticina and transcript profiles were assessed at two timepoints using the Affymetrix wheat GeneChip. Genes upregulated in the Lr34 line included those encoding defense and stress-related proteins, secondary metabolism enzymes, and genes involved in transcriptional regulation and cellular signaling. Our results indicate that the Lr34-mediated defense response is energetically costly, based on coordinate upregulation of specific genes and pathways that provide a means of producing more ATP. In contrast, no genes were identified in Lr1-mediated resistance. In the compatible interaction, differentially expressed genes largely function in wide-ranging aspects of basic cellular metabolism. Thus, at the molecular level the modes of action of the leaf rust resistance genes Lr34 and Lr1 are distinctly different, as predicted by the distinct differences in their resistance phenotypes.