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Poster: Molecular & Cellular Plant-Microbe Interactions: Biochemistry & Cell Biology


Spectral signatures of chemical changes in the wheat cell-wall resulting from stripe rust infection in compatible and incompatible near isogenic lines
R. LAHLALI (1), G. Brar (2), D. Qutob (3), C. Karunakaran (1), H. Kutcher (2) (1) Canadian Light Source Inc., Canada; (2) Department of Plant Sciences/Crop Development Centre, University of Saskatchewan, Canada; (3) Canadian National Research Council- Pla

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most devastating diseases in North America. The biotrophic fungus produces uredia, consisting asexual urediospores, on wheat leaves along the veins and obtains nutrition from host through haustoria. In a compatible interaction, the fungus damages the cell-wall in a susceptible cultivar, however in a resistant cultivar the incompatible interaction occurs as a result of hypersensitive cell death in the host. The purpose of this study was to understand the biomolecular changes in cell-wall compounds in each of the interactions. Two Avocet lines: one carrying Yr10 and other susceptible (no resistance allele) were inoculated with two isolates (one virulent on both and the other virulent only on Yr10). Infected and freeze dried leaves collected at 1 day and 15 days post inoculation were assessed by Fourier transform infrared (IR) spectroscopy. A significant difference in disease severity was observed between the two wheat lines. Principal component analysis of the IR spectra indicated substantial differences in the cell-wall components of the two wheat lines before and after pathogenic infection. There was a significant difference in the biomolecular changes between compatible and incompatible interactions. The most important IR peaks in the leaf cell wall that contributed to such differences were assigned to phenolic and aromatic rings, and proteins.