Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/14/2012
Publication Date: 7/1/2012
Citation: Lu, S., Friesen, T.L., Faris, J.D. 2012. Differential expression of the pathogenesis-related protein 1 (PR-1) gene family in stem rust (Puccinia graminis f. sp. tritici)-wheat interactions. American Phytopathological Society, August 4-8, 2012, Providence, RI. Available: http://www.apsnet.org/meetings/Documents/2012_Meeting_Abstracts/aps12abP582.htm
Technical Abstract: The group 1 pathogenesis-related (PR-1) proteins, known as hallmarks of defense pathways, are encoded by a multigene family in hexaploid wheat (Triticum aestivum L.) that includes at least 12 closely related TaPr-1 genes responsive to infection by the necrotrophic pathogen Stagonospora nodorum (Sn) (Lu et al., 2011). Here we report an expression analysis of the same set of TaPr-1 genes in response to the biotrophic stem rust (SR) fungus Puccinia graminis f. sp. tritici. A SR-resistant cultivar (Bobwhite) and three susceptible lines (derived from Bobwhite) were grown and inoculated in the greenhouse under the same conditions. Reverse transcriptase PCR using TaPr-1-specific untranslated region-specified discrimination primers revealed that most Sn-inducible TaPr-1 genes were also expressed in SR-wheat interactions, but the expression patterns differed significantly. Two TaPr-1 genes that are up-regulated in both incompatible and compatible Sn-wheat interactions were found to be induced only in the SR-infected resistant line that showed a hypersensitive response (HR). In susceptible lines, several TaPr-1 genes were expressed in un-inoculated plants, but not (or at a lower level) in inoculated plants that developed stem rust symptoms. These results suggested that PR-1 proteins play important roles in HR-based resistance and are controlled by independent defense pathways in necrotrophic vs. biotrophic pathogen-wheat interactions.