Poster: Plant-pathogen interactions
Abs #
515: Role of Lipids in Systemic Acquired Resistance
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Presenter: |
Nandi, Ashis K, ashis@ksu.edu |
Authors | Nandi, Ashis K (A) Krothapalli, Kartikeya (A) Morton, Jessica (A) Omoluab, Ozozoma (A) Buseman, Christen (A) Baughman, Ethan (A) Welti, Ruth (A) Shah, Shah (A) | | Affiliations: |
(A): Division of Biology, Kansas State University
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Systemic acquired resistance (SAR) is an induced response activated in the distal organs of a plant by the prior exposure of another organ to a necrotizing pathogen. The activation of SAR confers resistance to a broad-spectrum of pathogens. There is an increase in the content of salicylic acid (SA) in the distal tissues that manifest SAR. This accumulation of SA in the distal tissue, and the key SA signaling factor, NPR1 are required for activation of SAR in Arabidopsis.
Recently, we have shown that mutations in the Arabidopsis SFD1 gene compromise SAR (Nandi et al. Plant Cell 16: 465-477, 2004). However, unlike NPR1, SFD1 is not required for the basal resistance to bacterial pathogen, Pseudomonas syringae. SFD1 is required for the SAR-associated accumulation of SA in the distal leaves, but not in the pathogen- infected leaves. SFD1 encodes a dihydroxyacetone phosphate reductase involved in lipid biosynthesis, suggesting an important role for lipid metabolism in the activation of SAR. Previously, we have shown that a mutation in the Arabidopsis SSI2 gene, which encodes a fatty acid desaturase, constitutively activates a SAR-like defense response in the ssi2 mutant plant. A putative lipid transfer protein, DIR1, and a SA-binding lipase activity, SABP2, are also required for the activation of SAR in Arabidopsis and tobacco, respectively, providing further support for the involvement of lipids in the activation of SAR (Maldonado, et al. Nature 419: 399-402, 2002; Kumar and Klessig, Proc. Natl. Acad. Sci. USA 100: 16101-16106, 2003). A combination of genetic and lipidomic approaches are underway to improve our understanding of the role of lipids in plant defense.
