The fungal pathogen Sclerotinia sclerotiorum (Lib.) de Bary is capable of infecting over 400 plant species including canola (Brassica napus L.). The fungus secretes oxalic acid (OA), which plays an important role in infection and disease progression. An analysis of proteome-level changes associated with infection of susceptible canola leaves by S. sclerotiorum revealed significant changes in the abundance of 32 proteins, including proteins involved in photosynthesis and metabolism, hormone signaling, and antioxidant defense. A similar subset of 37 proteins was affected when leaves were treated with OA alone; this compound also caused a reduction in the activities of a number of antioxidant enzymes, suggesting an OA-mediated suppression of the oxidative burst. To further understand the mechanisms of pathogenesis, the role of Sssp, a predicted secreted protein from S. sclerotiorum, was targeted for analysis. Mutant strains of S. sclerotiorum were generated by disruption of the Sssp gene and characterized for virulence on canola. Based on the extent of symptom development, the virulence of the Sssp-disrupted mutants was significantly reduced relative to the wild-type, indicating that Sssp may play a role in the infection process. Finally, the development of sclerotia, long-term survival structures that serve as a primary source of inoculum for the fungus, was examined. A total of 88 proteins were found to exhibit temporal changes in abundance during sclerotium formation and maturation, including proteins involved in the regulation of melanogenesis. A total of 56 proteins were also identified in the sclerotial exudates, providing a basis for future studies. Collectively, the studies described in this dissertation represent the most comprehensive proteome-level analysis of the canola/S. sclerotiorum interaction and sclerotial development, and could contribute to the development of novel strategies for the management of S. sclerotiorum. / Plant Science
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/1228 |
| Date | 11 1900 |
| Creators | Liang, Yue |
| Contributors | Kav, Nat (Agricultural, Food and Nutritional Science), Strelkov, Stephen (Agricultural, Food and Nutritional Science), Kav, Nat (Agricultural, Food and Nutritional Science), Strelkov, Stephen (Agricultural, Food and Nutritional Science), Deyholos, Michael (Biological Sciences), Dosdall, Lloyd (Agricultural, Food and Nutritional Science), Willenborg, Chris (Agricultural, Food and Nutritional Science), Rampitsch, Christof (Agriculture and Agri-Food Canada, Cereal Research Centre) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 30622577 bytes, application/pdf |
| Relation | Liang, Yue et al. (2008) J. Agric. Food Chem. 56, 1963-1976., Liang, Yue et al. (2009) Proteomics 9, 3156-3173., Liang, Yue et al. (2010) Fungal Biology, doi:10.1016/j.funbio.2010.05.003, Liang, Yue et al. (2010) J. Proteome Res. 9, 3290-3298. |
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