Project description:In this project, we made a comprehensive quantitative proteomic analysis of four defined developmental stages of S. parasitica (mycelium, primary cysts, secondary cysts and germinated cysts) to gain greater insight into the types of proteins specifically linked to each stage. A total of 2423 unique proteins were identified using qualitative (gel-based) and quantitative (iTRAQ, isobaric tags for relative and absolute quantitation) approaches. Of these, 358 proteins, associated with various biological processes, were found to be significantly enriched between different life cycle stages of S. parasitica. The transcript abundance of several cyst and mycelium enriched proteins was also checked by quantitative real-time PCR. This is the first large scale proteomic analysis on Saprolegnia and the data from this study will enhance our current knowledge about this pathogen by identifying biological processes key to each developmental stage.
Project description:Oomycete cells are surrounded by a polysaccharide rich cell wall matrix that, in addition to being essential for cell growth, also functions as protective ”armour”. It follows, that the enzymes responsible for the synthesis of the cell wall provide potential targets for disease management. Interestingly, the oomycete cell wall enzymes are predicted to be plasma membrane proteins. In this project, we used a quantitative (iTRAQ) mass spectrometry-based proteomics approach to characterize the plasma membrane proteome of the hyphal cells of S. parasitica, providing the first complete plasma membrane proteome of an oomycete species. Of significance, is the identification of proteins enriched in functional microdomains (Detergent-Resistant Microdomains; DRMs). In silico analysis showed that DRM-enriched proteins are mainly involved in both molecular transport and β-1,3-glucan synthesis, potentially contributing to post infection pathogenesis.
Project description:Oomycetes from the genus Phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. Due to particular physiological characteristics, no treatments against diseases caused by oomycetes are presently available. To develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between Phytophthora species and host plants. The present project is focused on the molecular mechanisms that underlie the compatible plant-oomycete interaction and plant disease. The laboratory developed a novel interaction system involving the model plant, Arabidopsis thaliana, and Phytophthora parasitica, a soil-borne pathogen infecting a wide host range, thus representing the majority of Phytophthora species. A characteristic feature of the compatible Arabidopsis/P. parasitica interaction is an extended biotrophic phase, before infection becomes necrotrophic. Because the initial biotrophic phase is extremely short on natural (e.g. solanaceous) hosts, the Arabidopsis system provides the opportunity to analyze, for both interaction partners, the molecular events that determine the initiation of infection and the switch to necrotrophy. The present project aims at analyzing the compatible interaction between A. thaliana roots and P. parasitica. The Affymetrix A. thaliana full genome chip will be used to characterize modulations of the transcriptome occurring over a period of 24h from the onset of plant root infection to the beginning of necrotrophy. Parallel to this study, a custom-designed P. parasitica biochip will enable analyzing of P. parasitica gene expression during the same stages.
Project description:Oomycetes from the genus Phytophthora are fungus-like plant pathogens that are devastating for agriculture and natural ecosystems. Due to particular physiological characteristics, no treatments against diseases caused by oomycetes are presently available. To develop such treatments, it appears essential to dissect the molecular mechanisms that determine the interaction between Phytophthora species and host plants. The present project is focused on the molecular mechanisms that underlie the compatible plant-oomycete interaction and plant disease. The laboratory developed a novel interaction system involving the model plant, Arabidopsis thaliana, and Phytophthora parasitica, a soil-borne pathogen infecting a wide host range, thus representing the majority of Phytophthora species. A characteristic feature of the compatible Arabidopsis/P. parasitica interaction is an extended biotrophic phase, before infection becomes necrotrophic. Because the initial biotrophic phase is extremely short on natural (e.g. solanaceous) hosts, the Arabidopsis system provides the opportunity to analyze, for both interaction partners, the molecular events that determine the initiation of infection and the switch to necrotrophy. The present project aims at analyzing the compatible interaction between A. thaliana roots and P. parasitica. The Affymetrix A. thaliana full genome chip will be used to characterize modulations of the transcriptome occurring over a period of 24h from the onset of plant root infection to the beginning of necrotrophy. Parallel to this study, a custom-designed P. parasitica biochip will enable analyzing of P. parasitica gene expression during the same stages. 10 samples were used in this experiment.