Molecular biology of the Ectocarpus / Eurychasma pathosystem

Abstract

Ectocarpus siliculosus is commonly challenged by the intracellular oomycete pathogen Eurychasma dicksonii and unlike most other pathogens affecting algae, it is available in a laboratory-controlled pathosystem.  In the context of this PhD project, the molecular processes of algal response to pathogen infection has for the first time been studied on a pathosystem using genome-enabled approaches. The proteomic investigation of the compatible (disease-causing) interaction between E. siliculosus and Eu. dicksonii via comparative two-dimensional electrophoresis elucidated 21 differentially expressed proteins. A number of proteins, identified in this course, have been associated with various stress responses (e.g. heat shock proteins, superoxide dismutases) including defence response in previous studies on macroalgae.  Most important, some  results of this study uncovered molecular aspects of the host response to biotic stress which have not been documented with elicitor-based studies so far, stressing the biological value of this pathosystem. The identification of a Eurychasma-resistant Ectocarpus strain via a qPCR assay, specifically developed for this pathosystem, will allow future applications of the proteomic approach in the investigation of the incompatible (resistant) interaction. Furthermore, in-silico analysis of the E. siliculosus genome identified homologues of plant defence-related genes, coding for so-called pathogenesis-related (PR) proteins.  Taken together, these results open new routes for the understanding of algal host pathogen interactions.EThOS - Electronic Theses Online ServiceGBUnited Kingdo