Comparative proteomic analysis of responses to pathogen infection and wounding in Fagus sylvatica

Defense responses of Fagus sylvatica seedlings elicited by infection with the root pathogen Phytophthora citricola and root or leaf wounding were compared at local and systemic levels in differential display experiments using two-dimensional gel electrophoresis followed by homology-driven mass spectrometric identification of proteins. A total of 68 protein spots were identified representing 51 protein functions related to protein synthesis and processing, energy, primary and secondary metabolism, as well as signal transduction, stress and defense. Changes in the abundance of root and leaf proteins partly overlapped between plant responses to the different stressors. The response to pathogen infection was rather late, weak and unspecific and accompanied by adjustments of the energy and primary metabolism which suggested either a lack of recognition or a suppression of host's defense reaction by the invading pathogen. The response to wounding involved changes in the basal metabolism as well as activation of defense mechanisms. Both types of changes were largely specific to the wounded organ. Similarities between the defense mechanisms activated by root infection and root wounding were also observed.