Considerations on post-translational modification and protein targeting in the Arabidopsis defense proteome.

The immune response of plants to potential pathogens consists of two levels of defense; basal resistance triggered by pattern recognition (PTI) and effector triggered immunity (ETI). Recent analysis of the Arabidopsis proteome after challenge by three strains of Pseudomonas syringae identified proteins implicated in the establishment of disease, PTI and ETI. In this addendum we discuss the significance of some of the putative post-translational modifications and the predicted localisation of these proteins. We speculate on the apparent bias of chloroplast targeted proteins amongst those identified and consider the strengths and weaknesses inherent to a comparative proteomics approach.