Revealing plant defense signaling: getting more sophisticated with phosphoproteomics.

The regulation mechanisms of any plant-pathogen interaction are complex and dynamic. A proteomic approach is necessary in understanding regulatory networks because it identifies new proteins in relation to their function and ultimately aims to clarify how their expression, accumulation and modification is controlled. One of the major control mechanisms for protein activity in plant-pathogen interactions is protein phosphorylation, and an understanding of the significance of protein phosphorylation in plant-pathogen interaction can be overwhelming. Due to the high number of protein kinases and phosphatases in any single plant genome and specific limitations of any technologies, it is extremely challenging for us to fully delineate the phosphorylation machinery. Current proteomic approaches and technology advances have demonstrated their great potential in identifying new components. Recent studies in well-developed plant-pathogen systems have revealed novel phosphorylation pathways, and some of them are off the core phosphorylation cascades. Additional phosphoproteomic studies are needed to increase our comprehension of the different mechanisms and their fine tuning involved in the host resistance response to pathogen attacks.