MAP kinase as regulators for stress responses in plants: An overview

Abstract

Living cells adapt to various kind of stresses by perceiving changes in the extracellular environment and communicating these changes from outside of the cell to the inside and ultimately to the nucleus where expression of a specific set of genes occurs in order to provide appropriate response to the stress. Plant cells have evolved several signaling cascades to accomplish this signal transduction. One of the major mechanisms is the cascade of protein phosphorylation by specific Mitogen Activated Protein Kinase (MAPK) cascade. This cascade comprises of three kinase modules, a MAPK kinase kinase (MAPKKK/MAKKK/MEKK/MAP3K), a MAPK kinase (MAPKK/MKK/MEK/MAP2K) and a MAPK, which are sequentially activated by an event of protein phosphorylation. In plants, MAPKs are large signaling families of proteins, which have been shown to be involved in cross-talk with various abiotic and biotic stress responses forming complex networks in cells. Abiotic stresses such as heat, cold, changing light intensities, heavy metals and salinity, and biotic stress such as pathogen attack are key factors, which affect growth and development of plants. In response to these stresses, MAPK signaling cascade regulate growth of plants by transcriptional and post-transcriptional regulation such as protein–protein interactions. In this chapter, we discuss the latest findings and insights in relation to the role of all the modules, MAPKKK, MAPKK, and MAPKs of different MAPK signaling cascades in various abiotic and biotic stresses in plants.