Arabidopsis thaliana AtGCN2 Kinase is Involved in Disease Resistance against Pathogens with Diverse Life Styles

Abstract

The ability of the plants to detect diverse stress conditions and initiate cellular responses is vital to their survival in a constantly changing environment. General regulatory molecules often play crucial roles in controlling a multitude of cellular processes throughout the life span of an organism. GCN2 (general control nonderepressible 2) is a serine/threonine-protein kinase that acts as a global translational regulator in all eukaryotes from yeast to mammals to plants. GCN2 plays universal roles in mitigating cellular stresses by directly binding with uncharged tRNAs and phosphorylating its target, eukaryotic initiation factor 2 alpha (eIF2α). Here, we demonstrate that Arabidopsis thaliana GCN2 (AtGCN2) serves as a general regulator of salicylic acid- and jasmonic acid-mediated immune responses triggered upon infection with biotrophic and necrotrophic pathogens. Intriguingly, we found examples of both positive and negative influence of AtGCN2 on plant immunity at different developmental stages. This effect is consistent with the variable amount of abscisic acid accumulation in plants lacking functional AtGCN2 at early stages of development. Finally, we illustrate that AtGCN2 positively contributes to water loss and might also be involved in the epidermis-mediated defense responses.