This proposal aims to deliver fundamental insights into the role of early DNA hypomethylation and histone modification changes - a phenomenon that we call the ‘epigenetic shock’ - in plant immunity. By focusing on two model plants, Arabidopsis and rice, this proposal will allow to assess the evolutionary conservation of the epigenetic shock, increasing the potential broad impact of the project results. Rice is one of the most important staple crops in the world, it feeds more than 50% of the human population on a daily basis. The Kyndt research group focusses on rice immunity and epigenetics, an increasingly important subject to sustainably deal with pathogens/pests. Preliminary results from the group, together with recent Arabidopsis research (a.o. from the co-promoter of this application) indicate a role for DNA hypomethylation in pattern triggered immunity and induced resistance, and of unilateral histone modifications in plant immunity. This proposal will expand the fragmented data, check the conservation of this response over different stimuli and assess the causes and consequences of the epigenetic shock, which remain largely elusive today. The project includes ELISA assays to assess the epigenetic changes over time, stimuli and species; mRNA-seq and mutant analyses to identify the mediators; and ATAC-Me sequencing to check the consequences. In the long term, our research aims at providing answers to the growing problems with diseases in agriculture.