High soil salinity is a major environmental stress that adversely affects crop production throughout the world. It is now estimated that half of the world’s cropland is affected by salt stress. To cope with various environmental stresses, plants are able to spatially and temporally regulate gene expression through changes in DNA methylation and chromatin conformation, known as epigenetic modifications. Recent studies indicated that epigenetic modifications induced by environmental stress can be inherited over several generations, despite a genomewide epigenetic resetting of epigenetic imprints that takes place during plants reproduction. In this thesis, I evaluated in Arabidopsis thaliana the effect of multigeneration salt stress treatments on the genome-wide dynamics of DNA methylation and tolerance to high salinity. My results show that the immediate progenies of stressed plants displayed better germination and survival rate under high salinity, but contrary to current theories this effect is lost in the following non-stressed generation. Genome-wide DNA methylation analysis revealed that stress induced discrete de novo methylation and demethylation changes on epigenetically labile regions of the plant genome. These acquired tolerance and methylation marks are likely under parent-of-origin control as a result of a robust epigenetic reprogramming that takes place in the male germline. Stress-induced methylation marks identified are associated with transcriptional changes of stress responsive genes and correlated with antisense long-non coding RNA expression. Overall this work establish for the first time a link between differential DNA methylation, gene expression and shortterm adaptation to stress in plants.