Mild drought in the vegetative stage induces phenotypic, gene expression and DNA methylation plasticity in Arabidopsis but no transgenerational effects

International audienceWhether environmentally-induced changes in phenotypes can be heritable is a topic with revived interest. In plants, heritable trait variation can occur without DNA sequence mutations through epigenetic mechanisms involving DNA methylation. However, it remains unknown if this other system of inheritance responds to environmental changes and if it can provide a rapid way for plants to generate adaptive heritable phenotypic variation. To obtain a comprehensive assessment of potential transgenerational effects induced by the environment, we subjected four natural accessions as well as the reference accession Col-0 of A. thaliana to mild drought in a multigenerational design. As expected, plastic responses to drought were observed in each accession, as well as a number of intergenerational effects of parental environments. However, after an intervening generation without stress, descendants of stressed and non-stressed plants were phenotypically indistinguishable, except for very few trait-based parental effects and irrespective of whether they were grown in control conditions or under water deficit. In addition, genome-wide analysis of DNA methylation and gene expression in the reference accession Col-0 demonstrated that, while mild drought induced changes in the DNA methylome of exposed plants, variants were not inherited. We conclude that mild drought stress does not induce transgenerational epigenetic effects