The Arabidopsis DNA methylome is stable under transgenerational drought stress.

5 years ago

The Arabidopsis DNA methylome is stable under transgenerational drought stress.

Eichten, Crisp, Pogson, Ganguly

Improving the responsiveness, acclimation, and memory of plants to abiotic stress holds substantive potential for improving agriculture. An unresolved question is the involvement of chromatin marks in the memory of agriculturally-relevant stresses. Such potential has spurred numerous investigations yielding both promising and conflicting results. Consequently, it remains unclear to what extent robust stress-induced DNA methylation variation can underpin stress memory. Using a slow onset water deprivation treatment in Arabidopsis we investigated the malleability of the DNA methylome to drought stress within a generation and under repeated drought stress over five successive generations. Whilst drought-associated epi-alleles in the methylome were detected within a generation they did not correlate with drought responsive gene expression. Six traits were analysed for transgenerational stress memory and the descendants of drought stressed lineages showed one case of memory in the form of increased seed dormancy, and that persisted one generation removed from stress. With respect to transgenerational drought stress there were negligible conserved DMRs in drought-exposed lineages compared to unstressed lineages. Instead, the majority of observed variation was tied to stochastic or pre-existing differences in the epigenome occurring at repetitive regions of the Arabidopsis genome. Furthermore, experience of repeated drought stress was not observed to influence transgenerational epi-allele accumulation. Our findings demonstrate that while transgenerational memory is observed in one of six traits examined they are not associated with causative changes in the DNA methylome, which appears relatively impervious to drought stress.

Publisher URL: http://doi.org/10.1104/pp.17.00744

DOI: 10.1104/pp.17.00744