Arabidopsis seeds as a system to understand desiccation tolerance

Desiccation tolerance (DT) is observed across all biological kingdoms and is a relevant phenomenon in an ecological, social and economic context. In face of imminent climate changes DT will become a highly relevant trait for crop production, as well as for wild plant species conservation. When did desiccation tolerance first appear? How can any organism survive complete drying? What are the structural, molecular, biochemical and genetic principles involved in this phenomenon? Are the mechanisms orchestrating DT conserved among the biological kingdoms? Inspired by these questions and the proven complexity of this trait we have developed an experimental system to re-establish DT in Arabidopsis thaliana seeds. We show that the incubation of desiccation sensitive (DS) germinated Arabidopsis seeds in a polyethylene glycol (PEG) solution, in exogenous abscisic acid (ABA), or a combination of both, re-activates the mechanisms necessary for expression of DT. By using this model of loss and reestablishment of DT in combination with ABA-deficient and -insensitive mutants, we prove that ABA is necessary for the reestablishment of DT and hypothesize that the events upstream of ABA signaling are not necessary to rescue DT. Furthermore, we demonstrate that ABA sensitivity correlates with the developmental window of the seed/seedling in which DT can be rescued. We also explored this system to investigate the transcriptome, the primary metabolome and the total proteome involved in DT as a first attempt to uncouple osmotic and ABA specific pathways that are regulating this trait.