Deciphering the molecular bases for drought tolerance in Arabidopsis autotetraploids

Whole genome duplication (autopolyploidy) is common in many plant species and often leads to better adaptation to adverse environmental conditions. However, little is known about the physiological and molecular mechanisms underlying these adaptations. Drought is one of the major environmental conditions limiting plant growth and development. Here, we report that, in Arabidopsis thaliana, tetraploidy promotes alterations in cell proliferation and organ size in a tissue-dependent manner. Furthermore, it potentiates plant tolerance to salt and drought stresses and decreases transpiration rate, likely through controlling stomata density and closure, abscisic acid (ABA) signalling and reactive oxygen species (ROS) homeostasis. Our transcriptomic analyses revealed that tetraploidy mainly regulates the expression of genes involved in redox homeostasis and ABA and stress response. Taken together, our data have shed light on the molecular basis associated with stress tolerance in autopolyploid plants. Entire-genome duplication (autopolyploidy) is a common phenomenon in many plant species and often leads to better adaptation to environmental conditions. However, we lack information about the physiological, cellular and molecular mechanisms that explain better adaptation to different stresses in autotetraploid plants. Our work indicates that, in Arabidopsis thaliana, tetraploidy promotes alterations in cell proliferation and organ size in a tissue-dependent manner. Furthermore, this is the first report showing that autotetraploid Arabidopsis increased drought tolerance by altering stomatal activity, ABA signaling and ROS homeostasis. In addition, transcriptomic data shed light on the molecular basis associated with stress tolerance in polyploid plants, that includes hormonal regulation and redox processes.