β-Aminobutyric acid increases drought tolerance and reorganizes solute content and water homeostasis in flax (Linum usitatissimum)

β-Aminobutyric acid (BABA) is a non-protein amino acid that induces drought tolerance in plants. The mechanisms involved in this tolerance are still poorly understood. In the present study, metabolomic and ionomic profiling performed in flax ( Linum usitatissimum ) leaves revealed that BABA induces a major reorganization in solute content. This reorganization resulted in increased accumulation of non-structural carbohydrates and proline and a decrease in inorganic solutes. This response has high similarities with that obtained when flax is exposed to an osmotic stress. BABA treatment also induced a decrease in osmotic potential and a change in water status of flax leaves. These modifications are accompanied by an improvement in drought tolerance.