Molecular plasticity during drought recovery is characterized by metabolite and protein turnover dynamics in Medicago truncatula

Trabajo presentado en la 2nd General Meeting of COST FA1306 (The quest for tolerant varieties - Phenotyping at plant and cellular level. PhenomenALL), celebrada en Copenhagen del 18 al 20 de abril de 2016.Plants are continuously exposed to extreme environmental changes. Especially water availability is subjected to a considerable fluctuation; several days of drought are often followed by periods of sufficient rain. This requires a molecular plasticity that enables plants to regulate drought acclimation and deacclimation processes for recovery and continuous growth. A complex network, including proteomic and metabolomic turnover dynamics, is part of this regulatory process. To study this, a partial 15N-metabolic labelling strategy in planta was introduced. Nitrogen incorporation was analyzed over a drought-recovery experiment determining the relative isotope abundances (RIA). Severely drought stressed plants (10 days of water withhold) were rewatered over a period of 4 days until full physiological recovery. The RIA of metabolites and proteins was monitored using mass spectrometry from samples taken 2, 24, 48, 72 and 96 hours after re-watering. The data reveal independent regulatory mechanisms for stress recovery with different dynamic phases that, during the course of recovery, define the plants` deacclimation from stress. An early transition phase that seems key for recovery initiation through water re-supply was observed. Furthermore, the data indicate that plasticity may also be related to the nutritional status of the plant prior to stress initiation.N