Exogenous pyruvate mitigates the detrimental effects of water stress in contrasting peanut genotypes

Water stress triggers various cellular responses in plants, altering normal metabolic flow. Pyruvate, an important component of the glycolysis pathway, is directly involved in cell processes, triggering genes that influence drought tolerance. Research with Arabidopsis has shown that synthetic pyruvate relieves drought damage. We evaluated the effects of exogenous pyruvate at 100 and 50,000 mu M on mitigation of drought stress in two peanut cultivars submitted to water restriction. The evaluations were based on growth, gas exchange, and photosynthesis rate analyses. In addition, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) enzymes, and free proline were also assayed. In general, exogenous application of pyruvate contributed to mitigate the effects of water stress in the cultivar IAC Caiapo (sensitive to drought), based on gas exchange and instantaneous efficiency of water use. Exogenous pyruvate contributed to restore the action of antioxidative enzymes in BR 1 (tolerant to drought), based on measures of SOD (45%), CAT (129%) and APX (60%) in stressed plants, and full recovery at 50,000 mu M. When treated with proline, stress attenuation was found only at 100 mu M in both cultivars; the excess seemed to have a negative effect on stressed plants, probably affecting the cell environment.