Malate root metabolsim in processes associated with the maintainig of cellular water status

ARIAS, C. L.; BADIA, MARIANA; ANDREO, CARLOS S; MARIA FABIANA DRINCOVICH; MARIEL GERRARD WHEELER; MARIANA SAIGO

Congreso; LI Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Water scarcity is a major cause of crop losses worldwide and great efforts are being made to achieve drought tolerant crops, especially in countries like Argentina, whose economy is based on the agricultural production. In Arabidopsis cells, the malic enzyme (ME) family is represented by four enzymes which catalyze the malate oxidative decarboxylation in the presence of NADP. NADP-ME1 is a cytosolic isoform which stands out due to its evolutionarily conservation, delimited expression to roots and kinetic characteristics. Here, a more detailed analysis using reporter gene fusions showed the presence of NADP-ME1 in the region of maturation. The treatment with absicic acid (ABA), a drought response mediator, specifically induced the expression of NADP-ME1 in the meristematic cells. In line with this, Arabidopsis mutant plants lacking NADP-ME1 presented an increased resistance to drought and lower response of root growth to ABA. These results suggest that NADP-ME1 plays a very specialized role in roots possibly regulating the concentration of the substrates and/or reaction products to feed metabolic pathways and regulatory functions triggered by the water stress signal.