Malate root metabolism in processes associated with the maintaining of cellular water status

ARIAS, C. L.; BADIA, M. B.; ANDREO, C. S.; DRINCOVICH, M. F; GERRARD WHEELER, M. C.; SAIGO, M

Mar del Plata

Congreso; LI Reunión Anual 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 tolerantcrops, especially in countries like Argentina, whose economy is based on the agricultural production. In Arabidopsiscells, the malic enzyme (ME) family is represented by four enzymes which catalyze the malate oxidativedecarboxylation in the presence of NADP. NADP-ME1 is a cytosolic isoform which stands out due to itsevolutionarily conservation, delimited expression to roots and kinetic characteristics. Here, a more detailed analysisusing reporter gene fusions showed the presence of NADP-ME1 in the region of maturation. The treatment withabsicic acid (ABA), a drought response mediator, specifically induced the expression of NADP-ME1 in themeristematic cells. In line with this, Arabidopsis mutant plants lacking NADP-ME1 presented an increased resistanceto drought and lower response of root growth to ABA. These results suggest that NADP-ME1 plays a veryspecialized role in roots possibly regulating the concentration of the substrates and/or reaction products to feedmetabolic pathways and regulatory functions triggered by the water stress signal.