The form of nitrogen nutrition affects cadmium toxicity in Arabidopsis plants

VÁZQUEZ A.; RECALDE L.; IANNONE M.F.; GROPPA M.D.; BENAVIDES M.P.

Congreso; 11 th Congress of Internacional Plant Molecluar Biology. IPMB; 2015

THE FORM OF NITROGEN NUTRITION AFFECTS CADMIUM TOXICITY IN ARABIDOPSIS PLANTSVázquez A, Recalde L, Iannone MF, Groppa MD, Benavides MPBiological Chemistry Department, Faculty of Pharmacy and Biochemistry, University of Buenos Aires. analia_vzq@hotmail.comThe nitrogen supply of growing leaves is a dominant target of whole plant nitrogen metabolism. In agricultural soils, N is supplied in the form of nitrate (NO3-), ammonium (NH4+), or a combination of both. In the last years, cadmium has become an important pollutant in soils. In Arabidopsis plants, it has been reported that nitrate transport in the roots is strongly stimulated by cadmium supply. In this work, we studied the importance of the nitrogen source in Cd-induced toxicity in Arabidopsis thaliana plants. Seeds were grown in commercial substrate for 20d, transferred to a complete nutrient solution 7d for acclimation and then to treatment solutions for 8d: Control (NO3-/NH4+), NO3- or NH4+, either with or without 2,5 µM CdCl2. Cadmium did not change chlorophyll content but in the presence of ammonium, the pigment increased slightly, with or without Cd.The nitrogen source did not influence Cd-induced inhibition of root elongation, but seemed to modify Cd effect on biomass accumulation. The NH4+ source appeared to be detrimental in biomass acquisition under Cd stress. Cadmium decreased nia 1 and nia2 gene expression in leaves in full nitrogen medium, but affected NR genes expression differently depending on the nitrogen source. While nitrate increased nia 2 gene expression, ammonium decreased nia2 expression, independently of Cd. Cadmium greatly increased total anthocyanins content, more markedly when the nitrogen source was ammonium. The knowledge about the relevance of the nitrogen source in relation to growth and metabolism reprogramming under Cd stress will provide further important insights into the mechanisms whereby plant development is modulated by response to changes in the environment.