Nitric Oxide modulates the induction of FRO2 and FIT1 in iron-deficient Arabidopsis thatliana

SUELDO, D.; ARRUEBARRENA, A.; FORLETTI, A.; LAMENZA, P.; MARIN, M.; MILTON, F. M.; DALESSANDRO, C.; ANA MARIA LAXALT; LAMATTINA, L.

Rosario

Congreso; SAIB; 2006

NITRIC OXIDE MODULATES THE INDUCTION OF FRO2 AND FIT1 IN IRONDEFICIENT ARABIDOPSIS THALIANA Arruebarrena Di Palma1, A., Forletti1, A., Lamenza1, P., Marin1, M., Mitton1, F. M., Sueldo1, D., D’Alessandro C., Laxalt A. M. and L. Lamattina e-mail: djsueldo@hotmail.com Cátedra Biología Molecular II, IIB, UNMdP, Mar del Plata, Argentina. 1. These authors have equally contributed to this work Iron (Fe) is an essential mineral for plants and its deficiency is associated with the presence of insoluble forms in soil. To solve this, plants develope strategies to improve the Fe uptake. The molecular responses under Fe deficiency in Arabidopsis thaliana involve the induction of Fe+3-reductase (FRO2), ion metal transporter (IRT1) and the transcription factor FIT1, that regulates FRO2. Nitric oxide (NO), synthesized by the nitrate reductase (NR) and other enzymes, has emerged as a signaling molecule in Fedeficiency responses in tomato. The aim of this work was to know the role of NO in regulating the expression of FRO2 and FIT1 in roots of Fe-deficient A. thaliana. Plants were treated with the NO donor nitrosoglutathione (GSNO) or inhibitor of NR, tungstate (Tg) and the expression of FRO2 and FIT1 was analyzed by RT-PCR. The induction of FRO2 was enhanced by GSNO only in Fe-deficient plants and was not inhibited by Tg. However, the activity of Fe-reductases was increased by GSNO and reduced by Tg. Microscopic observation revealed an increase in NO content in Fedeficient roots. Tg-treated roots diminished NO levels suggesting that NR activity is the main source of NO in A. thaliana during Fe-deficiency. These results support a role for NO in regulating the molecular response of A. thaliana to Fe-deficiency.