Iron deficiency-induced responses in Arabidopsis thaliana roots: role of ethylene

NEGRI, P; CABALLERO, V; D'IPPOLITO, S.; MASSAZZA, D. ; RAMIREZ, L.; SCHROTT, G.; TAGLIOTTI, M; PAGNUSSAT, L; PINEDO, M; LAMATTINA L.

Rosario, Santa Fe, Argentina

Congreso; XLII, reunion anual - Sociedad argentina de investigación en Bioquímica y Biología Molecular (SAIB); 2006

A low iron availability in soil generates a series of plant root responses that lead to the increase of the iron uptake. Fe+3 reductase (FRO2) under the control of the translation factor (FIT1) and morphologic changes in roots have been described to be induced by iron defiency. Since different reports have involved nitric oxide (NO) and ethylene in plant iron metabolism, we decided to study the role of ethylene and its crosstalk with NO in plant root responses to iron deficiency. Plants of Arabidopsis thaliana grown in presence or absence of iron were treated with ethephon (ethylene donor) or CoCl2 (ethylene synthesis inhibitor). The morphologic analysis of the roots showed that depletion of endogenous ethylene completely inhibited root hairs development. NO production in roots was increased by ethylene treatment and decreased when adding CoCl2. Beside, FRO2 and FIT1 expresion were evaluated by semiquantitative RT-PCR. Result indicated that, while CoCl2 did not affect the FRO2 and FIT1 mRNA levels in presence or obsence of iron, the ethylene addition decreased those levels. In conclusion, ethylene would play a role in root hairs development and NO production and, at less extent, would also influence FRO2 and FIT1 expression as well as FRO2 activity.[The authors have contributed equally to this work].