Endogenous NO protects Frataxin defcient Arabidopsis plants from oxidative stress

RODRIGUEZ-COLMAN, M. J.; GÓMEZ-CASATI, D.; LAMATTINA, L.; EDUARDO JULIAN ZABALETA; MARTIN, M.

Mar del Plata

Congreso; 43th SAIB Annual meeting; 2007

Frataxin is a mitochondrial proteinhighly conserved througout evolution. The function of frataxin remains essentially unknown. We studied the A thaliana mutant atfh-1 which is deficient in frataxin. Previous results indicated that frataxin is a regulatory component on iron homeostasisin Arabidopsis. atfh-1 plants present a constitutively high iron content likely accumulated in mitochondria suggesting this mutant has a defect in iron distribution. Probably, as a consequence or iron accumulation, atfh-1 plants present a higher sensitivity to hydrogen peroxide compared to wt. In addition, frataxin deficiency produces constitutively high NO levels. The aim of this work is to investigate the role (protective/toxic) of NO in atfh-1 plants. We present evidences that the high level of NOproduced in atfh-1 rootscould be abnomally accumulated in mitochondria. Furthermore, NO acts in a protective way against oxidative stress by induction of mitochondrial predicted ferritin (FER-4) which could contribute to diminish free-Fe levels within the organelle. Preliminary results suggest that endogenous levels of NO in wt roots is necessary for the basal expressio levels of frataxin. We conclude that in atfh-1 plants the higher level of NO could be a compensatory response that may attenuate the oxidative damage generated by frataxin deficiency.