AtHscB and its role in plant iron homeostasis

LEADEN, L; PAGANI, M.A; GOMEZ-CASATI, D.F; BUSI, M.V

Rosario

Congreso; Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Iron is an essential nutrition element in all organisms. Since Fe is a substrate of the [Fe-S] cluster biogenesis, it has been suggested an intimate connection between Fe homeostasis and Fe-S cluster formation. In this work we evaluate the effect of AtHscB (co-chaperone, involved in the Fe-S cluster biogenesis) on iron transport in A. thaliana. We characterized two AtHscB over-expressing and AtHscB knock- down mutant lines. The activities of [Fe-S] enzymes ACO and SDH were reduced in both leaves and shoots knock-down lines. Conversely, these activities were increased in over-expressing roots, but notoriously decreased in their leaves. Under Fe sufficient conditions, over-expressing and knock-down lines present altered Fe levels distribution between roots and shoots. Furthermore, these lines are less sensitive to growth under Fe deficiency. Studies after 48 h of metal absence showed that all lines decrease iron levels in root. In addition, Fe content in wt, knock-down mutant leaves decreases in comparison to their control conditions, while a clear increment in over-expressing leaves was shown. Moreover, changes in foliar iron content were correlated with variations in [Fe-S] enzymes activities. Our results indicate that AtHscB might produce a deregulation of the iron transport root to shoot, suggesting that Fe-S clusters could regulate the Fe transport in plants.