Is ABA playing a role in Arabidopsis responses to iron deficiency?

RAMIREZ LEONOR; LAMATTINA LORENZO

Mar del Plata, Buenos Aires

Congreso; SAIB; 2007

SAIB

Iron is an essential mineral nutrient for plant growth and development. When faced with iron deficiency, all plants except the grasses induce a set of responses: (i) ATPase-mediated acidification of the rhizosphere, (ii) enhanced activity and expression of a plasma membrane-bound reductase (FRO2), (iii) increased expression of a Fe2+ transporter (IRT1) and (iv) root hair proliferation. Control of genes expression in response to different stresses is often mediated by transduction pathways which involve the plant hormone abscisic acid (ABA). In maize, it has been demonstrated that ABA promotes in the induction of ferritin synthesis. Ferritins play a key role because of their ability to sequester several thousand iron atoms in their central cavity. In this work, we treated Arabidopsis plants with ABA to induce the ferritin expression. We hypothesized that this could generate a reduction of available iron and then induce the characteristic responses associated to iron deficiency. Accordingly, we found that FRO2 and IRT1 expression, and root hair proliferation were induced by ABA. Previously, we have demonstrated that Nitric Oxide (NO) participates in iron homeostasis in plants. Experiments are in progress to show whether a link between ABA and NO takes place during the induction of plant responses to iron deficiency