Assay of Fe(III) Chelate Reductase Activity in Arabidopsis thaliana Root

A sensitive FerroZine assay is used to measure the membrane-bound ferric-chelate reductase activity in the Arabidopsis thaliana roots. In Arabidopsis, FRO2 (FERRIC CHELATE REDUCTASE 2) encodes the Fe(III) chelate reductase and its expression is induced by iron deficiency. As FRO2 reduces Fe(III) to soluble Fe(II), the resulting Fe(II) forms a purple-colored complex with the dye FerroZine. The concentration of the Fe(II)-FerroZine is directly proportional to the absorbance at 562 nm.