Ferric reductive enzymes and iron transporters
Dicotyledon and non-gramineous monocotyledon can
activate a differential H+-ATPase to acidify the soil,
increasing the solubility of iron, and a special root ferricreductase
to reduce iron in the Fe3+-chelate; Fe2+ is
then transported through the root cytoplasmic membrane
by transporters [14]. Thus, ferric-reductase and
iron transporters take an important role in this process.
Eide et al. [17] firstly cloned the Fe2+-transporter gene
IRT1 in dicotyledon Arabidopsis by expression in two
yeast mutant strains fet3 and fet4 by applying functional
heterogenous complementation. Cohen et al. [18] also
found the Fe2+-transporter IRT1 in pea root. Yin et al.
[19] successfully constructed a DNA library of corn root
induced by iron deficiency, with Fe2+-transporter genes.
Robinson et al. separated and cloned Fe3+-reductase
(froh) [20] and Fe3+-chelate reductase (fro2) [21] from
Arabidopsis. In addition, they also identified three other
fro genes (froh gene family), their products may play a
role in different organs or specialized cells, or be
involved in the transport of iron [20].