Fig. 2.

Schematic diagram of iron uptake mechanisms and metabolism in diatoms. A summary schematic of the proteins discussed in this review and of their cellular location. In the chloroplast, we review the replacement of ferredoxin with its iron-free equivalent, flavodoxin, and the substitution of cytochrome c₆ with plastocyanin. Reductive and non-reductive iron uptake mechanisms are considered, the latter employing the cell’s vesicular network to direct iron to the plastid. Two alternative iron storage mechanisms are reviewed: the accumulation of iron in the mineral core of ferritin (FTN), and vacuolar storage. For the storage proteins, the cellular localization of the putative proteins has not been confirmed through microscopy analyses (indicated with dashed lines).