Frontiers in Plant Science (May 2013)
Searching iron sensors in plants by exploring the link among 2’-OG-dependent dioxygenases, the iron deficiency response and metabolic adjustments occurring under iron deficiency
Abstract
Knowledge accumulated on the regulation of iron (Fe) homeostasis, its intracellular trafficking and transport across various cellular compartments and organs in plants; storage proteins, transporters and transcription factors involved in Fe metabolism have been analysed in detail in recent years. However, the key sensor(s) of cellular plant Fe status triggering the long-distance shoot-root signalling and leading to the root Fe-deficiency responses is (are) still unknown. Local Fe sensing is also a major task for roots, for adjusting the internal Fe requirements to external Fe availability: how such sensing is achieved and how it leads to metabolic adjustments in case of nutrient shortage, is mostly unknown. Two proteins belonging to the 2′-OG dependent dioxygenases family accumulate several folds in Fe-deficient Arabidopsis roots. Such proteins require Fe(II) as enzymatic cofactor; one of their subgroups, the HIF-P4H (Hypoxia Inducible Factor- Prolyl 4-Hydroxylase), is an effective oxygen sensor in animal cells. We envisage here the possibility that some members of the 2′-OG dioxygenase family may be involved in the Fe-deficiency response and in the metabolic adjustments to Fe deficiency or even in sensing Fe, in plant cells.
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