Iron Uptake Mechanisms in Plant Systems

Plants acquire iron through two principal strategies adapted to soil chemistry and taxonomy. Non-graminaceous species employ a reduction-based pathway (Strategy I) in which root epidermal cells acidify the rhizosphere, induce ferric chelate reductase to convert Fe(III) to Fe(II), and transport Fe(II) across the plasma membrane. Graminaceous species use a chelation-based pathway (Strategy II) in which roots secrete phytosiderophores—low-molecular-weight iron-chelating compounds such as deoxymugineic acid—to solubilise Fe(III) before uptake of the Fe(III)–phytosiderophore complex via specific transporters. Once inside the root, iron is bound by nicotianamine for intracellular trafficking and long-distance distribution through xylem and phloem vessels. Iron-sensing proteins, including hemerythrin-like domains within E3 ubiquitin ligases, modulate transcriptional networks to maintain iron homeostasis and prevent both deficiency and toxicity. Advances in molecular genetics and imaging have revealed complex cross-talk between hormone signalling, redox status and iron uptake machinery, offering routes to enhance crop nutrition and stress tolerance through targeted manipulation of transporters, chelator biosynthesis and sensor components.

Research from Nature Portfolio

Recent studies have characterised the iron-binding and redox-active properties of N-terminal hemerythrin-like domains in plant E3 ubiquitin ligases, demonstrating reversible oxidation of diiron centres that regulate downstream iron-deficiency responses. These findings provide biochemical evidence for how plants sense cellular iron status and adjust uptake and redistribution pathways. In parallel, field trials of transgenic indica rice lines co-expressing nicotianamine synthase and ferritin genes have achieved polished grain iron concentrations exceeding nutritional targets without yield penalty. X-ray fluorescence imaging confirmed endosperm enrichment, while cell-culture assays demonstrated enhanced iron bioavailability. These advances exemplify how insights into iron chelator biosynthesis and intracellular storage can be translated into agronomic solutions for micronutrient malnutrition.

Iron Uptake Mechanisms in Plant Systems publication trend

The graph below shows the total number of articles in iron uptake mechanisms in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Strategy I: Reduction-based mechanism in non-graminaceous plants involving rhizosphere acidification, ferric chelate reductase and Fe(II) uptake.

Strategy II: Chelation-based mechanism in graminaceous plants involving phytosiderophore secretion and uptake of Fe(III)–chelator complexes.

Phytosiderophore: Molecule such as deoxymugineic acid secreted by roots to solubilise and chelate Fe(III) in soil.

Ferric chelate reductase (FCR): Membrane-bound enzyme that reduces Fe(III) to Fe(II) at the root surface.

Hemerythrin-like domain: Protein motif that coordinates diiron centres and mediates redox-sensitive iron sensing in plants.

Nicotianamine: Internal metal chelator that facilitates transport and distribution of iron within plant tissues.

References

1. Iron-sensing and redox properties of the hemerythrin-like domains of Arabidopsis BRUTUS and BRUTUS-LIKE2 proteins. Nature Communications (2025).
2. A major role of coumarin-dependent ferric iron reduction in strategy I-type iron acquisition in Arabidopsis. The Plant Cell (2023).
3. Biofortified indica rice attains iron and zinc nutrition dietary targets in the field. Scientific Reports (2016).
4. Rice OsYSL15 Is an Iron-regulated Iron(III)-Deoxymugineic Acid Transporter Expressed in the Roots and Is Essential for Iron Uptake in Early Growth of the Seedlings*. Journal of Biological Chemistry (2008).
5. Phytosiderophore Efflux Transporters Are Crucial for Iron Acquisition in Graminaceous Plants*. Journal of Biological Chemistry (2010).