Iron deficiency in plants: an update on homeostasis and its regulation by nitric oxide and phytohormones

Iron is an essential micronutrient for plants as it involves in several important physiological processes. Understanding iron homeostasis in plants is pivotal, not only for improving their growth and development but also for enhancing human nutrition as plants are the principal dietary source of iron. This calls for the need to enrich bioavailable iron in crops to resolve iron starvation issue especially in low income and rural populations who have limited access to food markets and proper health facilities. The uptake of iron from rhizosphere, its transporters and transcription factors that regulate iron acquisition are well characterized. Here, the present review emphasizes on the role of signalling molecules particularly phytohormones and nitric oxide and their interactive co-ordination in iron homeostasis in agriculturally important crops that grow at pH 6.0-7.5 and have limited access to Fe2+. The involvement of these signalling molecules in up-regulating iron acquisition genes (FRO2 and IRT1), iron translocation to the cellular compartments and accessibility of iron storage which are important for proper iron homeostasis hence can be considered as vital biofortification strategy for crop plants to address hidden hunger.

Automated summary

Iron is a crucial micronutrient for plant growth and human nutrition. Understanding iron homeostasis in plants is essential for improving growth and development and addressing iron deficiency in low-income rural populations. This review focuses on the role of signaling molecules, particularly phytohormones and nitric oxide, and their coordination in iron homeostasis in agriculturally important crops. These signaling molecules play a vital role in up-regulating iron acquisition genes, facilitating iron translocation, and enhancing iron accessibility, making them important biofortification strategies for addressing hidden hunger.