Plant iron nutrition in the long road from soil to seeds.

Iron (Fe) is an essential plant micronutrient since photosynthesis, respiration, the scavenging of reactive oxygen species and many other cellular processes depend on adequate Fe levels. Nonetheless, non-complexed Fe ions can be dangerous for cells, as they can act as a pro-oxidant. Therefore, plants possess a complex homeostatic control system for safely taking up Fe from the soil, transporting it to the various cellular destinations and for its subcellular compartmentalization. At the end of the plant's life cycle, maturing seeds are loaded with the required amount of Fe for germination and early seedling establishment. In this review, we discuss recent findings on how the microbiota in the rhizosphere influence and interact with the strategies adopted by plants to take up iron from the soil. We also focus on the process of seed loading with Fe and take into account the Fe metabolism in wild crops' relatives. These aspects of plant Fe nutrition can represent promising avenues for a better comprehension of the long road of Fe from soil to seeds.