How Plants Recalibrate Cellular Iron Homeostasis

Abstract Insufficient iron supply poses severe constraints on plants, restricting species with inefficient iron uptake mechanisms from habitats with low iron availability and causing yield losses in agricultural ecosystems. Iron deficiency also poses a severe threat on human health. Anemia resulting from insufficient iron intake is affecting one of four people in the world. It is, therefore, imperative to understand the mechanisms by which plants acquire iron against a huge soil-cell gradient and how iron is distributed within the plant to develop strategies that increase its concentration in edible plant parts. Research into the processes that are employed by plants to adjust cellular iron homeostasis revealed an astonishingly complex puzzle of signaling nodes and circuits, which are intertwined with the perception and communication of other environmental cues such as pathogens, light, nutrient availability and edaphic factors such as pH. In a recent Spotlight issue in this journal, a collection of review articles summarized the state-of-the-art in plant iron research, covering the most active and, debatably, most important topics in this field. Here, we highlight breakthroughs that were reported after the publication date of this review collection, focusing on exciting and potentially influential studies that have changed our understanding of plant iron nutrition.