In concert with oxygen, soil alkalinity strongly restricts the availability of iron, an essential nutrient with a multitude of functions in living organisms. In addition to its role in mitochondrial energy metabolism and as a cofactor for enzymes, in plants iron also plays key roles in photosynthesis and is required for chlorophyll biosynthesis. The ability to thrive in calcareous soils, referred to as calcicole behaviour, is the readout of an amalgam of traits of which efficient foraging of iron is a decisive factor. Recently, the well-established concept of two distinct iron uptake strategies, phylogenetically separating grasses from other land plants, was expanded by the discovery of auxiliary mechanisms that extend the range of edaphic conditions to which a species can adapt. Secretion of a tailor-made cocktail of iron-mobilising metabolites into the rhizosphere, the composition of which is responsive to a suite of edaphic and internal cues, allows survival in calcareous soils through a competitive iron acquisition strategy, which includes intricate interactions with the consortium of associated microorganisms in, on, and around the roots. This versatile, reciprocal plant-microbiome interplay affects iron mobilisation directly, but also collaterally by impacting growth, fitness, and health of the host. Here, we review the mechanisms and the multifaceted regulation of iron acquisition in plants, taking into consideration the specific constraints associated with the uptake of iron from alkaline soils. Knowledge on how plants extract iron from such soils sets the stage for a better understanding of essential ecological processes and for combatting iron malnutrition in humans.

与氧气一起，土壤碱度严重限制了铁的可用性，铁是一种在生物体中具有多种功能的必需营养素。除了在线粒体能量代谢中的作用和作为酶的辅助因子外，铁在植物中还在光合作用中发挥关键作用，并且是叶绿素生物合成所必需的。在石灰质土壤中茁壮成长的能力，被称为钙化行为，是对多种性状的读出，其中铁的有效觅食是决定性因素。最近，通过发现扩展物种可以适应的土壤条件范围的辅助机制，扩展了两种不同的铁吸收策略的成熟概念，即在系统发育上将草与其他陆生植物区分开来。将特制的铁动员代谢物混合物分泌到根际，其成分对一系列土壤和内部线索有反应，通过竞争性铁获取策略允许在石灰质土壤中生存，其中包括与财团的复杂相互作用根内、根上和周围的相关微生物。这种多功能的、相互作用的植物-微生物组相互作用直接影响铁动员，但也通过影响宿主的生长、健康和健康而附带影响。在这里，我们回顾了植物获取铁的机制和多方面的调节，同时考虑了与从碱性土壤中吸收铁相关的特定限制。