Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
J Exp Bot. 2021 Mar 17;72(6):2045-2055. doi: 10.1093/jxb/erab003.
Iron (Fe) is one of the essential micronutrients required by both plants and animals. In humans, Fe deficiency causes anemia, the most prevalent nutritional disorder. Most people rely on plant-based foods as their major Fe source, but plants are a poor source of dietary Fe. Therefore, there is a critical need to better understand the mechanisms involved in the uptake and trafficking of Fe and how plants adapt to Fe deficiency. Fe participates in key cellular functions such as photosynthesis and respiration. Perturbations of Fe uptake, transport, or storage affect plant growth as well as crop yield and plant product quality. Excess Fe has toxic effects due to its high redox activity. Plants, therefore, tightly regulate Fe uptake, distribution, and allocation. Here, we review the regulatory mechanisms involved at the transcriptional and post-translational levels that are critical to prevent Fe uptake except when plants experience Fe deficiency. We discuss the key regulatory network of basic helix-loop-helix (bHLH) transcription factors, including FIT, subgroup Ib, subgroup IVc, and URI (bHLH121), crucial for regulating Fe uptake in Arabidopsis thaliana. Furthermore, we describe the regulators of these transcription factors that either activate or inhibit their function, ensuring optimal Fe uptake that is essential for plant growth.
铁（Fe）是植物和动物都需要的必需微量元素之一。在人类中，缺铁会导致贫血，这是最常见的营养失调症。大多数人依赖植物性食物作为主要的铁来源，但植物是膳食铁的贫源。因此，人们迫切需要更好地了解铁的吸收和运输以及植物如何适应缺铁的机制。铁参与关键的细胞功能，如光合作用和呼吸作用。铁吸收、运输或储存的干扰会影响植物的生长以及作物的产量和植物产品的质量。由于其高氧化还原活性，过量的铁具有毒性作用。因此，植物严格调节铁的吸收、分布和分配。在这里，我们回顾了在转录和翻译后水平上涉及的调节机制，这些机制对于防止铁吸收至关重要，除非植物经历缺铁。我们讨论了基本螺旋-环-螺旋（bHLH）转录因子的关键调节网络，包括 FIT、亚组 Ib、亚组 IVc 和 URI（bHLH121），它们对拟南芥铁的吸收至关重要。此外，我们描述了这些转录因子的调节剂，它们可以激活或抑制它们的功能，从而确保铁的最佳吸收，这对植物的生长是必不可少的。
