Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, Japan.
Plant Cell Physiol. 2019 Jul 1;60(7):1440-1446. doi: 10.1093/pcp/pcz038.
Under iron-deficient conditions, plants induce the expression of a set of genes involved in iron uptake and translocation. This response to iron deficiency is regulated by transcriptional networks mediated by transcription factors (TFs) and protein-level modification of key factors by ubiquitin ligases. Several of the basic helix-loop-helix TFs and the HRZ/BTS ubiquitin ligases are conserved across graminaceous and non-graminaceous plants. Other regulators are specific, such as IDEF1 and IDEF2 in graminaceous plants and FIT/FER and MYB10/72 in non-graminaceous plants. IMA/FEP peptides positively regulate the iron-deficiency responses in a wide range of plants by unknown mechanisms. Direct binding of iron or other metals to some key regulators, including HRZ/BTS and IDEF1, may be responsible for intracellular iron-sensing and -signaling events. In addition, key TFs such as FIT and IDEF1 interact with various proteins involved in signaling pathways of plant hormones, oxidative stress and metal abundance. Thus, FIT and IDEF1 might function as hubs for the integration of environmental signals to modulate the responses to iron deficiency. In addition to local iron signaling, root iron responses are modulated by shoot-derived long-distance signaling potentially mediated by phloem-mobile substances such as iron, iron chelates and IMA/FEP peptides.
在缺铁条件下，植物会诱导一组参与铁吸收和转运的基因表达。这种对缺铁的反应受转录因子（TFs）介导的转录网络和关键因子通过泛素连接酶的蛋白水平修饰调控。一些基本的螺旋-环-螺旋 TF 和 HRZ/BTS 泛素连接酶在禾本科和非禾本科植物中是保守的。其他调节剂是特异性的，如禾本科植物中的 IDEF1 和 IDEF2，以及非禾本科植物中的 FIT/FER 和 MYB10/72。IMA/FEP 肽通过未知机制在广泛的植物中正向调节缺铁反应。直接结合铁或其他金属可能是某些关键调节剂（包括 HRZ/BTS 和 IDEF1）负责细胞内铁感应和信号转导事件的原因。此外，FIT 和 IDEF1 等关键 TF 与参与植物激素、氧化应激和金属丰度信号通路的各种蛋白质相互作用。因此，FIT 和 IDEF1 可能作为整合环境信号的枢纽，调节对缺铁的反应。除了局部铁信号外，根铁反应还受到可能由韧皮部可移动物质（如铁、铁螯合物和 IMA/FEP 肽）介导的地上部长距离信号的调节。
