高等植物铁元素的吸收、转位和调控

Iron uptake,translocation,and regulation in higher plants

铁(Fe)是大多数生物体必需的微量营养元素.虽然铁在许多土壤中是丰富的,但铁在土壤中的可溶性非常低,常常限制植物生长.此外,铁自身存在高度的氧化还原特性,对细胞具有潜在的毒性.因此,细胞内铁的动态平衡需要严格调控.植物细胞中形成了一个复杂的信号网络来调节对铁的摄取、分配、运输及其代谢等过程.非禾本科和禾本科植物物种分别通过基于铁还原和铁螯合的两种不同策略从土壤中获得铁.植物对铁的吸收受到局部和全身信号的调控.系统信号通路似乎整合了激素信号、一氧化氮(NO)信号和植物营养需求等多种因素.综述了两种策略所依赖的分子机制和在铁缺乏条件下负责诱导这些策略的因素.

Iron is an essential micronutrient element for most living organisms. However,although iron is abundant in many soils,iron availability is very often limiting for plant growth. In addition,iron is potentially highly toxic to cells. Therefore,iron homeostasis needs to be strictly regulated. Higher plants have developed a complex regulatory network in their cells to control the uptake,translocation,transportation,and metabolism of Fe. Nongraminaceous and graminaceous plant species acquire iron from the soil through two distinct strategies based on iron reduction and iron chelation,respectively. The acquisition of iron by plants is regulated at several levels by local and systemic signals. The systemic signaling pathway appears to integrate multiple inputs from hormonal signals,NO signals,and the plant nutritional demand. This paper reviewed the molecular mechanisms by which these strategies depend and the factors that are responsible for inducing these strategies under iron deficiency.