Haydon Michael J, Cobbett Christopher S
Department of Genetics, The University of Melbourne, Parkville, Australia 3010.
New Phytol. 2007;174(3):499-506. doi: 10.1111/j.1469-8137.2007.02051.x.
Essential metals are required for healthy plant growth but can be toxic when present in excess. Therefore plants have mechanisms of metal homeostasis which involve coordination of metal ion transporters for uptake, translocation and compartmentalization. However, very little metal in plants is thought to exist as free ions. A number of small, organic molecules have been implicated in metal ion homeostasis as metal ion ligands to facilitate uptake and transport of metal ions with low solubility and also as chelators implicated in sequestration for metal tolerance and storage. Ligands for a number of essential metals have been identified and proteins involved in the transport of these ligands and of metal-ligand complexes have been characterized. Here we review recent advances in understanding the role of mugineic acid, nicotianamine, organic acids (citrate and malate), histidine and phytate as ligands for iron (Fe), zinc (Zn), copper (Cu), manganese (Mn) and nickel (Ni) in plants, and the proteins identified as their transporters.
必需金属元素是植物健康生长所必需的，但过量存在时可能具有毒性。因此，植物具有金属稳态机制，其中涉及金属离子转运蛋白在吸收、转运和区室化方面的协调作用。然而，人们认为植物中以游离离子形式存在的金属非常少。一些小分子有机分子作为金属离子配体参与金属离子稳态，以促进低溶解度金属离子的吸收和运输，同时也作为螯合剂参与金属耐受性和储存的螯合作用。已鉴定出多种必需金属的配体，并对参与这些配体以及金属 - 配体复合物运输的蛋白质进行了表征。在此，我们综述了近年来在理解麦根酸、烟酰胺、有机酸（柠檬酸和苹果酸）、组氨酸和植酸作为植物中铁（Fe）、锌（Zn）、铜（Cu）、锰（Mn）和镍（Ni）的配体的作用以及被鉴定为它们转运蛋白的蛋白质方面取得的进展。
