Huang Xin, Duan Songpo, Wu Qi, Yu Min, Shabala Sergey
International Research Center for Environmental Membrane Biology, Foshan University, Foshan, China.
Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Australia.
Plants (Basel). 2020 Feb 9;9(2):223. doi: 10.3390/plants9020223.
Cadmium (Cd) is present in many soils and, when entering the food chain, represents a major health threat to humans. Reducing Cd accumulation in plants is complicated by the fact that most known Cd transporters also operate in the transport of essential nutrients such as Zn, Fe, Mn, or Cu. This work summarizes the current knowledge of mechanisms mediating Cd uptake, radial transport, and translocation within the plant. It is concluded that real progress in the field may be only achieved if the transport of Cd and the above beneficial micronutrients is uncoupled, and we discuss the possible ways of achieving this goal. Accordingly, we suggest that the major focus of research in the field should be on the structure-function relations of various transporter isoforms and the functional assessment of their tissue-specific operation. Of specific importance are two tissues. The first one is a xylem parenchyma in plant roots; a major "controller" of Cd loading into the xylem and its transport to the shoot. The second one is a phloem tissue that operates in the last step of a metal transport. Another promising and currently underexplored avenue is to understand the role of non-selective cation channels in Cd uptake and reveal mechanisms of their regulation.
镉（Cd）存在于许多土壤中，一旦进入食物链，就会对人类健康构成重大威胁。由于大多数已知的镉转运蛋白也参与锌、铁、锰或铜等必需营养元素的运输，因此减少植物中镉的积累变得很复杂。这项工作总结了目前关于植物中镉吸收、径向运输和转运机制的知识。得出的结论是，只有当镉与上述有益微量营养元素的运输解偶联时，该领域才可能取得实质性进展，并且我们讨论了实现这一目标的可能途径。因此，我们建议该领域的主要研究重点应放在各种转运蛋白亚型的结构 - 功能关系及其组织特异性运作的功能评估上。有两个组织特别重要。第一个是植物根中的木质部薄壁细胞，它是镉装载到木质部并运输到地上部分的主要“控制者”。第二个是在金属运输最后一步起作用的韧皮部组织。另一个有前景且目前尚未充分探索的途径是了解非选择性阳离子通道在镉吸收中的作用，并揭示其调节机制。
