Seregin I V, Kozhevnikova A D
K.A. Timiryazev Institute of Plant Physiology RAS, IPPRAS, Botanicheskaya st., 35, Moscow, Russian Federation, 127276.
Photosynth Res. 2021 Dec;150(1-3):51-96. doi: 10.1007/s11120-020-00768-1. Epub 2020 Jul 11.
Mineral nutrition is one of the key factors determining plant productivity. In plants, metal homeostasis is achieved through the functioning of a complex system governing metal uptake, translocation, distribution, and sequestration, leading to the maintenance of a regulated delivery of micronutrients to metal-requiring processes as well as detoxification of excess or non-essential metals. Low-molecular-weight ligands, such as nicotianamine, histidine, phytochelatins, phytosiderophores, and organic acids, play an important role in metal transport and detoxification in plants. Nicotianamine and histidine are also involved in metal hyperaccumulation, which determines the ability of some plant species to accumulate a large amount of metals in their shoots. In this review we extensively summarize and discuss the current knowledge of the main pathways for the biosynthesis of these ligands, their involvement in metal uptake, radial and long-distance transport, as well as metal influx, isolation and sequestration in plant tissues and cell compartments. It is analyzed how diverse endogenous ligand levels in plants can determine their different tolerance to metal toxic effects. This review focuses on recent advances in understanding the physiological role of these compounds in metal homeostasis, which is an essential task of modern ionomics and plant physiology. It is of key importance in studying the influence of metal deficiency or excess on various physiological processes, which is a prerequisite to the improvement of micronutrient uptake efficiency and crop productivity and to the development of a variety of applications in phytoremediation, phytomining, biofortification, and nutritional crop safety.
矿物质营养是决定植物生产力的关键因素之一。在植物中，金属稳态是通过一个复杂系统的功能来实现的，该系统控制着金属的吸收、转运、分配和螯合，从而维持向需要金属的过程有规律地输送微量营养素，并对过量或非必需金属进行解毒。低分子量配体，如烟酰胺、组氨酸、植物螯合肽、植物铁载体和有机酸，在植物的金属运输和解毒中发挥着重要作用。烟酰胺和组氨酸也参与金属超积累，这决定了一些植物物种在其地上部分积累大量金属的能力。在这篇综述中，我们广泛总结并讨论了这些配体生物合成的主要途径、它们在金属吸收、径向和长距离运输以及植物组织和细胞区室中的金属流入、隔离和螯合方面的现有知识。分析了植物中不同的内源性配体水平如何决定它们对金属毒性作用的不同耐受性。这篇综述重点关注了在理解这些化合物在金属稳态中的生理作用方面的最新进展，这是现代离子组学和植物生理学的一项重要任务。研究金属缺乏或过量对各种生理过程的影响至关重要，这是提高微量营养素吸收效率和作物生产力以及开发植物修复、植物采矿、生物强化和营养作物安全等多种应用的前提条件。
