Molecular mechanisms of metal hyperaccumulation in plants

Summary Metal hyperaccumulator plants accumulate and detoxify extraordinarily high concentrations of metal ions in their shoots. Metal hyperaccumulation is a fascinating phenomenon, which has interested scientists for over a century. Hyperaccumulators constitute an exceptional biological material for understanding mechanisms regulating plant metal homeostasis as well as plant adaptation to extreme metallic environments. Our understanding of metal hyperaccumulation physiology has recently increased as a result of the development of molecular tools. This review presents key aspects of our current understanding of plant metal – in particular cadmium (Cd), nickel (Ni) and zinc (Zn) – hyperaccumulation. Contents Summary 759 I. Hyperaccumulation: the phenomenon 759 II. Macroevolution of hyperaccumulation 760 III. Microevolution of hyperaccumulation: variation within hyperaccumulator species 760 IV. Genetic analysis of trace metal accumulation and tolerance 761 V. Mechanisms of trace metal accumulation 762 VI. General discussion and research perspectives 769 Acknowledgements 772 References 772