Harnessing hyperaccumulator plants to recover technology-critical metals: where are we at?

Abstract

Since its inception over three decades ago, phytomining has finally reached the stage of commercial-scale implementation, at least for nickel. Much potential remains to be realised for other elements, notably cobalt, selenium, and thallium, but this requires scientific impetus leveraging recent advances in insights garnered from molecular mechanisms of hyperaccumulation, domestication and agronomic development. These advances will also enable us to (genetically) improve hyperaccumulators for use in phytomining by targeted breeding, as well as synthetic biology approaches.

Keywords: biomass; hyperaccumulator; metals; phytomining; phytoremediation; transporters.

Fig. 1

Emergence of phytomining and current market value of potential phytomining target elements. (a) Number of publications in National Center for Biotechnology Information search (http://dan.carlan.net/medline‐trend.html) for listed terms. Note that additional publications can be found in other online databases, and when using alternative term suffixes. (b) Market values for elements plotted against minimum defined threshold definition levels of hyperaccumulator species. Note that only exemplar rare earth elements (REEs) are shown and that both the individual or the sum of REEs make up the threshold value, see Supporting Information Table S1 for sources and further information.

Fig. 2

Schematic showing route of, and target points for engineering, metal (M) uptake, and storage in plants.