Agromining of Nickel: Finally Becoming a Reality at Commercial Scale

Initially proposed over 40 years ago, the biotechnology of agromining has had a long and tortuous gestational process on the way to becoming a proven commercial reality. The field has been marred by claims for unrealistic yields made by startup companies. Nevertheless, nickel agromining has become a viable business proposition for several companies now operating "metal farms" around the world. In this review, we provide a critical perspective on the current direction of the field and potential pitfalls still to overcome. Challenges and risks include the urgency for discovery of suitable metal crop species before extinction from habitat loss, the rapid domestication of wild species to be accommodated in regular cultivation systems, and the potential introduction and escape of non-native plant species. Initiatives to identify new hyperaccumulators using X-ray fluorescence scanning of herbarium collections should target the biodiversity hotspots of the world and should be coupled with <i>ex situ</i> conservation of threatened hyperaccumulator plant species in botanical gardens. With the rapid progress in the science needed to find and develop more effective hyperaccumulators, it is an exciting time for nickel agromining. The next few years are expected to be a make-or-break period in its transformation to a commercial reality.