An interesting recent video on plants for metals hyperaccumulation can be found here:
https://www.youtube.com/watch?v=yqXyq64VdVY&feature=youtu.be&t=0s
and an article on the same subject:
http://www.fastcoexist.com/3033295/cleaning-up-polluting-mines-with-plants-plants-that-then-turn-into-precious-metals
Just remember, these plants may not be practical for phytomining at this point For example, as one of my colleagues Dr. Rufus Chaney, pointed out in a recent email to me:
Streptanthus (featured in this video and article) is unlikely to become a significant phytomining species because of its growth habit. It forms a very low to the ground rosette, and then after vernalization, send up flowering stems with small leaves and then flowers and seeds. This was reported earlier by the USGS Bureau of Mines test of Streptanthus in CA. It is not practicable to harvest the rosette where most of the plant Ni exists.
It is always hoped that with the full genome data and genetic engineering, one might either obtain and transfer these genes to a high yielding, harvestable, plant species, or transfer in genes which will change the growth habit of Streptanthus to give higher harvestable biomass. But these remain hopes for the future. When we ask our crop colleagues, no one agrees that it would be reasonable to transfer hyperaccumulator genes to a crop plant that does sexual reproduction. (KK: We don’t want plants to spread and invade!)
So it is good PR, but still just a dream.
Thank you to Dr. Chaney for his very important insight!