Assessing Cadmium Partitioning in Transgenic Plants

Several research groups have undertaken gene transfer studies to test the feasibility of using animal metallothionein (MT; a Cd, Zn, Cu, Au, Ag, etc. binding peptide) to partition and sequester pollutant metals in plant tissues. To date, several mammalian MT genes have been expressed constitutively in Nicotiana and Brassica species and the effects of their presence on Cd accumulation and Cd tolerance have been assessed. General objectives of these studies have been:

1.	To sequester metal in unconsumed tissues of food crops in order to reduce the transfer of undesirable metals from crops to humans, and
2.	To make plants more tolerant to the presence of accumulated metal so as to develop super-accumulators that might be useful for bioremediation of contaminated environments or for biomining of valuable metals.