Other Investigations into Potential Transgenic Plants in Phytoremediation


There are numerous examples that demonstrate the potential of using transgenic plants for phytoremediation.

 
 
Pb and Ni

Zn
 
 

Al
 
 

Se

Au
As

 Arazi et. al. has described a tobacco plasma membrane calmodulin-binding transporter that confers Ni2+ tolerance and Pb2+ hypersensitivity.
Van der Zaal et. al. isolated an Arabidopsis gene, ZAT, related to putative Zinc-transporter genes from animals.  To investigate the in vivo role of this gene, transgenic plants with the ZAT coding sequence exhibited increased Zn resistance and accumulation in the roots at high Zn concentrations.
Furthermore, ZIP genes that confer Zn uptake activities in yeast have also recently been described.
Moffat reported the characterization of two Arabidopsis mutants that were resistant to high levels of aluminum.  The genes have yet to be cloned but one of the mutants, on chromosome 1, secretes organic acids to bind Al in the soil before it enters the plant.  The second mutant, mapped to chromosome 4, increased the flux of hydrogen outside the root, changing the pH, which transformed the Al3+ ions into aluminum hydroxides and aluminum precipitates.  These forms are incapable of entering the plant via the roots.
Rate-limiting steps in selenium assimilation and volatilization have been deduced in Indian Mustard.  ATP sulfurylase was determined to be involved in selenate reduction and when overexpressed in Indian Mustard conferred Se accumulation, tolerance and volatilization
The Arabidopsis transgenic plants with mer operon (see Hg remediation this site) have conferred tolerance to gold.
Schmoger et. al. demonstrated that phytochelatins can be coupled to arsenic.  This has important implications for the glutathione, phytochelatin synthetase pathway transgenics.

*This list is not intended to be exhaustive.  Currently, there is investigation into many genes involved in various heavy metal transportation in plants that may confer tolerance plants.


 
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