Molecular Mechanism of Nickel Hyperaccumulation in Thlaspi goesingense

Northern Arizona University, Flagstaff AZ

Investigators

Abstract

Intensive industrial and agricultural activity over the last 150 years has imposed a large burden of heavy metals on the environment. Phytoextraction, the use of plants for environmental cleanup of pollutants, including toxic metals, from soils, holds the potential to allow the economic restoration of these contaminated sites. For phytoextraction to be a viable alternative to existing soil remediation strategies it will require the existence of high biomass, rapidly growing metal-accumulating plants. Unfortunately, plants do not exist at present that have all these desirable characteristics. There are, however, a limited numbers of plants, collectively termed hyperaccumulators, that grow on soils naturally enriched in various metals including Zn, Ni and Se. These plants have the ability to naturally accumulate these metals to between 0.1 and 3% of their shoot dry weight; this is at least 1000-fold higher than most other plants. This unique ability makes these plants an ideal starting point for the development of phytoextraction crops. One way to develop such crops is to identify the genes responsible for metal accumulation in these hyperaccumulator plants. Once identified and fully characterized these genes could be transferred into high biomass, rapidly-growing plants to generate crops ideally suited for phytoremediation. This grant will fund the identification of such "metal hyperaccumulation" genes from the nickel hyperaccumulator Thlaspi goesingense. Once identified, the usefulness of these genes for phytoremediation will be rapidly assessed by their transfer to Arabidopsis thaliana, a convenient model plant. Genes identified for enhanced metal tolerance and accumulation in this model plant will then be selected for transfer to plants more suited to phytoremediation applications.