Phytochelatin-based heavy metal detoxification in phytoremediation and agricultural applications

AtPCS gene encoding multispecific heavy metal resistance factor from plants

Problem:

Environmental contamination with heavy metals such as arsenic, cadmium, lead and/or mercury is implicated in human disease and agricultural losses. Industrial and mining activities, as well as natural mineral outcrops, have resulted in the contamination of soils and groundwater with heavy metals that are taken up by crops to decrease agricultural productivity and enter the human food chain. There is an urgent need for environmental cleanup to improve crop yield and decrease the heavy metal content of harvestable crops.

The use of plants to extract heavy metals from the environment, in a process termed phytoremediation, is particularly appealing due to its low cost and the ease with which plants can be harvested, in contrast with conventional physical and chemical methods for environmental cleanup, which carry a price tag upward of $200 billion in the US alone.

Solution:

Professor Rea and colleagues have identified genes encoding multispecific heavy metal resistance factors from plants. These factors are involved in the synthesis of a class of peptides that play an important role in heavy metal tolerance by binding to heavy metals and decreasing their free concentrations. Transgenic plants expressing these genes can be used to remove heavy metals from the soil. In addition or alternatively, expression of these genes in a non-harvestable part of a plant can decrease the level of heavy metals in the harvestable parts. This discovery has significant market potential in agriculture and environmental safety applications.

General structure of a representative phytochelatin (PC) synthesized by the AtPCS1 gene product phytochelatin synthase. The example shown is PC2, which contains two γ-glutamylcysteine repeats. PC synthase, which localizes to the cytoplasm, catalyzes the heavy metal-activated synthesis of PCs to yield heavy metal-PC complexes that are transported into the vacuole.

Advantages:

More efficient, less expensive method to remove heavy metals from contaminated soils and groundwater
Potential for remediation of a broad range of heavy metals
Broaden and enhance the range of tools available for environmental remediation

Applications:

Transgenic plants for phytoremediation
Transgenic arable crops with diminished heavy metal levels in their harvestable parts
New strategies for directed metabolic pathway engineering

Stage of Development:

Proof-of-concept

Intellectual Property: