Research

Metal Homeostasis and Stress Responses in Plants

Associate Professor Chris Cobbett

Some heavy metals, such as zinc and copper, are essential for life. In plants there are mechanisms for the uptake of these metals from soil, their translocation from root to shoot and their distribution to tissues and cells. In addition, there are mechanisms to deal with toxic excess of both essential and non-essential heavy metals.

Zinc-deficient soils – particularly in Australia – have severe effects on crop production and crop grains are an important source of dietary zinc for humans and animals. Long-term benefits of this research may be a greater understanding of the mechanisms of zinc uptake and distribution from the soil, particularly the delivery of zinc to developing grain. In addition, plants must respond to toxic metals from the soil and to the oxidative stress such metals cause. Understanding mechanisms of metal detoxification may assist in the development of plants for the bioremediation (phytoremediation) of contaminated soils.

Plants have evolved multiple mechanisms for metal homeostasis and metal detoxification.

These mechanisms include:

• metal binding compounds – (organic acids, amino acids, peptides and proteins)
• metal transport proteins 
• antioxidant compounds – (glutathione and ascorbic acid)

The main aims of our research are to identify:

• important processes in heavy metal (especially zinc) homeostasis
• important processes in excess heavy metal (especially cadmium) detoxification
• roles of antioxidant compounds (especially glutathione)

We are using the model organism Arabidopsis with genetic, physiological, biochemical and molecular approaches to understanding these problems.

Arabidopsis Links:

http://www.nsf.gov/pubs/2002/bio0202/start.htm

http://www.arabidopsis.org/

Recent Publications

Current topics of research are as follows:

Topic 1: Heavy Metal Transporting P-type ATPases are essential for zinc homeostasis

Topic 2: Major Facilitator Superfamily transporters have an unexpected role in zinc homeostasis

Topic 3: Glutathione is essential for growth and development and plays an important role in responses to heavy metal stress

Cobbett Lab Personnel