Using plants to remove soil pollutants and impede desertification

press release of September 11, 2006

Enrico Martinoia, a member of the National Centre of Competence in Research (NCCR) Plant Survival and plant biology professor at the University of Zurich, is participating in a vast South Korean project to remove soil pollutants. Its aim? To improve certain plants' capacities to survive in polluted soils and to store the pollutants found in contaminated soils by identifying the genes responsible for these properties.

Pretty much everywhere on the planet, pollutants of diverse origins (industrial wastes, fertilisers, pesticides) contaminate the soils. The category of heavy metals (lead, cadmium, arsenic) is a particular concern for agriculture because these toxic products could end up in the harvested crops. The idea of using specially selected plants to accumulate heavy metals - a phenomenon called phytoremediation - goes back fifteen years.

This method has the advantage of being inexpensive and environmentally friendly. However, the complexity of the genetic processes that control the plant's capacity to accumulate heavy metals pose a challenge. Therefore, even creating plants that are simply resistant to heavy metals would already be a victory for the researchers. These plants could be used to stop the advancement of deserts into highly polluted soils, such as in China.

Enrico Martinoia has been working on this subject for several years with Youngsook Lee, professor at the Pohang University of Science and Technology (POSTECH) in South Korea, which explains why he enthusiastically welcomed the new offer by the Korean researcher for a collaboration. Together, they have recently received financing from the Seoul government for a project that should last 9 years. Part of the Swiss researcher's contribution comes from results obtained by his group during the first phase of the NCCR Plant Survival (between 2001 and 2005). 

Enrico Martinoia's group has specialised in the study of toxic waste transport at the plant cellular level, as well as the tolerance of plants to heavy metals and drought. Within the framework of the NCCR Plant Survival, he has acquired considerable knowledge on a family of proteins - the ABC transporters - that act as dump trucks in the cells. The main goal of the project is to highlight the genes responsible for the transport of specific heavy metals within the plant.

At first, the researchers will be using the model plant Arabidopsis thaliana for this project. Its completely deciphered genome makes it possible to better target the desired characteristics. The idea is to develop transgenic plants that can transfer heavy metals from their roots to their stems and leaves where toxic substances are stored. The scientists will use the same genetic methods to test plants that are tolerant to drought and salt in the soil: planted in the semi-desert areas of China and Mongolia, these plants would help to improve the air quality in Korea, which is subject to dust winds during the spring.       

Once the genes have been clearly identified in Arabidopsis, parts of the DNA will be integrated into the poplar's genome using genetic engineering, a task confided to Dr. Eun Woon Noh of the Korea Forest Research Institute. The reasons for using this particular tree are because of its high biomass and its rapid growth, two essential factors for an efficient phytoremediation.  

The use of transgenic plants is no cause for alarm since the plants are not destined for human or animal consumption. There is also no need to worry from an environmental point of view: the researchers will be using lines of poplar that do not flower, removing the danger of its pollen contaminating neighbouring species. The propagation of the transgenic trees will be from cuttings. This work, when successfully carried out, will provide a model for a way to clean the polluted environment with a nature-friendly technology which does not impair the landscape.


Prof. Enrico Martina
Universität Zürich
Institut für Pflanzenbiologie
tel +41 1 634 8222
Prof. Youngsook Lee
POSTECH-UZH cooperative laboratory,
University of Science and Technology, Pohang,
790-784, Korea
tel +82 54 279 2296