In order to survive, plants should take up neither too many nor too few minerals from the soil. New insights into how they operate this critical balance have now been published by biologists at the Ruhr-Universitt in a series of three papers in the journal The Plant Cell. The researchers discovered novel functions of the metal-binding molecule nicotianamine. "The results are important for sustainable agriculture and also for people to prevent health problems caused by deficiencies of vital nutrients in our diet" says Prof. Dr. Ute Krmer of the RUB Department of Plant Physiology.
Plants: at the start of the food chain
All organisms need iron, zinc, and copper as nutrients. They contribute to the essential catalytic functions within the cell. Because plants are at the beginning of the food chain, sufficient content of these minerals in them is essential for the human diet. These metals are chemically very similar, making it difficult for organisms to distinguish between them.
How the cell tells the competitors zinc and iron apart
The metal-binding molecule nicotianamine is important for iron transport in plants. In her time at the universities of Heidelberg and Bochum, Krmer has demonstrated that it also makes a major contribution to the zinc balance. "Too much zinc can poison iron-dependent processes and vice versa" the biologist explains. How much zinc is available in the cytosol depends on where the nicotianamine is stored in the cell. The membrane transport protein Zinc-Induced Facilitator1 (ZIF1) can move the metal-binding molecule from the cytosol to the vacuole a separate area of the cell which stores substances, among other roles. Given high zinc concentrations in the cytosol, ZIF1 transports nicotianamine into the vacuole. As a consequence, zinc ions are also transported into the vacuole and thus removed from the cytosol and the internal transport routes of the plant. The zinc is now less competi
|Contact: Prof. Dr. Ute Krmer|