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Evaluation of Transgenic Poplars Over‐Expressing Enzymes of Glutathione Synthesis for Phytoremediation of Cadmium
Author(s) -
Koprivova A.,
Kopriva S.,
Jäger D.,
Will B.,
Jouanin L.,
Rennenberg H.
Publication year - 2002
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1055/s-2002-37399
Subject(s) - phytoremediation , glutathione , hydroponics , cadmium , biology , transgene , botany , glutathione reductase , genetically modified crops , enzyme , soil water , biochemistry , gene , chemistry , ecology , glutathione peroxidase , organic chemistry
Recently, phytoremediation of soils polluted with heavy metals has received a lot of attention. Since glutathione (GSH) and its derivatives (e.g., phytochelatins) play a major role in plant defence against environmental pollutants, we tested the effects of over‐expression of bacterial genes for GSH synthesis in poplar on cadmium accumulation. A pilot experiment with CdCl 2 in hydroponics revealed that poplars over‐expressing γ‐glutamylcysteine synthetase (γ‐ECS) accumulated significantly more Cd in root tissue than wild type or glutathione synthetase over‐expressing poplars. To test the partitioning of Cd in different organs, poplar lines over‐expressing γ‐ECS in the cytosol and in chloroplasts were treated with 0.2 mM CdCl 2 in hydroponics. Significant amounts of Cd were translocated to leaves, but significant differences in Cd accumulation were not observed between transgenic and wild type plants. To evaluate these lines for large‐scale phytoremediation of cadmium, plants were treated with 2 mM Cd in soil. Over a four‐week period, the poplar plants were able to accumulate up to 5.3 mg Cd. Most remarkably, in young leaves of both transgenic lines, Cd was accumulated to concentrations 2.5 ‐ 3 times higher than in the wild type. The increased allocation of cadmium to the young leaves represents a potentional advantage for the phytoremediation process using the same plants over several vegetation periods. The use of transgenic poplar lines with enhanced glutathione production capacity seems to be of particular advantage in highly polluted soils.