Open AccessExpression of mercuric ion reductase in Eastern cottonwood ( Populus deltoides ) confers mercuric ion reduction and resistance
Author(s) -
Che Dongsheng,
Meagher Richard B.,
Heaton Andrew C. P.,
Lima Amparo,
Rugh Clayton L.,
Merkle Scott A.
Publication year - 2003
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1046/j.1467-7652.2003.00031.x
Subject(s) - shoot , phytoremediation , mercury (programming language) , biology , botany , environmental remediation , genetically modified crops , salicaceae , transgene , genetically modified rice , horticulture , environmental chemistry , soil water , woody plant , contamination , chemistry , gene , ecology , biochemistry , computer science , programming language
Summary Mercury is one of the most hazardous heavy metals and is a particular problem in aquatic ecosystems, where organic mercury is biomagnified in the food chain. Previous studies demonstrated that transgenic model plants expressing a modified mercuric ion reductase gene from bacteria could detoxify mercury by converting the more toxic and reductive ionic form [Hg( ii )] to less toxic elemental mercury [Hg(0)]. To further investigate if a genetic engineering approach for mercury phytoremediation can be effective in trees with a greater potential in riparian ecosystems, we generated transgenic Eastern cottonwood ( Populus deltoides ) trees expressing modified merA9 and merA18 genes. Leaf sections from transgenic plantlets produced adventitious shoots in the presence of 50 µ m Hg( ii ) supplied as HgCl 2 , which inhibited shoot induction from leaf explants of wild‐type plantlets. Transgenic shoots cultured in a medium containing 25 µ m Hg( ii ) showed normal growth and rooted, while wild‐type shoots were killed. When the transgenic cottonwood plantlets were exposed to Hg( ii ), they evolved 2–4‐fold the amount of Hg(0) relative to wild‐type plantlets. Transgenic merA9 and merA18 plants accumulated significantly higher biomass than control plants on a Georgia Piedmont soil contaminated with 40 p.p.m. Hg( ii ). Our results indicate that Eastern cottonwood plants expressing the bacterial mercuric ion reductase gene have potential as candidates for in situ remediation of mercury‐contaminated soils or wastewater.