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Yeast Metallothionein in Transgenic Tobacco Promotes Copper Uptake from Contaminated Soils
Author(s) -
Thomas John C.,
Davies Elizabeth C.,
Malick Farah K.,
Endreszl Charles,
Williams Chandra R.,
Abbas Mohammed,
Petrella Sally,
Swisher Krystal,
Perron Mike,
Edwards Ryan,
Ostenkowski Pam,
Urbanczyk Nicolas,
Wiesend Wendy N.,
Murray Kent S.
Publication year - 2003
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp025623q
Subject(s) - metallothionein , phytoremediation , copper , yeast , genetically modified crops , cadmium , transgene , kanamycin , transformation (genetics) , botany , biology , horticulture , chemistry , environmental chemistry , biochemistry , gene , heavy metals , organic chemistry
Metallothioneins (MTs) are metal‐binding proteins that confer heavy metal tolerance and accumulation in yeast. To augment higher plant metal sequestration, the yeast metallothionein (CUP 1) was introduced into tobacco plants. The CUP 1 gene expression and copper and cadmium phytoextraction were determined. To confirm transformation, selfed and kanamycin‐resistant third generation plants were subjected to DNA blot and polymerase chain reaction (PCR) analysis. A 4 mM CuSO 4 stress for 7 days resulted in a decline in CUP 1 transcripts versus nonstress conditions. Despite low mRNA levels, CUP 1 transformants accumulated up to seven times more copper in older versus younger leaves during copper stress. Pooled leaves of transgenic plants grown in soils from copper stamp‐sands contained two to three times the copper content as that of the control plants. Unlike some previous reports featuring MT overexpression in plants, CUP 1 seedlings did not significantly sequester or demonstrate tolerance to CdCl 2 . Using this transgenic approach, yeast CUP 1 expression under nonstressed conditions contributed to copper metal phytoextraction during a subsequent copper challenge. This strategy could be incorporated into plants designed for enhanced phytoremediation of metal contaminants.