Transgenic Indian mustard (Brassica juncea) plants expressing an Arabidopsis phytochelatin synthase (AtPCS1) exhibit enhanced As and Cd tolerance
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Phytochelatins (PCs) are post-translationally synthesized thiol reactive peptides that play important roles in detoxification of heavy metal and metalloids in plants and other living organisms. The overall goal of this study is to develop transgenic plants with increased tolerance for and accumulation of heavy metals and metalloids from soil by expressing an Arabidopsis thaliana AtPCS1 gene, encoding phytochelatin synthase (PCS), in Indian mustard (Brassica juncea L.). A FLAG-tagged AtPCS1 gDNA, under its native promoter, is expressed in Indian mustard, and transgenic pcs lines have been compared with wild-type plants for tolerance to and accumulation of cadmium (Cd) and arsenic (As). Compared to wild type plants, transgenic plants exhibit significantly higher tolerance to Cd and As. Shoots of Cd-treated pcs plants have significantly higher concentrations of PCs and thiols than those of wild-type plants. Shoots of wild-type plants accumulated significantly more Cd than those of transgenic plants, while accumulation of As in transgenic plants was similar to that in wild type plants. Although phytochelatin synthase improves the ability of Indian mustard to tolerate higher levels of the heavy metal Cd and the metalloid As, it does not increase the accumulation potential of these metals in the above ground tissues of Indian mustard plants.
KeywordsArsenic Brassica juncea L. Cadmium Heavy metal accumulation Phytochelatin synthase Phytoremediation
Arabidopsis phytochelatin synthase
γ- glutamylcysteine synthetase
We would like to thank Dr. Norman Terry for supplying us with Indian mustard seed, including transgenic line GS7, and Dr. Peter Goldsbrough for helping us with PCs analyses. This material is based upon work supported by the Illinois Department of Natural Resources.
- Bennett LE, Burkhead JL, Hale KL, Terry N, Pilon M, Pilon-Smits EA (2003) Analysis of transgenic Indian mustard plants for phytoremediation of metal-contaminated mine tailings. J Environ Qual 31:431–440Google Scholar
- Creissen G, Firmin J, Fryer M, Kular B, Leyland N, Reynolds H, Pastori G, Wellburn F, Baker N, Wellburn A, Mullineaux P (1999) Elevated gluthatione biosynthetic capacity in the chloroplasts of the tobacco plants paradoxically causes increased oxidative stress. Plant Cell 11:1277–1291PubMedCrossRefGoogle Scholar
- Gasic K, Korban SS (2005) Nonspecific binding of monoclonal anti-flag M2 antibody in Indian mustard (Brassica juncea). Plant Mol Biol Rep 23:9–16Google Scholar
- Roche Diagnostics (2000) DIG Application manual for filter hybridization. In: Eisel D et al. (ed). Roche Diagnostics GmbH, Mannheim, GermanysGoogle Scholar