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First published online December 11, 2003; 10.1104/pp.103.026989 Plant Physiology 135:377-383 (2004) © 2004 American Society of Plant Biologists Overexpression of Selenocysteine Methyltransferase in Arabidopsis and Indian Mustard Increases Selenium Tolerance and Accumulation1Department of Plant and Microbial Biology, University of California, Berkeley, California 94720 (D.L.L., A.S.T., M.F.M., C.P.W., M.A., C.-Y.C., A.T., M.D., N.T.); Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221 (M.M.-B., J.M., J.C.); and Microbiology, Department of Biology I, University of Munich, D80638 Munich, Germany (B.N., A.B.)
A major goal of phytoremediation is to transform fast-growing plants with genes from plant species that hyperaccumulate toxic trace elements. We overexpressed the gene encoding selenocysteine methyltransferase (SMT) from the selenium (Se) hyperaccumulator Astragalus bisulcatus in Arabidopsis and Indian mustard (Brassica juncea). SMT detoxifies selenocysteine by methylating it to methylselenocysteine, a nonprotein amino acid, thereby diminishing the toxic misincorporation of Se into protein. Our Indian mustard transgenic plants accumulated more Se in the form of methylselenocysteine than the wild type. SMT transgenic seedlings tolerated Se, particularly selenite, significantly better than the wild type, producing 3- to 7-fold greater biomass and 3-fold longer root lengths. Moreover, SMT plants had significantly increased Se accumulation and volatilization. This is the first study, to our knowledge, in which a fast-growing plant was genetically engineered to overexpress a gene from a hyperaccumulator in order to increase phytoremediation potential.
1 This work was supported by the National Science Foundation SGER (grant no. 9900054), NSF Metabolic Biochemistry (grant no. 9904643), and the Novartis-Syngenta Research Foundation (grant to N.T.). 2 These authors contributed equally to the paper. 3 Present address: University of California, San Francisco, and University of California, Berkeley, Richmond Field Station, Richmond, CA 94804. 4 Present address: University of Oviedo, Oviedo, Asturias, Spain. 5 Present address: Bio-Rad Laboratories, Hercules, CA 94547. 6 Present address: Institute of Molecular Biology, Academica Sinica, Nankang, Taipei 115, Taiwan R.O.C. 7 Present address: Salk Institute, La Jolla, CA 92037. 8 Present address: Dyax, Cambridge, MA 02139. 9 Present address: GSF-Research Center for Environment and Health, Marchionistr. 25, D81377 Munich, Germany. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.103.026989. * Corresponding author; e-mail nterry{at}nature.berkeley.edu; fax 5106423510. Received May 19, 2003; returned for revision June 30, 2003; accepted September 17, 2003. This article has been cited by other articles:
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