This Article Full Text Full Text (PDF) All Versions of this Article: 132/3/1344    most recent pp.103.020958v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (62) Citing Articles via Google Scholar Google Scholar Articles by Ruiz, O. N. Articles by Daniell, H. Search for Related Content PubMed PubMed Citation Articles by Ruiz, O. N. Articles by Daniell, H. Agricola Articles by Ruiz, O. N. Articles by Daniell, H.

ENVIRONMENTAL STRESS AND ADAPTATION

Phytoremediation of Organomercurial Compounds via Chloroplast Genetic Engineering¹

Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, Florida 32816–2360 (O.N.R., H.D.); and Department of Plant and Molecular Biology, University of California, Berkeley, California 94720–3102 (H.S.H., N.T.)

Mercury (Hg), especially in organic form, is a highly toxic pollutant affecting plants, animals, and man. In plants, the primary target of Hg damage is the chloroplast; Hg inhibits electron transport and photosynthesis. In the present study, chloroplast genetic engineering is used for the first time to our knowledge to enhance the capacity of plants for phytoremediation. This was achieved by integrating a native operon containing the merA and merB genes (without any codon modification), which code for mercuric ion reductase (merA) and organomercurial lyase (merB), respectively, into the chloroplast genome in a single transformation event. Stable integration of the merAB operon into the chloroplast genome resulted in high levels of tolerance to the organomercurial compound, phenylmercuric acetate (PMA) when grown in soil containing up to 400 µM PMA; plant dry weights of the chloroplast transformed lines were significantly higher than those of wild type at 100, 200, and 400 µM PMA. That the merAB operon was stably integrated into the chloroplast genome was confirmed by polymerase chain reaction and Southern-blot analyses. Northern-blot analyses revealed stable transcripts that were independent of the presence or absence of a 3'-untranslated region downstream of the coding sequence. The merAB dicistron was the more abundant transcript, but less abundant monocistrons were also observed, showing that specific processing occurs between transgenes. The use of chloroplast transformation to enhance Hg phytoremediation is particularly beneficial because it prevents the escape of transgenes via pollen to related weeds or crops and there is no need for codon optimization to improve transgene expression. Chloroplast transformation may also have application to other metals that affect chloroplast function.

¹ This work was supported in part by funding from Chlorogen Inc. (St. Louis).

^* Corresponding author; e-mail daniell{at}mail.ucf.edu; fax 407–823–0956.

Received January 24, 2003; returned for revision March 4, 2003; accepted April 1, 2003.

This article has been cited by other articles:

				F.-H. Wu, D.-P. Kan, S.-B. Lee, H. Daniell, Y.-W. Lee, C.-C. Lin, N.-S. Lin, and C.-S. Lin Complete nucleotide sequence of Dendrocalamus latiflorus and Bambusa oldhamii chloroplast genomes Tree Physiol, June 1, 2009; 29(6): 847 - 856. [Abstract] [Full Text] [PDF]

				D. Verma and H. Daniell Chloroplast Vector Systems for Biotechnology Applications Plant Physiology, December 1, 2007; 145(4): 1129 - 1143. [Full Text] [PDF]

				H. Daniell Transgene containment by maternal inheritance: Effective or elusive? PNAS, April 24, 2007; 104(17): 6879 - 6880. [Full Text] [PDF]

				V. Koya, M. Moayeri, S. H. Leppla, and H. Daniell Plant-Based Vaccine: Mice Immunized with Chloroplast-Derived Anthrax Protective Antigen Survive Anthrax Lethal Toxin Challenge Infect. Immun., December 1, 2005; 73(12): 8266 - 8274. [Abstract] [Full Text] [PDF]

				O. N. Ruiz and H. Daniell Engineering Cytoplasmic Male Sterility via the Chloroplast Genome by Expression of {beta}-Ketothiolase Plant Physiology, July 1, 2005; 138(3): 1232 - 1246. [Abstract] [Full Text] [PDF]

				T. Quesada-Vargas, O. N. Ruiz, and H. Daniell Characterization of Heterologous Multigene Operons in Transgenic Chloroplasts. Transcription, Processing, and Translation Plant Physiology, July 1, 2005; 138(3): 1746 - 1762. [Abstract] [Full Text] [PDF]

				P. V. Viitanen, A. L. Devine, M. S. Khan, D. L. Deuel, D. E. Van Dyk, and H. Daniell Metabolic Engineering of the Chloroplast Genome Using the Echerichia coli ubiC Gene Reveals That Chorismate Is a Readily Abundant Plant Precursor for p-Hydroxybenzoic Acid Biosynthesis Plant Physiology, December 1, 2004; 136(4): 4048 - 4060. [Abstract] [Full Text] [PDF]

				S. Kumar, A. Dhingra, and H. Daniell Plastid-Expressed Betaine Aldehyde Dehydrogenase Gene in Carrot Cultured Cells, Roots, and Leaves Confers Enhanced Salt Tolerance Plant Physiology, September 1, 2004; 136(1): 2843 - 2854. [Abstract] [Full Text] [PDF]

				A. Dhingra, A. R. Portis Jr., and H. Daniell Enhanced translation of a chloroplast-expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants PNAS, April 20, 2004; 101(16): 6315 - 6320. [Abstract] [Full Text] [PDF]