Metallothionein expression in chloroplasts enhances mercury accumulation and phytoremediation capability

Wiley - Tập 9 Số 5 - Trang 609-617 - 2011
Oscar N. Ruiz1, Derry Alvarez1, César I. Torres1, Laura Román1, Henry Daniell2
1Department of Natural Sciences and Mathematics, Inter American University of Puerto Rico, Bayamon, Puerto Rico
2Department of Molecular Biology and Microbiology, University of Central Florida, College of Medicine, Orlando, FL, USA

Tóm tắt

SummaryGenetic engineering to enhance mercury phytoremediation has been accomplished by expression of the merAB genes that protects the cell by converting Hg[II] into Hg[0] which volatilizes from the cell. A drawback of this approach is that toxic Hg is released back into the environment. A better phytoremediation strategy would be to accumulate mercury inside plants for subsequent retrieval. We report here the development of a transplastomic approach to express the mouse metallothionein gene (mt1) and accumulate mercury in high concentrations within plant cells. Real‐time PCR analysis showed that up to 1284 copies of the mt1 gene were found per cell when compared with 1326 copies of the 16S rrn gene, thereby attaining homoplasmy. Past studies in chloroplast transformation used qualitative Southern blots to evaluate indirectly transgene copy number, whereas we used real‐time PCR for the first time to establish homoplasmy and estimate transgene copy number and transcript levels. The mt1 transcript levels were very high with 183 000 copies per ng of RNA or 41% the abundance of the 16S rrn transcripts. The transplastomic lines were resistant up to 20 μm mercury and maintained high chlorophyll content and biomass. Although the transgenic plants accumulated high concentrations of mercury in all tissues, leaves accumulated up to 106 ng, indicating active phytoremediation and translocation of mercury. Such accumulation of mercury in plant tissues facilitates proper disposal or recycling. This study reports, for the first time, the use of metallothioniens in plants for mercury phytoremediation. Chloroplast genetic engineering approach is useful to express metal‐scavenging proteins for phytoremediation.

Từ khóa


Tài liệu tham khảo

10.1002/bies.950060608

10.1016/0014-5793(93)80612-X

10.1073/pnas.96.12.6808

10.1073/pnas.0702219104

Daniell H., 2004, Chloroplast genetic engineering to improve agronomic traits, Methods Mol. Biol., 286, 111

10.1038/83559

10.1073/pnas.0400981101

Environmental Protection Agency. (1992)EPA Method 3010A: Acid digestion of aqueous samples and extracts for total metals for analysis by FLAA or ICP spectroscopy. URLhttp://www.epa.gov/wastes/hazard/testmethods/sw846/pdfs/3010a.pdf.

10.1046/j.1467-7652.2003.00008.x

10.1007/BF00630869

10.1146/annurev.bi.55.070186.004405

10.1080/10588339891334384

10.1897/02-442

10.1007/s11270-005-7111-4

10.1016/j.jhazmat.2008.04.079

10.1021/es070908q

10.1007/BF00015975

10.1111/j.1467-7652.2005.00147.x

10.1104/pp.104.045187

10.1093/jxb/47.2.259

10.1023/A:1022100404542

Lossl A., 2003, Polyester synthesis in transplastomic tobacco (Nicotiana tabacum L.): significant contents of polyhydroxybutyrate are associated with growth reduction, Plant Cell Rep., 21, 891, 10.1007/s00299-003-0610-0

10.1111/j.1399-3054.1962.tb08052.x

10.1248/bpb.29.2350

10.1007/s00253-006-0336-3

10.1007/s00425-006-0329-6

10.1104/pp.105.063040

10.1073/pnas.93.8.3182

10.1104/pp.109.152017

10.1104/pp.104.057729

10.1016/j.copbio.2009.02.010

10.1104/pp.103.020958

10.1007/BF00282744

10.1104/pp.107.112946

10.1105/tpc.10.10.1713

10.1038/73796

10.1007/BF00015612

10.1002/etc.5620140108

10.1104/pp.107.106690

Thông tin
Thông tin xuất bản

Wiley

Tập 9 Số 5

609-617

Thông tin tác giả