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First published online May 27, 2005; 10.1104/pp.104.058107 Plant Physiology 138:827-836 (2005) © 2005 American Society of Plant Biologists AtPDR12 Contributes to Lead Resistance in Arabidopsis1National Research Laboratory of Phytoremediation, Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang, 790784, Korea (M.L., K.L., J.L., Y.L.); and Korea Forest Research Institute, Suwon, 441350, Korea (E.W.N., Y.L.)
Arabidopsis (Arabidopsis thaliana) contains about 130 ATP-binding cassette (ABC) proteins, which are likely to contribute to the transport of diverse materials, including toxic substances. However, the substrates of ABC transporters remain unknown in most cases. We tested which ABC transporter is involved in detoxification of lead [Pb(II)]. Among the many tested, we found that the message level of only AtPDR12 increased in both shoots and roots of Pb(II)-treated Arabidopsis, suggesting that it may be involved in the detoxification of Pb(II). AtPDR12-knockout plants (atpdr12) were used to further test this possibility. In Pb(II)-containing medium, atpdr12 plants grew less well and had higher Pb contents than those of wild-type plants. In contrast, AtPDR12-overexpressing Arabidopsis plants were more resistant to Pb(II) and had lower Pb contents than wild-type plants. The mutant phenotypes and their Pb contents, as well as the localization of the GFP:AtPDR12 fusion protein at the plasma membrane, suggest that AtPDR12 functions as a pump to exclude Pb(II) and/or Pb(II)-containing toxic compounds from the cytoplasm. Inhibition of glutathione synthesis by addition of buthionine sulfoximine to the growth medium exacerbated the Pb(II)-sensitive phenotype of atpdr12 plants, consistent with a glutathione-dependent detoxification mechanism operating in parallel with an AtPDR12-dependent mechanism. Thus, we propose that AtPDR12 is an ABC transporter that contributes to Pb(II) resistance in Arabidopsis.
1 This work was supported by Pohang Steel Company (grants to Y.L.) and by the National Research Laboratory program of the Ministry of Science and Technology of Korea. 2 Present address: Dartmouth College, Biological Science Department, 6044 Gilman, Hanover, NH, 03755. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.058107. * Corresponding author; e-mail ylee{at}postech.ac.kr; fax 82542792199. Received December 13, 2004; returned for revision January 25, 2005; accepted February 2, 2005. This article has been cited by other articles:
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