title: AtPDR12 contributes to lead resistance in Arabidopsis.
abstract: 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.
authors.affiliation: National Research Laboratory of Phytoremediation, Division of Molecular Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Miyoung
authors.initials: M
authors.lastname: Lee
authors.forename: Kiyoul
authors.initials: K
authors.lastname: Lee
authors.forename: Joohyun
authors.initials: J
authors.lastname: Lee
authors.forename: Eun Woon
authors.initials: EW
authors.lastname: Noh
authors.forename: Youngsook
authors.initials: Y
authors.lastname: Lee
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001693:Biological Transport, Active; D004351:Drug Resistance / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D007854:Lead / Q000378:metabolism* / Q000633:toxicity; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype
chemical_list: D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; C482841:PDR12 protein, Arabidopsis; D007854:Lead