title: Characterization of the high affinity Zn transporter from Noccaea caerulescens, NcZNT1, and dissection of its promoter for its role in Zn uptake and hyperaccumulation.
abstract: • In this paper, we conducted a detailed analysis of the ZIP family transporter, NcZNT1, in the zinc (Zn)/cadmium (Cd) hyperaccumulating plant species, Noccaea caerulescens, formerly known as Thlaspi caerulescens. NcZNT1 was previously suggested to be the primary root Zn/Cd uptake transporter. Both a characterization of NcZNT1 transport function in planta and in heterologous systems, and an analysis of NcZNT1 gene expression and NcZNT1 protein localization were carried out. • We show that NcZNT1 is not only expressed in the root epidermis, but also is highly expressed in the root and shoot vasculature, suggesting a role in long-distance metal transport. Also, NcZNT1 was found to be a plasma membrane transporter that mediates Zn but not Cd, iron (Fe), manganese (Mn) or copper (Cu) uptake into plant cells. • Two novel regions of the NcZNT1 promoter were identified which may be involved in both the hyperexpression of NcZNT1 and its ability to be regulated by plant Zn status. • In conclusion, we demonstrate here that NcZNT1 plays a role in Zn and not Cd uptake from the soil, and based on its strong expression in the root and shoot vasculature, could be involved in long-distance transport of Zn from the root to the shoot via the xylem.
authors.affiliation: Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Milner
authors.forename: Eric
authors.initials: E
authors.lastname: Craft
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamaji
authors.forename: Emi
authors.initials: E
authors.lastname: Koyama
authors.forename: Jian Feng
authors.initials: JF
authors.lastname: Ma
authors.forename: Leon V
authors.initials: LV
authors.lastname: Kochian
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D019607:Brassicaceae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism / Q000493:pharmacokinetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D003300:Copper / Q000378:metabolism / Q000493:pharmacokinetics; D018506:Gene Expression Regulation, Plant; D008345:Manganese / Q000378:metabolism / Q000493:pharmacokinetics; D059828:Plant Cells; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D015032:Zinc / Q000378:metabolism* / Q000493:pharmacokinetics
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D010940:Plant Proteins; C017800:zinc-binding protein; D002104:Cadmium; D008345:Manganese; D003300:Copper; D015032:Zinc