title: A member of the Phosphate transporter 1 (Pht1) family from the arsenic-hyperaccumulating fern Pteris vittata is a high-affinity arsenate transporter.
abstract: Pteris vittata exhibits enhanced arsenic uptake, but the corresponding mechanisms are not well known. The prevalent form of arsenic in most soils is arsenate, which is a phosphate analog and a substrate for Phosphate transporter 1 (Pht1) transporters. Herein we identify and characterize three P. vittata Pht1 transporters. Pteris vittata Pht1 cDNAs were isolated and characterized via heterologous expression in Saccharomyces cerevisiae (yeast) and Nicotiana benthamiana leaves. Expression of the PvPht1 loci in P. vittata gametophytes was also examined in response to phosphate deficiency and arsenate exposure. Expression of each of the PvPht1 cDNAs complemented the phosphate uptake defect of a yeast mutant. Compared with yeast cells expressing Arabidopsis thaliana Pht1;5, cells expressing PvPht1;3 were more sensitive to arsenate, and accumulated more arsenic. Uptake assays with yeast cells and radiolabeled (32)P revealed that PvPht1;3 and AtPht1;5 have similar affinities for phosphate, but the affinity of PvPht1;3 for arsenate is much greater. In P. vittata gametophytes, PvPht1;3 transcript levels increased in response to phosphate (Pi) deficiency and arsenate exposure. PvPht1;3 is induced by Pi deficiency and arsenate, and encodes a phosphate transporter that has a high affinity for arsenate. PvPht1;3 probably contributes to the enhanced arsenate uptake capacity and affinity exhibited by P. vittata.
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Sandra Feuer
authors.initials: SF
authors.lastname: DiTusa
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Elena B
authors.initials: EB
authors.lastname: Fontenot
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Wallace
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Molly A
authors.initials: MA
authors.lastname: Silvers
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Steele
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Alia H
authors.initials: AH
authors.lastname: Elnagar
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Kelsey M
authors.initials: KM
authors.lastname: Dearman
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Smith
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001149:Arsenates / Q000378:metabolism* / Q000493:pharmacokinetics; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D028061:Phosphate Transport Proteins / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D032495:Pteris / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D001149:Arsenates; D028061:Phosphate Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; C025657:arsenic acid
keywords: Phosphate transporter 1 (Pht1); Pteris vittata; arsenate (AsV); arsenic; phosphate (Pi); transporter