A member of the Phosphate transporter 1 (Pht1) family from the arsenic‐hyperaccumulating fern Pteris vittata is a high‐affinity arsenate transporter

Abstract

Summary 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 32P 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.

Interaction of As and Sb in the hyperaccumulator Pteris vittata L.: changes in As and Sb speciation by XANES

“…The possible transporters for AsIII and AsV in P. vittata were recently disclosed. A member of phosphate transporter family PvPht1;3 was identified as an AsV transporter (DiTusa et al 2016). An aquaporin PvTIP4;1 was suggested to be involved in AsIII uptake (He et al 2016).…”

Phytate induced arsenic uptake and plant growth in arsenic-hyperaccumulator Pteris vittata

“…During plant uptake, AsV and P compete for root P transporters (de Oliveira et al, 2015;Ditusa et al, 2016). For instance, As accumulation in duckweed (Spirodela polyrhiza) is negatively correlated with P uptake when they co-exist (Rahman et al, 2007).…”

Physiological and molecular mechanisms of heavy metal accumulation in nonmycorrhizal versus mycorrhizal plants

“…In addition to essential HMs, plants can also absorb nonessential and toxic HMs from the soil solution through their uptake system because some transporters can take up several similar HM ions. For instance, root transporters for Zn 2+ and Ca 2+ can also take up Cd 2+ (Rogers, Eide, & Guerinot, ; Williams, ), and the transporters for phosphate can also absorb arsenate (AsO 3 − ; Ditusa et al, ). As a result, these nonessential and toxic HMs can be absorbed by plants including crops, eventually entering the food chain.…”