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Phytate and Arsenic Enhance Each Other's Uptake in As-hyperaccumulator Pteris vittata : Root Exudation of Phytate and Phytase, and Plant Uptake of Phytate-P.

Ran HanJia-Yi ChenSi-Xue HeChen-Jing LiuZhi-Hua DaiXue LiuYue CaoLena Q Ma
Published in: Environmental science & technology (2022)
Phytate as a root exudate is rare in plants as it mainly serves as a P storage in the seeds; however, As-hyperaccumulator Pteris vittata effectively secretes phytate and utilizes phytate-P, especially under As exposure. This study investigated the effects of As on its phytate and phytase exudation and the impacts of As and/or phytate on each other's uptake in P. vittata through two hydroponic experiments. Under 10-100 μM arsenate (AsV), the exudation of phytate and phytase by P. vittata was increased by 50-72% to 20.4-23.4 μmol h -1 g -1 and by 28-104% to 18.6-29.5 nmol h -1 plant -1 , but they were undetected in non-hyperaccumulator Pteris ensiformis at 10 μM AsV. Furthermore, compared to 500 μM phytate, the phytate concentration in the growth media was reduced by 69% to 155 μM, whereas the P and As contents in P. vittata fronds and roots were enhanced by 68-134% and 44-81% to 2423-2954 and 82-407 mg kg -1 under 500 μM phytate plus 50 μM AsV. The increased P/As uptake in P. vittata was probably attributed to 3.0-4.5-fold increase in expressions of P transporters PvPht1;3-1;4 . Besides, under As exposure, plant P may be converted to phytate in P. vittata roots, thereby increasing phytate's contents by 84% to 840 mg kg -1 . Overall, our results suggest that As-induced phytate/phytase exudation and phytate-P uptake stimulate its growth and As hyperaccumulation by P. vittata .
Keyphrases
  • mass spectrometry
  • drinking water
  • high speed
  • cell wall