Identification of plant vacuolar transporters mediating phosphate storage

Nat Commun. 2016 Mar 31;7:11095. doi: 10.1038/ncomms11095.

Abstract

Plant vacuoles serve as the primary intracellular compartments for inorganic phosphate (Pi) storage. Passage of Pi across vacuolar membranes plays a critical role in buffering the cytoplasmic Pi level against fluctuations of external Pi and metabolic activities. Here we demonstrate that the SPX-MFS proteins, designated as PHOSPHATE TRANSPORTER 5 family (PHT5), also named Vacuolar Phosphate Transporter (VPT), function as vacuolar Pi transporters. Based on (31)P-magnetic resonance spectroscopy analysis, Arabidopsis pht5;1 loss-of-function mutants accumulate less Pi and exhibit a lower vacuolar-to-cytoplasmic Pi ratio than controls. Conversely, overexpression of PHT5 leads to massive Pi sequestration into vacuoles and altered regulation of Pi starvation-responsive genes. Furthermore, we show that heterologous expression of the rice homologue OsSPX-MFS1 mediates Pi influx to yeast vacuoles. Our findings show that a group of Pi transporters in vacuolar membranes regulate cytoplasmic Pi homeostasis and are required for fitness and plant growth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology*
  • Biological Transport / genetics
  • Homeostasis
  • Magnetic Resonance Spectroscopy
  • Oryza / genetics
  • Phosphate Transport Proteins / genetics
  • Phosphate Transport Proteins / metabolism
  • Phosphate Transport Proteins / physiology*
  • Phosphates / metabolism*
  • Vacuoles / metabolism*

Substances

  • Arabidopsis Proteins
  • Phosphate Transport Proteins
  • Phosphates