Identification and characterization of the Arabidopsis PHO1 gene involved in phosphate loading to the xylem

Plant Cell. 2002 Apr;14(4):889-902. doi: 10.1105/tpc.000745.


The Arabidopsis mutant pho1 is deficient in the transfer of Pi from root epidermal and cortical cells to the xylem. The PHO1 gene was identified by a map-based cloning strategy. The N-terminal half of PHO1 is mainly hydrophilic, whereas the C-terminal half has six potential membrane-spanning domains. PHO1 shows no homology with any characterized solute transporter, including the family of H(+)-Pi cotransporters identified in plants and fungi. PHO1 shows highest homology with the Rcm1 mammalian receptor for xenotropic murine leukemia retroviruses and with the Saccharomyces cerevisiae Syg1 protein involved in the mating pheromone signal transduction pathway. PHO1 is expressed predominantly in the roots and is upregulated weakly under Pi stress. Studies with PHO1 promoter-beta-glucuronidase constructs reveal predominant expression of the PHO1 promoter in the stelar cells of the root and the lower part of the hypocotyl. There also is beta-glucuronidase staining of endodermal cells that are adjacent to the protoxylem vessels. The Arabidopsis genome contains 10 additional genes showing homology with PHO1. Thus, PHO1 defines a novel class of proteins involved in ion transport in plants.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Arabidopsis / physiology
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Biological Transport / genetics
  • Biological Transport / physiology
  • Chromosome Mapping
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • Molecular Sequence Data
  • Mutation
  • Phosphate Transport Proteins / genetics*
  • Phosphate Transport Proteins / metabolism
  • Phosphates / metabolism*
  • Phosphorus / pharmacology
  • Plant Structures / genetics*
  • Plant Structures / physiology
  • Plants, Genetically Modified
  • Sequence Homology, Amino Acid
  • Signal Transduction / genetics


  • Arabidopsis Proteins
  • PHO1 protein, Arabidopsis
  • PHO1;H1 protein, Arabidopsis
  • Phosphate Transport Proteins
  • Phosphates
  • Phosphorus

Associated data

  • GENBANK/AF474076