Functional analysis of water channels in barley roots

Plant Cell Physiol. 2002 Aug;43(8):885-93. doi: 10.1093/pcp/pcf102.

Abstract

We identified three genes homologous to water channels in the plasma membrane type subfamily from roots of barley seedlings. These genes were designated HvPIP2;1, HvPIP1;3, and HvPIP1;5 after comparison to Arabidopsis aquaporins. Competitive reverse transcription (RT)-PCR was applied in order to distinguish and to quantify their transcripts. The HvPIP2;1 transcript was the most abundant among the three in roots. Salt stress (200 mM NaCl) down-regulated HvPIP2;1 (transcript and protein), but had almost no effect on the expressions of HvPIP1;3, or HvPIP1;5. Approximately equal amounts of the transcripts of the three were detected in shoots, and salt stress enhanced the expression of HvPIP2;1 but not of HvPIP1;3, or HvPIP1;5. HvPIP2;1 protein was confirmed to be localized in the plasma membrane. Functional expression of HvPIP2;1 in Xenopus oocytes confirmed that HvPIP2;1 encoded an aquaporin that transports water. This water permeability was reduced by HgCl(2), which is a typical water channel inhibitor. This activity was not modified by some inhibitors against protein kinase and protein phosphatase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / genetics
  • Adaptation, Physiological / physiology
  • Algorithms
  • Amino Acid Sequence
  • Animals
  • Aquaporins / antagonists & inhibitors
  • Aquaporins / genetics*
  • Aquaporins / physiology
  • Arabidopsis Proteins*
  • Carbazoles / pharmacology
  • Cell Membrane / metabolism
  • Cell Membrane Permeability / drug effects
  • DNA, Complementary / genetics
  • DNA, Complementary / metabolism
  • Female
  • Gene Expression Regulation, Plant
  • Hordeum / drug effects
  • Hordeum / genetics*
  • Hordeum / physiology
  • Indole Alkaloids
  • Ion Channels / genetics
  • Mercuric Chloride / pharmacology
  • Molecular Sequence Data
  • Okadaic Acid / pharmacology
  • Oocytes / physiology
  • Osmotic Pressure / drug effects
  • Phosphoprotein Phosphatases / antagonists & inhibitors
  • Phosphorylation
  • Phylogeny
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plant Roots / drug effects
  • Plant Roots / genetics*
  • Plant Roots / physiology
  • Protein Kinase Inhibitors
  • Sequence Homology, Amino Acid
  • Sodium Chloride / pharmacology
  • Water / pharmacology
  • Water / physiology
  • Xenopus laevis

Substances

  • Aquaporins
  • Arabidopsis Proteins
  • Carbazoles
  • DNA, Complementary
  • Indole Alkaloids
  • Ion Channels
  • Plant Proteins
  • Protein Kinase Inhibitors
  • major intrinsic protein, plant
  • plasma membrane intrinsic protein 2 Arabidopsis
  • Water
  • Okadaic Acid
  • Sodium Chloride
  • Mercuric Chloride
  • staurosporine aglycone
  • Phosphoprotein Phosphatases

Associated data

  • GENBANK/AB009307
  • GENBANK/AB009308
  • GENBANK/AB009309