Reactive Oxygen Species Produced by NADPH Oxidase Regulate Plant Cell Growth

Nature. 2003 Mar 27;422(6930):442-6. doi: 10.1038/nature01485.

Abstract

Cell expansion is a central process in plant morphogenesis, and the elongation of roots and root hairs is essential for uptake of minerals and water from the soil. Ca2+ influx from the extracellular store is required for (and sets the rates of) cell elongation in roots. Arabidopsis thaliana rhd2 mutants are defective in Ca2+ uptake and consequently cell expansion is compromised--rhd2 mutants have short root hairs and stunted roots. To determine the regulation of Ca2+ acquisition in growing root cells we show here that RHD2 is an NADPH oxidase, a protein that transfers electrons from NADPH to an electron acceptor leading to the formation of reactive oxygen species (ROS). We show that ROS accumulate in growing wild-type (WT) root hairs but their levels are markedly decreased in rhd2 mutants. Blocking the activity of the NADPH oxidase with diphenylene iodonium (DPI) inhibits ROS formation and phenocopies Rhd2-. Treatment of rhd2 roots with ROS partly suppresses the mutant phenotype and stimulates the activity of plasma membrane hyperpolarization-activated Ca2+ channels, the predominant root Ca2+ acquisition system. This indicates that NADPH oxidases control development by making ROS that regulate plant cell expansion through the activation of Ca2+ channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Arabidopsis / cytology*
  • Arabidopsis / enzymology
  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Calcium / metabolism
  • Calcium Channels / metabolism
  • Calcium Signaling
  • Cell Division
  • Electrophysiology
  • Genes, Plant / genetics
  • In Situ Hybridization
  • Mutation / genetics
  • NADPH Oxidases / genetics
  • NADPH Oxidases / metabolism*
  • Plant Roots / cytology
  • Plant Roots / enzymology
  • Plant Roots / genetics
  • Plant Roots / metabolism
  • Reactive Oxygen Species / metabolism*

Substances

  • Arabidopsis Proteins
  • Calcium Channels
  • Reactive Oxygen Species
  • Rhd2 protein, Arabidopsis
  • NADPH Oxidases
  • Calcium