cGMP regulates hydrogen peroxide accumulation in calcium-dependent salt resistance pathway in Arabidopsis thaliana roots

Planta. 2011 Oct;234(4):709-22. doi: 10.1007/s00425-011-1439-3. Epub 2011 May 27.

Abstract

3',5'-cyclic guanosine monophosphate (cGMP) is an important second messenger in plants. In the present study, roles of cGMP in salt resistance in Arabidopsis roots were investigated. Arabidopsis roots were sensitive to 100 mM NaCl treatment, displaying a great increase in electrolyte leakage and Na(+)/K(+) ratio and a decrease in gene expression of the plasma membrane (PM) H(+)-ATPase. However, application of exogenous 8Br-cGMP (an analog of cGMP), H(2)O(2) or CaCl(2) alleviated the NaCl-induced injury by maintaining a lower Na(+)/K(+) ratio and increasing the PM H(+)-ATPase gene expression. In addition, the inhibition of root elongation and seed germination under salt stress was removed by 8Br-cGMP. Further study indicated that 8Br-cGMP-induced higher NADPH levels for PM NADPH oxidase to generate H(2)O(2) by regulating glucose-6-phosphate dehydrogenase (G6PDH) activity. The effect of 8Br-cGMP and H(2)O(2) on ionic homeostasis was abolished when Ca(2+) was eliminated by glycol-bis-(2-amino ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA, a Ca(2+) chelator) in Arabidopsis roots under salt stress. Taken together, cGMP could regulate H(2)O(2) accumulation in salt stress, and Ca(2+) was necessary in the cGMP-mediated signaling pathway. H(2)O(2), as the downstream component of cGMP signaling pathway, stimulated PM H(+)-ATPase gene expression. Thus, ion homeostasis was modulated for salt tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / drug effects*
  • Arabidopsis / genetics
  • Arabidopsis / growth & development
  • Arabidopsis / physiology
  • Calcium / pharmacology*
  • Cell Membrane / enzymology
  • Cell Membrane / metabolism
  • Cyclic GMP / analogs & derivatives*
  • Cyclic GMP / pharmacology
  • Germination
  • Glucosephosphate Dehydrogenase / drug effects
  • Glucosephosphate Dehydrogenase / metabolism
  • Homeostasis / drug effects
  • Hydrogen Peroxide / analysis
  • Hydrogen Peroxide / metabolism*
  • NADP / analysis
  • NADP / drug effects
  • NADP / metabolism
  • Plant Roots / drug effects*
  • Plant Roots / genetics
  • Plant Roots / growth & development
  • Plant Roots / physiology
  • Potassium / analysis
  • Proton-Translocating ATPases / drug effects
  • Proton-Translocating ATPases / genetics
  • Salt Tolerance
  • Seeds / drug effects
  • Seeds / genetics
  • Seeds / growth & development
  • Seeds / physiology
  • Signal Transduction
  • Sodium / analysis
  • Sodium Chloride / pharmacology*
  • Stress, Physiological
  • Thionucleotides / pharmacology*

Substances

  • Thionucleotides
  • 8-bromoguanosino-3',5'-cyclic monophosphorothioate
  • Sodium Chloride
  • NADP
  • Sodium
  • Hydrogen Peroxide
  • Glucosephosphate Dehydrogenase
  • Proton-Translocating ATPases
  • Cyclic GMP
  • Potassium
  • Calcium