Long-chain bases and their phosphorylated derivatives differentially regulate cryptogein-induced production of reactive oxygen species in tobacco (Nicotiana tabacum) BY-2 cells

New Phytol. 2015 Feb;205(3):1239-49. doi: 10.1111/nph.13094. Epub 2014 Oct 10.

Abstract

The proteinaceous elicitor cryptogein triggers defence reactions in Nicotiana tabacum (tobacco) through a signalling cascade, including the early production of reactive oxygen species (ROS) by the plasma membrane (PM)-located tobacco respiratory burst oxidase homologue D (NtRbohD). Sphingolipid long-chain bases (LCBs) are emerging as potent positive regulators of plant defence-related mechanisms. This led us to question whether both LCBs and their phosphorylated derivatives (LCB-Ps) are involved in the early signalling process triggered by cryptogein in tobacco BY-2 cells. Here, we showed that cryptogein-induced ROS production was inhibited by LCB kinase (LCBK) inhibitors. Additionally, Arabidopsis thaliana sphingosine kinase 1 and exogenously supplied LCB-Ps increased cryptogein-induced ROS production, whereas exogenously supplied LCBs had a strong opposite effect, which was not driven by a reduction in cellular viability. Immunogold-electron microscopy assay also revealed that LCB-Ps are present in the PM, which fits well with the presence of a high LCBK activity associated with this fraction. Our data demonstrate that LCBs and LCB-Ps differentially regulate cryptogein-induced ROS production in tobacco BY-2 cells, and support a model in which a cooperative synergism between LCBK/LCB-Ps and NtRbohD/ROS in the cryptogein signalling pathway is likely at the PM in tobacco BY-2 cells.

Keywords: Nicotiana tabacum (tobacco) BY-2 cells; Nicotiana tabacum respiratory burst oxidase homologue D (NtRbohD); cryptogein elicitor; long-chain base (LCB); long-chain base kinase; plasma membrane; reactive oxygen species (ROS).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Death / drug effects
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Fungal Proteins / pharmacology*
  • Phosphorylation / drug effects
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Plant Cells / drug effects
  • Plant Cells / metabolism
  • Protein Kinase Inhibitors / pharmacology
  • Protein Transport / drug effects
  • Reactive Oxygen Species / metabolism*
  • Sphingolipids / metabolism*
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / metabolism
  • Tobacco / cytology
  • Tobacco / drug effects
  • Tobacco / metabolism*

Substances

  • Fungal Proteins
  • Protein Kinase Inhibitors
  • Reactive Oxygen Species
  • Sphingolipids
  • cryptogein protein, Phytophthora cryptogea
  • Phosphotransferases (Alcohol Group Acceptor)
  • sphingolipid long-chain base kinase