Elicitor-activated phospholipase A(2) generates lysophosphatidylcholines that mobilize the vacuolar H(+) pool for pH signaling via the activation of Na(+)-dependent proton fluxes

• Published in: The Plant cell 2002-07, Vol.14 (7), p.1509-1525
• Main Authors: Viehweger, Katrin, Dordschbal, Batsuch, Roos, Werner
• Format: Article
• Language: English
• Subjects: Amiloride - pharmacology; Biosynthesis; Cell Membrane Permeability - drug effects; Cells, Cultured; Enzyme Activation - drug effects; Fluoresceins - pharmacology; Hydrogen-Ion Concentration; Ionization; Lysophosphatidylcholines - biosynthesis; Lysophosphatidylcholines - pharmacology; Mass spectrometry; Microscopy, Confocal; Papaveraceae - cytology; Papaveraceae - enzymology; Phospholipases A - drug effects; Phospholipases A - metabolism; Phytoalexins; Plant Extracts - biosynthesis; Sesquiterpenes; Signal Transduction - physiology; Sodium Chloride - pharmacology; Sodium-Hydrogen Exchangers - drug effects; Sodium-Hydrogen Exchangers - metabolism; Terpenes; Vacuolar Proton-Translocating ATPases - antagonists & inhibitors; Vacuolar Proton-Translocating ATPases - metabolism; Vacuoles - enzymology; Yeasts
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.002329

The elicitation of phytoalexin biosynthesis in cultured cells of California poppy involves a shift of cytoplasmic pH via the transient efflux of vacuolar protons. Intracellular effectors of vacuolar proton transport were identified by a novel in situ approach based on the selective permeabilization of the plasma membrane for molecules of < or = 10 kD. Subsequent fluorescence imaging of the vacuolar pH correctly reported experimental changes of activity of the tonoplast proton transporters. Lysophosphatidylcholine (LPC) caused a transient increase of the vacuolar pH by increasing the Na(+) sensitivity of a Na(+)-dependent proton efflux that was inhibited by amiloride. In intact cells, yeast elicitor activated phospholipase A(2), as demonstrated by the formation of LPC from fluorescent substrate analogs, and caused a transient increase of endogenous LPC, as determined by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. It is suggested that LPC generated by phospholipase A(2) at the plasma membrane transduces the elicitor-triggered signal into the activation of a tonoplast H(+)/Na(+) antiporter.