Phosphatidic acid produced by phospholipase D is required for tobacco pollen tube growth.
Phospholipase D (PLD) and its product phosphatidic acid (PA) are involved in a number of signalling pathways regulating cell proliferation, membrane vesicle trafficking and defence responses in eukaryotic cells. Here we report that PLD and PA have a role in the process of polarised plant cell expansion as represented by pollen tube growth. Both phosphatidylinositol-4,5-bisphosphate-dependent and independent PLD activities were identified in pollen tube extracts, and activity levels during pollen tube germination and growth were measured. PLD-mediated PA production in vivo can be blocked by primary alcohols, which serve as a substrate for the transphosphatidylation reaction. Both pollen germination and tube growth are stopped in the presence 0.5% 1-butanol, whereas secondary and tertiary isomers do not show any effect. This inhibition could be overcome by addition of exogenous PA-containing liposomes. In the absence of n-butanol, addition of a micromolar concentration of PA specifically stimulates pollen germination and tube elongation. Furthermore, a recently established link between PLD and microtubule dynamics was supported by taxol-mediated partial rescue of the 1-butanol-inhibited pollen tubes. The potential signalling role for PLD-derived PA in plant cell expansion is discussed.
Department of Plant Physiology, Faculty of Science, Charles University, Vinicná 5, 128 44, Prague 2, Czech Republic.
Martin
M
Potocký
Marek
M
Eliás
Bronislava
B
Profotová
Zuzana
Z
Novotná
Olga
O
Valentová
Viktor
V
Zárský
D020001:1-Butanol / Q000494:pharmacology; D000440:Butanols / Q000494:pharmacology; D005298:Fertility / Q000187:drug effects; D035264:Flowers / Q000187:drug effects / Q000254:growth & development*; D008870:Microtubules / Q000502:physiology; D010712:Phosphatidic Acids / Q000096:biosynthesis* / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014026:Nicotiana / Q000201:enzymology / Q000254:growth & development*; D020002:tert-Butyl Alcohol / Q000494:pharmacology
D000440:Butanols; D010712:Phosphatidic Acids; C043958:2-butanol; D020001:1-Butanol; D010739:Phospholipase D; D020002:tert-Butyl Alcohol