Nitric oxide triggers phosphatidic acid accumulation via phospholipase D during auxin-induced adventitious root formation in cucumber

LANTERI ML, LAXALT AM, LAMATTINA L

PLANT PHYSIOLOGY.

American Society of Plant Biologists

Lugar: Rockville, USA; Año: 2008 vol. 147 p. 188 - 198

0032-0889

Auxin and nitric oxide (NO) play fundamental roles throughout plant life. NO is a second messenger in the auxin signal transduction leading to root developmental processes. The mechanisms triggered by auxin and NO that direct adventitious root (AR) formation are beginning to be unraveled. The goal of this work was to study phospholipid (PL) signaling during the auxin- and NO-induced AR formation in cucumber (Cucumis sativus) explants. Explants were labeled with 32Pi and treated with the auxins IAA or NAA, or the NO donor SNAP, in the presence or absence of the specific NO scavenger cPTIO. PLs were separated by TLC and quantified. We report that the signaling PLs phosphatidic acid (PA), phosphatidylinositol phosphate (PIP) and phosphatidylinositol bisphosphate (PIP2) accumulated within 1 min after auxin or NO treatments. Both auxin and NO evoked similar and transient time course responses, since signaling PLs returned to control levels after 20 or 30 min of treatment. Results indicate that auxin relies on NO in inducing PA, PIP and PIP2 accumulation. Furthermore, we demonstrate that auxin and NO trigger PA formation via phospholipase D (PLD) activity. Explants treated for 10 min with auxin or NO displayed a 200% increase of AR number in comparison with control ones. In addition, PLD activity was required for the auxin- and NO-induced AR formation. Finally, exogenously applied PA increased up to 300% the number of ARs. Altogether, our data support that PLD-derived PA is an early signaling event during AR formation induced by auxin and NO in cucumber explants.