Auxin and Nitric Oxide trigger Phosphatidic Acid accumulation via Phospholipase D in cucumber

LANTERI, M. L.; ANA MARIA LAXALT; LAMATTINA, L.

Mar del Plata

Congreso; SAIB; 2007

AUXIN AND NITRIC OXIDE TRIGGER PHOSPHATIDIC ACID ACCUMULATION VIA PHOSPHOLIPASE D IN CUCUMBER Lanteri ML, LaxaltAM, Lamattina L. Instituto de Investigaciones Biológicas, UNMdP, CC 1245, 7600 Mar del Plata. E-mail: lanteri@mdp.edu.ar Cucumis sativus Supported byCONICET,ANPCyT, TWAS andUNMdP. We have previously demonstrated that nitric oxide (NO), cGMP, MAP kinases, Ca and Ca -dependent protein kinases are messengers in the auxin-induced adventitious root (AR) formation in cucumber ( ). The goal of this work was to study phospholipid (PL) signaling during auxin treatments and to evaluate the requirement of NO on this. Cucumber explants were labeled with P and treated with auxin or NO, in the presence or absence of the specific NO-scavenger cPTIO. PLs were analyzed by thin layer chromatography. Here we report that the PL signaling molecules phosphatidic acid (PA), phosphatidylinositol phosphate and bisphosphate are rapidly (after 1 min) and transiently (within 30 min) accumulated during auxin treatment. The application of cPTIO abolished this auxin effect, indicating that auxin depends on NO in inducing PL accumulation. Accordingly, the application of NOmimicked the effect of auxin. Furthermore, we demonstrate that auxin and NO trigger PA formation via phospholipase D (PLD) activity. We show that 10 min treatment with auxin or NO is sufficient to induceAR formation, and that PLD activity is required on this. Finally, AR formation increased 150 % by exogenously applied PA. Altogether, our data suggest that PLD-derived PAis an early signaling event in theAR formation process induced by auxin and NO