PHOSPHATIDIC ACID AND DIACYLGLYCEROL PYROPHOSPHATE SIGNALING DURING THE STRESS RESPONSE OF BARLEY

PEPPINO MARGUTTI, MY; REYNA, M; RACAGNI, GE ; VILLASUSO, AL.

Puerto Iguazú

Congreso; 56th International Conference on the Bioscience of lipids; 2015

CIQUIBIC (UNC-CONICET)

PHOSPHATIDIC ACID AND DIACYLGLYCEROL PYROPHOSPHATE SIGNALING DURING THE STRESS RESPONSE OF BARLEYPeppino Margutti, MY, Reyna, M, Racagni, GE and Villasuso, AL. Dpto. Biol. Molecular. Universidad Nacional de Río Cuarto, Argentina. E-mail: mpeppino@exa.unrc.edu.arDiacylglycerol pyrophosphate (DGPP) is a minor lipid that attenuates the phosphatidic acid (PA) signal, and also DGPP itself would be a signaling lipid. Evidence suggests that DGPP may act as a novel second messenger with important roles in diverse cellular processes in plants that are related to stress. In barley, lipid signaling is regulated by the activities of phospholipases (PLC-PLD), phosphatases (LPPs) and lipid kinases (DGK-PAK) through the dinamic changes in signal lipids as PA and DGPP. The aim of this study was to determine the lipid kinase activities in relation with proline accumulation during the cold exposition. Seedling grown at 25ºC for 4d were allowed at 4ºC for 30-180 min. Cold seedling exposition by 180 min evoked an increase on PAK and DGK activities in root tissue. In contrast, PA and DGPP levels were not modified by cold treatment in young leaves. Cold seedling exposition triggered the proline accumulation in young leaves while there were no significant changes observed on root tissues. This suggested a possible translocation of proline from the root to the young leaves. Proline accumulated because the balance between its synthesis and its catabolism was altered or because the proline was traslocated. To test this hypothesis, we have impaired its movement through the use of physical methods. In relation to this, no proline accumulation was observed in young leaves. The results obtained allow us to suggest that the changes in the lipid kinase activities with its corresponding levels of PA and DGPP could be modulating the proline metabolism and its translocation to compensate the effect provoked by low temperatures in barley tissue.