PLD/PA MODULATES PROLINE AND H2O2 LEVELS IN BARLEY EXPOSED TO SHORT-AND LONG-TERM CHILLING STRESS

PEPPINO MARGUTTI, M; REYNA, M; RACAGNI, G E; VILLASUSO, A L

Córdoba

Congreso; Lll Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

Sociedad Argentina de Investigaciones en Bioquímica

PLD hydrolyses phospholipids to produce PA and a head group and it is involved in the response to various environmental stresses. In this work, we investigated the roles of PLD/PA in response to short and long-term chilling stress through the regulation of proline and ROS levels in barley. Seedling grown at 25ºC for 4d were maintained at 4ºC for 0.5-36 h. Short-term chilling stress increased rapidly and transiently the PLD activity and modulated proline and ROS levels in young leaves. Pre-treatment with 1-butanol augmented the proline synthesis, and the treatment with PA exogenous amplified H2O2 formation. In contrast, long-term chilling stress reduced enzymatic activity of PLD; while the proline synthesis and the ROS signal were stimulated in roots. H2O2 application stimulated the proline level while the exogenous proline decreased the ROS level. Bioinformatic search of the barley database revealed the presence of highly homologous sequences of P5CS and ProDH Arabidopsis protein. Ours results indicate that PLD contributes to the signalling pathway during 0.5-3h at 4°C through the regulation of balance between P5CS activity and H2O2 level. On the contrary, reduced enzymatic activity of PLD during 24-36h at 4°C could not contribute to the proline level. This suggests that PLD/PA signal is involved in the relationship between ROS signalling and proline metabolism.