EVALUATION OF RELATIONSHIP BETWEEN PUTRESCINE AND ABA IN Arabidopsis thaliana

ALET A.I.; SANCHEZ D.H.; CUEVAS J.C.; CARRASCO, P.; ALTABELLA, RUIZ O.A

Rosario. Argentina

Congreso; Congreso XLII Reunión Anual SAIB; 2006

SAIB

Putrescine (Put), spermidine (Spd), and spermine (Spm) form a class of aliphatics amines that are ubiquitous in living organisms, and have been implicated in a wide range of biological processes, including plant growth and development. However, their mode of action remains a matter of speculation. In recent years, attention has been focused on the involvement of PAs in response to environmental stresses. In plants PAs biosynthesis begins principally with Arg decarboxylation by Arginine decarboxylase (ADC; EC 4.1.1.19). There are general agreement in consider this enzyme as a key enzyme playing a decisive role in the regulation of the PAs levels. On the other hand, abscisic acid (ABA) appears to play an important role in plant response to these stresses. In orther to further analyze PAs involvement in abiotic stresses and their relationship with stress hormone ABA, we obtained transgenic Arabidopsis thaliana plants expressing oat ADC under the stress inducible promoter rd29A. When treated with ABA or acclimated to cold, differences in the expression of genes involved in stress response (analyzed by real-time PCR) were observed. We also evaluated the performance of these plants under freezing and dehydration stresses, suggesting that endogenous Put levels could be involved in the tolerance mechanism and the different gene expression patterns observed in the transgenic plants.