Avena sativa polyamine biosynthesis under saline stress

GUIRADO ALEJANDRA; SANCHEZ DIEGO; CUEVAS JUAN C; MAIALE SANTIAGO; RUIZ OSCAR

villa Carlos Paz, Cordoba

Congreso; 28 Reunion anual de la sociedad argentina de investigaciones en bioquimica y biologia molecualr; 2002

Sociedad Argentina de Investigaciones en Bioquimica y Biologia Molecular

Putrescine (Put), spermidine (Spd) and spermine (Spm) form a class of aliphatic 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, there are general agreement in consider the arginine decarboxylase (ADS; EC 4.1.1.19) and the Sadenosylmethionine decarboxylase (SAMDC; EC 4.1.1.50) as key enzyme playing a decisive role in the regulation of the Pas levels. In this work, we analyzed the activity of these and other enzymes included in the catabolic PAs biosynthetic pathway (i.e. di- DAO- and poliaminooxidase- PAO) in shoots from 9 days old seedlings of Avena sativa under long and short time expositions to high and low NaCl concentrations. Moreover, we determined the free polyamine and proline levels simultaneously, in order to check the osmotic status and their relative importance as osmolytes. We concluded that: 1) ADC activity and Put levels don’t change in short times but decarboxylase activity increase after five days, while the diamine concentration shut down. 2) The SAMDC activity show a good correlation with Spm levels and 3) Long stress exposition resulting in a high tetraamine and proline accumulation.