The polyamines as saline tolerance markers in rice

MAIALE, SANTIAGO; GUIRADO ALEJANDRA; SANCHEZ, DIEGO; VIDAL ALFONSO; RUIZ OSCAR

villa carlos Paz, Cordoba

Congreso; 27 Reunion anual de la sociedad argentina de investigaciones en bioquimica y biologia molecular; 2001

Sociedad Argentina de Investigaciones en ioquimica y Biologia Molecular

The polyamines are ubiquitous polycations. Their role in cell growth and differentiation has been well established. In animals and fungi, their biosynthesis is controlled primarily by two enzymes: ornithine descarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC). In higher plants, there is an additional biosynthetic enzyme, arginine decarboxylase (ADC). Many cereals develop a rapid response to abiotic stress showing an increase of ADC activity. The triamine spermidine derives from the condensation, catalyzed by spermidine synthase (EC2.5.1.6), of putrescine with decarboxylated S-adenosylmethionine (SAMdc) synthesized by SAMDC. The tetramine spermine arises from the further condensation of spermidine with SAMdc catalyzed by spermine synthase (EC2.5.1.22). The plyamines are catabolized by diamino oxidase (DAO EC1.4.3.6) and polyamine oxidase (PAO EC1.4.3.3) specific of plants. The aims oh this project is the characterization of the expression ADC in rice cultivars with different levels of salinity tolerance and evaluation of this methodology as selection criterion in breeding programs. We analyzed ADC, SAMDC, DAO, spermine and spermidine synthase activities and polyamines levels in different rice lines obtained by the “Rice program” of UNLP under saline conditions, observing that the levels of spermine increase in tolerant lines in contrast to sensitive ones. These results are according to biosynthetic enzymes activities observed. The tolerant status determined in basis of foliar damage.