Polyamines and saline stress in plants

SÁNCHEZ DH, JC CUEVAS, MA CHIESSA, S MAIALE, A GUIRADO, A SANNAZARO, FL PIECKENSTAIN, OA RUIZ

Villa Carlos Paz, Argentina

Congreso; XXXVIII Reunión Anual de la Sociedad Argentina de Investigaciones Bioquímicas; 2002

Sociedad Argentina de Investigaciones Bioquímicas

Polyamines are ubiquitous cellular components that play an essential role in growth and development. In plants, these amines are important in many aspects of development, but their exact role needs to be established. Intracellular levels of polyamines are related to many developmental events such as cell division, flower formation, membrane stability, pathogen stress protection, as well as senescence. Recently, with the cloning of the genes for some polyamine biosynthetic enzymes, a number of studies have involved their artificial over-expression in plant systems. In our lab, we evaluated the changes in polyamine biosynthetic enzymes and polyamine levels in Lotus spp, rice and oat, under short and long term saline stress. On the basis of our results, we generated Lotus transgenic plants over-expressing the tobacco spermidine synthase gene under the control of the 35S promoter and other lines were transformed with the ADC gene under the control of the inducible A. thaliana RD29A promoter. Previously, we analysed the expression of driven b the RD29A promoter in hairy roots transformed with ADC and Gus, observing a a temporal bi-phasic induction by cold and salinity. The physiological relevance of spermine accumulation observed in plants under saline stress in the regulation of polyamine oxidase (PAO) and NADPH oxidase activities will be discussed.