THERMOSPERMINE CAN PERFORM SIMILAR FUNCTIONS TO SPERMINE IN A. thaliana DEFENSE AGAINST PATHOGENS

MARINA, MARÍA; VERA-SIRERA, FRANCISCO; RAMBLA, JOSÉ L; GONZALEZ, MARÍA E; CARBONELL, JUAN; BLÁZQUEZ, MIGUEL A; RUIZ, OSCAR A; PIECKENSTAIN, FERNANDO L

Puerto Madryn

Congreso; XLVI REUNIÓN ANUAL SOCIEDAD ARGENTINA DE INVESTIGACIÓN EN BIOQUÍMICA Y BIOLOGÍA MOLECULAR; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Polyamines (PAs) are natural aliphatic polycations with multiple functions. Previously, our group demonstrated that the accumulation and oxidation of the common tetraamine spermine (Spm) protect plants against the biotrophic bacterium Pseudomonas viridiflava. In this work, we analyzed the functional specificity of Spm and its structural isomer, the uncommon thermospermine (TSpm). The ability of P. viridiflava to colonize A. thaliana plants harboring mutations in the Spm and TSpm biosynthetic genes (ACL5 and SPMS) was compared to wild type plants (WT). Both mutants showed increased colonization by P. viridiflava, which was reverted by TSpm addition. The patterns of global changes in gene expression induced by Spm and TSpm were analyzed by transcript profiling of transgenic plants that constitutively over-express ACL5 and SPMS, which were previously reported to be more resistant to P. viridiflava than WT. Genes whose expression was significantly changed in both transgenic lines, exhibited an enrichment in ontology groups related to pathogen perception and defense responses. It can be concluded that TSpm can, at least partly, play similar roles to those of Spm in plant defense. Further analysis of the relationship between the differential localization of ACL5 and SPMS and their roles in plant defense will increase our understanding of the physiological functions of TSpm and Spm.