New insights into the action mechanisms of genes from the oxidation-resistance family in plant

COLOMBATTI, FRANCISCO; GARCÍA, LUCILA; GONZALEZ, DANIEL H.; WELCHEN, ELINA

San Luis

Congreso; XLVII Reunión Anual de Investigación en Bioquímica y Biología Molecular (SAIB).; 2011

We studied the molecular mechanisms of action of two genes (AtOXR2 and AtOXR4) belonging to the eukaryotic oxidation resistance (OXR) family from Arabidopsis thaliana. Proteins from this family are implicated in protection to oxidative stress in animals and fungi. Using GFP fusions we demonstrated a nuclear and cytoplasmic localization for AtOXR2 and AtOXR4, respectively. To assess the function of these proteins in Arabidopsis, we studied T-DNA insertional mutants in both genes. Under normal growth conditions, AtOXR4 knockout plants showed no phenotypic differences with wild-type. In contrast, AtOXR2 mutant plants had reduced biomass, accelerated water loss and differences in photosynthetic responses under high irradiance conditions. Plants overexpressing AtOXR2 showed opposite characteristics and had higher expression levels of APX1, ASO, CAT3 and other genes related with defense against oxidative stress. In addition, AtOXR2 improved the capacity of yeast cells mutant in the ScOXR gene to grow in the presence of H2O2. According to our results, we propose that members of the OXR family have different roles that may in part be related to their subcellular localization and the interaction with other proteins. Particularly for AtOXR2, the pleitropic phenotypes and the nuclear localization of this protein suggest its participation as a modulator of developmental events in plants.