COX17, copper and stress: a new menage a trios in Arabidopsis thaliana.

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

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular (SAIB).; 2012

A series of accessory proteins is essential to delivery and insertion of copper in cytochrome c oxidase (CcO). However, resent findings suggest that these accessory proteins have additional functions in Arabidopsis thaliana. In order to understand the functions of COX17-1 (At3g15352) and COX17-2 (At1g66590), homologues of yeast copper chaperones involved in COX assembly, we silenced their expression in A. thaliana using artificial microRNAs. Copper homeostasis is altered in these plants, as was evidence by the higher copper content and the repression of the cooper-responsive miR398. Besides the influence of COX17-1 and COX17-2 on copper metabolism, these silenced plants shown accumulation of reactive oxygen species, higher electron transfer rate (ETR) and lower dark respiration rate when grown under different stress conditions (high salt concentration and high light). In addition, transcript levels of genes involved in the alternative pathway (AOX1a and NDB2) so as other stress-responsive genes (BCS-I, CAT, APX1 and ASO) were lower in silenced plants. In this way, COX17-1 and COX17-2 have a function in copper homeostasis and plant stress response. Our results would suggest a link between copper metabolism, mitochondrial function and stress response.