Mitochondrial copper metallochaperones modulate COX activity levels and respiration during stress and iron deficiency

MANSILLA N; GONZALEZ DH; WELCHEN E; GARCIA L

Congreso; 12th Congress of the International Plant Molecular Biology ? (IPMB2018).; 2018

Cytochrome c Oxidase (COX) is the final complex of the mitochondrial electron transport chain. COX requires copper and heme for its function. We studied the role of several genes encoding putative Arabidopsis homologues of assembly factors involved in COX metallation. Plants with lower levels of AtCOX17 or AtHCC1 showed reduced expression of stress-responsive genes under basal growth conditions. On the contrary, mutant plants in AtHCC2 exhibited an induction of stress-responsive genes. The transcriptional response, as well as the sensitivity to salinity stress was also altered in these plants. Furthermore, decreased expression of AtHCC1 or AtHCC2 had opposite effects on respiration and COX levels under stress conditions. We also analyzed plants with decreased AtCOX19 levels. Increased expression of stress-responsive genes and genes related to iron deficiency was observed in these plants, which also showed defects in respiration and COX assembly under iron deficiency conditions. Our results suggest that COX biogenesis factors would be connected to mechanisms controlling plant responses to stress and changes in metal availability in order to ensure a proper COX assembly and mitochondrial activity during unfavorable growth conditions.