AtCOX10, a protein required for heme a synthesis during COX assembly, is involved in plant embryogenesis and senescence.

MANSILLA, NATANAEL; GARCÍA, LUCILA; GONZALEZ, DANIEL H.; WELCHEN, ELINA

Congreso; XXX Reunión Argentina de Fisiología Vegetal (RAFV), Organizada por la Sociedad Argentina de Fisiología Vegetal (SAFV).; 2014

Cytochrome c oxidase biogenesis requires more than 20 accessory proteins implicated, among other processes, in copper and heme a insertion. COX10 catalyzes the conversion of heme b to heme o, and is essential for the insertion of the heme a in the COX1 subunit in yeast. By complementation analysis of yeast ∆cox10 mutant, with the putative Arabidopsis homologous AtCOX10, we observed its ability to restore growth on non-fermentable carbon. We have also studied Arabidopsis mutant plants with a T-DNA insertion in the coding region of the AtCOX10 gene. Segregation analysis demonstrated the impossibility to obtain knockout plants. The siliques contained 25% abnormal seeds with embryos arrested at early stages of development which were negative to COX staining-activity, suggesting that AtCOX10 is an essential protein during plant embryogenesis process. Accordingly, by histochemical detection of Arabidopsis plants transformed with AtCOX10 promoter-GUS fusion we observed expression at early-stage of seeds development. Moreover, normal embryogenesis was restored in homozygous mutants complemented with AtCOX10 gene expressed under its own promoter. In addition, senescence of heterozygous plants progressed faster than WT plants, with lower Fv/Fm value and chlorophyll content and higher levels of transcripts for SAGs. However, no differences were observed in other stages of development, suggesting the relevance of Complex IV and AtCOX10 during embryogenesis and senescence in plants