Functional characterization of double mutants defective in complex I integrated carbonic anhydrases in Arabidopsis thaliana

SOTO, DÉBORA; CÓRDOBA, JUAN PABLO; VILLARREAL, FERNANDO; BARTOLI CARLOS GUILLERMO; SCHMITZ, JESSICA; MAURINO, VERÓNICA; BRAUN, HANS-PETER; PAGNUSSAT, GABRIELA; ZABALETA, EDUARDO

The Plant Journal

John Wiley & Sons Ltd

Año: 2015

The NADH-ubiquinone oxidoreductase complex (Complex I -CI- EC 1.6.5.3) is the main entrance site of electrons into the respiratory chain. In a variety of eukaryotic organisms, except animal and fungi (Opisthokonta), it contains an extra domain composed of trimers of putative gamma carbonic anhydrases, named CA domain, which has been proposed to e essential for assembly of the complex I. However, its physiological role in plants is not fully understood. In this work, we report that Arabidopsis mutants defective in two CA subunits show a photorespiratory phenotype. Corresponding mutants grown in ambient air show growth retardation compared to wild type plants, a feature that is reverted by cultivating plants in a high carbon dioxide atmosphere. Moreover, under photorespiratory conditions, carbon assimilation is diminished and glycine accumulates, suggesting an imbalance with respect to photorespiration. Additionally, transcript levels of specific CA subunits are reduced in plants grown under non-photorespiratory conditions. Taken together, these results suggest that the CA domain of plant complex I contribute to sustain efficient photosynthesis at ambient (photorespiratory) conditions.