Functional characterization of mutants affected in the carbonic anhydrase domain of the respiratory complex I in Arabidopsis thaliana

SOTO DEBORA; CORDOBA JUAN PABLO; VILLARREAL, F.; BARTOLI, C.; SCHMITZ J; MAURINO V; BRAUN, H.P; PAGNUSSAT G; EDUARDO JULIAN ZABALETA

THE PLANT JOURNAL

WILEY-BLACKWELL PUBLISHING, INC

Año: 2015 vol. 83 p. 831 - 844

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 be 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.