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

authored by

Débora Soto, Juan Pablo Cõrdoba, Fernando Villarreal, Carlos Bartoli, Jessica Schmitz, Veronica G. Maurino, Hans Peter Braun, Gabriela C. Pagnussat, Eduardo Zabaleta

Abstract

The NADH-ubiquinone oxidoreductase complex (complex I) (EC 1.6.5.3) is the main entrance site of electrons into the respiratory chain. In a variety of eukaryotic organisms, except animals and fungi (Opisthokonta), it contains an extra domain comprising trimers of putative γ-carbonic anhydrases, named the CA domain, which has been proposed to be essential for assembly of complex I. However, its physiological role in plants is not fully understood. Here, we report that Arabidopsis mutants defective in two CA subunits show an altered photorespiratory phenotype. Mutants grown in ambient air show growth retardation compared to wild-type plants, a feature that is reversed by cultivating plants in a high-CO₂ 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 contributes to sustaining efficient photosynthesis under ambient (photorespiratory) conditions. Significance Statement Photorespiration is thought to be an inevitable metabolism derived from the oxygenation activity of Rubisco which produces 2-phosphoglycolate. This pathway allows recycling of a percentage of carbon in plants. In this work we present experimental evidence that the CA domain of the mitochondrial NADH dehydrogenase complex is relevant for the photorespiratory pathway and thus contributes to sustain photosynthesis.

Organisation(s)

Institute of Plant Genetics

External Organisation(s)

Universidad Nacional de Mar del Plata
Universidad Nacional de La Plata
University Hospital Düsseldorf

Type

Article

Journal

Plant Journal

Volume

83

Pages

831-844

No. of pages

14

ISSN

0960-7412

Publication date

03.07.2015

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Genetics, Plant Science, Cell Biology

Electronic version(s)

https://doi.org/10.1111/tpj.12930 (Access: Open)