The Gamma Carbonic Anhydrase domain is essential for mitochondrial complex I viability and embryo development in Arabidopsis thaliana

PAGNUSSAT GABRIELA; MARCHETTI FERNANDA, SOTO DÉBORA; CORDOBA JUAN PABLO; ZABALETA EDUARDO

Chascomús

Taller; IV Taller de Biología Celular y del Desarrollo; 2018

Mitochondria are involved in several mechanisms and metabolic pathways. One of the main functions they possess is the cellular ATP synthesis through Electron Transport Chain (ETC). The biggest protein complex of ETC (and all mitochondria) is the NADH dehydrogenase complex or Complex I, which is the main entrance of electrons. Through the evolution, and organism complexation, the Complex I gained more protein subunits called ?accessory subunits?. An example of this is the presence of highly similar subunits to gamma-type carbonic anhydrases (gammaCAs), which are grouped into the CA Domain. In Arabidopsis thaliana, five members (CA1, CA2, CA3, CAL1 and CAL2) compose the gammaCA family. Since single null mutant plants did not show visible alterations, multiple null mutants were studied. In this way, we found that disruption of CA1/CA2 or CA1/CA3 genes leads to delay on embryo development and inability of embryos to survive after germination. Developing embryos show deficiencies in mitochondrial activity, with highly reactive oxygen species accumulation, null fully assembled complex I and therefore, absence of NADH dehydrogenase activity. In addition, these double mutants show alterations in reserve accumulation, such as abnormal oil storage in oil bodies in developing seeds. Despite double mutant seedlings are unable to survive, sucrose supplementation ?rescues? that phenotype. Finally, a discussion about complex I essentiality for plant life is proposed.