Plant gamma carbonic anhydrases and their role in growth and embryogenesis. The importance of CA3 protein subunit

FASSOLARI S; CORDOBA JUAN PABLO; MARCHETTI, MARIA FERNANDA; SOTO DEBORA; PAGNUSSAT G; EDUARDO JULIAN ZABALETA

Córdoba

Congreso; LII Reunión Anual SAIB; 2016

SAIB

In Arabidopsis thaliana, attached to the respiratory Complex I, there is a spherical domain named Carbonic Anhydrase (CA) domain, which is composed by five gamma-typeCarbonicAnhydrases (CA1, CA2, CA3, CAL1 and CAL2). This domainwas demonstrated that is involved in Complex I assembly, photorespiratory pathway and embryo development. In ourlaboratory, we are working with multiple mutants in these genesin order to elucidate new roles of CA domain, its composition inCA proteins and the attachment site within Complex I.Apparently, CA3 protein is outside of CA domain, which isintriguing because double mutants, ca1ca3 and ca2ca3 showlethal and slow growth phenotypes, respectively. The delay inembryo development is most likely due to low mitochondrial activity (as mitochondrial membrane potential). This delay provokes abnormal seed shapes and impairs seed germination.However, ca1ca3 embryos can be rescued by sowing inartificial medium complemented with sucrose. On the other hand, ca2ca3 mutant exhibits slow growth and late flowering being partially recovered by sucrose or high CO2 atmospheres.Preliminary results show that Complex I activity is lower than WT in ca2ca3, and totally absent in ca1ca3. Our results and observations focus on CA3 role in CA domain composition, and its importance in Complex I functions.