Plant Gamma-Carbonic Anhydrases and their role in growth and embryogenesis: the importance of CA3 protein.

FASSOLARI MARISOL; CORDOBA JUAN PABLO; MARCHETTI FERNANDA; SOTO DEBORA; PAGNUSSAT GABRIELA; ZABALETA EDUARDO

Córdoba

Congreso; LII Reunión anual sociedad argentina de investigación en bioquímica y biología molecular; 2016

Plant mitochondrial proteome contains specific proteins that have special functions involved in photosynthesis, metabolism and many other processes. 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-type Carbonic Anhydrases (CA1, CA2, CA3, CAL1 and CAL2). This domain was demonstrated that is involved in Complex I assembly, photorespiratory pathway and embryo development. In our laboratory, we are working with multiple mutants in these genes in order to elucidate new roles of CA domain, its composition in CA proteins and the attachment site within Complex I. Apparently, CA3 protein is outside of CA domain, which is intriguing because double mutants, ca1ca3 and ca2ca3 show lethal and slow growth phenotypes, respectively. The delay in embryo 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 in artificial 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.