IAL   21557
INSTITUTO DE AGROBIOTECNOLOGIA DEL LITORAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Characterization of enzymes involved in raffinose biosynthesis in Brachypodium distachyon
Autor/es:
IGLESIAS, ALBERTO A.; FIGUEROA, CARLOS M.; MINEN, ROMINA I.
Lugar:
Paraná
Reunión:
Congreso; LIV Reunión Anual de la SAIB; 2018
Institución organizadora:
SAIB
Resumen:
Raffinose(Raf, an α-1,6-galactosylextension of sucrose) is important for membrane stabilization during seeddesiccation. Raf also plays a key role as osmoprotectant in leaves of plantsexposed to heat, cold, salinity and drought. To better understand the molecularmechanisms regulating Raf synthesis in plants, we cloned the genes coding forUDP-sugar pyrophosphorylase, galactinol synthase, and Raf synthase from Brachypodiumdistachyon,a model grass closely related to rice and wheat. All proteins were successfullyexpressed in Escherichia coli andpurified to electrophoretic homogeneity by IMAC and gel filtrationchromatography. UDP-sugar pyrophosphorylase (which synthesizes UDPgalactose) displayeda Vmax of 1000 U mg-1 and S0.5 values of 0.25 and 0.06 mM for galactose-1P andUTP, respectively. Galactinol synthase (which produces galactinol) showed aVmax of 8 U mg-1 and S0.5 values of 0.09 and 1.0 mM for UDP-galactose andmyo-inositol, respectively. These results are in good agreement with thosepreviously reported for enzymes from dicotyledonous species. To the best of ourknowledge, this is the first report showing kinetic parameters for UDP-sugarpyrophosphorylase and galactinol synthase from a grass species. We considerthis information will be valuable to better understand the reaction mechanismsand regulatory properties of these enzymes, a key step to obtain geneticallymodified organisms with improved abiotic stress resistance.