IQUIFIB   02644
INSTITUTO DE QUIMICA Y FISICOQUIMICA BIOLOGICAS "PROF. ALEJANDRO C. PALADINI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Metabolomic response of isolated maize embryonic axes to oxidative conditions subjected by cadmium, methylviologen and hydrogen peroxide
Autor/es:
M ARÁN; SM GALLEGO; LB PENA; AAE MÉNDEZ; CJ MORATTO; CL MATAYOSGI
Lugar:
Salta
Reunión:
Congreso; XIV PABMB Congress- LV Annual Meeting of the Argentinean Society for Biochemistry and Molecular Biology Research; 2019
Institución organizadora:
SAIB
Resumen:
Germination process starts with the uptake of water (imbibition) by the dry seed, followed by metabolism reactivation, and ends when radicle protrudes. Successful seed germination will depend on the abilities of the embryo to gain its metabolic activity and for its capacity to cope with adverse environmental conditions. Although high levels of reactive oxygen species (ROS) produce oxidative stress, a basal level of ROS plays fundamental roles in the early stage of embryonic axes imbibitions. The objective of this study was to contribute to understand the metabolomic adjustment that needs to be established to a successful equilibrium between growth and resistance. Intact embryo axes isolated from Zea mays cv. Chalqueño seeds were imbibided with 50 mM Tris-HCl pH 7.6, 50 mM KCl, 2% (w/v) sucrose, 10 mM MgCl2 without (C) or containing 10 μM CdCl2, 0.5 μM methylviologen (MV) or 1 mM H2O2. The study was focused in 24 and 48 h of imbibition. The absolute elongation rate of 0.43 mm d-1 for control axes was reduced 60, 62 and 49% in Cd-, MV- and H2O2-treated ones, respectively. Also, treatments disrupted cell redox balance by inducing the accumulation of O2- and H2O2 and modifying antioxidant enzymes defense system (catalase, superoxide dismutase, ascorbate and guaiacol peroxidases, glutathione and dehydroascorbate reductases). Oxidative cell damage was determined by the increase in protein carbonylation. Increment in proteolytic activities was determined during the axes imbibitions and also during the oxidative conditions generated by treatments. Water-methanol extracts were used to evaluate the polar metabolites profile using nuclear magnetic resonance (H1-NMR) spectroscopy. Hierarchical cluster analysis showed that after 24 h of imbibition, the metabolome of Cd-treated axes showed a lower response respect to MV and H2O2 since its cluster was closer to the control. After 48 h of imbibitions, stress conditions clustered in a group that was distinct to the control. Our results are indicating that during growth arrest, metabolic reorganization of the maize embryonic axes depends on an intense protein degradation to produce free amino acids. This metabolic module would be necessary to improve the cell defence systems, by allowing the synthesis of new proteins and by maintaining metabolic homeostasis.