HEME OXYGENASE/CARBON MONOXIDE SYSTEM REGULATES GLUTATHIONE LEVELS IN PLANTS

ZILLI, CG; SANTA CRUZ, DM; TOMARO ML.; BALESTRASSE, KB

Congreso; XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

This objective of this work was to investigate whether hemeoxygenase (HO) is involved in the regulation of GSH. Experimentswere performed in plants treated with Zn-protoporphyrin (ZnPPIX)(specific inhibitor of HO) and then subjected to sodiumnitroprusiate (SNP) concentrations (NO donor, HO inductor) or CO(HO reaction product) for 48 h. In soybean plants pretreated withZnPPIX for 72 h before Hoagland (H) treatment (ZnPPIX/H), GSHlevel diminished 20% respect to controls. NO (ZnPPIX/SNP) aswell as CO (ZnPPIX/H) enhanced GSH levels (40% and 15%,respectively). HO-1 expression decreased and oxidative stressparameters were increased. When the inhibitor was added beforeNO or CO treatment, HO-1 expression as well as GSH content andGR activity were increased. This increase is positively correlatedwith GSH content and GR activity. The enhancement of GSH is notrelated to oxidative stress. In contrast, HO inhibition brought aboutan enhancement (28%) in TBARS levels. In plants treated withZnPPIX, CO does not induce HO-1, but an augmentation of GSHlevels and GR activity was observed. CO released enhanced GRactivity and in this way, GSH content was regulated. These dataprovide evidence of other possible roles that NO, as well as COcould play against the oxidative insult.