Oxidative stress and immunolocalization of heme oxygenase in soybean plants

BALESTRASSE, KARINA B.; ZILLI, CARLA G.; SANTA-CRUZ, DIEGO M.; TOMARO, MARÍA L.

Villa Carlos Paz, Córdoba, Argentina

Congreso; XLIII Reunión Nacional de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2008

SAIB

We have previously demonstrated that the induction of heme oxygenase-1 (HO-1) (EC 1.14.99.3) plays a protective role for plant cells against oxidative stress. Here, we investigated the possible signal transduction pathways involved in HO-1 induction in soybean leaves and we determined for the first time the tissular localization of HO-1 in soybean nodules subjected to salt stress. Treatment with 100 mM NaCl in leaves increased 30% TBARS content, whereas GSH decreased 50%, respect to controls. These effects were prevented by preincubation with NADPH oxidase inhibitor, guanylate cyclase inhibitor or LaCl3 (calcium channel blocker). Treatment with 100 mM NaCl were used for immunohistochemical studies which did not allow properly establish the enzyme localization in soybean nodules, but electron-microscope examination of immunogold-labeled sections of nodules showed that the inducible isoform of HO was only present on the peribacteroid membrane. These results clearly demonstrated that the signal transduction pathways involved in oxidative stress, triggered by salt were similar to those implicated in HO-1 induction, and provide additional information suggesting that HO might play a key role in the antioxidative protection machinery of higher plants.