HEME OXYGENASE BEHAVIOUR AND OXIDATIVE STRESS SIGNALLING IN SOYBEAN LEAVES SUBJECTED TO SALT STRESS

SANTA CRUZ, D; ZILLI, C; BALESTRASSE, K; TOMARO, ML

Rosario, Argentina

Congreso; XIII Reunión Latinoamericana. XXVII Reunión Argentina de Fisiología Vegetal; 2008

SAFV

We have previously demonstrated that the induction of heme oxygenase-1 (EC 1.14.99.3) plays a protective role for soybean plants against cadmium and UV-B stress. Here, we have investigated the possible signal transduction pathways involved in haem oxygenase-1 induction in leaves of soybean plants subjected to salt stress. Treatment with 100 mM NaCl during 48 h increased 30% thiobarbituric acid reactive substances, whereas GSH decreased 50%, respect to controls. These effects were prevented by preincubation with diphenyleneiodonium (DPI, NADPH oxidase inhibitor), [1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, guanylate cyclase inhibitor) or LaCl3 (calcium channel blocker). 100 mM NaCl produced in situ accumulation of H2O2 and O2?-, which were also prevented by DPI, ODQ or LaCl3. Moreover, salt- induced haem oxygenase-1 activity was too totally abolished by pretreatment with the different inhibitors. These results clearly demonstrated that the signal transduction pathways involved in oxidative stress, triggered by salt stress were similar to those implicated in heme oxygenase-1 induction, and provide additional information suggesting that heme oxygenase might play a key role in the anti-oxidative protection machinery of higher plants.