Heme oxygenase is involved in the protection exerted by jasmonic acid against cadmium stress in soybean roots

NORIEGA, GO; SANTA CRUZ, DM; BATLLE, A; TOMARO, M.L; BALESTRASSE, KB

JOURNAL OF PLANT GROWTH REGULATION

SPRINGER

Lugar: New York; Año: 2011 vol. 31 p. 79 - 89

0721-7595

<!-- @page { size: 21cm 29.7cm; margin: 2cm } P { margin-bottom: 0.21cm } --> The present study was undertaken to test the influence of exogenously applied jasmonic acid (JA) upon the oxidative stress exerted by Cd in soybean plants. It was found that depending on its concentration, JA can improve plant antioxidant responses against Cd. Pre-treatment with 20 µM JA effectively ameliorated Cd induced oxidative stress, as indicated by the decrease in thiobarbituric reactive substances (TBARS) levels, enhancement of glutathione (GSH) content and diminution of H2O2 and O2.- formation. On one hand, the activities of classical antioxidant enzymes, such as catalase (CAT) and superoxide dismutase (SOD) were also augmented by JA treatment This behaviour was not observed in plants treated with Cd alone. On the other hand, 20 µM JA caused the enhancement of heme oxygenase (HO) activity (71% with respect to controls) and protein amount (60% with respect to controls). But no gene induction was observed. Pretreatment with 20 µM JA previous to Cd addition provoked the highest values of HO activity and protein expression (138% and 122% respectively). Once again, these enhancements were not correlated with transcript levels. Plants pretreated with Zn- protoporphyrin IX (ZnPPIX), a well-known irreversible HO-1 inhibitor, could not cope with the oxidative damage caused by Cd. This fact indicates that HO-1 is involved in the protection exerted by JA against the oxidative stress due to Cd treatment.