Dimethylthiourea, a hydrogen peroxide trap, partially prevents stress effects and ascorbate peroxidase increase in spermidine-treated maize roots |
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Authors: | M De Zacchini & M De Agazio |
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Institution: | Istituto di Biochimica ed Ecofisiologia Vegetali (IBEV), CNR, Via Salaria Km. 29·300, 00016 Monterotondo Scalo, Rome, Italy |
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Abstract: | Inhibition of root growth and accumulation of putrescine caused by exogenous spermidine in roots of maize seedlings (Zea mays L., cv Samodek) were partially prevented by a concomitant treatment with dimethylthiourea (DMTU), that traps H2O2 produced from spermidine by the activity of polyamine oxidase (PAO) in the apoplast. Treatment with spermidine caused a strong increase of ascorbate peroxidase (APX) gene expression, that was induced to a lesser extent by removing spermidine-generated H2O2 by DMTU. Over-expression of APX was associated with increased APX activity in spermidine-treated seedlings whereas the addition of DMTU to spermidine completely prevented spermidine-induced increase of APX activity. Thus, DMTU permitted the demonstration that exogenous spermidine supplied to maize seedlings causes an oxidative stress and induces APX, a key enzyme of the antioxidant defence mechanism, through H2O2, a spermidine catabolic product. |
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Keywords: | Zea mays L APX activity APX m-Rna dimethylthiourea root spermidine |
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