Increase in ascorbate-glutathione metabolism as local and precocious systemic responses induced by cadmium in durum wheat [Triticum durum] plants

Durum wheat plants (Triticum durum cv Creso) were grown in the presence of cadmium (0-40 microM) and analysed after 3 and 7 d for their growth, oxidative stress markers, phytochelatins, and enzymes and metabolites of the ascorbate (ASC)-glutathione (GSH) cycle. Cd exposure produced a dose-dependent...

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Bibliographic Details
Published in:Plant and cell physiology 2008-03, Vol.49 (3), p.362-374
Main Authors: Paradiso, A.(Universita degli Studi di Bari (Italy)), Berardino, R, de Pinto, M.C, di Toppi, L.S, Storelli, M.M, Tommasi, F, De Gara, L
Format: Article
Language:English
Subjects:
ACIDE ASCORBIQUE
ACIDO ASCORBICO
Ascorbate–glutathione cycle
ASCORBIC ACID
Ascorbic Acid - metabolism
CADMIO
CADMIUM
Cadmium - pharmacology
Dose-Response Relationship, Drug
ESTRES OXIDATIVO
FITOQUELATOS
GLUTATHION
GLUTATHIONE
Glutathione - metabolism
GLUTATION
HYDROGEN PEROXIDE
l-Galactono-γ-lactone
Oxidation-Reduction
OXIDATIVE STRESS
PEROXIDO DE HIDROGENO
PEROXYDE D'HYDROGENE
PHYTOCHELATINE
PHYTOCHELATINS
Phytochelatins - biosynthesis
Plant Leaves - drug effects
Plant Leaves - metabolism
Plant Roots - drug effects
Plant Roots - metabolism
RACINE
RAICES
ROOTS
STRESS OXYDATIF
Sugar Acids - metabolism
Triticum - drug effects
Triticum - growth & development
Triticum - metabolism
TRITICUM DURUM
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Summary:Durum wheat plants (Triticum durum cv Creso) were grown in the presence of cadmium (0-40 microM) and analysed after 3 and 7 d for their growth, oxidative stress markers, phytochelatins, and enzymes and metabolites of the ascorbate (ASC)-glutathione (GSH) cycle. Cd exposure produced a dose-dependent inhibition of growth in both roots and leaves. Lipid peroxidation, protein oxidation and the decrease in the ascorbate redox state indicate the presence of oxidative stress in the roots, where H2O2 overproduction and phytochelatin synthesis also occurred. The activity of the ASC-GSH cycle enzymes significantly increased in roots. Consistently, a dose-dependent accumulation of Cd was evident in these organs. On the other hand, no oxidative stress symptoms or phytochelatin synthesis occurred in the leaves; where, at least during the time of our analysis, the levels of Cd remained irrelevant. In spite of this, enzymes of the ASC-GSH cycle significantly increased their activity in the leaves. When ASC biosynthesis was enhanced, by feeding plants with its last precursor, L-galactono-gamma-lactone (GL), Cd uptake was not affected. On the other hand, the oxidative stress induced in the roots by the heavy metal was alleviated. GL treatment also inhibited the Cd-dependent phytochelatin biosynthesis. These results suggest that different strategies can successfully cope with heavy metal toxicity. The changes that occurred in the ASC-GSH cycle enzymes of the leaves also suggest that the whole plant improved its antioxidant defense, even in those parts which had not yet been reached by Cd. This precocious increase in the enzymes of the ASC-GSH cycle further highlight the tight regulation and the relevance of this cycle in the defense against heavy metals.
ISSN:0032-0781
1471-9053
DOI:10.1093/pcp/pcn013