The heavy metal cadmium (Cd) is a widespread environmental contaminant with harmful effects on living cells. In plants, phytochelatin (PC)-dependent Cd detoxification requires that PC-Cd complexes are transported into vacuoles. Here, it is shown that Arabidopsis thaliana seedlings defective in the ABCC transporter AtABCC3 (abcc3) have an increased sensitivity to different Cd concentrations, and that seedlings overexpressing AtABCC3 (AtABCC3ox) have an increased Cd tolerance. The cellular distribution of Cd was analysed in protoplasts from abcc3 mutants and AtABCC3 overexpressors grown in the presence of Cd, by means of the Cd-specific fluorochromes 5-nitrobenzothiazole coumarin (BTC-5N) and Leadmium™ Green AM dye. This analysis revealed that Cd is mostly localized in the cytosol of abcc3 mutant protoplasts whereas there is an increase in vacuolar Cd in protoplasts from AtABCC3ox plants. Overexpression of AtABCC3 in cad1-3 mutant seedlings defective in PC production and in plants treated with l-buthionine sulphoximine (BSO), an inhibitor of PC biosynthesis, had no effect on Cd tolerance, suggesting that AtABCC3 acts via PCs. In addition, overexpression of AtABCC3 in atabcc1 atabcc2 mutant seedlings defective in the Cd transporters AtABCC1 and AtABCC2 complements the Cd sensitivity of double mutants, but not in the presence of BSO. Accordingly, the level of AtABCC3 transcript in wild type seedlings was lower than that of AtABCC1 and AtABCC2 in the absence of Cd but higher after Cd exposure, and even higher in atabcc1 atabcc2 mutants. The results point to AtABCC3 as a transporter of PC-Cd complexes, and suggest that its activity is regulated by Cd and is co-ordinated with the activity of AtABCC1/AtABCC2. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Cadmium-inducible expression of the ABC-type transporter AtABCC3 increases phytochelatin-mediated cadmium tolerance in Arabidopsis / Brunetti, Patrizia; Zanella, Letizia; De Paolis, Angelo; Di Litta, Davide; Cecchetti, Valentina; Falasca, Giuseppina; Barbieri, Maurizio; Altamura, Maria Maddalena; Costantino, Paolo; Cardarelli, Maura. - In: JOURNAL OF EXPERIMENTAL BOTANY. - ISSN 0022-0957. - STAMPA. - 66:13(2015), pp. 3815-3829. [10.1093/jxb/erv185]

Cadmium-inducible expression of the ABC-type transporter AtABCC3 increases phytochelatin-mediated cadmium tolerance in Arabidopsis

BRUNETTI, PATRIZIA;ZANELLA, LETIZIA
;
CECCHETTI, VALENTINA;FALASCA, Giuseppina;BARBIERI, Maurizio;ALTAMURA, Maria Maddalena;COSTANTINO, Paolo;CARDARELLI, Maura
2015

Abstract

The heavy metal cadmium (Cd) is a widespread environmental contaminant with harmful effects on living cells. In plants, phytochelatin (PC)-dependent Cd detoxification requires that PC-Cd complexes are transported into vacuoles. Here, it is shown that Arabidopsis thaliana seedlings defective in the ABCC transporter AtABCC3 (abcc3) have an increased sensitivity to different Cd concentrations, and that seedlings overexpressing AtABCC3 (AtABCC3ox) have an increased Cd tolerance. The cellular distribution of Cd was analysed in protoplasts from abcc3 mutants and AtABCC3 overexpressors grown in the presence of Cd, by means of the Cd-specific fluorochromes 5-nitrobenzothiazole coumarin (BTC-5N) and Leadmium™ Green AM dye. This analysis revealed that Cd is mostly localized in the cytosol of abcc3 mutant protoplasts whereas there is an increase in vacuolar Cd in protoplasts from AtABCC3ox plants. Overexpression of AtABCC3 in cad1-3 mutant seedlings defective in PC production and in plants treated with l-buthionine sulphoximine (BSO), an inhibitor of PC biosynthesis, had no effect on Cd tolerance, suggesting that AtABCC3 acts via PCs. In addition, overexpression of AtABCC3 in atabcc1 atabcc2 mutant seedlings defective in the Cd transporters AtABCC1 and AtABCC2 complements the Cd sensitivity of double mutants, but not in the presence of BSO. Accordingly, the level of AtABCC3 transcript in wild type seedlings was lower than that of AtABCC1 and AtABCC2 in the absence of Cd but higher after Cd exposure, and even higher in atabcc1 atabcc2 mutants. The results point to AtABCC3 as a transporter of PC-Cd complexes, and suggest that its activity is regulated by Cd and is co-ordinated with the activity of AtABCC1/AtABCC2. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.
ABC-type transporters; Arabidopsis; cadmium stress; cadmium tolerance; phytochelatins; vacuolar compartmentalization; ATP-binding cassette transporters; adaptation physiological; Arabidopsis; Arabidopsis proteins; buthionine sulfoximine; cadmium; cytosol; gene expression regulation plant; mutation; phytochelatins; plant leaves; plants genetically modified; protoplasts; RNA messenger seedlings; vacuoles; plant science; physiology
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Cadmium-inducible expression of the ABC-type transporter AtABCC3 increases phytochelatin-mediated cadmium tolerance in Arabidopsis / Brunetti, Patrizia; Zanella, Letizia; De Paolis, Angelo; Di Litta, Davide; Cecchetti, Valentina; Falasca, Giuseppina; Barbieri, Maurizio; Altamura, Maria Maddalena; Costantino, Paolo; Cardarelli, Maura. - In: JOURNAL OF EXPERIMENTAL BOTANY. - ISSN 0022-0957. - STAMPA. - 66:13(2015), pp. 3815-3829. [10.1093/jxb/erv185]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/898161
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