Journal
JOURNAL OF PLANT PHYSIOLOGY
Volume 167, Issue 3, Pages 169-175Publisher
ELSEVIER GMBH, URBAN & FISCHER VERLAG
DOI: 10.1016/j.jplph.2009.07.017
Keywords
Arsenic; gamma-Glutamylcysteine; Glutathione; Phytochelatin synthase; Tobacco
Categories
Funding
- EU [QLRT-385 200000479, FOOD-CT-2006-016253]
- MNiSW [K118/TO9/2005]
- COST Action [859]
- EU Mazowieckie Stypendium Doktoranckie
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Phytochelatins (PCs) are small, cysteine-rich peptides, known to play a major role in detoxification of both cadmium and arsenic. The aim of this study was to determine whether overexpression of either of two PC synthase (PCS) genes, AtPCS1 and CePCS in Nicotiana tabacum (previously shown to cause decrease and increase, respectively, of cadmium tolerance of tobacco - Wojas et al., 2008) also contributes to such contrasting phenotypes with respect to arsenic (As) tolerance and accumulation, and how observed responses relate to non-protein thiol (NPT) metabolism. The expression of both genes resulted in an increase of As-tolerance, with CePCS plants most tolerant. We showed for the first time that the response of PCS overexpressing plants to As qualitatively depends on the external As(V) concentration. At the less toxic 50 mu M As(V), AtPCS1 and CePCS transformants accumulated more As in roots and leaves than WT. An increase in PC production and the level of PC2 species was detected in leaves of AtPCS1 and CePCS plants, which might explain their enhanced As-accumulation and tolerance. In contrast, at the highly toxic 200 mu M As(V), several disturbances in thiol metabolism of PCS overexpressing plants were found, surprisingly, including decrease of PC levels both in roots and leaves of transgenic plants relative to WT. The increase in As-tolerance and accumulation due to AtPCS1 and CePCS overexpression, observed at the As(V) concentrations similar to those found in As-contaminated soils, makes these genes promising candidates for plant engineering for phytoremediation. (C) 2009 Elsevier GmbH. All rights reserved.
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