Tolerance, arsenic uptake, and oxidative stress in Acacia farnesiana under arsenate-stress
Acacia farnesiana is a shrub widely distributed in soils heavily polluted with arsenic in Mexico. However, the mechanisms by which this species tolerates the phytotoxic effects of arsenic are unknown. This study aimed to investigate the tolerance and bioaccumulation of As by
A. farnesiana seedlings exposed to high doses of arsenate (AsV) and the role of peroxidases (POX) and glutathione S-transferases (GST) in alleviating As-stress. For that, long-period tests were performed in vitro under different AsV treatments. A. farnesiana showed a remarkable tolerance to
AsV, achieving a half-inhibitory concentration (IC50) of about 2.8 mM. Bioaccumulation reached about 940 and 4380 mg As·kg−1 of dry weight in shoots and roots, respectively, exposed for 60 days to 0.58 mM AsV. Seedlings exposed to such
conditions registered a growth delay during the first 15 days, when the fastest As uptake rate (117 mg kg−1 day−1) occurred, coinciding with both the highest rate of lipid peroxidation and the strongest up-regulation of enzyme activities. GST activity
showed a strong correlation with the As bioaccumulated, suggesting its role in imparting AsV tolerance. This study demonstrated that besides tolerance to AsV, A. farnesiana bioaccumulates considerable amounts of As, suggesting that it may be useful for phytostabilization purposes.
Keywords: arsenic phytostabilization; glutathione S-transferase; oxidative stress
Document Type: Research Article
Affiliations: 1: Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa., Iztapalapa, D.F. Mexico, Mexico 2: Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa., Iztapalapa, D.F. Mexico, Mexico 3: Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa., Iztapalapa, D.F. Mexico, Mexico 4: Facultad de Ciencias, Universidad Autónoma del Estado de México, Campus El Cerrillo, Toluca, Estado de México, Mexico
Publication date: 02 July 2016
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