The metabolic effects of mercury during the biological cycle of vines (Vitis vinifera)

Mercury (Hg) is a major environmental pollutant that can be disposed to the environment by human activities, reaching crops like vineyards during irrigation with contaminated waters. A 2-year study was performed to monitor Hg variations during reproductive and vegetative stages of vines after Hg supplementation. Variations were focused on total Hg concentration, the molecular weight of Hg fractions and Hg-proteins associations in roots, stems and leaves. Total Hg concentrations increased during reproductive stages and decreased during vegetative stages. Variations in length of these stages were observed, according to an extension of the vegetative period. Six months post Hg administration, in roots, stems and leaves, initial Hg proteic fractions of 200 kDa were catabolized to 66 kDa fractions according to a transition from reproductive to vegetative stages. However, 24 months after Hg supplementation, the 66 kDa Hg proteic fraction was continuously determined in a prolonged senescence. Accordingly, the identified proteins associated to Hg show catabolic functions such as endopeptidases, hydrolases, glucosidases and nucleosidases. Stress associated proteins, like peroxidase and chitinase were also found associated to Hg. During the reproductive periods of vines, Hg was associated to membrane proteins, such as ATPases and lipid transfer proteins, especially in roots where Hg is absorbed.