Populus × canescens grown on Cr-rich tannery waste: Comparison of leaf and root biochemical and proteomic responses

• Cr-rich tannery waste changed the physiological status of Populus × canescens.
• The activation of antioxidative systems suppressed metal stress symptoms.
• The molecular responses were different in the roots and leaves.
• Proteins involved in metabolic adaptation to growth on tannery waste were identified.
• Tannery waste can be a potential substrate for the growth of poplar.

Treatment of tannery effluents generates large amounts of sediments containing concentrated doses of metals (mainly chromium). Such waste is most commonly disposed of by landfilling, which is hazardous to the ecosystem due to Cr leaching. Afforestation of disposal sites with fast growing trees could stabilize contaminants in the soil and prevent them from spreading. The aim of this study was to examine the adaptation of Populus × canescens Sm. to tannery waste using biochemical and proteomic methods. We analyzed changes in the leaves and fine roots of poplar planted in soil or tannery waste. We found no obvious symptoms of metal stress, such as: elevated hydrogen peroxide levels or lipid peroxidation, but we observed activation of many elements of antioxidative system. Comparison of 2-DE protein profiles of leaves and fine roots from poplar grown on soil or tannery waste revealed increased expression of glycolytic enzymes and proteins involved in the synthesis of cell wall components, changes in the levels of proteins associated with photosynthesis, stress-related proteins, proteasome subunits and methionine biosynthesis enzymes. This experiment demonstrated that proteomic analysis has the potential to link the effects of Cr-rich tannery waste with biological consequences.