The response of Populus spp. to cadmium stress: Chemical, morphological and proteomics study

• Poplar clones analyzed showed a marked physiological and proteomic different response to Cd toxicity.
• Cd exposure caused after 14 d more visible signs of toxicity in clones Poli and 58-861 than in A-4A.
• Proteins expression changed in time and according to the different clones.
• The clone A-4A might be useful for Cd phytoremediation.

Poplar (Populus) species are seen as candidates for removing heavy metal contamination from polluted soil. A bottom-up multidisciplinary approach was utilized to compare the performances of clones 58-861 and Poli (Populus nigra) and A4A, a Populus nigra × Populus deltoides hybrid to Cd toxicity. Qualitative and quantitative differences in their tolerance to Cd exposure and the uptake, accumulation and translocation of Cd were noted following the hydroponic exposure of rooted cuttings to 20 μM CdSO4 for either 48 h or 14 d. Cadmium was less toxic for the hybrid clone A4A as compared to Poli and 58-861. Cd uptake and root to shoot translocation were determined by AAS, and its compartmentation was analyzed using SEM/EDX. A comparative proteomic approach was utilized to identify changes in proteins expression according to dose and time of exposure. Toxicity to Cd mainly influenced proteins related to general defense, stress response and carbohydrate metabolism.