The Greater Sudbury Region (GSR) is one of the most ecologically disturbed regions of Canada. Recent studies have shown that Betula papyrifera accumulate metals in roots or leaves. The main objectives of the present study were to 1) determine the effects of copper treatment on B. papyrifera under controlled conditions and 2) assess the level of expression of genes associated with copper resistance in B. papyrifera populations from metal-contaminated and uncontaminated areas. Significant differences for damage rating were observed among copper dosages after eight days of treatment. There was also a trend of reduced plant growth as the dosage increased. RT-qPCR analysis showed 2x to 25x increase in leaves compared to roots of the expression of the gene for Multi-drug resistance associated protein (MRP4) belonging to the subfamily of ATPbinding cassette (ABC) transporters. A significant upregulation (ranging from 3x to 8 x increase) of

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Toxicity of metals is a major abiotic stressor of plants. Copper (Cu) is one of the most abundant metals in soils from the Greater Sudbury Region (GSR) due to its mining history. Recent studies have described several transporters and chelating proteins involved in copper resistance. Quercus rubra (Red Oak) is a common species that grows in metal contaminated soils in Northern Ontario (Canada). The main objectives of this study were1) to evaluate the toxicity of copper to Q. rubrum plants and 2) assess the level of transcriptionof genes associated with copper resistance (RAN1, MT2b and MRP4). Q. rubra seedlings were grown in growth chambers and treated with copper at different doses. Total RNA was extracted from leaves and amplified by RT-qPCR. All the plants tested were resistant to Cu even at high concentrations of 1312 mg of Cu per kg of dry soil since no damage associated with Cu toxicity was observed after 14 days of treatment. RAN1 transporter and the chelating protein MT2b were significantly downregulated (p≤0.05) at high doses of 656 mg and 1312 mg of copper per kg of dry soil compared to water control. The transcription of MRP4 was significantly increased in the presence of copper at a concentration of 1312 mg/kg. No gene demonstrated differential transcription in samples treated with a low dose of 130 mg of copper/kg of dry soil that is equivalent to the bioavailable amount of copper under natural conditions in the Greater Sudbury Region.

Although many studies have reported mechanisms of resistance to metals in herbaceous species, there is very little information on metal coping strategy in hardwood species such as Quercus rubra. The main objective of this study was to determine the expression of genes associated with nickel resistance in red oak (Q. rubra) populations from metal contaminated and uncontaminated sites in the Northern Ontario. Six genes associated with nickel resistances in model and non-model plants were targeted. Differential expressions of these genes were observed in Q. rubra from all the sites, but association between metal contamination and gene expression was not established. This suggests that the bioavailable amounts of metals found in metal contaminated soils in mining sites in northern Ontario and likely in many mining regions around the world cannot trigger a genetic response in higher plant species.