Ecophysiology and genetic analysis of plant adaptation to soil metal contamination

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Excessive concentrations of metals in soil represent serious threats to plant ecosystem sustainability. Knowledge of the effects of long term exposure to high levels of metals on physiological and genetic mechanisms is lacking. In the last 15 years, we have determined soil factors important to tree size distribution, function, adaptation and restoration process in metal contaminated regions; we have assessed the allelic changes and genetic variability of fragmented plant populations growing in metal areas; and we have established a clear linkage between metal contamination and cytological disruption in Deschampsia cespitosa. The genetic mechanisms of plant tolerant to nickel and copper, the main pollutants found in several mining areas in Canada are not well understood. Recently, we have established that the main physiological mechanism involved in D. cespitosa (tufted hair grass) and hardwood species [(Populus tremuloides (poplar), Quercus rubra (red oak), and Acer rubrum (red maple)] tolerance to Cu and Ni are different. The main objectives of this proposed research is to know cell compartment locations of metal and proteins associated with metal accumulation in cells. This can eventually lead us to identifying genes involved in metal tolerance in D. cespitosa and P. tremuloides. Our study will combine electron microscopy, fluorescence in situ, cell culture, and protein characterization techniques to determine cellular and extracellular location et effects of metals along with the transport proteins involved. Genes associated with Cu and Ni tolerance in D. cespitosa will be determined by QTL mapping and linkage analysis using a unique set of Cu and Ni tolerant progenies developed in a D. cespitosa breeding program. Detailed analysis of D. cespitosa from metal contaminated and uncontaminated sites at “omics” levels will be performed to understand metabolic functions associated with Cu and Ni tolerance. Comparative analysis using microarrays will allow the identification of functional gene sets that are differentially regulated during the response to excess Cu and Ni. More importantly, one post-Doctoral fellow, two Ph.D. and two M.Sc. students are expected to be trained during this phase of the research program to fill the void in biotechnology and bioremediation in Canada