Ecophysiology and genetic analysis of plant adaptation to soil metal contamination

土壤中金属浓度过高对植物生态系统的可持续性构成严重威胁。关于长期接触高水平金属对生理和遗传机制的影响的知识缺乏。近15年来，我们确定了影响金属污染地区树木大小分布、功能、适应和恢复过程的重要土壤因子；对金属区破碎化植物种群的等位基因变化和遗传变异进行了评价；我们已经建立了金属污染与斑蚤细胞学破坏之间的明确联系。在加拿大几个矿区发现的主要污染物镍和铜，植物耐镍和铜的遗传机制尚不清楚。最近，我们已经确定了D. cespitosa（丛生毛草）和阔叶树（杨树）、栎（红橡树）和槭（红枫）对铜和镍的耐受性的主要生理机制不同。本研究的主要目的是了解金属在细胞中的位置和与细胞中金属积累相关的蛋白质。这最终可以帮助我们鉴定出与金属耐受性有关的基因。我们的研究将结合电子显微镜、原位荧光、细胞培养和蛋白质表征技术来确定金属在细胞和细胞外的位置和影响，以及所涉及的运输蛋白质。利用一组独特的铜、镍耐受性后代，通过QTL定位和连锁分析，确定与铜、镍耐受性相关的基因。从金属污染和未污染的位点对D. cespitosa进行“组学”水平的详细分析，以了解与Cu和Ni耐受相关的代谢功能。使用微阵列的比较分析将允许识别在对过量Cu和Ni的反应中受到差异调节的功能基因集。更重要的是，在这一阶段的研究计划中，预计将培养一名博士后，两名博士和两名硕士，以填补加拿大在生物技术和生物修复方面的空白

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