Ecophysiology and genetic analysis of plant adaptation to soil metal contamination

土壤金属浓度过高对植物生态系统的可持续性构成严重威胁。本研究项目旨在获取具有生物修复潜力的重要植物物种如何应对金属污染的新基础知识。我们的实验室首次证明了Deschampsia cespitosa（簇毛草）是一种金属排斥物；tremuloides（颤杨），Betula papyrifera（白桦树）和Quercus rubra（红橡树）是蓄能器，Acer rubrum（红枫）使用回避来应对金属。我们已经建立了B. papyrifera， A.rubrum和A. saccharum（银枫）的耐镍遗传。重要的是;我们完成并鉴定了纸莎草杆菌的首个转录组。我们已经从这个转录组中鉴定出5个耐镍候选基因。我们认为，为了更好地了解植物对金属污染的应对机制，最有力的替代方法是使用多种方法的组合。利用遗传分析、转录组测序和RT-qPCR对五个目标植物物种进行比较分析，将使鉴定在对过量镍和铜的反应中受到差异调节的功能基因集成为可能。电子显微镜、原位荧光和蛋白质表征技术将用于建立细胞和细胞外分布图，以及Ni和Cu的主要作用以及所涉及的转运蛋白。我们将通过LC- MS/MS、甲基化敏感扩增多态性（MSAP）和减少代表性测序（RRS）加深我们对DNA甲基化的理解。我们研究项目的信息将有助于构建重金属稳态是如何实现的，以及不同基因的作用，认识到不同物种中转运体的运作可能存在重大差异，例如金属积聚体和排除体。挑战在于定义和操纵植物吸收、挤压和划分金属的机制，并将它们重新分配到不同的组织中。如果我们作为科学家实现了这些目标，我们不仅回答了一些基本问题，而且还可以解决重大的生物技术应用，这些应用可以在人类营养和植物修复方面得到利用。因此，为这些应用设计或选择工厂的策略无疑是非常重要的。

Excessive soil concentrations of metals represent serious threats to plant ecosystem sustainability. This research program aims to acquire new fundamental knowledge on how key plant species with high potential in bioremediation cope with metal contamination. Our lab has demonstrated for the first time that Deschampsia cespitosa (tufted hair grass) is a metal excluder; Populus tremuloides (trembling aspen), Betula papyrifera (white birch), and Quercus rubra (red oak) are accumulators, and Acer rubrum (red maple) uses avoidance to cope with metals. We have established the genetics of nickel resistance in B. papyrifera, A.rubrum, and A. saccharum (silver maple). Importantly; we have completed and characterized the first transcriptome of B. papyrifera. We have identified five candidate genes for nickel resistance from this transcriptome. We believe that the most robust alternative to facilitate a better understanding of plant coping mechanisms to metal contamination is to use a combination of approaches. Comparative analysis of five targeted plant species using genetic analysis, transcriptome sequencing and RT-qPCR will allow the identification of functional gene sets that are differentially regulated during the response to excess nickel and copper. Electron microscopy, fluorescence in situ, and protein characterization techniques will be used to establish cellular and extracellular distribution maps as well as main effects of Ni and Cu along with the transport proteins involved. We will deepen our understanding of DNA methylation by using LC- MS/MS, methylation-sensitive amplified polymorphism (MSAP), and reduced representation sequencing (RRS). The information from our research program will contribute to building a picture of how heavy metal homeostasis is achieved, and the role of different genes, recognizing that there may be major differences in the operation of transporters in different species e.g. metal accumulators and excluders. The challenge is to define and manipulate the mechanisms by which plants take up, extrude and compartmentalize metals, and also redistribute them in the different tissues. If we achieve these goals as scientists, we will not only have answered a number of fundamental questions but also can address significant biotechnological applications, which can be exploited, both in terms of human nutrition and phytoremediation. Thus strategies to engineer or select plants for such applications will undoubtedly be very important.