Genome-Wide Hunt For Metal Hyperaccumulation Genes

01297747大卫E.本项目的总体目标是鉴定与金属超积累植物中金属超积累有关的基因。这些独特的植物物种能够积累0.1%至3%的地上部干生物量的镉，镍，硒或锌取决于物种。这些特性对于目前利用植物清理金属污染场地（植物补救）的努力可能是非常宝贵的。 已知的重金属富集物由于体积小、生长缓慢，不太适合植物修复。 然而，它们是金属过度积累基因的独特来源。超过25%的已知超富集植物是拟南芥科的成员，因此它们与拟南芥有关。通过对A.研究人员将利用拟南芥基因组计划期间开发的技术和遗传资源，利用强大的功能基因组学技术在遗传水平上剖析金属超积累。将收集来自世界各地的菊科植物中的金属超积累，并将使用三种互补的方法来确定超积累中的重要基因。将从北美、法国、德国、奥地利、意大利、希腊和土耳其收集来自菊科中20多种不同种的金丝桃属的大约40个种质的种子。将鉴定发现适合于T-DNA插入诱变的金属超氧化物的加入，并将产生超过100，000个遗传系。 在正向遗传方法中，将筛选这些品系中表现出金属敏感性和金属超积累丧失的突变体。将从这些突变体中分离出T-DNA标记的基因，并确定它们在金属超积累中的作用。在反向遗传方法中，将从这些品系中产生基因组DNA池，并通过PCR筛选以鉴定在已知或怀疑参与金属超积累的基因中含有T-DNA插入的品系。助理拟南芥基因组序列将为这种反向遗传方法提供丰富的候选基因来源。在第三种方法中，cDNA表达文库将在E.大肠杆菌和酵母菌的超积累物种和筛选基因赋予重金属抗性和敏感性。总之，这些方法将提供一个全面的框架，在植物中的金属超积累的基因识别。 本项目中确定的基因组将为未来开发适合于金属污染场地植物修复的植物提供宝贵的资源。该项目由环境保护局、国家科学基金会、海军研究办公室和战略环境研究与发展计划共同赞助的植物修复联合计划资助。

01297747David E. SaltThe overall objective of this project is to identify genes involved in metal hyperaccumulation in metal-hyperaccumulating plants. These unique plant species are able to accumulate between 0.1 and 3% of their shoot dry biomass as Cd, Ni, Se or Zn depending on the species. Such characteristics could be invaluable in current efforts to use plants to clean metal-contaminated sites (phytoremediation). The known metal hyperaccumulators are not well suited for phytoremediation because of their small size and slow growth. However, they are a unique source of genes for metal hyperaccumulation. Over 25% of the known hyperaccumulator species are members of the Brassicaceae family, and as such they are related to Arabidopsis thaliana. By investigating the molecular genetics of metal hyperaccumulation in species related to A. thaliana, the investigators will utilize the technical and genetic resources developed during the Arabidopsis genome project, harnessing powerful functional genomics technologies to dissect metal hyperaccumulation at the genetic level. Metal hyperaccumulators in the Brassicaceae will be collected from around the world, and genes important in hyperaccumulation will be identified using three complementary approaches. Seed from approximately 40 accessions of over 20 different species of hyperaccumulators in the Brassicaceae family will be collected from North America, France, Germany, Austria, Italy, Greece and Turkey. Accessions of metal hyperaccumulators found to be amenable to T-DNA insertional mutagenesis will be identified and over 100,000 genetic lines will be generated. In a forward genetic approach, these lines will be screened for mutants exhibiting metal-sensitivity and loss of metal-hyperaccumulation. T-DNA tagged genes from these mutants will be isolated, and their role in metal hyperaccumulation determined. In a reverse genetic approach, genomic DNA pools will be generated from these lines and screened by PCR to identify lines containing T-DNA insertions in genes already known or suspected to be involved in metal hyperaccumulation. The A. thaliana genome sequence will provide a rich source of candidate genes for this reverse genetic approach. In a third approach, cDNA expression libraries will be created in E. coli and yeast from hyperaccumulating species and screened for genes conferring heavy-metal resistance and sensitivity. Taken together these approaches will provide a comprehensive framework for the identification of genes involved in metal hyperaccumulation in plants. The set of genes identified in this project will provide a valuable resource for the future development of plants ideally suited for the phytoremediation of metal polluted sites. This project was funded through the Joint Program on Phytoremediation, co-sponsored by the Environmental Protection Agency, the National Science Foundation, the Office of Naval Research, and the Strategic Environmental Research and Development Program.