The Ionome

该项目的目标是使用高通量ICP-MS技术来识别控制多种矿物质（“离子素”）摄取和积累的基因网络。目标基因的优先列表基于四个标准。首先，所有的基因都有未知的功能。其次，优先考虑主要在根中表达的基因，因为根的吸收和转运功能对叶片和种子的离子谱有显著影响。第三，优先考虑那些在营养反应中表现出表达谱变化的基因。需要验证的一个关键假设是，表达谱的变化是否可以用于识别功能重要的基因。第四，将优先考虑独特基因，以验证独特基因缺陷比基因组中同源基因突变更容易产生表型的假设。完整的基因列表可在http://www.cbs.umn.edu/arabidopsis/ionome/上获得。所有的离子谱数据都可以在网上获得和搜索，各种线路的种子可以通过ABRC获得。分析离子素及其与其他细胞过程的相互作用对于了解植物如何对养分可用性和有毒金属作出反应至关重要。该合作小组将作为一个“专家中心”来验证5%的基因组在植物矿物质营养中起作用的假设。长期目标是量化拟南芥中每个基因对矿物质营养和离子稳态的功能贡献。主要目的是：对1600个功能未知基因分离的纯合子断裂系以及拟南芥群落提供的数千个其他系的叶片和种子进行离子谱分析（定量分析Fe、Zn、Ca、K、Mn、P、S、Se、Na、Pb、As等）。o进行饱和诱变，使用100,000个快中子诱变系来识别调节矿物质营养积累的基因。o鉴定从FN诱变获得的50多个离子谱突变体中的突变基因。o在10个改变离子谱的细胞系上进行表达谱实验。目标是将离子组和转录组分析结果联系起来，以了解控制离子稳态的网络。更广泛的影响：拟议研究的更广泛影响有四个关键贡献。1)教育拓展将包括对本科生和研究生的培训。2)关于科学对人类健康、农业和生物修复的贡献的信息将通过博物馆展览和与pi当地社区的互动传播。3)研究工具将通过网站和库存中心的种系存款向公众提供。4)将提供基础知识，以促进未来提高产量和更有营养的农作物的工程。对世界上大部分地区来说，植物是必需矿物质的主要来源。以食物为基础的“隐性饥饿”解决方案为营养不良问题提供了可持续的解决方案。因此，该项目将有助于增加植物中的生物可利用矿物质，并解决人类健康的重要问题。此外，了解有毒金属在植物中积累的途径将使作物工程能够排除有毒金属并创造更健康的食物来源，或者从土壤中提取有毒金属作为清理受污染土地和水的策略。

The objective of the project is to use high throughput ICP-MS technology to identify gene networks that control uptake and accumulation of a wide array of minerals, the "ionome". The prioritized list of target genes is based on four criteria. First, all genes have unknown functions. Second, priority has been given to genes expressed primarily in roots, as uptake and translocation functions in the root have a significant influence on leaf and seed ion profiles. Third, priority is given to those genes that show expression profile changes in response to nutrients. A critical hypothesis to be tested is whether expression profiling changes can be used to identify functionally important genes. Fourth, priority will be given to unique genes to test the hypothesis that defects in unique genes are more likely to generate a phenotype than mutations in genes with close homologs in the genome. A complete gene list is available at http://www.cbs.umn.edu/arabidopsis/ionome/. All the ion profiling data will be available and searchable online, with seeds for various lines available through the ABRC. Analysis of the ionome and its interactions with other cellular processes is essential to understand how plants respond to nutrient availability and toxic metals. The collaborative group will serve as a "Center of Expertise" to test the hypothesis that 5% of the genome functions in plant mineral nutrition. The long-term goal is to quantify the functional contribution to mineral nutrition and ion homeostasis of every gene in Arabidopsis. The main objectives are to:o Conduct ion profiling (quantitation of Fe, Zn, Ca, K, Mn, P, S, Se, Na, Pb, As, etc.) in leaves and seeds of 1600 homozygous disruption lines isolated in genes of unknown function, and thousands of additional lines made available by the Arabidopsis community.o Conduct saturation mutagenesis, using 100,000 fast neutron (FN) mutagenized lines to identify genes that regulate mineral nutrient accumulation. o Identify the mutant genes in more than 50 ion profile mutants obtained from FN mutagenesis. o Conduct expression profiling experiments on 10 lines with altered ion profiles. The goal is to correlate ionome and transcriptome profiling results to understand the networks controlling ion homeostasis.Broader Impacts: There are four key contributions to the Broader Impacts of the proposed research. 1) Educational outreach will include training of undergraduate and graduate students. 2) Information on the contribution of science to human health, agriculture, and bioremediation will be disseminated through museum exhibits and interactions with the PIs' local communities. 3) Research tools will be provided to the public through web sites and seed line deposits at stock centers. 4) Fundamental knowledge will be provided to facilitate future engineering of increased yields and of more nutritious agricultural crops. For most of the world, plants are the major source of essential minerals. Food-based solutions to "hidden hunger" offer sustainable solutions to problems of malnutrition. Therefore, this project will contribute to increasing bio-available minerals in plants and to solving important problems in human health. Furthermore, understanding the pathways by which toxic metals accumulate in plants will enable the engineering of crops to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.