Gene Discovery in Aid of Plant Nutrition, Human Health and Environmental Remediation

植物对矿质营养的吸收和转运是植物生长和人类营养所必需的。 尽管最近在确定参与营养物质运输的基因方面取得了进展，但控制个体营养物质获得的系统仍然在很大程度上未知。 该项目的主要目标是确定控制各种植物养分和有毒金属的吸收和积累的基因网络。 该方法利用电感耦合等离子体原子发射光谱（ICP-AES）的最新技术进步，现在允许在35秒内测量每个植物样品中多达72种不同的元素。 确定控制溶质吸收和积累的基因对农业、人类健康和环境具有重要意义。 例如，提高作物调动土壤养分的能力应减少化肥的使用，从而使农业更具成本效益，污染更少。 由于植物是人类的主要食物来源，无论是直接还是通过动物饲料，植物的营养价值对人类健康至关重要。 世界上最普遍的营养问题是缺铁。 提高植物提供更高水平的矿物质（如铁）的能力将对人类健康产生巨大影响。 此外，了解有毒金属在植物中积累的途径将使植物工程能够排除有毒金属并创造更健康的食物来源，或从土壤中提取有毒金属作为清理污染土地和水的策略。 该项目的主要目标是：1）利用生物信息学来识别可能编码转运蛋白的基因。2)使用mRNA表达谱来识别响应营养剥夺或过度喂养而改变表达的基因。3)使用营养分析来筛选元素组成异常的突变植物。 ICP-AES将用于高通量策略，以确定约50，000个“标记”诱变植物（拟南芥和水稻或玉米，如果标记品系在第2年容易获得）的相对元素组成。4)使用酵母获得植物同源基因的功能预测。 主要方法是对大约5，000个酵母敲除系进行ICP-AES营养分析。5）建立一个网站，提供数据集访问和增强的基因注释。6）启动合作研究，重点关注控制Fe的选定突变、锌、K、钠、钙、硒和镉，以进一步证明这种新方法的力量。7）建立一个计划，培养本科生和研究生在基因组学，信息学和植物分子生物学技术。8)与蒙特希尔科学博物馆合作，开发关于环境中金属的科学课程。该项目将从功能上确定许多重要的基因，包括参与以下活动的基因：1）根际养分的动员，2）细胞吸收和流出系统，3）溶质的亚细胞区室化，4）韧皮部和木质部转运系统的运作，5）中枢调节机制，6）感测营养水平，以及7）控制根结构。 这项功能性基因组研究将提供第一幅涉及所有生命系统的基本特征--必需矿物质选择性积累的基因的综合图片。参与者：玛丽卢格里诺，PI，达特茅斯学院大卫艾德，联合PI，密苏里大学迈克尔格里布斯科夫，联合PI，加州大学圣地亚哥分校杰弗里F。哈珀，共同PI，斯克里普斯研究所大卫E。盐，合作PI，北方亚利桑那大学朱利安一。Schroeder，合作PI，加州大学圣地亚哥分校

Uptake and translocation of mineral nutrients in plants is essential for plant growth and human nutrition. In spite of recent advances in identifying genes involved in nutrient transport, the systems that control acquisition of individual nutrients remain largely unknown. The major objective of the project is to identify gene networks that control uptake and accumulation of a wide array of plant nutrients and toxic metals. The approach makes use of recent technical advances in inductively-coupled plasma atomic emission spectroscopy (ICP-AES) which now permit the measurement of up to 72 different elements in 35 seconds per plant sample. Identifying genes controlling solute uptake and accumulation has significance for agriculture, human health and the environment. For example, enhancing the ability of a crop plant to mobilize soil nutrients should reduce the use of fertilizers, thereby making agriculture more cost efficient and less polluting. Because plants are the primary source of food for humans, either directly or through animal feed, the nutritional value of plants is of central importance to human health. The most widespread nutritional problem in the world is iron deficiency. Increasing the ability of plants to provide higher levels of minerals, such as iron, will have a dramatic impact on human health. Furthermore, understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants 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. The main aims of the project are to:1) Use bioinformatics to identify genes that potentially encode transporters. 2) Use mRNA expression profiling to identify genes that change expression in response to nutrient deprivation or overfeeding. 3) Use nutrient profiling to screen for mutant plants with abnormal element compositions. ICP-AES will be used in a high-throughput strategy to determine the relative element composition of approximately 50,000 "tagged" mutagenized plants (Arabidopsis and either rice or maize if tagged lines are readily available in year 2). 4) Use yeast to obtain functional predictions of plant orthologs. The primary approach will be to conduct ICP-AES nutrient profiling of approximately 5,000 knockout lines of yeast.5) Establish a Web site to provide access to data sets and enhanced annotation of genes.6) Initiate collaborative research focused on selected mutations that control accumulation of Fe, Zn, K, Na, Ca, Se and Cd to further demonstrate the power of this novel approach.7) Establish a program to train undergraduate and graduate students in genomics, informatics and plant molecular biological techniques. 8) Work with the Montshire Museum of Science to develop science curricula on metals in the environment.This project will functionally identify many important genes, including those that are involved in: 1) mobilizing nutrients in the rhizosphere, 2) cellular uptake and efflux systems, 3) subcellular compartmentalization of solutes, 4) the operation of phloem and xylem translocation systems, 5) central regulation mechanisms, 6) sensing nutrient levels, and 7) controlling root structure. This functional genomic investigation will provide the first integrated picture of the genes involved in a fundamental feature of all living systems - the selective accumulation of essential minerals.Participants:Mary Lou Guerinot, PI, Dartmouth CollegeDavid Eide, Co-PI, University of MissouriMichael Gribskov, Co-PI, University of California at San DiegoJeffrey F. Harper, Co-PI, The Scripps Research InstituteDavid E. Salt, Co-PI, Northern Arizona UniversityJulian I. Schroeder, Co-PI, University of California at San Diego