Integrating Iron Sensing and Iron Deficiency Signaling in Plants

铁常常限制植物生长和农业产量。此外，超过20亿人缺铁，因为他们的植物性饮食不是铁的丰富来源，使缺铁成为当今世界最普遍的营养问题。显然，无论是从改善植物生长和作物产量的角度，还是从改善人类营养的角度来看，了解植物中的铁代谢都是至关重要的。尽管在追踪铁如何在植物中移动方面取得了进展，但科学家们仍然不了解植物如何感知和响应铁的可获得性。这个项目将有助于解释一种名为URI的蛋白质是如何接收并传递有关细胞铁状态的信息的。从植物生产力和植物养分含量来看，这类信息应转变为可持续提高作物产量的努力。与石溪大学艾伦·阿尔达科学传播中心合作，将举办研讨会，培训科学家更有效地与广大受众进行沟通：科学家即兴创作、提炼你的信息和科学写作。当然，这样的培训对所有科学家都很重要，但对从事转基因食品领域工作的科学家来说尤其重要。铁是植物必不可少的营养物质。它具有接受和给予电子的功能，在光合作用和呼吸作用的电子传递链中发挥着重要作用。虽然控制土壤铁吸收的机制相对较好，但对植物缺铁信号知之甚少。这项拟议的研究将建立在Pi对IRT1(Uri)上游调控基因突变的分离的基础上，该突变不再显示根中大多数铁调控基因的诱导。原因突变映射到bHLH转录因子的编码区，该编码区本身不受铁供应的转录调控。实验旨在测试有关URI的磷酸化状态、稳定性和/或定位的变化如何传递有关铁状态变化的信息的假说。磷酸化残基将通过质谱学鉴定，并将构建磷酸仿体以确认哪些残基对URI活性重要。将使用表达URI-GFP融合蛋白的转基因植物来评估蛋白质的半衰期。这些植物也将被用来确定URI是否经历了核质洗牌，以响应铁水平的变化。第四组实验解决了URI直接与铁结合的假设，这改变了它的活性/稳定性和/或定位。长期目标是了解整个基因网络，该网络负责整合有关铁状态的信息并协调反应。植物铁营养的改善将使植物能够更好地在目前被认为是边缘的土壤上生长，并将增加目前种植的土壤上的作物生物量。重要的是，富铁种子的生产应带来农艺效益，如增加苗木活力、抵抗疾病和其他胁迫、提高作物产量，同时还应通过提供富铁食物来解决人类健康中的一个重要问题。

Iron often limits plant growth and agricultural yield. Furthermore, more than 2 billion people are iron deficient because their plant-based diets are not a rich source of iron, making iron deficiency the most prevalent nutritional problem in the world today. Clearly, understanding iron metabolism in plants is crucial, both from the point of view of improving plant growth and crop yields as well as improving human nutrition. Despite progress in tracing how iron moves throughout the plant, scientists still do not understand how plants sense and respond to iron availability. This project will help to explain how a protein called URI receives and then conveys information about the iron status of a cell. Such information should transform efforts towards sustainable improvements of crop yields in terms of plant productivity and plant nutrient content. In partnership with the Alan Alda Center for Communicating Science at Stony Brook University, workshops will be offered to train scientists to communicate more effectively with broad audiences: Improvisation for Scientists, Distilling your Message and Science Writing. Such training is, of course, important for all scientists but it is especially important for scientists who work in the area of genetically modified foods.Iron is an essential nutrient for plants. It functions to accept and donate electrons and plays important roles in the electron transport chains of photosynthesis and respiration. Although the mechanisms controlling iron uptake from the soil are relatively well understood, little is known about iron deficiency signaling in plants. The proposed research will build upon PI's isolation of a mutant, upstream regulator of IRT1 (uri), that no longer shows induction of most of the iron-regulated genes in the root. The causal mutation maps to the coding region of a bHLH transcription factor that itself is not transcriptionally regulated by iron availability. Experiments have been designed to test hypotheses on how changes in URI's phosphorylation state, stability and/or localization convey information about changes in iron status. Phosphorylated residues will be identified via mass spectrometry and phosphomimics will be constructed to confirm which residues are important for URI activity. Protein half -life will be assessed using transgenic plants expressing a URI-GFP fusion protein. These plants will also be used to determine whether URI undergoes nucleocytoplasmic shuffling in response to changes in iron levels. The fourth set of experiments address the hypothesis that URI binds iron directly and this alters its activity/stability and/or localization. The long-term goal is to understand the entire network of genes responsible for integrating information about iron status and orchestrating a coordinated response. The improvement of plant iron nutrition will deliver plants better able to grow in soils now considered marginal and will increase crop biomass on soils now in cultivation. Importantly, the production of iron-rich seed should lead to agronomic benefits such as increased seedling vigor, resistance to disease and other stresses and increased crop yields, while also addressing an important problem in human health by providing iron-rich foods.