Integrating Signals in Iron Homeostasis

铁通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，了解植物中的铁代谢是至关重要的，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。 尽管在追踪铁如何在整个植物中移动方面取得了进展，但科学家仍然不了解植物如何整合铁供应和光照条件的信息。该项目将有助于解释一种名为URI的蛋白质如何接收并传递有关细胞铁状态和光质量的信息。 在与科学的新罕布什尔州科学院的合作伙伴关系，在6-12年级的学生将提供研究经验，这将提高他们对所有植物做的赞赏，并教他们如何利用植物的力量，以确保长期的可持续性和健康。NHAS为来自NH和VT广泛地理区域的学生提供夏季和课后基于发现的科学研究计划。他们的推广覆盖农村地区，那里的学生通常很少有机会体验真正的科学研究。 更广泛的影响还包括培训下一代科学家。来自几个不同辅导项目的本科生将参与这项拟议中的工作。铁是植物必需的营养素，但过多的铁可能是有毒的。 因此，植物只在需要时才吸收铁。必需的bHLH转录因子，URI/bHLH 121，需要安装缺铁反应。 一种磷酸化形式的URI在缺铁时积累，与亚组bHLH IVc转录因子形成异二聚体，并诱导另一类转录因子Ib亚组bHLH的转录。这些Ib bHLH又与FIT/bHLH 29异源二聚化，并驱动编码铁转运蛋白IRT 1和铁螯合还原酶FRO 2的基因的转录，以增加铁摄取。虽然控制从土壤中吸收铁的机制现在相对较好地理解，很少有人知道URI如何整合有关铁供应和光照条件的信息。 光是URI磷酸化所必需的，这表明光调节激酶参与其中。 遗传实验旨在确定URI磷酸化是红光还是蓝光反应，以及是否涉及光调节激酶（PPK）家族的成员。 实验还将解决缺铁途径中需要光信息的第二点，即FIT转录因子的诱导。长期目标是了解负责在整个植物水平上协调对缺铁反应的整个基因网络。这一认识将使我们的努力朝着可持续提高作物产量的方向转变，包括植物生产力和养分含量。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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 integrate information about iron supply and light conditions. This project will help to explain how a protein called URI receives and then conveys information about both the iron status of a cell and light quality. In partnership with the New Hampshire Academy of Science, students in grades 6-12 will be offered research experiences that will raise their appreciation for all that plants do and teach them how to leverage the power of plants to ensure long term sustainability and health. NHAS runs summer and after school discovery-based scientific research programs for students from a wide geographic section of NH and VT. Their outreach covers rural areas where students generally have few opportunities to experience authentic scientific research. Broader impacts will also include training the next generation of scientists. Undergraduates from several different mentoring programs will participate in the proposed work.Iron is an essential nutrient for plants, yet too much iron can be toxic. Therefore, plants only take up iron when needed. The essential bHLH transcription factor, URI/bHLH121, is required for mounting the iron deficiency response. A phosphorylated form of URI accumulates under iron deficiency, forms heterodimers with subgroup bHLH IVc transcription factors and induces transcription of another class of transcription factors, the sub-group Ib bHLH. These Ib bHLH in turn heterodimerize with FIT/bHLH29, and drive the transcription of the genes encoding the iron transporter IRT1 and the ferric chelate reductase FRO2, to increase iron uptake. Although the mechanisms controlling iron uptake from the soil are now relatively well understood, little is known about how URI may integrate information about iron supply and light conditions. Light is required for URI phosphorylation, suggesting that a light-regulated kinase is involved. Genetic experiments were designed to determine whether URI phosphorylation is a red light or blue light response, and whether members of the photoregulatory kinase (PPK) family are involved. Experiments will also address a second point in the iron deficiency pathway where light information is required, namely the induction of the FIT transcription factor. The long-term goal is to understand the entire network of genes responsible for orchestrating a coordinated response to iron deficiency at the whole plant level. Such an understanding will transform efforts towards sustainable improvements of crop yields, in terms of plant productivity and nutrient content.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.