Integrating Signals in Iron Homeostasis

将信号整合到铁稳态中

• 批准号: 2343917
• 负责人: Mary Lou Guerinot
• 金额: $ 80.92万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2343917&HistoricalAwards=false
• 关键词: Integrating; Signals; Iron; Homeostasis

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.

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并不富含铁，这使得缺铁成为当今世界最普遍的营养问题。显然，从改善植物生长和作物产量以及改善人类营养的角度来看，了解植物中的铁代谢至关重要。 尽管在追踪铁如何在植物中移动方面取得了进展，但科学家们仍然不明白植物如何整合有关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。 与新罕布什尔州科学院合作，将为 6 至 12 年级的学生提供研究经验，提高他们对植物所做的一切的认识，并教会他们如何利用植物的力量来确保长期的可持续性和健康。 NHAS 为来自新罕布什尔州和佛蒙特州广大地理区域的学生开展暑期和课后发现型科学研究项目。他们的服务范围覆盖农村地区，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。来自多个不同指导项目的本科生将参与拟议的工作。铁是植物的必需营养素，但过多的铁可能有毒。 因此，植物仅在需要时吸收铁。必需的 bHLH 转录因子 URI/bHLH121 是产生缺铁反应所必需的。 URI 的磷酸化形式在缺铁时积累，与 bHLH IVc 转录因子亚组形成异二聚体，并诱导另一类转录因子 Ib bHLH 亚组的转录。这些 Ib bHLH 反过来与 FIT/bHLH29 异二聚化，并驱动编码铁转运蛋白 IRT1 和铁螯合还原酶 FRO2 的基因转录，以增加铁的吸收。尽管现在人们对控制从土壤中吸收铁的机制已经有了相对较好的了解，但对于 URI 如何整合有关铁供应和光照条件的信息却知之甚少。 URI 磷酸化需要光，这表明涉及光调节激酶。 基因实验旨在确定 URI 磷酸化是红光反应还是蓝光反应，以及光调节激酶 (PPK) 家族成员是否参与其中。 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协调整个植物水平缺铁反应的整个基因网络。这种理解将在植物生产力和营养成分方面转变为可持续提高作物产量的努力。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。