Perception and integration of nutritional signals in plant root systems: Solving the mystery of K-Fe-P interactions.

植物根系中营养信号的感知和整合：解决 K-Fe-P 相互作用之谜。

基本信息

批准号：
BB/N018508/1
负责人：
Anna Amtmann
金额：
$ 62.84万
依托单位：
University of Glasgow
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FN018508%2F1
关键词：
Perception integration nutritional signals plant

项目摘要

Mineral elements are essential to human nutrition. For example, potassium (K) is the major electrolyte in the human body and is required for kidney, muscle, nerve and heart functions. Iron (Fe) is a component of redox enzymes enabling cellular energy metabolism and of hemoglobin carrying oxygen to the brain and to the peripheral tissues. Minerals are introduced into the food chain through plants. Their root systems actively forage the soil for beneficial mineral nutrients and extract them with the help of specialized transport proteins. As for humans, mineral nutrition is essential for plant health. The importance of the root system for yield and nutritional value of food crops has been recognized, and root research has taken a center stage in food security.Plants can perceive signals about mineral nutrient availability in the soil and translate them into developmental and physiological processes that adapt root shape and transport activity, thereby maximizing foraging and uptake capacity. If we want to enhance nutrient usage efficiency of crops we need to understand the signaling pathways that mediate between soil conditions and root adaptations. The underlying mechanisms are complicated. Root systems act simultaneously as receptors perceiving nutrient availability and as effectors carrying out nutrient uptake. To achieve the best result they need to differentially regulate growth of individual root parts and transport in different cells. Without a centralized brain this involves both local and systemic signals and responses. Roots also need to integrate information on different nutrients and prioritize their responses, which requires crosstalk between individual nutrient signaling pathways.We have recently made several discoveries that should enable a better understanding of how plants process multiple nutrient signals and regulate root system architecture. We identified two different ecotypes of the model species Arabidopsis thaliana that respond differently to low K supply. The Columbia (Col-0) accession maintains growth of the primary root but halts lateral root extension, thus displaying a long, narrow root system. By contrast, Catania (Ct-1) halts main root growth but extends lateral roots thus displaying a short, bulky root system. Both accessions look very similar when K supply is sufficient. Surprisingly, we could transform the Ct-1 root phenotype into the Col-0 root phenotype by subjecting the plants to low Fe together with low K - both accessions now developed long, narrow root architectures. Fe is known to play a role in root responses of Col-0 to low P, nevertheless, both accessions showed a similar response to low P (inhibition of main root only). Clearly, the Col-0/Ct-1 pair provides us with an excellent experimental model to discover the molecular processes that underpin developmental decisions of plants under nutrient stress, and to unravel nutrient-nutrient interactions.In this project, we will combine electrophysiological methods and confocal microscopy with molecular genetics and automated root phenotyping to address the following questions: How is low-K perceived by root cells and what is the link to Fe redox metabolism? Which cellular processes underlie main root inhibition? Which signals link developmental responses of the main root with those of the lateral roots? How do different root architectures impact on nutrient uptake and on final nutrient contents in the leaves? Which genes determine root architectural responses to nutrient signals? The results from this study can be expected to lead to a detailed understanding of the fundamental biological processes and genetic components that link soil-derived nutrient signals with root development and nutrient uptake. In particular we will provide new information on the functional relationship between three essential nutrients, K, P and Fe, which will be invaluable for future efforts to improve crop performance and nutritional quality.

矿物质元素对人体营养至关重要。例如，钾（K）是人体的主要电解质，是肾脏、肌肉、神经和心脏功能所必需的。铁 (Fe) 是促进细胞能量代谢的氧化还原酶的成分，也是将氧气输送到大脑和周围组织的血红蛋白的成分。矿物质通过植物进入食物链。它们的根系统积极地从土壤中寻找有益的矿物质营养物质，并在专门的运输蛋白的帮助下提取它们。对于人类来说，矿物质营养对于植物健康至关重要。根系对粮食作物产量和营养价值的重要性已得到认识，根部研究已成为粮食安全的中心舞台。植物可以感知土壤中矿质养分可用性的信号，并将其转化为发育和生理过程，适应根部形状和运输活动，从而最大限度地提高觅食和吸收能力。如果我们想提高作物的养分利用效率，我们需要了解介导土壤条件和根系适应之间的信号通路。其背后的机制很复杂。根系统同时充当感知养分可用性的受体和执行养分吸收的效应器。为了达到最佳结果，他们需要差异化调节各个根部部分的生长和不同细胞中的运输。如果没有集中的大脑，这涉及局部和系统的信号和反应。根部还需要整合不同营养物质的信息并优先考虑它们的反应，这需要各个营养信号通路之间的串扰。我们最近取得了几项发现，可以更好地了解植物如何处理多种营养信号并调节根系结构。我们确定了模式物种拟南芥的两种不同生态型，它们对低钾供应的反应不同。哥伦比亚 (Col-0) 种质保持主根生长，但停止侧根延伸，从而显示出长而窄的根系。相比之下，卡塔尼亚 (Ct-1) 会停止主根生长，但会延伸侧根，从而显示出短而粗大的根系。当钾供应充足时，两种材料看起来非常相似。令人惊讶的是，我们可以通过将植物置于低铁和低钾条件下，将 Ct-1 根表型转化为 Col-0 根表型 - 两种材料现在都发育出长而窄的根结构。已知 Fe 在 Col-0 对低磷的根反应中发挥作用，然而，两种材料对低磷表现出相似的反应（仅抑制主根）。显然，Col-0/Ct-1 对为我们提供了一个出色的实验模型，以发现支持植物在营养胁迫下发育决策的分子过程，并揭示营养物与营养物之间的相互作用。在这个项目中，我们将结合电生理学方法以及具有分子遗传学和自动根表型分析的共聚焦显微镜，以解决以下问题：根细胞如何感知低 K 以及与 Fe 氧化还原代谢有何联系？哪些细胞过程是主要根抑制的基础？哪些信号将主根的发育反应与侧根的发育反应联系起来？不同的根结构如何影响叶子的养分吸收和最终养分含量？哪些基因决定根结构对营养信号的反应？这项研究的结果预计将有助于详细了解将土壤来源的营养信号与根系发育和养分吸收联系起来的基本生物过程和遗传成分。特别是，我们将提供有关三种必需营养素 K、P 和 Fe 之间功能关系的新信息，这对于未来改善作物性能和营养质量的努力非常宝贵。