ABA transport at the nexus of nutrient deficiency and water stress in plants

ABA 转运与植物营养缺乏和水分胁迫的关系

基本信息

批准号：
BB/X002721/1
负责人：
Anna Amtmann
金额：
$ 69.3万
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：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FX002721%2F1
关键词：
ABA transport nexus nutrient deficiency

项目摘要

Agricultural food production heavily relies on mineral fertilization. To date, the global annual use of phosphorous (P) fertilizer alone stands at 43 Mio tons. The European Commission has classified P as a 'critical raw material' and the UK is 100% reliant on import. Adding the negative impacts on environment and human health, the current rate of P use is clearly not sustainable. Developing ways to grow crops with less P input is therefore paramount for national and global food security. Due to their sedentary lifestyle, plants are risk-adverse and prepare for the worst-case scenario when they perceive environmental challenges. They have mechanisms to detect a decrease in P supply and immediately react. Up-regulation of high-affinity transport and root branching enhances soil 'mining' while down-regulation of growth and energy consumption safeguards internal resources.. If we can delay the latter and optimize the former, we have an opportunity to close the gap between apparent and potential yield. However, to put these ideas into practice through crop breeding or genome editing, we need a precise understanding of molecular signalling pathways that underpin early responses of plants to P deficiency. Considering water shortage and climate change, we also need to know whether these pathways interact with those mediating responses to osmotic stress imposed by drought or salt intrusion.We recently discovered that knockout of a gene called NPF4.2 in Arabidopsis thaliana completely abolishes early main root inhibition in low P. NPF4.2 encodes a transporter for abscisic acid (ABA) and is located on the vacuolar membrane of cells located in the central vasculature of the root. While the roots of npf4.2 mutants continue to grow in low P they can still be inhibited by other nutrient deficiencies or by salt. These findings not only highlight an entirely new role of the 'stress hormone' ABA for P-deficiency responses but also point to new role of ABA transporters for endowing the pathway with specificity. The aim of this project is to precisely map differences and convergence of the signalling pathways that inhibit root growth in response to low-P and osmotic stress and to position NPF4.2 in this network. To this end we will take advantage of the advanced tools available for A. thaliana. We will employ recently developed technology for in-vivo ABA-imaging and single-cell transcriptomics alongside reverse genetics and protein biochemistry. The proposed work programme has three parts. Work package 1 will deliver spatial maps of stress-evoked ABA signatures in roots, which will be overlaid with response patterns of related signals such as Ca2+, ROS and pH, and with spatial root transcriptomes. Work package 2 will tell us how NP4.2 shapes the signal signatures, in collaboration with other ABA-transporters and with enzymes that mobilize ABA-storage forms. This work package will also identify the relationship between NPF4.2 and previously identified components of the low-P signalling pathway such as ferroxidases and CLE peptides. The last work package will produce information on how the NPF4.2 protein is regulated. Candidate targets will be selected from the transcriptomics studies with particular emphasis on interactions with low-P induced members CIPK and CBL gene families. CBL/CIPK regulons are already known for activating membrane transporters in a Ca2+-dependent manner thereby effectuating responses nutrient and salt stress. However, a role in regulating ABA transport would be entirely novel.The expected outcomes will provide a fundamental science base for the development of 'smart' crops combining improved resource use with robustness against abiotic stress. We will identify key points in the signalling pathways that will allow us to de-couple or connect different signal inputs and response outputs. This research will therefore open offers new opportunities for precision agriculture in different environment scenarios.

农业粮食生产严重依赖矿物肥料。迄今为止，全球每年仅磷 (P) 肥料的使用量就达 43 Mio 吨。欧盟委员会将磷列为“关键原材料”，英国100%依赖进口。再加上对环境和人类健康的负面影响，目前的磷使用率显然是不可持续的。因此，开发以较少磷投入种植作物的方法对于国家和全球粮食安全至关重要。由于其久坐的生活方式，植物具有规避风险的能力，当它们感知到环境挑战时，它们会为最坏的情况做好准备。他们有机制来检测磷供应的减少并立即做出反应。高亲和力运输和根分枝的上调增强了土壤“开采”，而生长和能量消耗的下调则保护了内部资源。如果我们能够延迟后者并优化前者，我们就有机会缩小两者之间的差距表观产量和潜在产量。然而，为了通过作物育种或基因组编辑将这些想法付诸实践，我们需要精确了解支撑植物对磷缺乏的早期反应的分子信号传导途径。考虑到水资源短缺和气候变化，我们还需要知道这些途径是否与介导干旱或盐分入侵造成的渗透胁迫反应的途径相互作用。我们最近发现，敲除拟南芥中的 NPF4.2 基因会完全消除早期主根NPF4.2 编码脱落酸 (ABA) 转运蛋白，位于根中央脉管系统细胞的液泡膜上。虽然 npf4.2 突变体的根在低磷条件下继续生长，但它们仍然会受到其他营养缺乏或盐的抑制。这些发现不仅强调了“应激激素”ABA 在 P 缺乏反应中的全新作用，而且还指出了 ABA 转运蛋白在赋予该途径特异性方面的新作用。该项目的目的是精确绘制响应低磷和渗透胁迫而抑制根生长的信号通路的差异和收敛，并在该网络中定位 NPF4.2。为此，我们将利用可用于拟南芥的先进工具。我们将采用最近开发的体内 ABA 成像和单细胞转录组学以及反向遗传学和蛋白质生物化学技术。拟议的工作计划分为三个部分。工作包 1 将提供根中胁迫诱发的 ABA 特征的空间图，该图将覆盖 Ca2+、ROS 和 pH 等相关信号的响应模式以及空间根转录组。工作包 2 将告诉我们 NP4.2 如何与其他 ABA 转运蛋白以及动员 ABA 存储形式的酶合作塑造信号特征。该工作包还将确定 NPF4.2 与先前确定的低磷信号通路成分（例如亚铁氧化酶和 CLE 肽）之间的关系。最后一个工作包将产生有关 NPF4.2 蛋白如何调控的信息。候选靶标将从转录组学研究中选择，特别强调与低磷诱导的 CIPK 和 CBL 基因家族成员的相互作用。众所周知，CBL/CIPK 调节子能够以 Ca2+ 依赖性方式激活膜转运蛋白，从而实现对营养和盐胁迫的反应。然而，调节ABA运输的作用将是全新的。预期结果将为开发“智能”作物提供基础科学基础，将改善资源利用与抵抗非生物胁迫的稳健性结合起来。我们将确定信号通路中的关键点，使我们能够解耦或连接不同的信号输入和响应输出。因此，这项研究将为不同环境场景下的精准农业提供新的机遇。