Defining the signalling network linking pathogen infection and asparagine accumulation in wheat grain

定义连接病原体感染和小麦籽粒中天冬酰胺积累的信号网络

基本信息

批准号：
BB/W007134/1
负责人：
Nigel Halford
金额：
$ 99.4万
依托单位：
Rothamsted Research
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FW007134%2F1
关键词：
Defining signalling network linking pathogen

项目摘要

This project arises from discoveries that an amino acid called asparagine accumulates in wheat grain in response to disease and that the plant's response to floral infection by a disease-causing fungus called Fusarium graminearum (Fg) involves a protein called SnRK1. SnRK1 is a master regulator of plant metabolism and it controls the activity of genes encoding an enzyme called asparagine synthetase that is responsible for making asparagine. The project will involve a multidisciplinary team from Rothamsted Research, with collaboration from a team from University College Dublin (not eligible for BBSRC funding but fully involved in the project through the sharing of resources, expertise and data analyses). It will define what we are calling a signalling hub (a control point within a network) involving SnRK1 and partner proteins that links pathogen infection with asparagine synthesis and accumulation in wheat grain. We believe that the increase in asparagine concentration induced through the activation of this hub upon Fg infection is an important part of how plants defend themselves when under attack from disease-causing organisms. Fg causes Fusarium head blight disease, which reduces yield and grain quality, and contaminates grain with toxic compounds called mycotoxins, of which the most common is called deoxynivalenol (DON). SnRK1 is involved in the regulation of defence mechanisms when wheat is infected by Fg and a protein that partners with SnRK1, called TaFROG, has also been shown to contribute to Fg and DON resistance. Recent work has shown that Fg infection and DON treatment both affect SnRK1 but in different ways, with Fg infection causing the SnRK1 protein to be divided into smaller proteins in a way not seen with DON on its own. Subsequently, a protein that is secreted by the fungus, called OSP24, has been shown to partner with SnRK1 and to cause SnRK1 to be broken down. TaFROG, on the other hand, competes with OSP24 for partnering with SnRK1 and protects SnRK1 from degradation. These fascinating discoveries mean that this project can focus directly on the signalling hub and its relationships to other proteins in SnRK1's wider network. That network likely includes several proteins called bZIP transcription factors. These proteins control the activity of some target genes, possibly including asparagine synthetase genes involved in asparagine synthesis, and have characteristics suggesting that they could be controlled by SnRK1. We aim to identify all the components of this signalling hub linking Fg infection with asparagine accumulation in wheat grain. We will dissect the hub in different types of wheat using different strains of Fg, such as strains that do not make DON and/or the OSP24 protein. We will use a technique called RNA-seq that will enable us to identify all of the genes affected by infection by Fg or treatment with DON, looking in particular for those that could be involved in making or breaking down asparagine. We will use protein-based studies to identify additional hub components, and find out if the bZIP transcription factors we are interested in do control the activity of asparagine synthetase genes. Finally, we will see if the ability of different Fg strains to cause disease is linked to their effect on the signalling hub and asparagine. These experiments will enable us to model the signalling hub and perform further experiments to target the genes involved in the hub so that we can test whether our model is correct. SnRK1 has been implicated in other plant defence mechanisms, including those against herbivores, viruses and bacteria, as well as other fungi. In addition, the amount of asparagine in wheat grain has implications for food safety because asparagine can be converted into a cancer-causing contaminant called acrylamide during baking. This means that the project, while focussed on basic science, will have potential impact for a range of stakeholders in the agrifood sector.

该项目源于以下发现：小麦籽粒中会积累一种名为天冬酰胺的氨基酸，以应对疾病，并且植物对禾谷镰刀菌 (Fg) 致病真菌对花的感染的反应涉及一种名为 SnRK1 的蛋白质。 SnRK1 是植物代谢的主要调节因子，它控制编码天冬酰胺合成酶的基因的活性，该酶负责制造天冬酰胺。该项目将涉及来自洛桑研究中心的多学科团队，并与都柏林大学学院的团队合作（不符合 BBSRC 资助的条件，但通过共享资源、专业知识和数据分析充分参与该项目）。它将定义我们所说的信号中枢（网络内的控制点），涉及 SnRK1 和伙伴蛋白，将病原体感染与小麦籽粒中的天冬酰胺合成和积累联系起来。我们认为，Fg 感染后通过激活该中枢而引起的天冬酰胺浓度增加是植物在受到致病生物体攻击时保护自身的重要部分。 Fg 会引起镰刀菌赤霉病，从而降低产量和谷物质量，并用称为霉菌毒素的有毒化合物污染谷物，其中最常见的是脱氧雪腐镰刀菌烯醇 (DON)。当小麦被 Fg 感染时，SnRK1 参与防御机制的调节，与 SnRK1 结合的蛋白质（称为 TaFROG）也被证明有助于 Fg 和 DON 抗性。最近的研究表明，Fg 感染和 DON 治疗都会影响 SnRK1，但影响方式不同，Fg 感染会导致 SnRK1 蛋白分裂成更小的蛋白质，而这种方式是 DON 本身所没有的。随后，真菌分泌的一种名为 OSP24 的蛋白质已被证明与 SnRK1 合作并导致 SnRK1 被分解。另一方面，TaFROG 与 OSP24 竞争与 SnRK1 的合作，并保护 SnRK1 免遭降解。这些令人着迷的发现意味着该项目可以直接关注信号中枢及其与 SnRK1 更广泛网络中其他蛋白质的关系。该网络可能包含几种称为 bZIP 转录因子的蛋白质。这些蛋白质控制一些靶基因的活性，可能包括参与天冬酰胺合成的天冬酰胺合成酶基因，并且具有表明它们可能受 SnRK1 控制的特征。我们的目标是确定该信号枢纽的所有组件，该信号枢纽将 Fg 感染与小麦籽粒中的天冬酰胺积累联系起来。我们将使用不同的 Fg 菌株（例如不产生 DON 和/或 OSP24 蛋白的菌株）来剖析不同类型小麦中的中枢。我们将使用一种称为 RNA-seq 的技术，使我们能够识别受 Fg 感染或 DON 治疗影响的所有基因，特别是寻找那些可能参与制造或分解天冬酰胺的基因。我们将使用基于蛋白质的研究来识别其他枢纽组件，并查明我们感兴趣的 bZIP 转录因子是否确实控制天冬酰胺合成酶基因的活性。最后，我们将了解不同 Fg 菌株引起疾病的能力是否与其对信号中枢和天冬酰胺的影响有关。这些实验将使我们能够对信号中枢进行建模，并针对中枢中涉及的基因进行进一步的实验，以便我们可以测试我们的模型是否正确。 SnRK1 与其他植物防御机制有关，包括针对食草动物、病毒和细菌以及其他真菌的防御机制。此外，小麦籽粒中天冬酰胺的含量对食品安全也有影响，因为天冬酰胺在烘烤过程中会转化为一种名为丙烯酰胺的致癌污染物。这意味着该项目虽然专注于基础科学，但将对农业食品行业的一系列利益相关者产生潜在影响。