New approaches to undermine late blight disease by exploiting an understanding of ubiquitin E3 ligases that positively regulate immunity

利用对积极调节免疫的泛素 E3 连接酶的了解，开发出消灭晚疫病的新方法

• 批准号: BB/P020569/1
• 负责人: Paul Birch
• 金额: $ 50.37万
• 依托单位: University of Dundee
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FP020569%2F1
• 关键词: New; approaches; undermine; late; blight

An increasing world population and impacts of climate change place ever-greater demands on the world food supply. A major constraint to global food security is crop loss due to plant pests and diseases. With the increasing stringency of conditions under which chemicals are approved for agriculture, the choice of effective fungicides and pesticides will become more limited in the near future. There is an urgent need to explore the development of novel, durable and sustainable means to combat crop diseases. The development of such new approaches requires a deep understanding of the plant immune system, how it is regulated, and how pathogens are able to overcome it.Plants defend themselves with an inducible immune system. Immunity is activated by recognition of essential, widely conserved molecules (called PAMPs) that are exposed by pathogens during infection. Successful (adapted) pathogens secrete and deliver proteins called effectors to suppress these defences. Plant immunity involves a complex network of inter-linked signalling and regulatory processes. Regulation occurs at many levels, and a major component involves protein modification and turnover. A key protein modification that is emerging as a central regulator of plant immunity is ubiquitination, which often results in 26S proteasome-mediated degradation of ubiquitinated proteins. In the past decade we and others have revealed key enzymes, ubiquitin E3 ligases, which either positively or negatively regulate plant immunity. Considerable advances have been made to reveal the modes-of-action of E3 ligases that suppress immunity, by identifying their protein substrates for ubiquitination, marking them for proteasome-mediated degradation. E3 ligases that positively regulate immunity are less well understood and their substrates for ubiquitination are unknown. This proposal will address this critical knowledge gap.We will focus on 3 major E3 ligases that positively regulate immunity, CMPG1, PUB17 and UBK, two of which are targeted by effectors from the late blight pathogen Phytophthora infestans, emphasising their importance as central immune regulators that must be modified by this pathogen to suppress immunity. We provide crucial preliminary evidence that our methods and approaches reveal substrates of E3 ligases that activate immunity. Specifically, our preliminary work has revealed a KH RNA binding protein (KH17) which we show is a substrate for ubiquitination by PUB17, targeting it for degradation. We aim to extend this work to identify substrates of all three E3 ligases, which are predicted to be negative regulators of immunity. A specific outcome will be the identification of whether the substrates act as susceptibility [S] factors (i.e. are required for infection), as these provide targets to remove, by conditional silencing, to enhance immunity and provide disease resistance. A further aim is to investigate the roles of P. infestans effectors in inhibiting the E3 ligases. We will exploit this knowledge to generate mutant forms of two E3 ligases so that corresponding effectors can no longer inhibit their activity, thus restoring disease resistance.Remarkably, although ubiquitination has emerged as a central regulator of growth, development and immunity in plants, little is known about how it controls immunity. The identification and functional characterisation of E3 ligase substrates and regulators in governing immunity thereby provide a step-change in our understanding of how plant defence is controlled by this critical post-translational modification.

越来越多的世界人口和气候变化的影响对世界粮食供应的需求不断增加。全球粮食安全的主要限制是由于植物有害生物和疾病而导致的作物损失。随着化学物质被批准用于农业的条件的严格程度越来越严格，在不久的将来，有效的杀菌剂和农药的选择将变得更加有限。迫切需要探索新颖，耐用和可持续的方法来打击作物疾病。这种新方法的发展需要对植物免疫系统，如何调节以及病原体如何克服它有深入的了解。植物使用可诱导的免疫系统来捍卫自己。通过识别基本的，广泛保守的分子（称为PAMP），这些分子在感染过程中暴露于病原体。成功（适应）病原体分泌并传递称为效应子来抑制这些防御的蛋白质。植物免疫涉及复杂的连接信号传导和调节过程的网络。调节在许多级别上发生，主要组成部分涉及蛋白质修饰和周转。成为植物免疫调节剂的关键蛋白质修饰是泛素化，通常导致26S蛋白酶体介导的泛素化蛋白质降解。在过去的十年中，我们和其他人揭示了关键的酶，泛素E3连接酶，它们对植物免疫进行了积极或负调节植物免疫。通过鉴定其蛋白质底物的泛素化蛋白质底物来揭示抑制免疫力的E3连接酶的作用模式，并标记了它们的蛋白酶体介导的降解。积极调节免疫力的E3连接酶的理解较少，其泛素化底物尚不清楚。该提案将解决这一关键知识差距。我们将重点介绍3种积极调节免疫力，CMPG1，Pub17和UBK的主要E3连接酶，其中两个是由晚期病原体病原体植物疫霉菌的效应者的目标，强调了它们必须通过这种免疫来修改的中央疫苗调节器的重要性，以通过这种免疫来进行抗药性。我们提供了至关重要的初步证据，表明我们的方法和方法揭示了激活免疫力的E3连接酶的底物。具体而言，我们的初步工作揭示了KH RNA结合蛋白（KH17），我们表明，它是Pub17泛素化的底物，针对降解。我们旨在扩展这项工作，以识别所有三种E3连接酶的底物，预计这将是免疫的负调节剂。具体的结果将是鉴定底物是否充当易感性[S]因素（即感染所需），因为这些因素可以通过有条件的沉默来消除以增强免疫力并提供抗病性的目标。进一步的目的是研究炎症性假单胞菌效应子在抑制E3连接酶中的作用。我们将利用这些知识来产生两个E3连接酶的突变形式，以便相应的效应子不能再抑制其活性，从而恢复抗病性。尽管如此，尽管泛素化已经成为植物中生长，发育和免疫力的核心调节剂，但对其控制的免疫力知之甚少。在管理免疫中，E3连接酶底物和调节剂的识别和功能表征，从而为我们理解如何通过这种关键的翻译后修饰来控制植物防御。

项目成果

Plant pathogen effector utilizes host susceptibility factor NRL1 to degrade the immune regulator SWAP70.

• DOI: 10.1073/pnas.1808585115
• 发表时间: 2018-08-14
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: He Q;Naqvi S;McLellan H;Boevink PC;Champouret N;Hein I;Birch PRJ
• 通讯作者: Birch PRJ

The Ubiquitin E3 Ligase PUB17 Positively Regulates Immunity by Targeting a Negative Regulator, KH17, for Degradation

• DOI: 10.1016/j.xplc.2020.100020
• 发表时间: 2020-07-13
• 期刊: PLANT COMMUNICATIONS
• 影响因子: 10.5
• 作者: McLellan, Hazel;Chen, Kai;Birch, Paul R. J.
• 通讯作者: Birch, Paul R. J.

A Phytophthora effector promotes homodimerization of host transcription factor StKNOX3 to enhance susceptibility.

疫霉效应子促进宿主转录因子 StKNOX3 的同二聚化以增强敏感性。

• DOI: 10.1093/jxb/erac308
• 发表时间: 2022
• 期刊: Journal of experimental botany
• 影响因子: 6.9
• 作者: Zhou J

Evolutionarily distinct Resistance proteins detect a pathogen effector through its association with different host targets.

• DOI: 10.1111/nph.17660
• 发表时间: 2021-08
• 期刊: The New phytologist
• 作者: Haixia Wang;F. Trusch;Dionne Turnbull;C. Aguilera-Galvez;Susan Breen;S. Naqvi;Jonathan D. G. Jones;I. Hein;Zhendong Tian;V. Vleeshouwers;Eleanor M. Gilroy;P. Birch

Exploiting breakdown in nonhost effector-target interactions to boost host disease resistance.

• DOI: 10.1073/pnas.2114064119
• 发表时间: 2022-08-30
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1