Mechanisms of Pathogenicity and Host Specificity of the Oomycete Plant Pathogen Phytophthora palmivora

卵菌类植物病原棕榈疫霉的致病机制和寄主特异性

• 批准号: 2303713
• 负责人: Miaoying Tian
• 金额: $ 22.5万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303713&HistoricalAwards=false
• 关键词: Mechanisms; Pathogenicity; Host; Specificity; Oomycete

Phytophthora palmivora is a fungus-like eukaryotic microorganism that causes devastating diseases of numerous agriculturally and ecologically important plants, including cacao, a tropical perennial tree that produces the major component of the multi-billion-dollar chocolate industry. The annual global loss on cacao due to diseases caused by P. palmivora is at least one billion U.S. dollars. As a very aggressive pathogen, P. palmivora is often capable of infecting almost all plant parts of a host, rendering its control extremely challenging. As a result, it has become an increasing threat to agricultural production and ecosystems. Diseases caused by P. palmivora are managed by frequent application of fungicides with limited success. The long-term goal of this project is to develop novel, effective and environmentally friendly strategies to control P. palmivora based on the fundamental understandings of its infection mechanisms. To this end, the specific objectives of this project are to identify the key pathogenicity factors of P. palmivora, how these factors act on plant cellular components to contribute to disease, and how their presence/absence in a P. palmivora isolate determines which plant species to infect. This project is expected to generate significant foundational knowledge essential for developing desirable disease control measures, thereby significantly contributing to food security, sustainability of natural ecosystems and the bioeconomy. In addition, the project will contribute to STEM workforce sustainability by providing training opportunities to graduate, undergraduate and high school students, and introducing plant pathology and gene-editing technology to middle/high-school teachers to attract a new generation into agriculture and life sciences. Oomycetes form a distinct phylogenetic lineage of eukaryotes, with many causing devastating diseases of plants and animals. Phytophthora palmivora is a destructive broad-host-range oomycete plant pathogen with host specificity. P. palmivora delivers a diverse array of effectors to manipulate the host cellular processes to facilitate infection, including the superfamily of RxLR effectors that are defined by an N-terminal signal peptide followed by a canonical RxLR (or RxLR-EER) translocation motif that mediates entry into host cells. The P. palmivora RxLR effector designated PpalRxLR1 contains a functional nuclear localization signal with potential DNA-binding activities and was identified as a key pathogenicity factor on cacao. It is present in all examined P. palmivora isolates obtained from cacao infections, but exhibits presence/absence polymorphisms across the species, suggesting that it may be a determinant of host range and specificity. This project is to: 1) determine the mechanisms by which PpalRxLR1 confers pathogenicity on cacao by determining its nuclear-localized molecular interaction dynamics and the subverted host cellular processes during infection, 2) determine the role of PpalRxLR1 as a key component in host range evolution of P. palmivora by analyzing its evolution relative to the species and association with host range, 3) identify additional effectors with key roles in pathogenicity of P. palmivora on specific or a broad range of hosts using the natural variation of P. palmivora isolates. Integrating across specific aims is expected to transform understanding of the molecular basis of pathogenicity and host range evolution of P. palmivora, key aspects of plant-microbe interactions.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.

棕榈疫霉是一种类似真菌的真核微生物，可引起许多农业和生态重要植物的毁灭性疾病，其中包括可可，一种热带多年生树种，生产价值数十亿美元的巧克力产业的主要成分。全球每年因棕榈假单胞菌引起的疾病造成的可可损失至少为 10 亿美元。作为一种极具攻击性的病原体，棕榈假单胞菌通常能够感染宿主的几乎所有植物部分，使其控制极具挑战性。结果，它已成为对农业生产和生态系统日益严重的威胁。通过频繁使用杀菌剂来控制棕榈假单胞菌引起的疾病，但效果有限。该项目的长期目标是在对棕榈假单胞菌感染机制的基本了解的基础上，开发新颖、有效且环境友好的策略来控制棕榈假单胞菌。为此，该项目的具体目标是确定棕榈树的关键致病因素，这些因素如何作用于植物细胞成分从而导致疾病，以及它们在棕榈树分离株中的存在/不存在如何决定哪种植物感染的物种。该项目预计将产生制定理想的疾病控制措施所必需的重要基础知识，从而为粮食安全、自然生态系统和生物经济的可持续性做出重大贡献。此外，该项目还将为研究生、本科生和高中生提供培训机会，并向初中/高中教师介绍植物病理学和基因编辑技术，以吸引新一代进入农业和生命科学领域，从而为 STEM 劳动力的可持续性做出贡献。卵菌形成了真核生物独特的系统发育谱系，其中许多会引起植物和动物的毁灭性疾病。棕榈疫霉是一种具有宿主特异性的破坏性广宿主范围卵菌植物病原体。 P. palmivora 提供多种效应子来操纵宿主细胞过程以促进感染，包括 RxLR 效应子超家族，该超家族由 N 端信号肽和随后介导的规范 RxLR（或 RxLR-EER）易位基序定义。进入宿主细胞。 PpalRxLR1 的 P. palmivora RxLR 效应子包含具有潜在 DNA 结合活性的功能性核定位信号，并被确定为可可的关键致病因子。它存在于从可可感染中获得的所有检查的 P. palmivora 分离株中，但在整个物种中表现出存在/不存在的多态性，表明它可能是宿主范围和特异性的决定因素。该项目旨在：1) 通过确定 PpalRxLR1 的核定位分子相互作用动力学和感染期间颠覆的宿主细胞过程，确定 PpalRxLR1 赋予可可致病性的机制，2) 确定 PpalRxLR1 作为宿主范围进化中关键组成部分的作用通过分析 P. palmivora 相对于物种的进化以及与宿主范围的关联，3) 确定在 P. palmivora 对特定或广泛范围的致病性中具有关键作用的其他效应子使用 P. palmivora 分离物的自然变异作为宿主。跨特定目标的整合预计将改变对棕榈树致病性和宿主范围进化的分子基础以及植物-微生物相互作用的关键方面的理解。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，被认为值得支持。智力价值和更广泛的影响审查标准。