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: 2418799
• 负责人: Miaoying Tian
• 金额: $ 22.5万
• 依托单位: University of Georgia Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2418799&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.

棕榈疫霉是一种真菌样的真核微生物，导致许多农业和生态重要植物的毁灭性疾病，包括可可，一种热带多年生树木，生产数十亿美元巧克力工业的主要成分。每年全球因棕榈疫霉引起的疾病造成的可可损失至少为10亿美元。作为一种非常具有侵略性的病原体，棕榈疫霉通常能够感染宿主的几乎所有植物部位，使其控制极具挑战性。因此，它对农业生产和生态系统的威胁越来越大。由棕榈腐霉引起的疾病通过频繁施用杀真菌剂来控制，但效果有限。本项目的长期目标是在了解棕榈疫霉感染机制的基础上，开发新的、有效的、环境友好的防治策略。为此，该项目的具体目标是确定棕榈假单胞菌的关键致病因子，这些因子如何作用于植物细胞组分以促成疾病，以及它们在棕榈假单胞菌分离株中的存在/不存在如何决定感染哪些植物物种。预计该项目将产生重要的基础知识，对制定理想的疾病控制措施至关重要，从而大大促进粮食安全、自然生态系统的可持续性和生物经济。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/高中教师介绍植物病理学和基因编辑技术，以吸引新一代人进入农业和生命科学领域，从而促进STEM劳动力的可持续性。卵菌是真核生物中一个独特的系统发育谱系，许多卵菌引起动植物的毁灭性疾病。棕榈疫霉是一种具有寄主特异性的广泛寄主范围的卵菌植物病原菌。棕榈假单胞菌递送多种效应物以操纵宿主细胞过程以促进感染，包括RxLR效应物的超家族，其由N末端信号肽随后介导进入宿主细胞的典型RxLR（或RxLR-EER）易位基序定义。棕榈疫霉RxLR效应子命名为PpalRxLR 1，包含具有潜在DNA结合活性的功能性核定位信号，并被鉴定为可可上的关键致病因子。它存在于从可可感染中获得的所有检查的棕榈假单胞菌分离株中，但在整个物种中表现出存在/不存在多态性，这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PpalRxLR 1的核定位分子相互作用动力学和感染过程中破坏的宿主细胞过程来确定PpalRxLR 1赋予可可致病性的机制，2）通过分析PpalRxLR 1相对于物种的进化以及与宿主范围的关联来确定PpalRxLR 1作为棕榈假单胞菌宿主范围进化中的关键组分的作用，3）利用棕榈疫霉分离株的自然变异，鉴定在棕榈疫霉对特定或广泛宿主的致病性中具有关键作用的其他效应子。整合特定目标有望改变对棕榈疫霉致病性和宿主范围进化的分子基础的理解，这是植物-微生物相互作用的关键方面。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。