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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Research Project #442484

Research Project: Diagnostics and Biological Approaches for Management of Emerging Oomycete Plant Pathogens

Location: Foreign Disease-Weed Science Research

Project Number: 8044-22000-052-000-D
Project Type: In-House Appropriated

Start Date: May 22, 2022
End Date: May 21, 2027

Objective 1. Develop genomic sequence resources and broad range nucleic acid and antibody-based diagnostics for novel emerging and invasive oomycete plant pathogens. (NP303, C1, PS1A, PS1B) Sub-objective 1.A: Diagnostic tools and resources for downy mildew pathogens of cereals and grasses. Sub-objective 1.B: Apply previously validated isothermal RPA-lateral flow assays for rapid point of care detection of Phytophthora ramorum in nursery irrigation water (Non-hypothesis research). Sub-objective 1.C: A molecular assay can be developed to detect and identify downy mildew species. Objective 2: Characterize pathogen biology and epidemiology of emerging and invasive oomycete plant pathogens. (NP303, C2, PS2A, PS2C) Sub-objective 2.A: Characterize the pathogen biology of emerging and invasive Phytophthoras. Sub-objective 2.B: Characterize the pathogen biology of emerging and invasive downy mildews. Sub-objective 2.C: Determine risk potential posed by exotic or hybrid oomycete pathogen species to U.S. agricultural plant species Sub-objective 2.D: Determine the diversity and virulence of foreign Phytophthora infestans genotypes.

This project will discover and utilize new knowledge to develop a low-cost and efficient detection assay for the invasive oomycete Phytopthora ramorum in nursery irrigation water and inoculate plants to confirm the pathogen’s host range. Newly introduced Phytophthora species also risk hybridizing with native Phytophthoras to create pathogens of unknown host range and pathogenicity; we propose to study the risk of hybrid development and evaluate isolates from a center of Phytophthora diversity. We will also better identify downy mildews and understand their life cycles. Hyaloperonospora brassicae, the crucifer downy mildew, is newly delimited with an unclear host range. Peronospora sparsa, a newly re-emerging disease of roses and Plasmopara destructor, invasive downy mildew of Impatiens, are poorly understood. This work capitalizes on the existing Biological Safety Level 3 Plant Pathogen Containment Facility at Fort Detrick, Maryland, required to study foreign plant pathogens and regulated plant pathogens limited to specific geographical regions within the U.S. The characterization of foreign or reemerging pathogens enables the development of robust detection methods, provides the critical information required for risk assessments and control measures, and allows for the screening of potential hosts to restrict spread.