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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-weed Science Research » Research » Research Project #432647

Research Project: Biology, Epidemiology, and Detection of Emerging Plant Pathogenic Oomycetes

Location: Foreign Disease-weed Science Research

Project Number: 8044-22000-045-00-D
Project Type: In-House Appropriated

Start Date: May 22, 2017
End Date: May 21, 2022

Objective:
Objective 1: Develop immuno-diagnostic assays for detection of Phytophthora ramorum and other emerging Phytophthora species in host plants as well as nursery irrigation and aquatic environmental samples. [NP303, C1, PS1] Subobjective 1A: Develop a molecular detection assay for Phytophthora ramorum based on cell wall-specific proteins. Objective 2: Develop formulations of antagonistic microorganisms including Trichoderma spp. that can be used as a management tool to reduce soil and leaf populations of Phytophthora ramorum and other emerging Phytophthora species. [NP303, C2, PS2] Subobjective 2A. Investigate the use of biocontrol agents against selected Phytophthora species, seek to enhance their effectiveness, and identify new biocontrol agents. Objective 3: Characterize the biology and epidemiology of emerging plant diseases caused by oomycetes such as Plasmopara obducens (Impatiens downy mildew) as the basis for improved disease management strategies. [NP303, C2, PS2C] Subobjective 3A: Determine key characteristics of epidemiology of emerging oomycete plant pathogens. Subobjective 3B: Determine the risk potential posed by exotic oomycete species to US agricultural plant species.

Approach:
Using specialized containment facilities, we will obtain data in key research areas to assist in detecting and managing emerging oomycete pathogens including Phytophthora ramorum, P. kernoviae, and Plasmopara obducens. For pathogen detection, our approach is to develop enzyme-linked immunosorbent and lateral flow device immunoassays for detection of P. ramorum in plant products and nursery irrigation and runoff samples. We will also continue to develop formulations of antagonistic microorganisms including Trichoderma sp. that can be used as a management tool to reduce soil and leaf populations of Phytophthora ramorum and other emerging Phytophthora species, and will seek to identify new biocontrol agents. To elucidate key characteristics of epidemiology of emerging oomycete pathogens, we will use a variety of experimental approaches in specialized laboratory and greenhouse facilities. We will determine the nature of systemic infection of Impatiens sp. by Plasmopara obducens, and whether the pathogen is seed-borne. We will also define parameters for sporulation and survival of P. ramorum on a key host plant species, and improve Phytophthora kernoviae detection in soil using plant leaves as bait. Understanding key features of biology, epidemiology, and detection will contribute to development of improved management practices and recommendations. Our results will also provide a scientific basis for development of nursery industry best management practices aimed at minimizing disease outbreaks and enhancing interstate commerce.