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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Disease and Pest Management Research Unit » Research » Research Project #441076

Research Project: Managing Phytophthora ramorum in the Pacific Northwest

Location: Horticultural Crops Disease and Pest Management Research Unit

Project Number: 2072-22000-045-020-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2021
End Date: Oct 31, 2025

Objective 1. Characterize the epidemiology of the three lineages of Sudden Oak Death (SOD) in Curry County, OR, using genomic approaches; Objective 2. Conduct genotypic and phenotypic characterization of the new NA2 lineage of P. ramorum in order to compare it to the NA1 and EU1 lineages; Objective 3. Develop new sequence based diagnostic tools for identifying the pathogen in infected plants; Objective 4. Understand the ecological impact of the continued spread of P. ramorum on the plant, animal, insect, and microbial communities of southwest Oregon.

In order to meet the objectives described above a range of molecular, evolutionary, genomic, epidemiological, horticultural, and plant pathological approaches will be used to characterize the epidemic of the SOD pathogen Phytophthora ramorum in Oregon and understand its impacts. Objective 1: A combination of field and growth chamber experiments will be conducted to develop a better understanding of how far and how fast P. ramorum spreads on the landscape. Field experiments will consist of measuring sporulation and rates of infection in forest stands infested with P. ramorum. Growth chamber experiments will consist of measuring the environmental conditions which trigger sporulation and quantify the amount of sporulation from different host plants and different strains of the pathogen. This information will then be used to develop a model that can be used to predict the spread of the pathogen on the landscape and fine tune management. Objective 2: Using inoculated plants in the growth chamber we will use a combination of next-generation sequencing and transcriptomics to understand how P. ramorum infects and kills trees. We will quantify the genetic and phenotypic differences between host plants and strains of the pathogen. Objective 3: Using the resequenced populations of P. ramorum we will develop new tools based on the Sherlock and/or LAMP technologies to improve field diagnostics. Objective 4: Establishing a permanent plot network in the forests of southwest Oregon to quantify the changes in biodiversity to the ecosystems of southwest Oregon caused by the continued spread of P. ramorum. This plot network consists of 200 plots located across the ecoregion in areas that have and have not been impacted by SOD. With our collaborators in the USFS we will quantify changes to the avian, small mammal, plant and microbial communities in areas where SOD is present and absent. Plots will be maintained and sampled yearly as needed.