Ongoing Research Projects

FY 2019/20 Research Projects at NORS-DUC

Advanced technology for detection and identification of Phytophthora species in U.S. nurseries

Doug Luster, USDA Ft. Detrick, MD; Karen Suslow, NORS-DUC, CA; Gary Chastagner, Washington State University, WA; Chaunxe Hong, Virginia Tech, VA; Monique Sakilidas, Michigan State University, MI; and Andrew Flannary, PathSensors, MD.

We propose to develop a rapid “triage” approach for detection and identification of multiple Phytophthora species in nurseries using new technologies. We will test a dual-technology, proof-of-concept system utilizing the CANARY (Cellular Analysis and Notification of Antigen Risks and Yields) Phytophthora biosensor for rapid detection at the generic level, coupled with loop mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA) for identification of Phytophthora species. We will apply this technology in the states of CA, MI, WA and, VA, sampling multiple nurseries in each state and analyzing the samples in laboratories at NORS-DUC, Michigan State University, Washington State University and Virginia Tech University. Samples will include runoff and/or irrigation water, plant roots and foliage when possible from nurseries in each state. The resulting dual technology assays will provide a significant improvement in speed and accuracy of detection and identification of Phytophthora spp., including the regulated pathogen P. ramorum, in nursery environments.

Risk assessment of two oak pathogens in the western U.S.: Phytophthora cinnamomi and emerging Phytophthora quercina

Ebba K. Peterson and Jennifer L. Parke, Oregon State University, OR

P. quercina and P. cinnamomi are highly associated with decline of multiple oak species in Europe, and also have been found in California. Despite documented virulence of both Phytophthora species on numerous oak hosts, their precise role in decline etiology is not always clear. Being non-native, both have the potential to harm native oak species by themselves, and dual-infection may contribute to rates of decline faster than either species alone. At risk and of priority for testing include: Q. agrifolia (coast live oak); Q. lobata (valley oak) and Q. garryana (Oregon white oak). The project’s overall goal is to assess the need for regulatory action against the further spread and establishment of P. quercina in the western United States. We will complete field and laboratory studies using 1-year-old seedlings inoculated with P. quercina. Due to its long history as a significant root-infecting pathogen, P. cinnamomi will be used as a pathogenic standard to determine relative aggressiveness of this emerging species. We will also test for the potential for greater damage attributable to co-infections. Understanding these dynamics will better direct future management, regulatory concern, and containment of P. quercina through the development of better models predicting establishment of this invasive pathogen.

The effect of steaming on soil microbial diversity and chemistry

Sharifa G. Crandall, Penn State, PA; V. Huffman and W. Schweigkofler, NORS-DUC, CA

Soilborne plant diseases are a major concern for plant nurseries and land managers. Many plant pathogens have the potential to spread into the environment through soil that is used for out-plantings. For instance, Phytophthora ramorum was introduced into the landscape through the ornamental nursery trade and has killed many oak trees in California. Recent studies show that steaming the soil at high temperatures can effectively inactivate Phytophthora spp., however, few studies investigate how steaming treatments can change the microbial communities in the soil and the soil chemistry. It is well established that beneficial soil microbes facilitate plant growth while others contribute to disease suppression and soil fertility. Understanding which microbes are present before and after a steaming event can help practitioners know if it is necessary to add bioproducts and fertilizers to adjust the soil post-steaming and target the type of amendment to ensure soil health and cost-effective amendments.  

By students of Dominican University’s MS in Biological Sciences program

  • Greg Huffman: Monitoring microbial biodiversity associated with native and non-native herbaceous plants in Coastal California
  • Franki Crites: Detection of Phytophthora sp. from water sources in Marin Co. with varying chemical/physical parameters
  • Bharati Gaonker: Effect of Phytophthora ramorum on several species of arctostaphylos (manzanita): symptoms, sporulation and transmission