Sarah L. Boggess, MS
Lab Manager and Sr. Research Associate
University of Tennessee - Knoxville, TN
Knoxville, Tennessee, United States
Katherine Kilbourne
Tennessee Department of Agriculture, Ellington Agricultural Center
Nashville, Tennessee, United States
Robert Trigiano
University of Tennessee, Entomology and Plant Pathology Department
Knoxville, Tennessee, United States
Matthew Huff
Medical University of South Carolina, Department of Regenerative Medicine
Charleston, South Carolina, United States
Marcin Nowicki, PhD
University of Tennessee, Entomology and Plant Pathology Department
Knoxville, Tennessee, United States
Dewayne Shoemaker, PhD
Professor & Head
University of Tennessee, Entomology and Plant Pathology Department
Knoxville, Tennessee, United States
Alina Pokhrel
UNIVERSITY OF TENNESSEE AT KNOXVILLE
KNOXVILLE, Tennessee, United States
Margaret Staton
University of Tennessee, Entomology and Plant Pathology Department
Knoxville, Tennessee, United States
John Bonkowski
Principal Extension Administrator
Purdue University, Plant and Pest Diagnostic Laboratory
West Lafayette, Indiana, United States
Marc Cubeta
North Carolina State University, Entomology and Plant Pathology
Raleigh, North Carolina, United States
Fulya Baysal-Gurel, n/a
Associate Professor
Tennessee State University, Otis L. Floyd Nursery Research Center, Department of Agriculture Sciences and Engineering
McMinnville, TN, USA
Farhat Avin
Tennessee State University, Otis L. Floyd Nursery Research Center, Department of Agriculture Sciences and Engineering
McMinnville, Tennessee, United States
Jean Williams-Woodward
University of Georgia, Department of Plant Pathology
Athens, Georgia, United States
Catarina Villari
University of Georgia, Warnell School of Forestry and Natural Resources
Athens, Georgia, United States
Colton Meinecke
University of Georgia, Warnell School of Forestry and Natural Resources
Athens, Georgia, United States
Denita Hadziabdic, PhD
Associate Professor
University of Tennessee, Entomology and Plant Pathology Department
Knoxville, Tennessee, United States
Vascular streak dieback (VSD) threatens the woody ornamental nursery industry across 12 U.S. states, affecting over 25 tree and shrub genera. Eastern redbud (Cercis canadensis), maple (Acer spp.), and dogwood (Cornus spp.) are the most commonly affected species. While pathogenicity testing is in progress to confirm the causal agent of VSD, the fungus Ceratobasidium sp. D.P. Rogers (Csp) is consistently associated with disease symptoms. We developed cost-effective molecular detection methods to amplify environmental DNA using TaqMan probes due to the difficulty of culturing. We sequenced a Tennessee Csp isolate from a C. canadensis host and developed and screened 50 microsatellite loci, resulting in ten optimized microsatellite loci and three TaqMan probes. We screened 39 additional Ceratobasidium and related Rhizoctonia species to test protocol specificity. Csp DNA was detected by the TaqMan probes with high specificity ranging from 0.7 pg to 7 pg. The method was also tested using a specialized blue wavelength technology to visualize results and decrease assay cost. The best-performing probe was tested in a ring test across four U.S. labs to confirm protocol accuracy and reproducibility. The ring test used eight DNA samples (three negative and five positive samples), divided equally and randomized as three biological (n = 24 samples) and three technical replicates (n = 72 total). Results were consistent and reliable among labs. The newly developed TaqMan probes will aid in the rapid detection of Csp, facilitating efforts to slow the spread of VSD in ornamental plants.