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ARS Home » Pacific West Area » Wapato, Washington » Temperate Tree Fruit and Vegetable Research » Research » Publications at this Location » Publication #420110
Research Project: Potato Germplasm Development for Improved Sustainability, Disease Resistance, Nutrition, and Quality

Location: Temperate Tree Fruit and Vegetable Research

Title: Development of a greenhouse screen for the identification of Potato mop-top virus and Spongospora subterranea resistance in Solanum tuberosum

Author
item Swisher Grimm, Kylie
item Quick, Richard
item Feldman, Maximilian
item CHARLTON, BRIAN - Oregon State University

Submitted to: PhytoFrontiers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2025
Publication Date: 3/11/2025
Citation: Swisher Grimm, K.D., Quick, R.A., Feldman, M.J., Charlton, B.A. 2025. Development of a greenhouse screen for the identification of Potato mop-top virus and Spongospora subterranea resistance in Solanum tuberosum. PhytoFrontiers. doi.org/10.1094/PHYTOFR-11-24-0127-R.
DOI: https://doi.org/10.1094/PHYTOFR-11-24-0127-R

Interpretive Summary: Potato mop-top virus has become a pathogen of concern for potato growers across the United States, where it induces internal necrosis in tubers and renders them unmarketable. Researchers with the USDA-ARS in Prosser, WA designed, optimized, and validated a greenhouse assay to screen different potato cultivars for resistance to Potato mop-top virus and its protist vector, Spongospora subterranea. Using inoculum generated from infected field-grown potatoes grown by an Oregon State University collaborator, inoculum pressure, incubation time, and potting container were optimized in the greenhouse using thirteen commercial cultivars and breeding lines with known susceptibility to the virus. Results demonstrated successful screening of potato plants for against Potato mop-top virus infection and indicate that this new assay can be used in the future to screen wild relatives of potato to identify Potato mop-top virus resistance in these related species.

Technical Abstract: Potato mop-top virus and its protist vector, Spongospora subterranea, cause internal and external damage to potato tubers that make them unmarketable. Currently there are no effective control methods to eliminate these soilborne and seedborne pathogens, so resistant germplasm is highly desired. A greenhouse assay was designed and validated to screen a large number of plants grown in both sandy soil and potting mix. High pathogen pressure was selected (20 sporosori/gram of soil) to ensure successful inoculation, with an incubation time of 60-90 days. The successful use of conetainers was demonstrated to screen a large number of plants in limited greenhouse space. Thirteen susceptible commercial cultivars or breeding lines were screened in the greenhouse, with S. subterranea detected in 99.5% of the plants grown in both soil types. Potato mop-top virus was detected in 79.4% of the plants grown in five-inch clay pots filled with sandy soil and 97.5% of the plants screened in conetainers filled with potting mix. The high pathogen levels detected in the 13 susceptible cultivars indicate that it is possible to assess potato germplasm resistance to S. subterranea and potato mop-top virus in the greenhouse. In the absence of a research field with consistently high pressure of S. subterranea and potato mop-top virus, this new greenhouse assay could rapidly identify germplasm with resistance to these two economically important pathogens year-round. Future identification of S. subterranea or potato mop-top virus resistant germplasm will enable development of disease resistance markers that can help breeders rapidly identify resistant material.