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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Disease and Pest Management Research Unit » Research » Publications at this Location » Publication #404765
Research Project: Disease Management in Small Fruit and Nursery Crops Based on Knowledge of Pathogen Diversity, Biology, and Environmental Effects

Location: Horticultural Crops Disease and Pest Management Research Unit

Title: A canister assay for evaluating host status of potato to Meloidogyne chitwoodi

Author
item Soule, Michelle
item Kitner, Megan
item Studebaker, Gabrielle
item Feldman, Max
item SATHUVALLI, VIDYASAGAR - Oregon State University
item Zasada, Inga

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/6/2023
Publication Date: 12/4/2023
Citation: Soule, M.L., Kitner, M.L., Studebaker, G.W., Feldman, M.J., Sathuvalli, V., Zasada, I.A. 2023. A canister assay for evaluating host status of potato to Meloidogyne chitwoodi. American Journal of Potato Research. https://doi.org/10.1007/s12230-023-09936-0.
DOI: https://doi.org/10.1007/s12230-023-09936-0

Interpretive Summary: Plant-parasitic nematodes, microscopic worms that attack plants, are a major constraint to the production of potatoes globally; of particular concern is the Columbia root-knot nematode. New ways are needed to control nematodes, and one of the most sustainable ways is plant resistance. However, screening of potatoes with or without resistance to nematodes is time consuming and expensive. The goal of this research was to develop rapid and reliable methods for screening potatoes against nematodes. A rapid method that can be conducted in a growth chamber was developed. Additionally, a method where DNA is extracted for nematodes for quantification was also developed. These results will be used by plant breeders to accelerate the development of potatoes with resistance to nematodes.

Technical Abstract: New, reliable strategies are needed to control Meloidogyne chitwoodi in potato; plant host resistance is central to this effort. While efforts to breed potato for resistance to M. chitwoodi are underway, a major bottleneck in this process is phenotyping material for nematode resistance. Currently, time and resource consuming phenotyping takes place in the greenhouse or field. The objective of this study was to establish a high throughput methodology for screening potato against M. chitwoodi and for quantifying egg densities at the end of experiments using qPCR. Various parameters were evaluated for a canister assay where soil was added to a small container, planted with potato, inoculated with nematodes, and incubated at a constant temperature in the dark. To obtain maximum reproduction factor (RF = final population density/initial population density) values, a minimum of 6 weeks after inoculation was required. Timing of inoculation was also important, with higher RF values when inoculation with eggs occurred at planting compared to 2 weeks after planting. The volume of water in which inoculum was delivered to soil did not impact RF values, nor did inoculation density (0.5, 1, or 5 eggs/g soil). The canister assay was evaluated using genotypes from a breeding population with varying levels of resistance to M. chitwoodi. Egg enumeration by qPCR was more sensitive than by microscopy, however, this increased sensitivity did not result in a significant difference in RF values nor the designation of a genotype being a good or poor host for M. chitwoodi. This method has the potential to greatly decrease the amount of time and resources needed to phenotype potato against M. chitwoodi and can allow for multiple screenings throughout the year, regardless of the season.