Development and application of a large-scale multiplex marker assay to detect PVY resistance sources in Solanum tuberosum

Authors: Elison, Gregory; Hall, Darren; Novy, Richard - Rich; Whitworth, Jonathan

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2020
Publication Date: 5/8/2020
Citation: Elison, G.L., Hall, D.G., Novy, R.G., Whitworth, J.L. 2020. Development and application of a large-scale multiplex marker assay to detect PVY resistance sources in Solanum tuberosum. American Journal of Potato Research. 97:289-296. https://doi.org/10.1007/s12230-020-09777-1.
DOI: https://doi.org/10.1007/s12230-020-09777-1

Interpretive Summary: Potato virus Y is a devastating disease which affects potato production worldwide. Wild relatives of potato have evolved multiple different resistance genes which confer immunity to the virus, and which have been bred into a few domestic potato varieties. During the breeding process, potential new varieties are genetically tested for the presence or absence of these genes years before they can be tested in the field. In the past, each resistance gene required a separate test, but we have developed a method to simultaneously test for each gene at the same time. This reduces the costs of testing and speeds up the processing of new material. After verifying the method, we applied the test to in-house selection material and test crosses to demonstrate its viability for use with large populations. This new method will allow for the development of virus resistant varieties in a faster and more cost-efficient manner.

Technical Abstract: Potato virus Y (PVY) is a major pathogen affecting potato production worldwide. Three independent genes (Ryadg, Rysto, and Rychc) conferring genetic resistance to all known strains of the virus are currently utilized by breeding programs to develop potato varieties containing extreme resistance to infection by PVY. These resistance genes are typically detected using primers specific for the generation of markers closely-linked to the resistance genes. In recent years there have been attempts to develop a multiplex PCR assay for all resistance genes, but all current published methods either omit at least one resistance gene or are unnecessarily complex and therefore difficult to incorporate successfully for marker-assisted selection. We have developed an assay which tests for the presence of all three sources of resistance in a single, easy to use PCR protocol. The multiplex PCR assay was applied to potato varieties, second-field year breeding germplasm, and a selection of test crosses having progeny segregating for multiple resistance genes to validate the methodology for use in marker-assisted selection in potato breeding programs.