Rapid screening of Colorado potato beetle resistance derived from Solanum okadae

Authors: MCCOY, HANNA - Agriculture And Agri-Food Canada; FENSTEMAKER, SEAN - Former ARS Employee; MACKINLEY, PAMELA - Agriculture And Agri-Food Canada; VICKRUCK, JESS - Agriculture And Agri-Food Canada; Bamberg, John; CALHOUN, LARRY - University Of New Brunswick; TAI, HELEN - Agriculture And Agri-Food Canada

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2024
Publication Date: 8/14/2024
Citation: Mccoy, H.J., Fenstemaker, S.R., Mackinley, P., Vickruck, J., Bamberg, J.B., Calhoun, L.A., Tai, H.H. 2024. Rapid screening of Colorado potato beetle resistance derived from Solanum okadae. Journal of Agricultural and Food Chemistry. 2024 p1-12. https://doi.org/10.1007/s12230-024-09963-5.
DOI: https://doi.org/10.1007/s12230-024-09963-5

Interpretive Summary: Potato is most eaten vegetable crop in the world, but needs constant improvement. The most damaging insect disease is Colorado Potato Beetle (CPB). The wild potato species Solanum okadae (oka) is known to have strong resistance. We examined a population of oka in which individiuals are very variable for CPB resistance. CPB resistance tracked very tightly with the amount of a particular chemical called cardiac glycosides. Since it is much easier to measure cardiac glycosides in the lab than test whole-plant response to beetles, this discovery provides a fast, simple, indicator of resistance. The payoff will be more efficient selection of higher-quality eating potatoes that have CPB resistance, improving food security, and allowing reduction of insecticide applications that may impact the health of people and the environment.

Technical Abstract: Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) is a major insect pest of potato and development of resistant varieties is part of a strategy for management. Wild relatives of potato are a resources for genetic improvement through breeding. Interspecies crosses to introgress CPB resistance will be facilitated with rapid and inexpensive selection methods. Solanum okadae feeding deterrence against the beetle was associated with production of a cardiac glycoside steroidal metabolite in the foliage. The Baljet assay has been used for decades for rapid screening of cardiac glycosides in pharmaceuticals. A modified Baljet assay was developed for plant leaves to rapidly screen for these compounds in the field, greenhouse, and laboratory. Screening of clones from wild accessions of S. okadae using the Baljet assay indicate that production of cardiac glycosides have a large variation in the species. Additionally, this inexpensive method will allow potato breeders to quickly select for potential CPB resistant clones and advance the breeding of sustainable crops.