Advancing molecular diagnostics and genetic analysis of potato cyst nematodes

The quarantine potato cyst nematodes (PCN), Globodera pallida and Globodera rostochiensis, are devastating plant-parasitic nematodes that threaten U.S. potato production. Globodera rostochiensis has been present in New York since 1941, while G. pallida was detected in Idaho in 2006. Both infestations cause significant yield losses and are difficult to eliminate once they are established. These nematodes are regulated by USDA-APHIS and their respective state partners. The European and Mediterranean Plant Protection Organization (EPPO) has established a Standard Diagnostic Protocol for G. pallida and G. rostochiensis. However, current standard molecular detection methods for these regulated pests, including those aligned in the EPPO protocol, have revealed discrepancies highlighting a critical need for enhanced diagnostic accuracy. This research will evaluate and compare existing PCR-based diagnostic methods to assess the ability to positively detect and identify diverse PCN populations from South America and elsewhere in the world that may enter the US inadvertently through international trade. Preliminary results have shown inconsistencies in species identification, across different methods, emphasizing the limitations of current methodologies when faced with diverse genetic backgrounds. Evaluating PCN populations from South America that possess high diversity will improve molecular diagnostic accuracy and enhance ongoing eradication efforts in the U.S. Strengthening diagnostic tools will provide USDA-APHIS and state agencies with reliable molecular diagnostic resources to prevent future infestations and safeguard the U.S. potato industry.