Globodera pallida virulence on major potato resistance has a common genetic basis across Western Europe

A recent preprint by a group of NEM-EMERGE researchers reveals that populations of the nematode Globodera pallida that have overcome potato resistance in different Western European countries all share the same gene variant. Importantly, this variant can be detected with a relatively simple test.

Potato farmers across Western Europe rely heavily on resistant potato varieties to protect their crops against potato cyst nematodes, particularly since the ban on the most effective, but environmentally harmful nematicides. These resistances were derived from wild potato relatives and prevent juvenile nematodes from reaching maturity.

However, the broad use of the same resistance puts nematode populations under strong selection pressure, favouring gene variants that do not trigger this resistance. Over time, the selection of individuals that escape the resistance causes the resistance to become ineffective. The aim of this research was to investigate if the virulent nematodes found in different European regions share the same genetic adaptation. In other words, are we dealing with the same problem, or multiple different ones?

In their experiments, they analysed 13 populations of Globodera pallida from the Netherlands, Great Britain and France. They found a gene variant that had been consistently selected in virulent nematode populations across Western Europe. More importantly, the frequency of this variant within a population closely predicts how damaging these populations will be in the field. Building on this insight, the team developed a PCR-based test that can measure virulence in Globodera pallida populations directly from field samples.

“This assay enables field-specific guidance for sustainable resistance deployment, prolonging the agronomical lifetime of potato varieties, and allows mapping of virulence distribution at different scales,” the authors explain. “It therefore offers practical value for farmers, service providers, breeding companies, and policymakers.”