A new study challenges the prevalent theory that the devastating potato blight pathogen, Phytophthora infestans, originated in Mexico. Researchers meticulously reconstructed its global migration history and found it likely originated in the South American Andes before spreading worldwide. This research provides significant insights into the pathogen’s evolutionary journey, crucial for developing better disease management strategies globally.
p. infestans, notorious for causing the 19th-century Irish potato famine, remains a major threat to potato crops globally. Understanding its migration and genetic diversity is crucial for combating its spread. Researchers used advanced statistical methods to trace its migration to Colombia by analyzing genotypic data from 1,706 worldwide isolates.
The study suggests that P. infestans originated in Peru, migrated north to Colombia and Mexico, and then spread to the United States, Europe, and Asia. This challenges earlier theories that proposed a Mexican origin followed by a spread to South America. Notably, the study found no evidence of the pathogen returning to northern South America after these migrations.
“Even though the current Colombian population originated from Peru, the apparent lack of repeated introductions from neighboring countries suggests internal migrations might be more prevalent,” said Camilo Patarroyo, first author of the study recently published in Phytopathology. “This should be carefully monitored to prevent the spread of new variants that could complicate disease control.”
The study also emphasized the importance of international collaboration in tracking and managing P. infestans according to a press release. The research underscores the necessity of global cooperation in tackling plant pathogens, with organizations like EuroBlight, USABlight, and Tizón Latino playing vital roles.
A key finding of the study was the strong geographic signal in the pathogen’s genetic data, indicating rare but significant migration events rather than continuous, small-scale movements. This insight is crucial for developing targeted control measures to prevent these impactful migrations.
Understanding the historical migration patterns of P. infestans allows scientists and farmers to better predict and prevent future outbreaks. This knowledge also aids in breeding more resistant potato varieties, ultimately contributing to global food security.
Silvia Restrepo, lead author of the study and president of the Boyce Thompson Institute, highlighted the broader impact, stating, “Our work not only unravels the past migrations of P. infestans but also provides a framework for predicting its future movements. This is essential for global efforts to safeguard potato crops against this persistent threat.”