A new study conducted by researchers from Boyce Thompson Institute (BTI) challenges the common theory that the devastating potato blight pathogen Phytophthora infestans originated in Mexico. The research team led by BTI President Silvia Restrepo, meticulously reconstructed the global migration history of P. infestans and found it likely originated in the South American Andes before spreading globally.

P. infestans caused the Irish potato famine in the 19th century, and remains a major threat to potato crops globally. The researchers used advanced statistical methods to reconstruct the likely migration routes by analyzing genotypic data from 1,706 isolates collected worldwide. The study proposes that P. infestans originated in Peru before migrating north to Colombia and Mexico and spreading to the United States, Europe, and Asia. This contrasts with earlier proposed theories suggesting a Mexican origin followed by spread to South America. The research team found no evidence of the pathogen returning to northern South America after these migrations.

One of the standout findings was the strong geographic signal observed in the pathogen's genetic data, supporting the hypothesis of rare, significant migration events rather than continuous, small-scale movements. Silvia Restrepo highlighted the broader impact of their study, saying, “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.”

For more details, read the article in the BTI website.

See https://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=20896