Genomic Analysis Reveals Andean Origin and Colombian Migration Route for P. infestans

A recent study challenges the widely held belief that Phytophthora infestans, the deadly potato blight pathogen, originated in Mexico. By meticulously reconstructing the history of its global migration, researchers found that it most likely originated in the Andes of South America before spreading worldwide.

This study provides valuable insights into the pathogen's evolutionary history, which is crucial for developing more effective global disease control strategies.

Despite its notorious history of triggering the Irish potato famine in the 1800s, P. infestans continues to pose a serious threat to potato crops worldwide. The secret to stopping its spread is to comprehend its genetic diversity and migration.

The researchers’ main focus was tracking the pathogen’s migration towards Colombia. To do this, they analyzed genotypic data from 1,706 isolates that were collected globally, and they used sophisticated statistical techniques to reconstruct the likely migration routes.

According to the study, P. infestans originated in Peru before moving north to Colombia and Mexico, and from there, it spread to Europe, Asia, and the United States. This is in opposition to previous theories that proposed a Mexican origin that later extended to South America. It is interesting to note that after these migrations, the study found no evidence of the pathogen returning to northern South America.

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. This should be carefully monitored to prevent the spread of new variants that could complicate disease control.”

Camilo Patarroyo, Study First Author, Boyce Thompson Institute

The study has been published in Phytopathology.

The study also underlined how crucial international cooperation is to the monitoring and control of P. infestans. The study emphasizes how important it is for countries to work together to combat plant diseases, with groups like USABlight, Tizón Latino, and EuroBlight playing a key role.

The pathogen's genetic data showed a strong geographic signal, which was one of the most notable findings. This signal supported the theory of rare, significant migration events rather than ongoing, small-scale movements. This knowledge is essential for creating focused control strategies that aim to stop these infrequent but significant migrations.

Acquiring knowledge of P. infestans's historical migration patterns helps scientists and farmers anticipate and stop outbreaks in the future. Additionally, by using this knowledge to breed more resilient potato varieties, food security worldwide is eventually improved.

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.”

Silvia Restrepo, Study Principal Author and President, Boyce Thompson Institute

This study shows how genetic analysis coupled with historical data can shed light on the life cycle of one of the most infamous agricultural pathogens. The results open the door to better disease control tactics and guarantee a more stable future for potato farming globally.