A recent study has unveiled exciting findings that could reshape agricultural practices worldwide by tracing the origins of a potato pathogen that still threatens crops today.
This research revisits the tragic Irish famine of the 19th century, which led to the loss of about a million lives.
While the blight responsible for this catastrophe is well-known, scholars have long debated whether its roots lie in the Andes of South America or in Mexico.
Origin of the Pathogen
According to a dedicated team of researchers, they have conducted one of the most thorough analyses of the infamous pathogen, Phytophthora infestans, and its related species.
Their evidence points strongly to a South American origin, particularly the Andes.
Co-author Professor Jean Ristaino from North Carolina State University articulated that the genetic data they compiled aligns with historical records, reinforcing the idea that the Andes might be the pathogen’s native region.
Reflecting on historical observations, Ristaino noted that during the blight’s devastation in 1845, indigenous farmers in the Andes were already facing issues with the disease.
Even though the topic remains open for debate, she believes the substantial data collected presents a compelling case that is hard to refute.
Research Findings
Published in the journal PLOS ONE, their study involved an in-depth examination of the genomes of the pathogen and its relatives found in both South America and Mexico.
The results indicated that strains from Mexico are comparatively younger than those from the Andes.
This finding hints at a more intricate evolutionary history among today’s potato blight pathogens.
While all current strains can trace their ancestry back to the 19th century, those from Mexico were identified as the most recent arrivals in the genealogical timeline.
If Mexico were the true origin of Phytophthora infestans, one might expect it to serve as the foundation of the pathogen’s evolutionary tree, but the team’s findings did not support this hypothesis.
Future Implications
Today, potato blight remains a significant threat, with reports of resistant pathogen strains emerging in Europe.
As a response, farmers are on the lookout for alternative treatments, and the agricultural community is exploring options like breeding and gene editing to develop more robust potato varieties.
Ristaino underscored the importance of understanding the pathogen’s origin, emphasizing that breeding programs should concentrate on ancient populations from the Andes to cultivate resistance.
Dr. David Cooke, a potato blight expert at the James Hutton Institute and not involved in this research, acknowledged the importance of this investigation.
He pointed out that the ongoing debate about the pathogen’s origins partly stems from the reproductive traits of Andean populations, which primarily reproduce asexually, in contrast to the sexually reproducing populations in Mexico.
The genetic diversity often associated with sexual reproduction helps mitigate harmful mutations, a feature expected of a true center of origin.
Cooke suggested that discovering a sexually reproductive population in South America would significantly bolster the argument that the Andes is the original home of this devastating pathogen.
Source: Theguardian