The strain of late blight which caused the Irish Potato Famine in the 1840s has been found on six continents, a study from North Carolina State University researchers has found.
The study, published in Scientific Reports, shows the strain called FAM-1 was found in nearly three-fourths of the samples and discovered on all six continents, a news release on the study notes. The genomes of about 140 pathogen samples from 37 countries on six continents were studied.
“FAM-1 was much more widespread than previously assumed, spreading from Europe to Asia and Africa along British colony trade routes,” Jean Ristaino, William Neal Reynolds, distinguished professor of plant Pathology and the corresponding author of the study, says in the release. “The lineage was also found over a span of more than 140 years.”
FAM-1 caused outbreaks of potato late blight in the United States in 1843 and then two years later in Great Britain and Ireland (the Irish Potato Famine), the release notes. It was also found in historic samples from Colombia — suggesting a South American origin.
FAM-1 survived for about 100 years in the U.S. but was then replaced by a sister strain of the pathogen called US-1, Ristaino says. US-1 has since been pushed out of the U.S. by even more aggressive strains of the pathogen from Mexico.