Researchers from North Carolina State University (NC State) continue to
track the evolution of different strains of/Phytophthora infestans/, the
plant pathogen that caused the Irish potato famine in the 1840s, which
set down roots in the United States before attacking Europe.

NC State plant pathologists studied thegenomesof about 140 pathogen
samples â?? historic and modern â?? from 37 countries on six continents to
track the evolution of different strains of/P. infestans/, a major cause
of late-blight disease on potato and tomato plants. The study shows that
the historic lineage called FAM-1 was found in nearly 73 percent of the
samples and was found on all six continents.

In 1843, FAM-1 caused potato blight outbreaks in theUnited States, and
two years later in Great Britain and Ireland. It was also found in
historic samples fromColombia, suggesting a South American origin. FAM-1
survived for about 100 years in the United States but was then displaced
by US-1, a different strain of the pathogen. US-1 is not a direct
descendant of FAM-1 and was found in 27 percent of the samples. US-1 has
since been elbowed out by more aggressive strains from Mexico.

Irish Potato Famine Pathogen Stoked Outbreaks on 6 Continents | NC State
News (ncsu.edu)
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