Movement and evolution of the potato famine pathogen
To track the evolution of differing strains of Phytophthora infestans, the pathogen responsible for the Irish potato famine and a major cause of late-blight disease on potato and tomato plants around the world, NC State plant pathologists studied 12 key regions on the genomes of 183 pathogen samples -- historic and modern -- from across the globe.
Moving into the United States, a lineage of the disease called FAM-1 caused outbreaks. FAM-1 wasn't just a one-hit wonder that made its mark and then quickly disappeared.
"FAM-1 was widespread and dominant in the United States in the mid-to-late 19th century and the early 20th century," Ristaino said. "It also was found in Costa Rica and Columbia in the early 20th century."
FAM-1 survived for about 100 years in the United States but was then displaced by a different strain of the pathogen called US-1, Ristaino said.
"US-1 is not a direct descendant of FAM-1, but rather a sister lineage," Ristaino said.
The pathogen's effects aren't limited to the decimation of Ireland's potato crop 170 years ago. Billions are spent worldwide each year in attempts to control the pathogen, Ristaino said. Potatoes in the developing world are particularly vulnerable as fungicides are less available and expensive.
source: sciencedaily.com
