Irish Potato Famine-Causing Pathogen More Virulent Now

A study conducted by researchers from North Carolina State University (NCSU) found that the pathogen that caused the Irish potato famine lives on today with a different genetic blueprint and a new set of harmful genes.

NCSU plant pathologist Jean Ristaino, and colleagues from the University of Copenhagen Mike Martin and Tom Gilbert compared the genomes of five 19th century strains of Phytophthora infestans with modern strains of the pathogen. They found that the genes in the historical plant samples were quite different from the modern P. infestans genes, and that some genes from modern plants make the pathogen more virulent than the historical strains. An example is the allele called AVR3a that was not virulent in the historical samples, but virulent in the modern-day samples.

Ristaino said "In the areas of the genome that today control virulence, we found little similarity with historical strains, suggesting that the pathogen has evolved in response to human actions like breeding more disease-resistant potatoes."

Results of the study are available in the journal Nature: http://www.nature.com/ncomms/2013/130718/ncomms3172/full/ncomms3172.html (doi:10.1038/ncomms3172).

To read the NCSU news release, go to http://news.ncsu.edu/releases/mk-ristaino-infestans-2013/.