The following is an edited excerpt.
The great potato famine of the 1840s was a defining event in Ireland’s recent history.
Working from 150-year-old dried leaves, two competing teams have now sequenced the genome of the single-celled organism that wreaked havoc on the Irish potato crop. It is the first ancient plant pathogen to have its genome decoded.
Phytophthora infestans, which causes potato late blight, is an oomycete — a type of single-celled organism related to brown algae. Carried by infected potatoes, the disease probably arrived at the port of Antwerp in Belgium in the summer of 1845, before quickly spreading through the Low Countries and much of western Europe.
Read the full story: Pathogen genome tracks Irish potato famine back to its roots