A large international research team has decoded the genome of the notorious organism that triggered the Irish potato famine in the mid-19th century and now threatens this season's tomato and potato crops across much of the US.
Published in the September 9 online issue of the journal Nature, the study reveals that the organism boasts an unusually large genome size more than twice that of closely related species and an extraordinary genome structure, which together appear to enable the rapid evolution of genes, particularly those involved in plant infection. These data expose an unusual mechanism that enables the pathogen to outsmart its plant hosts and may help researchers unlock new ways to control it.
"This pathogen has an exquisite ability to adapt and change, and that's what makes it so dangerous," said senior author Chad Nusbaum, co-director of the Genome Sequencing and Analysis Program at the Broad Institute of MIT and Harvard. "We now have a comprehensive view of its genome, revealing the unusual properties that drive its remarkable adaptability. Hopefully, this knowledge can foster novel approaches to diagnose and respond to outbreaks."
"Our findings suggest a 'two-speed' genome, meaning that different parts of the genome are evolving at different rates," said co-lead author Sophien Kamoun, head of the Sainsbury Laboratory in Norwich, UK. "Future sequencing of additional strains and close relatives of this pathogen will help test this hypothesis and could transform our understanding of how it adapts to immune plants."
The potato famine that gripped Europe, particularly Ireland, in the mid 1800's was the work of an insidious organism known as Phytophthora infestans. Long considered a fungus, it is now known to be a member of the oomycetes or "water molds," which are more closely related to the malaria parasite than to fungi. P. infestans thrives in cool, wet weather, and can infect potatoes, toma
|Contact: Nicole Davis|
Broad Institute of MIT and Harvard