Phytophthora infestans

Phytophthora infestans is a filamentous oomycete which causes the late blight disease of potato and tomato.  This disease erupted in 1843 in the USA and in 1845 in Europe where it caused the Irish potato famine.  The disease has the potential to destroy all plant parts (foliage, stems and tubers) with alarming speed.  Native to central Mexico, P. infestans is readily distributed via infected potato tubers, and now has a worldwide distribution. The disease is among the most devastating of all plant diseases, with worldwide costs estimated at > $6 billion annually.  P. infestans has become a model organism to investigate the molecular bases of pathogenicity (via small pathogen proteins that are secreted into or around host cells) and plant host resistance (via proteins that recognize pathogen proteins).