The potato late blight pathogen Phytophthora infestans and other pathogenic oomycota

Abstract

Potato late blight, caused by a member of the Oomycota, Phytophthora infestans (Mont.) De Bary, is one of the most important and devastating diseases of potato (Solanum tuberosum). The pathogen attacks both foliage and tubers, and spreads rapidly through host tissues, thereby causing a destructive necrosis. P. infestans is a hemibiotrophic pathogen with a rather narrow range of hosts, all of them members of the Solanaceae. The crop plants, potato and tomato (Lycopersicon esculentum), are the economically most important hosts. The first late blight epidemic in Europe in 1845 had disastrous effects on potato production. P. infestans spread over Europe within 1 year and was found in most potato-growing areas of the world soon thereafter. In Ireland the potato crop was destroyed in two successive years, leading to a famine. As a consequence, about one and a half million people died and another million emigrated, mainly to the United States. De Bary described the life cycle of the potato late blight pathogen and named it Phytophthora ("plant destroyer") infestans.