OutlineClick the species name for a description of the organism
Phytophthora infestans is a devastating pathogen of critical food crops, causing late blight of potato and tomato. It is notorious as the causal agent of the Irish Potato Famine more than 150 years ago, and the crop losses due to P. infestans remain staggering today . Worldwide losses in potato production alone caused by late blight exceed $5 billion annually, making P. infestans the single most important biotic threat to global food security [3,4]. In recent years, severe late blight epidemics occurred following the migration to North America, Europe and other regions of aggressive mating type strains [5,6,7]. Strategies for managing late blight remain unsustainable and costly and most populations are now resistant to previously effective fungicides [4,5,8,9,10]. As a result of the destruction caused by P. infestans, in 2003 The American Phytopathological Society ranked it among the Immediate Priority fungal and oomycete genome sequencing targets. In 2002 the same group had ranked P. infestans #2 among 26 fungal and oomycete species. The first ranked organism on that list, Magnaporthe grisea, has since been sequenced at the Broad Institute.
P. infestans belongs to the oomycetes, a diverse group of deeply branching eukaryotic microorganisms that includes pathogens of plants, insects, crustaceans, fish, vertebrate animals, and microbes [11,12]. The diseases caused by these pathogens are notoriously difficult to manage on thousands of crop and ornamental plants, resulting in tens of billions of dollars of losses annually . Because of their filamentous growth habit, oomycetes had been traditionally classified in the kingdom of fungi. In fact, modern molecular and biochemical analyses suggest that oomycetes have little taxonomic affinity with filamentous fungi, and are very distant in evolutionary terms from fungi, animals and plants. Rather, they are more closely related to brown algae (heterokonts) and diatoms in the Stramenopiles, one of several less well studied eukaryotic kingdoms [12,13,14].
The genome size of P. infestans is estimated to be 237 Mb  (preliminary assembly data suggest it is slightly larger, 240-245 Mb). Two independent analyses indicate that the genome has about 52% GC content. Microscopic analyses indicate that P. infestans has 8-10 chromosomes . Several studies suggest that genes are often tightly clustered in Phytophthora genomes [11,17,18].
Choice of Strain
T30-4 is an F1 of two aggressive strains of P. infestans originally isolated from potato in the Netherlands, and is considered the reference isolate for most genetic studies. This isolate was selected by the PIs after consultation with members of the P. infestans community. Significant resources have been generated in this strain: (1) a well characterized large insert BAC library has been constructed  and is available for use in this project; (2) it originates from the cross that was used to construct a genetic map based on AFLP markers  and that will be used for high density mapping in this project; and (3) it was the source for the 1X draft genome sequence produced previously by Syngenta .
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