Abstract
Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement. To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the worldĝ€™s population. Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion. Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars. Here we report the sequence of the P. infestans genome, which at 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
| Original language | English |
|---|---|
| Pages (from-to) | 393-398 |
| Number of pages | 6 |
| Journal | Nature |
| Volume | 461 |
| Issue number | 7262 |
| DOIs | |
| Publication status | Published - 9 Sept 2009 |
Funding
Acknowledgements We thank L. Gaffney for help with figures and tables, E. Blanco and R. Guigo for training the GeneID gene prediction software, J. Crabtree for providing a Sybil (http://sybil.sf.net) software component used to render genome comparison illustrations, the Broad Institute Genome Sequencing Platform for sequence data generation, and C. Cuomo and D. Neafsey for comments on the manuscript. The project was supported by the National Research Initiative of the USDA Cooperative State Research, Education and Extension Service, grant numbers 2004-35600-15024 and 2006-35600-16623, and the National Science Foundation grants EF-0333274 and EF-0523670, and the Gatsby Charitable Foundation.
Keywords
- phytophthora infestans
- Irish potato famine
- plant pathogen