Potato blight

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Potato blight
Symptom of late blight on the
underside of a potato leaf
Scientific classification
Domain: Eukaryota
Kingdom: Chromalveolata
Phylum: Heterokontophyta
Class: Oomycota
Order: Peronosporales
Family: Pythiaceae
Genus: Phytophthora
Binomial name
Phytophthora infestans

Potato blight is the so-called "fungal" disease which destroyed the Irish potatoes in 1845. Because there are other blights of potatoes, this one is sometimes called late blight of potato.

The infestation caused widespread famine. It was caused by an oomycete Phytophthora infestans. The oomycetes or water moulds have many features which are similar to fungi, but they are in a different Kingdom.

The blight[change | change source]

Phytophthora infestans in Ireland caused over one million to starve to death and another two million people emigrated from affected countries.[1] During the 1840s the blight damaged crops in Scotland and Europe also. It was the only important cash crop in Ireland, which explains its greater effect there. Also, most of the Irish crop was one variety, the Irish Lumper.

The first recorded instances of the disease were in the United States, in Philadelphia and New York City in early 1843. It crossed the Atlantic Ocean with a shipment of seed potatoes for Belgian farmers in 1845.[2] All of the potato-growing countries in Europe were affected, but the potato blight hit Ireland the hardest. The lack of genetic variability created a susceptible host population for the organism.[3]

Genetic engineering[change | change source]

Genetic engineering for resistant cultivars is developing. A resistance gene effective against most known strains of blight has been found in a wild relative of the potato. It is introduced by genetic engineering into cultivated varieties of potato.[4][5]

References[change | change source]

  1. Ross, David 2002. Ireland: history of a nation. New Lanark: Geddes & Grosset. ISBN 1-84205-164-4
  2. Reader, John (March 17, 2008), "The fungus that conquered Europe", New York Times, http://www.nytimes.com/2008/03/17/opinion/17reader.html, retrieved 2008-03-18
  3. "Great Famine potato makes a comeback after 170 years". IrishCentral. http://www.irishcentral.com/news/Great-Famine-potato-makes-a-comeback-after-170-years-194635321.html. Retrieved 2013-03-05.
  4. Song, Junqi 2003., "Gene RB cloned from Solanum bulbocastanum confers broad spectrum resistance to potato late blight", Proceedings of the National Academy of Sciences 100 (16): 9128–9133, doi:10.1073/pnas.1533501100 , PMC 170883 , PMID 12872003
  5. Jacobsen E. & Schouten H.J. 2008. Cisgenesis, a new tool for traditional plant breeding, should be exempted from the regulation on genetically modified organisms in a step by step approach. Potato Research 51: 75–88. Free version