Phytophthora infestans
MIkale Worthey

What microbe spread throughout Ireland and resulted in the death of millions?  Phytophthora infestans.  It is the fungus that caused the Great Potato Famine of Ireland in 1845 that lasted for six years.  P. infestans is an oomycete and is classified in the kingdom Chromaleveolata.  The reason the microbe is closer to eukaryotes instead of fungus is because the cell wall is composed of cellulose.  The fungus-like microbe targets tomatoes and potatoes.  And the name P. Infestans aptly means “infesting plant destroyer”.  The microbe currently causes an annual loss of $5 billion globally, making it the number one threat to food security globally.  The origin of P. Infestans is traced type of sexual reproducing P. infestans is restricted to Mexico.  The most wide spread type of P. infestans reproduce asexually though.  P. infestans is so wide spread because the spores can be blown by the wind or through water.  The spores produced by P. infestans, sporangia, are clear, football shaped, and germinate by generating germ tubes that penetrate the host.  They also are biflagellate, or have two flagella.  The microbe is continually growing and producing sporangia.  The sporangia have difficulty surviving exposure to solar radiation.  To host plant is infested through the stomata.  There are eight to ten chromosomes in a P. Infestans cell.  The cell also has a diploid nucleus.  The ideal condition for P. infestans is cool and wet.  P. infestans is so detrimental and easily spread that it was the main cause of plant pathology becoming a science today.  So thanks to mass of rotten potatoes we have modern phytopathology and a better understanding of how to make healthy and numerous crops.

Sources:
http://en.wikipedia.org/wiki/Phytophthora_infestans
http://botit.botany.wisc.edu/toms_fungi/mar2001.html
http://www.extento.hawaii.edu/kbase/crop/Type/p_infest.htm
http://www.broad.mit.edu/annotation/genome/phytophthora_infestans/Info.html
http://www.siu.edu/~ebl/leaflets/blight.htm
http://bioweb.uwlax.edu/bio203/s2007/benrud_jaco/index.htm

Pictures:
http://www-biol.paisley.ac.uk/bioref/Chromista/Phytophthora_infestans.html
http://botit.botany.wisc.edu/toms_fungi/mar2001.htmlhttp://en.wikipedia.org/wiki/File:Phytophtora_infestans-effects.jpg

 

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

Return to Missouri S&T Microbiology HomePage Go to DJW's HomePage