220px, Clubroot on cauliflower The Phytomyxea are a class of
parasite Parasitism is a symbiotic relationship between species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often def ...
s of plants. They are divided into the orders Plasmodiophorida ( ICZN, or Plasmodiophoromycota, ICBN) and Phagomyxida. A more common name for them is the plasmodiophorids, but this does not always include ''Phagomyxa'' (see taxobox).

Life cycle

They typically develop within plant cells, causing the infected tissue to grow into a gall or scab. Important diseases caused by phytomyxeans include club root in cabbage and its relatives, and powdery scab in potatoes. These are caused by species of ''Plasmodiophora'' and ''Spongospora'', respectively.Agrios, George N. (2005). ''Plant Pathology''. 5th ed. Academic Press
The vegetative form is a syncytium, multinucleate cell, called a plasmodium (slime mold), plasmodium. This ultimately divides to form new spores, which are released when the host's cells burst. Both resting spores and motile zoospores, which generally have two smooth flagellum, flagella, are produced at different stages. Within the plasmodium, dividing nuclei have a distinctive cross-like appearance.


Plasmodiophorids are traditionally considered slime moulds, because of the plasmodial stage. Thus they are often classified as fungus, fungi, and given names such as the Plasmodiophoromycota. However, genetic and ultrastructural studies indicate they belong to a diverse group of protists called the Cercozoa, or are closely related to them. * Class Phytomyxea Engler & Prantl 1897 em. Cavalier-Smith 1993 ** Genus ?''Pongomyxa'' ** Order Phagomyxida Cavalier-Smith 1993 *** Family Phagomyxidae Cavalier-Smith 1993 **** Genus ''Phagomyxa'' Karling 1944 ** Order Plasmodiophorida Cook 1928 em. Cavalier-Smith 1993 *** Family Endemosarcidae Olive & Erdos 1971 **** Genus ''Endemosarca'' Olive & Erdos 1971 *** Family Plasmodiophoridae Berl 1888 (plasmodial slime moulds) **** Genus ''Cystospora'' Elliott 1916 nomen dubium [''Acrocystis'' Ellis & Halsted ex Halsted 1890 non Zanardini 1872] **** Genus ''Maullinia'' Maier et al. 2000 **** Genus ''Phytomyxa'' Schröter 1886 **** Genus ''Ligniera'' Maire & Tison 1911 [''Anisomyxa'' Němec 1913; ''Rhizomyxa'' Borzí 1884; ''Sorolpidium'' Němec 1911] **** Genus ''Membranosporus'' Ostenfeld & Petersen 1930 **** Genus ''Octomyxa'' Couch, Leitner & Whiffen 1939 **** Genus ''Plasmodiophora'' Woronin 1877 [''Frankiella'' Maire & Tison 1909 non Speschnew 1900; ''Frankia'' Brunchorst 1886 non; ''Ostenfeldiella'' Ferdinandsen & Winge 1914] **** Genus ''Polymyxa'' Ledingham 1933 **** Genus ''Sorodiscus'' Lagerheim & Winge 1913 non Allman 1847 **** Genus ''Sorosphaera'' Schröter 1886 **** Genus ''Sorosphaerula'' Neuh. & Kirchm. 2011 **** Genus ''Spongospora'' Brunchorst 1887 [''Clathrosorus'' Ferdinandsen & Winge 1920] **** Genus ''Sporomyxa'' Léger 1908 **** Genus ''Tetramyxa'' Goebel 1884 [''Molliardia'' Maire & Tison 1911] **** Genus ''Woronina'' Cornu 1872


{{Taxonbar, from=Q134349 Endomyxa Parasitic rhizaria Parasites of plants Cercozoa classes