Class of protists
Life cycle of Plasmodiophora brassicae in cabbage . Clubroot on cauliflower The Phytomyxea are a class of parasites that are cosmopolitan, obligate biotrophic protist parasites of plants, diatoms, oomycetes and brown algae.[1] They are divided into the orders Plasmodiophorida (ICZN, or Plasmodiophoromycota , ICBN) and Phagomyxida .[2] Plasmodiophorids are best known as pathogens or vectors for viruses of arable crops (e.g. club root in Brassicaceae , powdery scab in potatoes, and rhizomania in beets, especially sugar beets and some spinaches).[3]
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.[4] These are caused by species of Plasmodiophora and Spongospora , respectively.[5]
The vegetative form is a multinucleate cell , called a 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 flagella , are produced at different stages. Within the plasmodium, dividing nuclei have a distinctive cross-like appearance.
Classification Plasmodiophorids were traditionally considered slime moulds , because of the plasmodial stage and are often wrongly classified as 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 , 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
References ^ Neuhauser, Sigrid; Kirchmair, Martin; Bulman, Simon; Bass, David (2014). "Cross-kingdom host shifts of phytomyxid parasites". BMC Evolutionary Biology . 14 (1): 33. doi:10.1186/1471-2148-14-33 . PMC 4016497 . PMID 24559266. ^ David Bass; Ema E.-Y. Chao; Sergey Nikolaev; Akinori Yabuki; Ken-ichiro Ishida; Cédric Berney; Ursula Pakzad; Claudia Wylezich; Thomas Cavalier-Smith (February 2009). "Phylogeny of novel naked filose and reticulose Cercozoa: Granofilosea cl. n. and Proteomyxidea revised". Protist . 160 (1): 75–109. doi:10.1016/j.protis.2008.07.002. PMID 18952499. ^ Schwelm, Arne; Badstöber, Julia; Bulman, Simon; Desoignies, Nicolas; Etemadi, Mohammad; Falloon, Richard E.; Gachon, Claire M. M.; Legreve, Anne; Lukeš, Julius; Merz, Ueli; Nenarokova, Anna; Strittmatter, Martina; Sullivan, Brooke K.; Neuhauser, Sigrid (2018). "Not in your usual Top 10: protists that infect plants and algae". Molecular Plant Pathology . 19 (4): 1029–1044. doi:10.1111/mpp.12580. PMC 5772912 . PMID 29024322. ^ Schwelm, Arne; Badstöber, Julia; Bulman, Simon; Desoignies, Nicolas; Etemadi, Mohammad; Falloon, Richard E.; Gachon, Claire M. M.; Legreve, Anne; Lukeš, Julius; Merz, Ueli; Nenarokova, Anna; Strittmatter, Martina; Sullivan, Brooke K.; Neuhauser, Sigrid (2018). "Not in your usual Top 10: protists that infect plants and algae". Molecular Plant Pathology . 19 (4): 1029–1044. doi:10.1111/mpp.12580. PMC 5772912 . PMID 29024322. ^ Agrios, George N. (2005). Plant Pathology . 5th ed. Academic Press. link.