The plasmodiophores
(also known as plasmophorids
or plasmodiophorids
) are a group of
obligate {{wiktionary, obligate
As an adjective, obligate means "by necessity" (antonym ''facultative'') and is used mainly in biology in phrases such as:
* Obligate aerobe, an organism that cannot survive without oxygen
* Obligate anaerobe, an organism that ...
endoparasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...
protists
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the excl ...
belonging to the subphylum
Endomyxa
Endomyxa is a subphylum of Rhizaria
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all ...
in
Cercozoa
Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eu ...
.
Taxonomically, they are united under a single family Plasmodiophoridae, order Plasmodiophorida, sister to the
phagomyxid
Phagomyxids are a group of obligate endoparasitic protists belonging to the subphylum Endomyxa in Cercozoa. Taxonomically, they are united under a single family Phagomyxidae, order Phagomyxida, sister to the plasmodiophores.
Ecology
Phagomyxids ...
s.
Ecology and pathology
Plasmodiophores are pathogenic for a wide range of organisms, but mainly
green plants
Viridiplantae (literally "green plants") are a clade of eukaryotic organisms that comprise approximately 450,000–500,000 species and play important roles in both terrestrial and aquatic ecosystems. They are made up of the green algae, which ar ...
. The more commonly recognized are agents of plant diseases such as
clubroot
Clubroot is a common disease of cabbages, broccoli, cauliflower, Brussels sprouts, radishes, turnips, stocks, wallflowers and other plants of the family Brassicaceae (Cruciferae). It is caused by ''Plasmodiophora brassicae'', which was once cons ...
,
powdery scab
Powdery scab is a disease of potato tubers. It is caused by the cercozoan ''Spongospora subterranea'' f. sp. ''subterranea'' and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the ...
and
crook root of watercress
Crook is another name for criminal.
Crook or Crooks may also refer to:
Places
* Crook, County Durham, England, a town
* Crook, Cumbria, England, village and civil parish
* Crook Hill, Derbyshire, England
* Crook, Colorado, United States, a ...
,
or vectors for
viruses
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
that infect
beets
The beetroot is the taproot portion of a beet plant, usually known in North America as beets while the vegetable is referred to as beetroot in British English, and also known as the table beet, garden beet, red beet, dinner beet or golden beet ...
,
peanut
The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible Seed, seeds. It is widely grown in the tropics and subtropics, important to both small ...
,
monocots
Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of t ...
and
potatoes
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern United ...
, such as the
potato mop-top virus
''Potato mop-top virus (PMTV)'' is a plant pathogenic virus transmitted through the vector ''Powdery scab, Spongospora subterranea'' that affects potatoes. PMTV belongs to family of ''Virgaviridae'', and the genus ''Pomovirus'' (Potato mop-top vi ...
or the
beet necrotic yellow vein virus
Beet necrotic yellow vein virus (BNYVV) is a plant virus, transmitted by the plasmodiophorid '' Polymyxa betae.'' The BNYVV is a member of the genus '' Benyvirus'' and is responsible for rhizomania, a disease of sugar beet (Rhizo: root; Mania: ma ...
.
Taxonomy
History
The plasmodiophores have historically been regarded as
Fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
. The first description of plasmodiophores as a taxonomic group was in 1885 by
Zopf
Zopf or Züpfe ( French and in Italian) is a type of Swiss, Austrian, German or Bavarian bread made from white flour, milk, eggs, butter and yeast. The dough is brushed with egg yolk, egg wash, or milk before baking, lending it its golden c ...
, who united two genera ''
Plasmodiophora
''Plasmodiophora'' is a genus in the phylum of cercozoa in the class Phytomyxea.
It includes the species ''Plasmodiophora brassicae'', which causes the disease cabbage clubroot
Clubroot is a common disease of cabbages, broccoli, cauliflowe ...
'' and ''
Tetramyxa
''Tetramyxa'' is a cercozoan protist, member of the plasmodiophores, parasite of several flowering plants. It was first described by Karl von Goebel in 1884, in his work ''Flora''. The genus is characterized by the appearance of resting spores ...
'' in a common family “Plasmodiophoreæ”, inside the group “Monadineæ”, as part of the division
Myxomycetes. The family was renamed “Plasmodiophoraceae” in 1888 by
Berlese Berlese or Berlèse is a surname. Notable people with the surname include:
* Antonio Berlese (1863–1927), Italian entomologist
* Augusto Napoleone Berlese (1864–1903), Italian botanist and mycologist, brother of Antonio
* Lorenzo Berlèse (1784 ...
.
In 1892,
Engler placed the family in its own class “Plasmodiophorales”, later renamed “Plasmodiophoromycetes” to fit
nomenclature standards.
[
In 1969 ]Whittaker
Whittaker is a surname of English origin, meaning 'white acre', and a given name. Variants include Whitaker and Whitacre (disambiguation), Whitacre. People with the name include:
Surname
A
*Aaron Whittaker (born 1968), New Zealand rugby player ...
, in his five-kingdom system
In biology, a kingdom is the second highest taxonomic rank, just below domain. Kingdoms are divided into smaller groups called phyla.
Traditionally, some textbooks from the United States and Canada used a system of six kingdoms (Animalia, Plant ...
, elevated the group to a separate phylum “Plasmodiophoromycota”, acknowledging them as protists
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the excl ...
instead of fungi.
In 1993 Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford.
His research has led to discov ...
included the plasmodiophores and their sister group Phagomyxida
Phagomyxids are a group of obligate endoparasitic protists belonging to the subphylum Endomyxa in Cercozoa. Taxonomically, they are united under a single family Phagomyxidae, order Phagomyxida, sister to the plasmodiophores.
Ecology
Phagomyx ...
in their current class, Phytomyxea
The Phytomyxea are a class of parasites that are cosmopolitan, obligate biotrophic protist parasites of plants, diatoms, oomycetes and brown algae. They are divided into the orders Plasmodiophorida (ICZN, or Plasmodiophoromycota, ICBN) and Pha ...
, as part of a polyphyletic
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...
phylum called Opalozoa, which at the time contained a diverse assemblage of unrelated zooflagellates, opalines and proteomyxids. Eventually this phylum was discarded, and the name Opalozoa
Opalozoa is a subphylum of heterotrophic protists of the phylum Bigyra, and is the sister group to Sagenista. Opalozoans are non-photosynthetic heterokonts that are ancestrally phagotrophic but many times have evolved to be osmotrophic saprotrop ...
was modified to label a group inside the phylum Bigyra
Bigyra is a grouping of heterokont organisms.
It includes Bicosoecida, Blastocystis and Labyrinthulida.
It has also been described as containing Opalozoa, Bicoecia, and Sagenista. Phylogeny
The cladogram below shows the internal relationship ...
containing the opalines, bicosoecids and related organisms.
Finally, after phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analyses, in 2002 Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford.
His research has led to discov ...
placed all Phytomyxea
The Phytomyxea are a class of parasites that are cosmopolitan, obligate biotrophic protist parasites of plants, diatoms, oomycetes and brown algae. They are divided into the orders Plasmodiophorida (ICZN, or Plasmodiophoromycota, ICBN) and Pha ...
, including plasmodiophores, in the subphylum Endomyxa
Endomyxa is a subphylum of Rhizaria
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all ...
, inside the rhizarian
The Rhizaria are an ill-defined but species-rich supergroup of mostly unicellular eukaryotes. Except for the Chlorarachniophytes and three species in the genus Paulinella in the phylum Cercozoa, they are all non-photosynthethic, but many foramin ...
phylum Cercozoa
Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eu ...
.
Systematics
The number of genera varies between sources. There are three accepted genera in the group according to the WoRMS Worms may refer to:
*Worm, an invertebrate animal with a tube-like body and no limbs
Places
*Worms, Germany, a city
**Worms (electoral district)
*Worms, Nebraska, U.S.
*Worms im Veltlintal, the German name for Bormio, Italy
Arts and entertainme ...
register: ''Plasmodiophora
''Plasmodiophora'' is a genus in the phylum of cercozoa in the class Phytomyxea.
It includes the species ''Plasmodiophora brassicae'', which causes the disease cabbage clubroot
Clubroot is a common disease of cabbages, broccoli, cauliflowe ...
'', ''Spongospora
Powdery scab is a disease of potato tubers. It is caused by the cercozoan ''Spongospora subterranea'' f. sp. ''subterranea'' and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the ...
'' and ''Tetramyxa
''Tetramyxa'' is a cercozoan protist, member of the plasmodiophores, parasite of several flowering plants. It was first described by Karl von Goebel in 1884, in his work ''Flora''. The genus is characterized by the appearance of resting spores ...
''. Below is a complete list with genera that are not included in the register but appear in relevant sources:
*''Ligniera
''Ligniera'' is a protist genus of the family Plasmodiophoraceae.
The genus name of ''Ligniera'' is in honour of Élie Antoine Octave Lignier (1855–1916), who was a French botanist, known for his work in the field of paleobotany
Paleobota ...
'' (=''Anisomyxa'' ; ''Rhizomyxa'' ; ''Sorolpidium'' )
*'' Membranosorus''
*'' Octomyxa''
*'' Polymyxa''
*''Plasmodiophora
''Plasmodiophora'' is a genus in the phylum of cercozoa in the class Phytomyxea.
It includes the species ''Plasmodiophora brassicae'', which causes the disease cabbage clubroot
Clubroot is a common disease of cabbages, broccoli, cauliflowe ...
'' (=''Ostenfeldiella'' )
*'' Sorodiscus''
*'' Sorosphaerula'' (=''Tuburcinia'' ; ''Sorosporium'' )
*''Spongospora
Powdery scab is a disease of potato tubers. It is caused by the cercozoan ''Spongospora subterranea'' f. sp. ''subterranea'' and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the ...
'' (=''Clathrosorus'' )
*''Tetramyxa
''Tetramyxa'' is a cercozoan protist, member of the plasmodiophores, parasite of several flowering plants. It was first described by Karl von Goebel in 1884, in his work ''Flora''. The genus is characterized by the appearance of resting spores ...
'' (=''Molliardia'' ; ''Thecaphora'' )
*'' Woronina''
These genera were once considered plasmodiophores until they were excluded:
*'' Cystospora'' – possibly a physiological symptom.
*''Frankiella
''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the ''Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of root ...
'' – synonym of the bacteria ''Frankia
''Frankia'' is a genus of nitrogen-fixing bacteria that live in symbiosis with actinorhizal plants, similar to the ''Rhizobium'' bacteria found in the root nodules of legumes in the family Fabaceae. ''Frankia'' also initiate the forming of root ...
''.
*'' Peltomyces'' – excluded as unclassifiable.
*'' Pyrrhosorus'' – considered Labyrinthulida
The Labyrinthulomycetes (ICBN) or Labyrinthulea ( ICZN) are a class of protists that produce a network of filaments or tubes, which serve as tracks for the cells to glide along and absorb nutrients for them. The two main groups are the labyrin ...
''incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
''.
*'' Sporomyxa'' – excluded as unclassifiable.
*'' Trematophlyctis'' – a chytrid fungus
Chytridiomycota are a division of zoosporic organisms in the kingdom Fungi, informally known as chytrids. The name is derived from the Ancient Greek ('), meaning "little pot", describing the structure containing unreleased zoöspores. Chytrids ...
.
References
{{taxonbar, from1=Q20675797, from2=Q20675800
Cercozoa families
Cercozoa orders
Endomyxa