Thraustochytriidae or Thraustochytriaceae is a family of heterotrophic protists. They are unicellular eukaryotes characterized by round cells that use a cytoplasmic network to feed and anchor to the substrate, with an appearance similar to chytrids.

Thraustochytriidae
SEM image of a Phycophthorum zoospore
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Bigyra
Class: Labyrinthulea
Order: Thraustochytrida
Family: Thraustochytriidae
Sparrow ex Cejp 1959[1]
Type genus
Thraustochytrium
Sparrow, 1936 emend. T.W. Johnson, 1961
Genera[2][3]
Synonyms[1]
Thraustochytriaceae

Characteristics

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Members of the Thraustochytriidae form ovoid or spherical thalli (or cells) associated with a fine ectoplasmic (i.e. outer cytoplasm) network of rhizoid-like threads that act as their anchoring and feeding structures. In general size and appearance, these thalli are superficially similar to those of hyphochytrids and chytrid fungi.[1]

Ecology

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Thraustochytriidae are mostly saprotrophic. Their usual substrates are decaying plants and macrophyte algae. The most common representatives from Thraustochytriidae are Aurantiochytrium, Schizochytrium, Thraustochytrium and Ulkenia, found on decaying plant remains, in sediments and in sea water. Most species have a very wide or cosmopolitan distribution. They are abundant in estuarines of coastal areas, where their usual substrate arrives from terrestrial ecosystems in the form of detritus.[4]

There are, however, some parasitic organisms present in the family. For example, Phycophthorum parasitizes pennate diatoms.[3] The QPX, of unknown genus or species, is a parasite of the hard clam.[5]

Systematics

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Thraustochytriidae/Thraustochytriaceae belongs to the Labyrinthulea, a group of heterotrophic stramenopiles that generate cytoplasmic networks outside their cells.[1] In particular, it is one of the two families of the labyrinthulean order Thraustochytrida, the other one being Althorniidae with only one genus, Althornia. As all remaining thraustochytrids belong to Thraustochytriidae, it is the most taxonomically diverse family of the order.[3]

References

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  1. ^ a b c d Bennett, Reuel M.; Honda, D.; Beakes, Gordon W.; Thines, Marco (2017). "Labyrinthulomycota". In Archibald, John M.; Simpson, Alastair G.B.; Slamovits, Claudio H. (eds.). Handbook of the Protists. Springer. pp. 507–542. doi:10.1007/978-3-319-28149-0_25. ISBN 978-3-319-28147-6.
  2. ^ Pan J, Del Campo J, Keeling PJ (January 2017). "Reference Tree and Environmental Sequence Diversity of Labyrinthulomycetes". Journal of Eukaryotic Microbiology. 64 (1): 88–96. doi:10.1111/jeu.12342. PMID 27329779. S2CID 19087480.
  3. ^ a b c Hasset, Brandon T. (April 2020). "A Widely Distributed Thraustochytrid Parasite of Diatoms Isolated from the Arctic Represents a gen. and sp. nov". Journal of Eukaryotic Microbiology. 67 (4): 480–490. doi:10.1111/jeu.12796. hdl:10037/19021. PMID 32249965.
  4. ^ Pereboev DD, Bubnova EN (September 2023). "Marine Labyrinthulomycetes". Russian Journal of Marine Biology. 49 (4): 241–250. Bibcode:2023RuJMB..49..241P. doi:10.1134/S1063074023040107. S2CID 261516095.
  5. ^ Liu Q, Allam B, Collier JL (July 2009). "Quantitative real-time PCR assay for QPX (Thraustochytriidae), a parasite of the hard clam (Mercenaria mercenaria)". Applied and Environmental Microbiology. 75 (14): 4913–4918. Bibcode:2009ApEnM..75.4913L. doi:10.1128/AEM.00246-09. PMC 2708448. PMID 19465523.