Thraustochytriidae

Thraustochytriidae
SEM image of a Phycophthorum zoospore
Scientific classification
Domain:	Eukaryota
Clade:	Sar
Clade:	Stramenopiles
Phylum:	Bigyra
Class:	Labyrinthulomycetes
Order:	Thraustochytrida
Family:	Thraustochytriidae Sparrow ex Cejp 1959 [1]
Type genus
Thraustochytrium Sparrow, 1936 emend. T.W. Johnson, 1961
Genera [2] [3]
Aurantiochytrium Botryochytrium Hondaea Japonochytrium Labyrinthulochytrium Monorhizochytrium Phycophthorum Schizochytrium Sicyoidochytrium Thraustochytrium Ulkenia
Synonyms [1]
Thraustochytriaceae

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.

Characteristics

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

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

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

1. 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. 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.