Symbiodinium

This article is about the genus sometimes called Zoox. For the company, see Zoox (company).

Symbiodinium
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Alveolata
Phylum: Myzozoa
Superclass: Dinoflagellata
Class: Dinophyceae
Order: Suessiales
Family: Symbiodiniaceae
Genus: Symbiodinium
Freudenthal, 1962 [1]
Species

See text

Symbiodinium is a genus of dinoflagellates that encompasses the largest and most prevalent group of endosymbiotic dinoflagellates known and have photosymbiotic relationships with many species. These unicellular microalgae commonly reside in the endoderm of tropical cnidarians such as corals, sea anemones, and jellyfish, where the products of their photosynthetic processing are exchanged in the host for inorganic molecules. They are also harbored by various species of demosponges, flatworms, mollusks such as the giant clams, foraminifera (soritids), and some ciliates. Generally, these dinoflagellates enter the host cell through phagocytosis, persist as intracellular symbionts, reproduce, and disperse to the environment. The exception is in most mollusks, where these symbionts are intercellular (between the cells). Cnidarians that are associated with Symbiodinium occur mostly in warm oligotrophic (nutrient-poor), marine environments where they are often the dominant constituents of benthic communities. These dinoflagellates are therefore among the most abundant eukaryotic microbes found in coral reef ecosystems.

Symbiodinium are colloquially called zooxanthellae, and animals symbiotic with algae in this genus are said to be "zooxanthellate". The term was loosely used to refer to any golden-brown endosymbionts, including diatoms and other dinoflagellates. Continued use of the term in the scientific literature is discouraged because of the confusion caused by overly generalizing taxonomically diverse symbiotic relationships.[2]

In 2018, the systematics of Symbiodiniaceae was revised, and the distinct clades have been reassigned into seven genera.[3] Following this revision, the name Symbiodinium is now sensu stricto a genus name for only species that were previously classified as Clade A.[3] The other clades were reclassified as distinct genera (see Molecular Systematics below).

Light and confocal images of Symbiodinium cells in hospite (living in a host cell) within scyphistomae of the jellyfish Cassiopea xamachana. This animal requires infection by these algae to complete its life cycle. The chloroplast imaged in 3-D is highly reticulated and distributed around the cell's periphery
  1. ^ Guiry, Michael D. (2014). "Symbiodinium Freudenthal, 1962". WoRMS. World Register of Marine Species. Retrieved 2015-01-29.
  2. ^ Blank, Rudolf J.; Trench, Robert K. (May 1986). "Nomenclature of Endosymbiotic Dinoflagellates". Taxon. 35 (2): 286–94. doi:10.2307/1221270. JSTOR 1221270.
  3. ^ a b LaJeunesse, Todd C.; Parkinson, John E.; Gabrielson, Paul W.; Jeong, Hae Jin; Reimer, James D.; Voolstra, Christian R.; Santos, Scott R. (2018). "Systematic revision of Symbiodiniaceae highlights the antiquity and diversity of coral endosymbionts". Current Biology. 28 (16): P2570–2580. doi:10.1016/j.cub.2018.07.008. hdl:10754/630499. PMID 30100341.