Algophthora
Species of fungus
From Wikipedia, the free encyclopedia
Algophthora mediterranea is a species of parasitic chytrid fungus in the order Lobulomycetales, and the type species of the genus Algophthora. It was first isolated from Mediterranean seawater off the coast of Catalonia, Spain, in 2021, and formally described in 2025.[1] It is notable for being a lethal parasite of the toxic bloom-forming dinoflagellate Ostreopsis cf. ovata, and for having an unusually broad host range that spans both dinoflagellates and diatoms.[2]
| Algophthora | |
|---|---|
| Scientific classification | |
| Kingdom: | |
| Division: | |
| Class: | Lobulomycetes |
| Order: | Lobulomycetales |
| Family: | Lobulomycetaceae |
| Genus: | Algophthora Pou-Solà, K. Seto & Fern.-Valero |
| Species: | A. mediterranea |
| Binomial name | |
| Algophthora mediterranea Pou-Solà, K. Seto & Fern.-Valero | |
Discovery and naming
Algophthora mediterranea was first detected in seawater collected on 15 July 2021 at the Sant Andreu de Llavaneres sampling station in the northwestern Mediterranean Sea (41°33′07.5″N 2°29′31.6″E), growing on cells of Ostreopsis cf. ovata.[1] It was isolated by scientists from the Institut de Ciències del Mar (ICM-CSIC) in Barcelona, Spain, under the direction of Esther Garcés and Albert Reñé. The species was later formally described by Núria Pou-Solà and Maiko Kagami at Yokohama National University.[2]
DNA analysis confirmed that the organism represents not only a new species but also a new genus.[2] The genus name Algophthora combines the Latin alga with the Greek phthora ("destruction"), referring to the fungus's ability to parasitize multiple phytoplankton groups.[1] The specific epithet mediterranea refers to the species' origin in the Mediterranean Sea.[1]
Description
The thallus is monocentric, eucarpic, and epibiotic. The zoosporangium has an operculate discharge pore and is irregularly shaped at maturity. The rhizoid is isodiametric and branches from a single rhizoidal axis. Zoospores are spherical, posteriorly uniflagellate, each containing one lipid globule.[1]
Phylogeny
Phylogenetic analysis based on concatenated 18S, 5.8S, and 28S rDNA sequences placed A. mediterranea within the order Lobulomycetales as a distinct lineage separate from all previously described species. Within this order, it formed a sister branch to a clade comprising Algomyces stechlinensis and Zygorhizidium affluens.[1] Despite some variation in branch position between different analyses, it consistently appeared as an isolated branch within the order, reinforcing its status as a distinct genus.[1]
Host range and ecology
Algophthora mediterranea is a generalist parasite with an unusually broad host range. Cross-infection experiments confirmed it can infect healthy cells of both dinoflagellates and diatoms, making it the first known chytrid capable of parasitizing such a wide range of marine phytoplankton.[1] Tested hosts include the dinoflagellate Ostreopsis cf. ovata as well as the diatom genera Chaetoceros, Coscinodiscus, and Leptocylindrus. Infection prevalence was higher in dinoflagellates than in diatoms.[1] Under laboratory conditions, the fungus also developed zoosporangia on pollen grains, using them as an alternative nutrient source.[1]
The fungus kills Ostreopsis cf. ovata cells within days.[2] This dinoflagellate produces ovatoxin (OVTX), a toxin that can cause respiratory symptoms, conjunctivitis, itching, and dermatitis in humans, and large blooms of this alga have been reported with increasing frequency in the Mediterranean.[3] The discovery suggests that chytrid fungi may play a greater role in marine ecosystems than previously recognized.[2]