Phycophthorum is a monotypicgenus of protists that parasitizediatoms, containing the sole species Phycophthorum isakeiti. It was discovered in 2020 in the coastal waters of Norway, as parasites of diatoms belonging to the genus Pleurosigma.
The zoospores of Phycophthorum are attracted to healthy Pleurosigma cells through chemotaxis. They move with their flagella towards the diatom cells and attach to the girdle band, valve or silica wall of their frustules. Once attached to the cell wall, the zoospores begin to penetrate the wall, lose their flagella and begin the formation of a sporangium. This structure generates new zoospores that cleave away from their group and obtain a new flagellum to gain motility. The new zoospores swim away from the original host diatom cell and seek out new hosts. The sporangium continues to occupy the dead remains of the host cell. Besides their flagellated form, zoospores can also assume an amoeboid form.[2]
Systematics
Discovery and etymology
Cells of Phycophthorum isakeiti were isolated from Arcticmarine sediment in the coastal waters around Tromsø Municipality, Norway.[3] The microbial culture was parasiting pennatediatoms of the genus Pleurosigma. The cells were examined and described as the genus Phycophthorum by marine microbiologist Brandon T. Hasset, with the results published in the Journal of Eukaryotic Microbiology in 2020. The genus name derives from Greek phyco 'algae' and phtheirein 'to destroy', in reference to its specialized parasitism of diatoms. The sole species, P. isakeiti, is named in honor of the plant pathologist Dr. Thomas Isakeit.[1]
^ abPereboev DD, Bubnova EN (September 2023). "Marine Labyrinthulomycetes". Russian Journal of Marine Biology. 49: 241–250. doi:10.1134/S1063074023040107.
^Bennett, Reuel M.; Honda, D.; Beakes, Gordon W.; Thines, Marco (2017). "Chapter 14. 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. ISBN978-3-319-28147-6.