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New Species of Saprobic Labyrinthulea (=Labyrinthulomycota) and the Erection of a gen. nov. to Resolve Molecular Polyphyly within the Aplanochytrids
Author(s) -
Hassett Brandon T.,
Gradinger Rolf
Publication year - 2018
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12494
Subject(s) - biology , polyphyly , phylogenetic tree , zoospore , phylogenetics , botany , zoology , evolutionary biology , genetics , gene , spore , clade
A culture of a unicellular heterotrophic eukaryote was established from pollen‐baited seawater acquired from the nearshore environment in Tromsø, Norway. Light microscopy revealed the production of ectoplasmic nets and reproduction by biflagellated zoospores, as well as binary division. After culturing and subsequent nucleotide extraction, database queries of the isolate's 18S small ribosomal subunit coding region identified closest molecular affinity to Aplanochytrium haliotidis , a pathogen of abalone. Testing of phylogenetic hypotheses consistently grouped our unknown isolate and A. haliotidis among the homoplasious thraustochytrids. Transmission electron microscopy revealed complex cell walls comprised of electron‐dense lamella that formed protuberances, some associated with bothrosomes. Co‐culturing experiments with the marine fungus Penicillium brevicompactum revealed prolonged interactions with hyphal strands. Based on the combined information acquired from electron microscopy, life history information, and phylogenetic testing, we describe our unknown isolate as a novel species. To resolve molecular polyphyly within the aplanochytrids, we erect a gen. nov. that circumscribes our novel isolate and the former A. haliotidis within the thraustochytrids.