Phylogeny and morphology of novel Labyrinthulomycetes in Nova Scotia, Canada

ABSTRACT Labyrinthulomycetes are ubiquitous marine decomposers and include the thraustochytrids, a lineage known for their extensive production of polyunsaturated fatty acids and biotechnology applications. Despite historical taxonomic confusion, environmental surveys have begun to expand the known diversity within labyrinthulomycetes. Here we present 18S ribosomal DNA (rDNA) sequences from 17 novel labyrinthulomycetes strains established as axenic cultures from natural samples taken from three locations in Nova Scotia, Canada. We also present light and transmission electron microscopic analysis for three of these isolates. The combination of phylogenetic and morphological analysis suggests that these isolates belong to three different genera, Thraustochytrium , Ulkenia and Oblongichytrium . Our results expand the known genetic diversity of labyrinthulomycetes in Atlantic Canadian waters, contributing new strains to understudied genera for future comparative genomic investigations, including Ulkenia and Oblongichytrium for which very few genomic resources are available.