The First Isolation and Characterisation of the Protist Labyrinthula sp. in Southeastern Australia

Abstract

As a result of anthropogenic influences and global climate change, emerging infectious marine diseases are thought to be increasingly more common and more severe than in the past. The aim of our investigation was to confirm the presence of Labyrinthula, the aetiological agent of the seagrass wasting disease, in Southeastern Australia and provide the first isolation and characterisation of this protist, in Australia. Colonies and individual cells were positively identified as Labyrinthula using published descriptions, diagrams, and photographs. Their identity was then confirmed using DNA barcoding of a region of the 18S rRNA gene. Species level identification of isolates was not possible as the taxonomy of the Labyrinthula is still poorly resolved. Still, a diversity of Labyrinthula was isolated from small sections of the southeast coast of Australia. The isolates were grouped into three haplotypes that are biogeographically restricted. These haplotypes are closely related to previously identified saprotrophic clades. The study highlights the need for further investigation into the global distribution of Labyrinthula, including phylogenetic pathogenicity and analysis of host-parasite interactions in response to stressors. Given the results of our analyses, it is prudent to continue research into disease and epidemic agents to better prepare researchers for potential future outbreaks.

Culturable Diversity and Lipid Production Profile of Labyrinthulomycete Protists Isolated from Coastal Mangrove Habitats of China

“…Labyrinthulomycetes are the most ubiquitous and widespread straminipilan protists in oceans with a total of 13 known genera and 30 described species so far [10]. They have been isolated, using the direct-plating and pollen-baiting methods, from various habitats (e.g., marine seawater, estuarine water, sediments, decaying mangrove leaves, and senescent macroalgae) [11,12,13,14,15,16]. Yet, the majority of the species described are isolated from only a limited number of coastal regions, for example, Japan [17], Australia [12,18], Canada [19], India [20,21,22], Chile [11], China [23], Malaysia [24,25], and Thailand [26].…”

“…Although the labyrinthulids group are important ecologically, there is no formal estimate of their culturable diversity. So far, only a few studies have reported on the isolation of labyrinthulids [15,27]. On the contrary, the group thraustochytrids has gained significant attention of researchers because of their biotechnological potential [28].…”

Labyrinthula diatomea n. sp.—A Labyrinthulid Associated with Marine Diatoms

“…Recent SSU rDNA analyses and ITS strain demarcation indicate a huge variety and a large number of undescribed species in Labyrinthula (Sullivan et al. ). Haplogroup compositions based on TCS haplotype networks from our study generally coincide with haplogroups previously delimited by the methods of neighbor joining and the maximum likelihood (Martin et al.…”

Review: Host-pathogen dynamics of seagrass diseases under future global change

“…Much of this work has been done in Z. marina and other North American and European species. However, more recently, research has emerged on the biology and ecology of Labyrinthula at the global level where researchers have investigated phylogeny and global trends in pathogenicity of Labyrinthula (Martin et al, 2016), including the most recent work describing isolation, phylogeny (Sullivan et al, 2016) and pathogenicity (Trevathan-Tackett et al, unpublished) of Labyrinthula spp. in the southern hemisphere.…”