Molecular Phylogeny of Labyrinthulids and Thraustochytrids Based On the Sequencing of 18s Ribosomal Rna Gene

Honda, Daiske; Yokochi, Toshihiro; Nakahara, Toro; Raghukumar, Seshagiri; Nakagiri, Akira; Schaumann, K.; Higashihara, Takanori

doi:10.1111/j.1550-7408.1999.tb05141.x

Cited by 166 publications

(103 citation statements)

References 52 publications

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“…Because the classifications of thraustochytrids based on morphology and molecular phylogeny do not necessarily agree with each other (21), it is difficult to discuss whether SssRNAV is species specific or strain specific based only on the present results. However, it is notable that the four SssRNAV-sensitive strains (NIBH N1-27, SEK 0209, MBIC 11066, and MBIC 11072) belong to a particular group (Table 1) based on molecular phylogeny (22; R. Yokoyama, personal.…”

Section: Resultsmentioning

confidence: 76%

“…They are comprised of six genera (33,47), Althornia (26), Aplanochytrium (2), Japonochytrium (32), Schizochytrium (18), Thraustochytrium (59), and Ulkenia (13). However, it has been shown that the current classification of these genera based on morphology does not agree with the molecular phylogenetic relationships based on the 18S rRNA gene sequences (21). Currently, in order to resolve the confusion regarding the classification and nomenclature of the thraustochytrids, further comparative studies based on morphology, molecular phylogeny, and chemotaxonomy are under way (R. Yokoyama, personal communication).…”

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confidence: 99%

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Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Takao

Nagasaki

Mise

et al. 2005

Appl Environ Microbiol

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Thraustochytrids are cosmopolitan osmoheterotrophic microorganisms that play important roles as decomposers, producers of polyunsaturated fatty acids, and pathogens of mollusks, especially in coastal ecosystems. SssRNAV, a novel single-stranded RNA (ssRNA) virus infecting the marine fungoid protist Schizochytrium sp. (Labyrinthulea, Thraustochytriaceae) was isolated from the coastal water of Kobe Harbor, Japan, in July 2000, and its basic characteristics were examined. The virus particle is icosahedral, lacks a tail, and is ca. 25 nm in diameter. SssRNAV formed crystalline arrays and random assemblies within the cytoplasm of host cells, and it was also concentrated along the intracellular membrane structures. By means of one-step growth experiments, the lytic cycle and the burst size were estimated to be <8 h and 5.8 ؋ 10 3 to 6.4 ؋ 10 4 infectious units per host cell, respectively. SssRNAV had a single molecule of ssRNA that was approximately 10.2 kb long, three major proteins (37, 34, and 32 kDa), and two minor proteins (80 and 18 kDa). Although SssRNAV was considered to have some similarities with invertebrate viruses belonging to the family Dicistroviridae based on its partial nucleotide sequence, further genomic analysis is required to determine the detailed classification and nomenclature of SssRNAV. Our results indicate that viral infection is one of the significant factors controlling the dynamics of thraustochytrids and provide new insights into understanding the ecology of these organisms.

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Section: Resultsmentioning

confidence: 76%

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confidence: 99%

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Takao

Nagasaki

Mise

et al. 2005

Appl Environ Microbiol

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“…As both approaches also utilize or require ecological (and other) data, combining numerous methods in future efforts should prove beneficial (Carstens et al 2013), and is probably vital to any revision of the group-which has been called for (e.g., Porter 1990;Honda et al 1999). However, as protistan genetic diversity is vastly greater than that within plant, animal or fungal groups, a single genetic marker has not emerged as ideal for approaching species-level investigations, though use of the ITS region has been common (Pawlowski et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Functional, Phylogenetic and Host-Geographic Signatures of Labyrinthula spp. Provide for Putative Species Delimitation and a Global-Scale View of Seagrass Wasting Disease

Martín

Chiari

Boone

et al. 2016

Estuaries and Coasts

102

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Seagrass meadows form ecologically and economically valuable coastal habitat on every continental margin except the Antarctic, but their areal extent is declining by approximately 2-5 % per year. Seagrass wasting disease is a contributing factor in these declines, with the protist Labyrinthula identified as the etiologic agent. To help elucidate the role of Labyrinthula spp. in global seagrass declines, we surveyed roughly one fourth of all seagrass species to identify Labyrinthula diversity at the strain and/or species level, combining results from culturing methods and two common nuclear DNA markers: the ITS and 18S regions of the ribosomal RNA gene complex. After assaying a subset of the resulting isolates (of which 170 were newly sequenced), we produced a cladogenic context for putative seagrasspathogenic versus non-pathogenic Labyrinthula while also defining host and geographic ranges. Assays also suggest that pathogenicity is consistently high (when present; and, even when comparing susceptibility of US East-versus West Coast Zostera marina hosts) while virulence is variable, that some isolate-host combinations have the potential for host cross-infection, and that several modes of transmission can be effective. Taken together, these data provide additional means for delimiting putative species of Labyrinthula, suggesting at least five seagrass-pathogenic and perhaps ten or more non-pathogenic marine Bspecies^, yielding a working definition for ecologists and epidemiologists attempting to reconcile the sundry data related to seagrass wasting disease.

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“…Thraustochytrids are cosmopolitan apochlorotic stramenopile protists classified in the class Labyrinthulomycetes within the kingdom Chromista (Cavalier-Smith et al 1994, Leipe et al 1994, Honda et al 1999. Based on phylogenetic analysis of 18S ribosomal RNA gene sequences, Honda et al (1999) suggested that thraustochytrid strains belong to either TPG (thraustochytrid phylogenetic group) which is a monophyletic group comprised of only thraustochytrid strains or LPG (labyrinthulid phylogenetic group) which includes all members of the family Labyrinthuraceae and some strains belonging to the family Thraustochytriaceae.…”

Section: Introductionmentioning

confidence: 99%

“…Based on phylogenetic analysis of 18S ribosomal RNA gene sequences, Honda et al (1999) suggested that thraustochytrid strains belong to either TPG (thraustochytrid phylogenetic group) which is a monophyletic group comprised of only thraustochytrid strains or LPG (labyrinthulid phylogenetic group) which includes all members of the family Labyrinthuraceae and some strains belonging to the family Thraustochytriaceae.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence in situ hybridization using 18S rRNA-targeted probe for specific detection of thraustochytrids (Labyrinthulomycetes)

Takao

Tomaru

Nagasaki

et al. 2007

Plankton Benthos Res

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Thraustochytrids are cosmopolitan osmotrophic or heterotrophic microorganisms that play, especially in coastal ecosystems, important roles as decomposers and producers of polyunsaturated fatty acids (PUFA), and are also known to be pathogens of mollusks and seaweeds. However, because of shortcomings in the current methods for detection and enumeration of thraustochytrids, very little information is available concerning their natural dynamics and ecological roles. In this study, we propose a new method for detecting thraustochytrids using a fluorescent 18S ribosomal RNA (rRNA)-targeted oligonucleotide probe (Probe ThrFL1). Detection of thraustochytrids by means of the fluorescence in situ hybridization (FISH) technique with ThrFL1 was specific; the probe did not react with the other stramenopile organisms or with the dinoflagellate that was tested. Because of the high specificity and intense reactivity, the FISH protocol is expected to be a strong tool for examining ecological features of thraustochytrids.

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Molecular Phylogeny of Labyrinthulids and Thraustochytrids Based On the Sequencing of 18s Ribosomal Rna Gene

Cited by 166 publications

References 52 publications

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Isolation and Characterization of a Novel Single-Stranded RNA Virus Infectious to a Marine Fungoid Protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea)

Functional, Phylogenetic and Host-Geographic Signatures of Labyrinthula spp. Provide for Putative Species Delimitation and a Global-Scale View of Seagrass Wasting Disease

Fluorescence in situ hybridization using 18S rRNA-targeted probe for specific detection of thraustochytrids (Labyrinthulomycetes)

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