The catastrophic loss of aquatic life in the Central European Oder River in 2022, caused by a toxic bloom of the haptophyte microalga Prymnesium parvum (in a wide sense, s.l.), underscores the need to improve our understanding of the genomic basis of the toxin. Previous morphological, phylogenetic, and genomic studies have revealed cryptic diversity within P. parvum s.l. and uncovered three clade-specific (types A, B, and C) prymnesin toxins. Here, we used state-of-the-art long-read sequencing and assembled the first haplotype-resolved diploid genome of a P. parvum type B from the strain responsible for the Oder disaster. Comparative analyses with type A genomes uncovered a genome-size expansion driven by repetitive elements in type B. We also found conserved synteny but divergent evolution in several polyketide synthase (PKS) genes, which are known to underlie toxin production in combination with environmental cues. We identified an approximately 20-kbp deletion in the largest PKS gene of type B that we link to differences in the chemical structure of types A and B prymnesins. Flow cytometry and electron microscopy analyses confirmed diploidy in the Oder River strain and revealed differences to closely related strains in both ploidy and morphology. Our results provide unprecedented resolution of strain diversity in P. parvum s.l. and a better understanding of the genomic basis of toxin variability in haptophytes. The reference-quality genome will enable us to better understand changes in microbial diversity in the face of increasing environmental pressures and provides a basis for strain-level monitoring of invasive Prymnesium in the future.
- Klíčová slova
- genomics, golden alga, haptophyte, harmful algal bloom, ploidy, polyketide synthase, prymnesin,
- MeSH
- fylogeneze MeSH
- haplotypy MeSH
- Haptophyta * genetika MeSH
- mikrořasy genetika MeSH
- mořské toxiny genetika MeSH
- polyketidsynthasy genetika metabolismus MeSH
- ryby genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- mořské toxiny MeSH
- polyketidsynthasy MeSH
PhyloFisher is a software package written primarily in Python3 that can be used for the creation, analysis, and visualization of phylogenomic datasets that consist of protein sequences from eukaryotic organisms. Unlike many existing phylogenomic pipelines, PhyloFisher comes with a manually curated database of 240 protein-coding genes, a subset of a previous phylogenetic dataset sampled from 304 eukaryotic taxa. The software package can also utilize a user-created database of eukaryotic proteins, which may be more appropriate for shallow evolutionary questions. PhyloFisher is also equipped with a set of utilities to aid in running routine analyses, such as the prediction of alternative genetic codes, removal of genes and/or taxa based on occupancy/completeness of the dataset, testing for amino acid compositional heterogeneity among sequences, removal of heterotachious and/or fast-evolving sites, removal of fast-evolving taxa, supermatrix creation from randomly resampled genes, and supermatrix creation from nucleotide sequences. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Constructing a phylogenomic dataset Basic Protocol 2: Performing phylogenomic analyses Support Protocol 1: Installing PhyloFisher Support Protocol 2: Creating a custom phylogenomic database.
- Klíčová slova
- evolution, genomics, systematics, transcriptomics,
- MeSH
- aminokyseliny * MeSH
- biologická evoluce * MeSH
- fylogeneze MeSH
- kultura MeSH
- sekvence aminokyselin MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aminokyseliny * MeSH
Phylogenomic analyses of hundreds of protein-coding genes aimed at resolving phylogenetic relationships is now a common practice. However, no software currently exists that includes tools for dataset construction and subsequent analysis with diverse validation strategies to assess robustness. Furthermore, there are no publicly available high-quality curated databases designed to assess deep (>100 million years) relationships in the tree of eukaryotes. To address these issues, we developed an easy-to-use software package, PhyloFisher (https://github.com/TheBrownLab/PhyloFisher), written in Python 3. PhyloFisher includes a manually curated database of 240 protein-coding genes from 304 eukaryotic taxa covering known eukaryotic diversity, a novel tool for ortholog selection, and utilities that will perform diverse analyses required by state-of-the-art phylogenomic investigations. Through phylogenetic reconstructions of the tree of eukaryotes and of the Saccharomycetaceae clade of budding yeasts, we demonstrate the utility of the PhyloFisher workflow and the provided starting database to address phylogenetic questions across a large range of evolutionary time points for diverse groups of organisms. We also demonstrate that undetected paralogy can remain in phylogenomic "single-copy orthogroup" datasets constructed using widely accepted methods such as all vs. all BLAST searches followed by Markov Cluster Algorithm (MCL) clustering and application of automated tree pruning algorithms. Finally, we show how the PhyloFisher workflow helps detect inadvertent paralog inclusions, allowing the user to make more informed decisions regarding orthology assignments, leading to a more accurate final dataset.
Recent surveys of marine microbial diversity have identified a previously unrecognized lineage of diplonemid protists as being among the most diverse heterotrophic eukaryotes in global oceans. Despite their monophyly (and assumed importance), they lack a formal taxonomic description, and are informally known as deep-sea pelagic diplonemids (DSPDs) or marine diplonemids. Recently, we documented morphology and molecular sequences from several DSPDs, one of which is particularly widespread and abundant in environmental sequence data. To simplify the communication of future work on this important group, here we formally propose to erect the family Eupelagonemidae to encompass this clade, as well as a formal genus and species description for the apparently most abundant phylotype, Eupelagonema oceanica, for which morphological information and single-cell amplified genome data are currently available.
- Klíčová slova
- Deep-sea pelagic diplonemids, euglenozoa, heterotrophic flagellate, kinetoplastids, marine diplonemids, single-cell amplified genome,
- MeSH
- Euglenozoa klasifikace cytologie genetika MeSH
- fylogeneze MeSH
- RNA protozoální analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- RNA protozoální MeSH
Marine alveolates (MALVs) are diverse and widespread early-branching dinoflagellates, but most knowledge of the group comes from a few cultured species that are generally not abundant in natural samples, or from diversity analyses of PCR-based environmental SSU rRNA gene sequences. To more broadly examine MALV genomes, we generated single cell genome sequences from seven individually isolated cells. Genes expected of heterotrophic eukaryotes were found, with interesting exceptions like presence of proteorhodopsin and vacuolar H+-pyrophosphatase. Phylogenetic analysis of concatenated SSU and LSU rRNA gene sequences provided strong support for the paraphyly of MALV lineages. Dinoflagellate viral nucleoproteins were found only in MALV groups that branched as sister to dinokaryotes. Our findings indicate that multiple independent origins of several characteristics early in dinoflagellate evolution, such as a parasitic life style, underlie the environmental diversity of MALVs, and suggest they have more varied trophic modes than previously thought.
- MeSH
- analýza jednotlivých buněk MeSH
- Dinoflagellata klasifikace genetika MeSH
- fylogeneze MeSH
- genomika MeSH
- geny rRNA MeSH
- Publikační typ
- časopisecké články MeSH
The guts of lower termites are inhabited by host-specific consortia of cellulose-digesting flagellate protists. In this first investigation of the symbionts of the family Serritermitidae, we found that Glossotermes oculatus and Serritermes serrifer each harbor similar parabasalid morphotypes: large Pseudotrichonympha-like cells, medium-sized Leptospironympha-like cells with spiraled bands of flagella, and small Hexamastix-like cells; oxymonadid flagellates were absent. Despite their morphological resemblance to Pseudotrichonympha and Leptospironympha, a SSU rRNA-based phylogenetic analysis identified the two larger, trichonymphid flagellates as deep-branching sister groups of Teranymphidae, with Leptospironympha sp. (the only spirotrichosomid with sequence data) in a moderately supported basal position. Only the Hexamastix-like flagellates are closely related to trichomonadid flagellates from Rhinotermitidae. The presence of two deep-branching lineages of trichonymphid flagellates in Serritermitidae and the absence of all taxa characteristic of the ancestral rhinotermitids underscores that the flagellate assemblages in the hindguts of lower termites were shaped not only by a progressive loss of flagellates during vertical inheritance but also by occasional transfaunation events, where flagellates were transferred horizontally between members of different termite families. In addition to the molecular phylogenetic analyses, we present a detailed morphological characterization of the new spirotrichosomid genus Heliconympha using light and electron microscopy.
- Klíčová slova
- Evolution, Parabasalia, Spirotrichosomidae, Trichomonadea, molecular phylogeny, symbiont, ultrastructure,
- MeSH
- Isoptera parazitologie MeSH
- mikroskopie elektronová rastrovací MeSH
- Parabasalidea klasifikace cytologie genetika ultrastruktura MeSH
- RNA protozoální analýza MeSH
- RNA ribozomální analýza MeSH
- střevní mikroflóra * MeSH
- transmisní elektronová mikroskopie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- RNA protozoální MeSH
- RNA ribozomální MeSH
Recent global surveys of marine biodiversity have revealed that a group of organisms known as "marine diplonemids" constitutes one of the most abundant and diverse planktonic lineages [1]. Though discovered over a decade ago [2, 3], their potential importance was unrecognized, and our knowledge remains restricted to a single gene amplified from environmental DNA, the 18S rRNA gene (small subunit [SSU]). Here, we use single-cell genomics (SCG) and microscopy to characterize ten marine diplonemids, isolated from a range of depths in the eastern North Pacific Ocean. Phylogenetic analysis confirms that the isolates reflect the entire range of marine diplonemid diversity, and comparisons to environmental SSU surveys show that sequences from the isolates range from rare to superabundant, including the single most common marine diplonemid known. SCG generated a total of ∼915 Mbp of assembled sequence across all ten cells and ∼4,000 protein-coding genes with homologs in the Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology database, distributed across categories expected for heterotrophic protists. Models of highly conserved genes indicate a high density of non-canonical introns, lacking conventional GT-AG splice sites. Mapping metagenomic datasets [4] to SCG assemblies reveals virtually no overlap, suggesting that nuclear genomic diversity is too great for representative SCG data to provide meaningful phylogenetic context to metagenomic datasets. This work provides an entry point to the future identification, isolation, and cultivation of these elusive yet ecologically important cells. The high density of nonconventional introns, however, also portends difficulty in generating accurate gene models and highlights the need for the establishment of stable cultures and transcriptomic analyses.
- Klíčová slova
- diplonemid, ecology, evolution, heterotroph, marine microbiology, protist,
- MeSH
- biodiverzita MeSH
- Euglenozoa klasifikace cytologie genetika MeSH
- fylogeneze MeSH
- genom protozoální * MeSH
- metagenomika MeSH
- plankton klasifikace cytologie genetika MeSH
- RNA protozoální genetika MeSH
- sekvence aminokyselin MeSH
- sekvenční seřazení MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Kalifornie MeSH
- Tichý oceán MeSH
- Názvy látek
- RNA protozoální MeSH
