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Jeon BS, Park MG. Morphology, phylogeny, and host range of the novel early-diverging oomycete Sirolpidium dinoletiferum sp. nov. parasitizing marine dinoflagellates. HARMFUL ALGAE 2024; 132:102567. [PMID: 38331547 DOI: 10.1016/j.hal.2024.102567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 02/10/2024]
Abstract
Oomycetes are fungus-like heterotrophic organisms with a broad environmental distribution, including marine, freshwater, and terrestrial habitats. They function as saprotrophs that use the remains of other organisms or as parasites of a variety of eukaryotes, including protists, diatoms, dinoflagellates, macroalgae, plants, fungi, animals, and even other oomycetes. Among the protist hosts, the taxonomy, morphology, and phylogenetic positions of the oomycete parasitoids of diatoms have been well studied; however, this information concerning the oomycete parasitoids of dinoflagellates is poorly understood. During intensive sampling along the east and west coasts of Korea in May and October 2019, a new species of oomycetes was discovered and two strains of the new parasitoid were successfully established in cultures. The new oomycete parasitoid penetrated the dinoflagellate host cell and developed to form a sporangium, which was very similar to the perkinsozoan parasitoids that infect marine dinoflagellates. The most distinctive morphological feature of the new parasitoid was a central large vacuole forming several long discharge tubes. The molecular phylogenetic tree inferred based on the small subunit (SSU) ribosomal DNA (rDNA) revealed that the new parasitoid forms a distinct branch unrelated to other described species belonging to early-diverging oomycetes. It clustered with species belonging to the genus Sirolpidium with strong support values in the cytochrome c oxidase subunit 2 (cox2) tree. Cross-infection experiments showed that infections by the new parasitoid occurred in only six genera belonging to dinoflagellates among the protists tested in this study. Based on the morphological and molecular data obtained in this study, we propose to introduce a new species, Sirolpidium dinoletiferum sp. nov., for this novel parasitoid, conservatively within the genus Sirolpidium.
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Affiliation(s)
- Boo Seong Jeon
- Research Institute for Basic Sciences, Chonnam National University, Gwangju 61186, Korea
| | - Myung Gil Park
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Korea.
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Buaya A, Tsai I, Thines M. Pontisma blauvikense sp. nov. the first member of the early-diverging oomycete genus Pontisma parasitizing brown algae. J Eukaryot Microbiol 2023; 70:e12957. [PMID: 36447377 DOI: 10.1111/jeu.12957] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/25/2022] [Accepted: 11/10/2022] [Indexed: 12/04/2022]
Abstract
Holocarpic oomycetes have been neglected over several decades, until interest in these organisms has recently resurged. One of the most widespread genera of holocarpic oomycetes is Pontisma, parasitic to red seaweeds throughout all oceans. Recently, the genus Sirolpidium (parasitic to green algae) was found to be congeneric with Pontisma. This hinted at a high pathogenic versatility and prompted the screening of other macroalgae on the coastline of Iceland. During this survey a parasite of the brown algae Pylaiella littoralis was found, which formed anisolpidium-like thalli, but produced biflagellate zoospores. Phylogenetic investigations revealed that the parasite was placed in the genus Pontisma. In reconstructions based on partial nrSSU sequences, it grouped with some sequences of parasitoids of the diatom genus Licmophora, but the more variable mitochondrial cox2 sequences were divergent. Based on phylogenetic evidence and the unique parasitism of brown algae, the parasitoid is described as Pontisma blauvikense in this study. Pontisma blauvikense is the fourth oomycete species parasitic to Pylaiella, which is also parasitised by Euychasma dicksonii and two Anisolpidium species. For a better understanding of the ecology and evolution of holocarpic oomycetes, further research is necessary to investigate the host spectrum of Pontisma in general and Pontisma blauvikense in particular.
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Affiliation(s)
- Anthony Buaya
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
| | - Ichen Tsai
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Marco Thines
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
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Buaya A, Thines M. Miracula blauvikensis: a new species of Miracula from Iceland, and report of a co-cultivation system for studying oomycete-diatom interactions. Fungal Syst Evol 2022; 10:169-175. [PMID: 36741555 PMCID: PMC9875693 DOI: 10.3114/fuse.2022.10.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
The genus Miracula represents an early-diverging lineage of diatom-parasitic Oomycota, straminipilous eukaryotes that have evolved fungal features independent from the opisthokont Fungi. Recent studies have revealed that diatom parasitoids are much more species-rich than previously thought and may play an important role in limnic and marine ecosystems. Of the different diatom-parasitic lineages, the genus Miracula is one of the most abundant in marine ecosystems. Here a species of Miracula parasitising Fragilaria capucina s.l. from Iceland is described as Miracula blauvikensis. In addition, its phylogenetic position is clarified and its life-cycle documented. The species has been brought into co-cultivation with its host, and due to the ease of cultivation and the convenient microscopy of the diatom threads, this co-culture might be a useful tool to study oomycete-diatom interactions in the future. Citation: Buaya A, Thines M (2022). Miracula blauvikensis: a new species of Miracula from Iceland, and report of a co-cultivation system for studying oomycete-diatom interactions. Fungal Systematics and Evolution 10: 169-175. doi: 10.3114/fuse.2022.10.07.
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Affiliation(s)
- A. Buaya
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany,*Corresponding authors: ,
| | - M. Thines
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany,Goethe University Frankfurt am Main, Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany,*Corresponding authors: ,
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Lagena—an overlooked oomycete genus with a wide range of hosts. Mycol Prog 2022. [DOI: 10.1007/s11557-022-01818-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AbstractLagena has so far only been known from the scarcely reported but widespread species Lagena radicicola, which is a parasite of root epidermal cells. While it was mostly reported from a wide range of cereals and other grasses, it has been shown to affect some dicot species under, e.g. tobacco and sugar beet. Due to the wide host spectrum under laboratory conditions, there were no attempts to subdivide the genus into several species, even though some morphological differentiation was reported and the species had been found in several continents. During a survey of diatoms, we came across some parasitoids that would have previously been assumed to be members of the genus Lagenidium. The species exhibited rather narrow host specificity in nature. One species was brought into dual culture with host diatoms of the genus Ulnaria, but could not be transferred to other host genera. Surprisingly, phylogenetic analyses revealed that Lagena radicicola was in a sister clade to that formed by the diatom parasitoids, suggesting a versatile pathogenicity of the genus. Interestingly, several phylogenetic lineages only known from environmental sequencing were clustered with the species found in this study, hinting an undiscovered diversity in the genus Lagena.
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Buaya AT, Thines M. Miracula einbuarlaekurica sp. nov., a new holocarpic endoparasitoid species from pennate freshwater diatoms in Iceland. Mycology 2022; 13:153-161. [PMID: 35711327 PMCID: PMC9196793 DOI: 10.1080/21501203.2021.1980446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Holocarpic oomycetes infecting freshwater diatoms are obligate endobiotic parasites reported from a wide range of habitats. So far, the taxonomy of and phylogeny of most species remains unresolved, since most have not been reported throughout the past decades and sequence data are available for only the four species, Aphanomycopsis bacillariacearum, Diatomophthora gillii, Ectrogella bacillariacearum, and the recently-discovered species Miracula moenusica. In the current study, a new freshwater diatom parasite resembling Ectrogella bacillariacearum in the sense of Scherffel was discovered from pennate diatoms (Ulnaria acus, Ulnaria ulna) collected from the small stream Einbúalækur on Víkurskarð, North Iceland and investigated for its life cycle and phylogenetic placement. In contrast to the original description, Scherffel reports an achlya-like spore discharge for Ectrogella bacillariacearum. The phylogenetic reconstruction and morphological characterisation in this study revealed that Scherffel’s E. bacillariacearum is largely unrelated to the epitype of the species and is a member of the early-diverging genus Miracula. Consequently, the new species is described as M. einbuarlaekurica in the present study. This adds a second freshwater member to the genus, demonstrating the high ecological adaptability of the genus, which thrives in both freshwater and marine ecosystems.
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Affiliation(s)
- Anthony T. Buaya
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Marco Thines
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
- Department of Biological Sciences, Goethe University Frankfurt am Main, Institute of Ecology, Frankfurt am Main, Germany
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Ilicic D, Grossart HP. Basal Parasitic Fungi in Marine Food Webs-A Mystery Yet to Unravel. J Fungi (Basel) 2022; 8:114. [PMID: 35205868 PMCID: PMC8874645 DOI: 10.3390/jof8020114] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 02/01/2023] Open
Abstract
Although aquatic and parasitic fungi have been well known for more than 100 years, they have only recently received increased awareness due to their key roles in microbial food webs and biogeochemical cycles. There is growing evidence indicating that fungi inhabit a wide range of marine habitats, from the deep sea all the way to surface waters, and recent advances in molecular tools, in particular metagenome approaches, reveal that their diversity is much greater and their ecological roles more important than previously considered. Parasitism constitutes one of the most widespread ecological interactions in nature, occurring in almost all environments. Despite that, the diversity of fungal parasites, their ecological functions, and, in particular their interactions with other microorganisms remain largely speculative, unexplored and are often missing from current theoretical concepts in marine ecology and biogeochemistry. In this review, we summarize and discuss recent research avenues on parasitic fungi and their ecological potential in marine ecosystems, e.g., the fungal shunt, and emphasize the need for further research.
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Affiliation(s)
- Doris Ilicic
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin, Germany;
| | - Hans-Peter Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin, Germany;
- Institute of Biochemistry and Biology, Potsdam University, Maulbeerallee 2, 14469 Potsdam, Germany
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Buaya AT, Scholz B, Thines M. A New Marine Species of Miracula ( Oomycota) Parasitic to Minidiscus sp. in Iceland †. MYCOBIOLOGY 2021; 49:355-362. [PMID: 34512079 PMCID: PMC8409938 DOI: 10.1080/12298093.2021.1952813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 06/29/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
Obligate endoparasitic oomycetes are known to ubiquitously occur in marine and freshwater diatoms, but their diversity is still largely unexplored. Many of these parasitoids are members of the early-diverging oomycete lineages (Miracula, Diatomophthora), others are within the Leptomitales of the Saprolegniomycetes (Ectrogella, Lagenisma) and some have been described in the Peronosporomycetes (Aphanomycopsis, Lagenidium). Even though some species have been recently described and two new genera were introduced (Miracula and Diatomophthora), the phylogeny and taxonomy of most of these organisms remain unresolved. This is contrasted by the high number of sequences from unclassified species, as recently revealed from environmental sequencing, suggesting the presence of several undiscovered species. In this study, a new species of Miracula is reported from a marine centric diatom (Minidiscus sp.) isolated from Skagaströnd harbor in Northwest Iceland. The morphology and life cycle traits of this novel oomycete parasite are described herein, and its taxonomic placement within the genus Miracula is confirmed by molecular phylogeny. As it cannot be assigned to any previously described species, it is introduced as Miracula islandica in this study. The genus Miracula thus contains three described holocarpic species (M. helgolandica, M. islandica, M. moenusica) to which likely additional species will need to be added in the future, considering the presence of several lineages known only from environmental sequencing that clustered within the Miracula clade.
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Affiliation(s)
- Anthony T. Buaya
- Senckenberg Biodiversity and Climate Research Center, Frankfurt am Main, Germany
| | | | - Marco Thines
- Senckenberg Biodiversity and Climate Research Center, Frankfurt am Main, Germany
- Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe-Universität Frankfurt am Main, Frankfurt am Main, Germany
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Langer JAF, Sharma R, Nam B, Hanic L, Boersma M, Schwenk K, Thines M. Cox2 community barcoding at Prince Edward Island reveals long-distance dispersal of a downy mildew species and potentially marine members of the Saprolegniaceae. Mycol Prog 2021. [DOI: 10.1007/s11557-021-01687-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractMarine oomycetes are highly diverse, globally distributed, and play key roles in marine food webs as decomposers, food source, and parasites. Despite their potential importance in global ocean ecosystems, marine oomycetes are comparatively little studied. Here, we tested if the primer pair cox2F_Hud and cox2-RC4, which is already well-established for phylogenetic investigations of terrestrial oomycetes, can also be used for high-throughput community barcoding. Community barcoding of a plankton sample from Brudenell River (Prince Edward Island, Canada), revealed six distinct oomycete OTU clusters. Two of these clusters corresponded to members of the Peronosporaceae—one could be assigned to Peronospora verna, an obligate biotrophic pathogen of the terrestrial plant Veronica serpyllifolia and related species, the other was closely related to Globisporangium rostratum. While the detection of the former in the sample is likely due to long-distance dispersal from the island, the latter might be a bona fide marine species, as several cultivable species of the Peronosporaceae are known to withstand high salt concentrations. Two OTU lineages could be assigned to the Saprolegniaceae. While these might represent marine species of the otherwise terrestrial genus, it is also conceivable that they were introduced on detritus from the island. Two additional OTU clusters were grouped with the early-diverging oomycete lineages but could not be assigned to a specific family. This reflects the current underrepresentation of cox2 sequence data which will hopefully improve with the increasing interest in marine oomycetes.
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Taxonomy and phylogeny of Aphanomycopsis bacillariacearum, a holocarpic oomycete parasitoid of the freshwater diatom genus Pinnularia. Mycol Prog 2021. [DOI: 10.1007/s11557-021-01668-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractInvestigations into simple holocarpic oomycetes are challenging, because of the obligate biotrophic nature of many lineages and the periodic presence in their hosts. Thus, despite recent efforts, still, the majority of species described remains to be investigated for their phylogenetic relationships. One of these species is Aphanomycopsis bacillariacearum, the type species of the genus Aphanomycopsis. Species of Aphanomycopsis are endobiotic holocarpic parasites of diverse hosts (e.g., diatoms, desmids, dinoflagellates). All species classified in this genus were assigned to it based on the presence of branching hyphae and the formation of two generations of zoospores, of which the first one is not motile. Originally, Aphanomycopsis with its type species, A. bacillariacearum, had been classified in the Saprolegniaceae. However, the genus has undergone multiple taxonomic reassignments (to Ectrogellaceae, Lagenidiaceae, and Leptolegniellaceae) in the past. To settle the taxonomy and investigate the phylogenetic placement of Aphanomycopsis, efforts were undertaken to isolate A. bacillariacearum from its original host, Pinnularia viridis and infer its phylogenetic placement based on nrSSU (18S) sequences. By targeted isolation, the diatom parasitoid was rediscovered from Heiðarvatn lake, Höskuldsstaðir, Iceland. Phylogenetic reconstruction shows that A. bacillariacearum from Pinnularia viridis is embedded within the Saprolegniales, and largely unrelated to both diatom-infecting oomycetes in the Leptomitales (Ectrogella, Lagenisma) and those placed within the early-diverging lineages (Miracula, Diatomophthora) of the Oomycota.
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Phylogeny and cultivation of the holocarpic oomycete Diatomophthora perforans comb. nov., an endoparasitoid of marine diatoms. Mycol Prog 2020. [DOI: 10.1007/s11557-020-01569-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
AbstractOomycetes infecting diatoms are biotrophic parasitoids and live in both marine and freshwater environments. They are ubiquitous, but the taxonomic affinity of many species remains unclear and the majority of them have not been studied for their molecular phylogeny. Only recently, the phylogenetic and taxonomic placement of some diatom-infecting, early-diverging oomycetes was resolved, including the genera Ectrogella, Miracula, Olpidiopsis, and Pontisma. A group of holocarpic diatom parasitoids with zoospores swarming within the sporangium before release were found to be unrelated to the known genera with diatom-infecting species, and were re-classified to a new genus, Diatomophthora. However, about a dozen species of holocarpic diatom parasitoids with unclear affinity remained unsequenced, which includes a commonly occurring species so far identified as Ectrogella perforans. However, this assignment to Ectrogella is doubtful, as the species was not reported to feature a clear-cut diplanetism, a hallmark of Ectrogella s. str. and the whole class Saprolegniomycetes. It was the aim of the current study to clarify the phylogenetic affinities of the species and if the rather broad host range reported is correct or a reflection of cryptic species. By targeted screening, the parasitoid was rediscovered from Helgoland Roads, North Sea and Oslo Fjord, Southern Norway and investigated for its phylogenetic placement using small ribosomal subunit (18S) sequences. Stages of its life cycle on different marine diatoms were described and its phylogenetic placement in the genus Diatomophthora revealed. A stable host-parasite axenic culture from single spore strains of the parasitoid were established on several strains of Pleurosigma intermedium and Coscinodiscus concinnus. These have been continuously cultivated along with their hosts for more than 2 years, and cultural characteristics are reported. Cross-infection trials revealed the transferability of the strains between hosts under laboratory conditions, despite some genetic distance between the pathogen strains. Thus, we hypothesise that D. perforans might be in the process of active radiation to new host species.
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Buaya AT, Thines M. Bolbea parasitica gen. et sp. nov., a cultivable holocarpic parasitoid of the early-diverging Saprolegniomycetes. Fungal Syst Evol 2020; 6:129-137. [PMID: 32904153 PMCID: PMC7451777 DOI: 10.3114/fuse.2020.06.07] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Holocarpic oomycetes convert their entire cytoplasm into zoospores and thus do not form dedicated sporangia or hyphal compartments for asexual reproduction. The majority of holocarpic oomycetes are obligate parasites and parasitoids of a diverse suite of organisms, among them green and red algae, brown seaweeds, diatoms, fungi, oomycetes and invertebrates. Most of them are found among the early diverging oomycetes or the Peronosporomycetes, and some in the early-diverging Saprolegniomycetes (Leptomitales). The obligate parasitism renders it difficult to study some of these organisms. Only a few members of the genus Haliphthoross. l. have been cultured without their hosts, and of the parasitoid Leptomitales, some transient cultures have been established, which are difficult to maintain. Here, the cultivation of a new holocarpic oomycete genus of the Leptomitales, Bolbea, is presented. Bolbea is parasitic to ostracods, is readily cultivable on malt extract agar, and upon contact with water converts its cytoplasm into zoospores. Its morphology and phylogenetic relationships are reported. Due to the ease of cultivation and the ready triggering of zoospore development, similar to some lagenidiaceous oomycetes, the species could be a promising model to study sporulation processes in detail.
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Affiliation(s)
- A T Buaya
- Goethe-Universität Frankfurt am Main, Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
| | - M Thines
- Goethe-Universität Frankfurt am Main, Department of Biological Sciences, Institute of Ecology, Evolution and Diversity, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany.,Senckenberg Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.,LOEWE Centre for Translational Biodiversity Genomics, Georg-Voigt-Str. 14-16, D-60325 Frankfurt am Main, Germany
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