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Wighard S, Witte H, Sommer RJ. Conserved switch genes that arose via whole-genome duplication regulate a cannibalistic nematode morph. SCIENCE ADVANCES 2024; 10:eadk6062. [PMID: 38598624 PMCID: PMC11006230 DOI: 10.1126/sciadv.adk6062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 03/07/2024] [Indexed: 04/12/2024]
Abstract
Experimental genetics in a nematode reveals a key role for developmental plasticity in the evolution of nutritional diversity.
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Affiliation(s)
- Sara Wighard
- Max Planck institute for Biology, Tübingen, 72076, Germany
| | - Hanh Witte
- Max Planck institute for Biology, Tübingen, 72076, Germany
| | - Ralf J. Sommer
- Max Planck institute for Biology, Tübingen, 72076, Germany
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2
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HODDA M. Phylum Nematoda: trends in species descriptions, the documentation of diversity, systematics, and the species concept. Zootaxa 2022; 5114:290-317. [DOI: 10.11646/zootaxa.5114.1.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/04/2022]
Abstract
This paper summarizes the trends in nematode species description and systematics emerging from a comparison of the latest comprehensive classification and census of Phylum Nematoda (Hodda 2022a, b) with earlier classifications (listed in Hodda 2007). It also offers some general observations on trends in nematode systematics emerging from the review of the voluminous literature used to produce the classification. The trends in nematodes can be compared with developments in the systematics of other organisms to shed light on many of the general issues confronting systematists now and into the future.
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HODDA M. Phylum Nematoda: feeding habits for all valid genera using a new, universal scheme encompassing the entire phylum, with descriptions of morphological characteristics of the stoma, a key, and discussion of the evidence for trophic relationships. Zootaxa 2022; 5114:318-451. [DOI: 10.11646/zootaxa.5114.1.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Indexed: 11/04/2022]
Abstract
This paper details a system for classifying the trophic relationships of the entire Phylum Nematoda, together with a table specifying the categories of every valid genus. This system encompasses both the diets of nematodes and how the food is obtained. The types of evidence used to evaluate trophic relationships and the inferences that can be drawn from each are evaluated. The general morphological and ecological characteristics of each trophic type are detailed, and a morphological key is presented. This information will enable the trophic relationships of any valid genus of nematodes to be assessed, along with currently undescribed genera, provided their affinities to existing genera can be ascertained. The system and list can add value to ecological, environmental and biodiversity studies where there is no morphological information, for example in environmental sequencing or metabarcoding studies.
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Harry CJ, Messar SM, Ragsdale EJ. Comparative reconstruction of the predatory feeding structures of the polyphenic nematode Pristionchus pacificus. Evol Dev 2022; 24:16-36. [PMID: 35239990 PMCID: PMC9286642 DOI: 10.1111/ede.12397] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/06/2022] [Accepted: 02/01/2022] [Indexed: 12/25/2022]
Abstract
Pristionchus pacificus is a nematode model for the developmental genetics of morphological polyphenism, especially at the level of individual cells. Morphological polyphenism in this species includes an evolutionary novelty, moveable teeth, which have enabled predatory feeding in this species and others in its family (Diplogastridae). From transmission electron micrographs of serial thin sections through an adult hermaphrodite of P. pacificus, we three‐dimensionally reconstructed all epithelial and myoepithelial cells and syncytia, corresponding to 74 nuclei, of its face, mouth, and pharynx. We found that the epithelia that produce the predatory morphology of P. pacificus are identical to Caenorhabditis elegans in the number of cell classes and nuclei. However, differences in cell form, spatial relationships, and nucleus position correlate with gross morphological differences from C. elegans and outgroups. Moreover, we identified fine‐structural features, especially in the anteriormost pharyngeal muscles, that underlie the conspicuous, left‐right asymmetry that characterizes the P. pacificus feeding apparatus. Our reconstruction provides an anatomical map for studying the genetics of polyphenism, feeding behavior, and the development of novel form in a satellite model to C. elegans. All cells making the dimorphic, novel form of an animal with cell constancy were identified. Although the number of cells is fully conserved, divergence in form and connectivity—including fixed asymmetries—sheds light on the origins of this trait.
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Affiliation(s)
- Clayton J Harry
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Sonia M Messar
- Department of Biology, Indiana University, Bloomington, Indiana, USA
| | - Erik J Ragsdale
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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Levis NA, Ragsdale EJ. Linking Molecular Mechanisms and Evolutionary Consequences of Resource Polyphenism. Front Integr Neurosci 2022; 16:805061. [PMID: 35210995 PMCID: PMC8861301 DOI: 10.3389/fnint.2022.805061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Resource polyphenism—the occurrence of environmentally induced, discrete, and intraspecific morphs showing differential niche use—is taxonomically widespread and fundamental to the evolution of ecological function where it has arisen. Despite longstanding appreciation for the ecological and evolutionary significance of resource polyphenism, only recently have its proximate mechanisms begun to be uncovered. Polyphenism switches, especially those influencing and influenced by trophic interactions, offer a route to integrating proximate and ultimate causation in studies of plasticity, and its potential influence on evolution more generally. Here, we use the major events in generalized polyphenic development as a scaffold for linking the molecular mechanisms of polyphenic switching with potential evolutionary outcomes of polyphenism and for discussing challenges and opportunities at each step in this process. Not only does the study of resource polyphenism uncover interesting details of discrete plasticity, it also illuminates and informs general principles at the intersection of development, ecology, and evolution.
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Kanzaki N, Ozawa M, Ota Y, Degawa Y. Four Pristionchus species associated with two mass-occurring Parafontaria laminata populations. J Nematol 2020; 52:e2020-115. [PMID: 33829169 PMCID: PMC8015285 DOI: 10.21307/jofnem-2020-115] [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] [Received: 09/09/2020] [Indexed: 12/04/2022] Open
Abstract
Phoretic nematodes associated with two mass-occurring populations of the millipede Parafontaria laminata were examined, focusing on Pristionchus spp. The nematodes that propagated on dissected millipedes were genotyped using the D2-D3 expansion segments of the 28S ribosomal RNA gene. Four Pristionchus spp. were detected: P. degawai, P. laevicollis, P. fukushimae, and P. entomophagus. Of the four, P. degawai dominated and it was isolated from more than 90% of the millipedes examined. The haplotypes of partial sequences of mitochondrial cytochrome oxidase subunit I examined for Pristionchus spp. and P. degawai showed high haplotype diversity.
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Affiliation(s)
- Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute, 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto 612-0855, Japan
| | - Minami Ozawa
- College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Yuko Ota
- College of Bioresource Sciences, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Yousuke Degawa
- Sugadaira Research Station, Mountain Science Center, University of Tsukuba, 1278-294 Sugadairakogen, Ueda, Nagano 386-2204, Japan
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Herrmann M, Kanzaki N, Weiler C, Yoshida K, RÖdelsperger C, Sommer RJ. Two new Species of Pristionchus (Nematoda: Diplogastridae) include the Gonochoristic Sister Species of P. fissidentatus. J Nematol 2019; 51:1-14. [PMID: 31088036 PMCID: PMC6930957 DOI: 10.21307/jofnem-2019-024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Indexed: 11/16/2022] Open
Abstract
The genus Pristionchus (Kreis, 1932) consists of more than 30 soil nematode species that are often found in association with scarab beetles. Three major radiations have resulted in the "maupasi species group" in America, the "pacificus species group" in Asia, and the "lheritieri species group," which contains species from Europe and Asia. Phylogenetic analysis indicates that a group of three species, including the gonochorists P. elegans and P. bucculentus and the hermaphrodite P. fissidentatus, is basal to the above-mentioned radiations. Two novel species are described here: Pristionchus paulseni sp. n. from Taiwan and P. yamagatae sp. n. from Japan by means of morphology, morphometrics and genome-wide transcriptome sequence analysis. Previous phylotranscriptomic analysis of the complete Pristionchus genus recognized P. paulseni sp. n. as the sister species of P. fissidentatus, and thus its importance for macro-evolutionary studies. Specifically, the gonochorist P. paulseni sp. n. and the hermaphrodite P. fissidentatus form a species pair that is the sister group to all other described Pristionchus species. P. paulseni sp. n. has two distinct mouth forms, supporting the notion that the mouth dimorphism is ancestral in the genus Pristionchus. The genus Pristionchus (Kreis, 1932) consists of more than 30 soil nematode species that are often found in association with scarab beetles. Three major radiations have resulted in the “maupasi species group” in America, the “pacificus species group” in Asia, and the “lheritieri species group,” which contains species from Europe and Asia. Phylogenetic analysis indicates that a group of three species, including the gonochorists P. elegans and P. bucculentus and the hermaphrodite P. fissidentatus, is basal to the above-mentioned radiations. Two novel species are described here: Pristionchus paulseni sp. n. from Taiwan and P. yamagatae sp. n. from Japan by means of morphology, morphometrics and genome-wide transcriptome sequence analysis. Previous phylotranscriptomic analysis of the complete Pristionchus genus recognized P. paulseni sp. n. as the sister species of P. fissidentatus, and thus its importance for macro-evolutionary studies. Specifically, the gonochorist P. paulseni sp. n. and the hermaphrodite P. fissidentatus form a species pair that is the sister group to all other described Pristionchus species. P. paulseni sp. n. has two distinct mouth forms, supporting the notion that the mouth dimorphism is ancestral in the genus Pristionchus.
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Affiliation(s)
- Matthias Herrmann
- Department of Evolutionary Biology, Spemannstraße 37, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto 612-0855, Japan
| | - Christian Weiler
- Department of Evolutionary Biology, Spemannstraße 37, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Kohta Yoshida
- Department of Evolutionary Biology, Spemannstraße 37, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Christian RÖdelsperger
- Department of Evolutionary Biology, Spemannstraße 37, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ralf J. Sommer
- Department of Evolutionary Biology, Spemannstraße 37, Max Planck Institute for Developmental Biology, Tübingen, Germany
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8
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Kanzaki N, Ekino T, Masuya H. Seinura caverna n. sp. (Tylenchomorpha: Aphelenchoididae), an androdioecious species isolated from bat guano in a calcareous cave. NEMATOLOGY 2019. [DOI: 10.1163/15685411-00003207] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Summary
A new species of a predator aphelenchoidid, Seinura caverna n. sp., is described and illustrated. The new species was isolated from bat guano collected from a calcareous cave in Japan. The new species is characterised by its three-lined lateral field, secretory-excretory pore at the level of the posterior two-thirds of the metacorpus, a long post-uterine sac, hermaphrodite tail shape elongate conoid with a filiform tip, and an androdioecious reproductive mode. The new species is typologically and biologically close to S. steineri, but is distinguished by its longer post-uterine sac, slightly longer stylet and slightly larger median bulb. The comparisons with other morphologically similar species, i.e., S. chertkovi, S. tenuicaudata and S. steineri, are discussed. A molecular phylogenetic analysis based on two small and large subunit ribosomal RNA genes revealed that the new species is located at the basal position of clade 3 of the Aphelenchoididae, clearly separate from S. demani, its congener with unclear rectum and anus, which is located at the derived position, suggesting that further generic revision is necessary for the genus. Aphelenchoides lii n. comb. (= Seinura lii) is proposed.
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Affiliation(s)
- Natsumi Kanzaki
- 1Kansai Research Center, Forestry and Forest Products Research Institute (FFPRI), 68 Nagaikyutaroh, Momoyama, Fushimi, Kyoto 612-0855, Japan
| | - Taisuke Ekino
- 2Department of Applied Biological Sciences, Saga University, Saga 840-8502, Japan
- 3The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan
| | - Hayato Masuya
- 4Tohoku Research Center, FFPRI, 92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan
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Pristionchus nematodes occur frequently in diverse rotting vegetal substrates and are not exclusively necromenic, while Panagrellus redivivoides is found specifically in rotting fruits. PLoS One 2018; 13:e0200851. [PMID: 30074986 PMCID: PMC6075748 DOI: 10.1371/journal.pone.0200851] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/05/2018] [Indexed: 01/31/2023] Open
Abstract
The lifestyle and feeding habits of nematodes are highly diverse. Several species of Pristionchus (Nematoda: Diplogastridae), including Pristionchus pacificus, have been reported to be necromenic, i.e. to associate with beetles in their dauer diapause stage and wait until the death of their host to resume development and feed on microbes in the decomposing beetle corpse. We review the literature and suggest that the association of Pristionchus to beetles may be phoretic and not necessarily necromenic. The view that Pristionchus nematodes have a necromenic lifestyle is based on studies that have sought Pristionchus only by sampling live beetles. By surveying for nematode genera in different types of rotting vegetal matter, we found Pristionchus spp. at a similar high frequency as Caenorhabditis, often in large numbers and in feeding stages. Thus, these Pristionchus species may feed in decomposing vegetal matter. In addition, we report that one species of Panagrellus (Nematoda: Panagrolaimidae), Panagrellus redivivoides, is found in rotting fruits but not in rotting stems, with a likely association with Drosophila fruitflies. Based on our sampling and the observed distribution of feeding and dauer stages, we propose a life cycle for Pristionchus nematodes and Panagrellus redivivoides that is similar to that of C. elegans, whereby they feed on the microbial blooms on decomposing vegetal matter and are transported between food patches by coleopterans for Pristionchus spp., fruitflies for Panagrellus redivivoides and isopods and terrestrial molluscs for C. elegans.
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Kanzaki N, Giblin-Davis RM. Acrostichus palmarum n. sp., a cryptic species separated from A. rhynchophori by molecular sequences and hybridisation tests. NEMATOLOGY 2018. [DOI: 10.1163/15685411-00003173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Summary
A new Acrostichus species is described based upon molecular sequence profiles and hybridisation testing. The new species, A. palmarum n. sp., had been previously described as local isolates (strains) of A. rhynchophori, i.e., an isolate recovered from Rhynchophorus cruentatus from South Florida (culture code RGD193) was designated as the type strain of A. rhynchophori, and other Central and South American strains (RGD194-196), recovered from R. palmarum were considered as conspecific regional isolates. However, additional sequencing of ribosomal DNA loci (near full-length of small subunit, full length of internal transcribed spacer and D2-D3 expansion segments of large subunit) and partial mitochondrial cytochrome oxidase subunit I gene and hybridisation testing suggested the independent species status of RGD194-196. Furthermore, two strains of A. palmarum n. sp., RGD194 and RGD195, showed partial reproductive isolation from each other, i.e., the fecundity of F1 progeny was obviously low, suggesting that geographical isolation within a widely-distributed species is occurring.
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Affiliation(s)
- Natsumi Kanzaki
- 1Kansai Research Center, Forestry and Forest Products Research Institute, Nagaikyutaroh, Fushimi, Kyoto 612-0855, Japan
- 2Fort Lauderdale Research and Education Center, University of Florida/IFAS, 3205 College Avenue, Davie, FL 33314-7799, USA
| | - Robin M. Giblin-Davis
- 2Fort Lauderdale Research and Education Center, University of Florida/IFAS, 3205 College Avenue, Davie, FL 33314-7799, USA
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Kanzaki N, Herrmann M, Yoshida K, Weiler C, Rödelsperger C, Sommer RJ. Samplings of Millipedes in Japan and Scarab Beetles in Hong Kong result in five new Species of Pristionchus (Nematoda: Diplogastridae). J Nematol 2018; 50:587-610. [PMID: 31094161 PMCID: PMC6909306 DOI: 10.21307/jofnem-2018-044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Indexed: 11/11/2022] Open
Abstract
The authors describe five new species of Pristionchus from Japan and Hongkong. Scarab beetle samplings in Hongkong identified P. hongkongensis sp. n. and P. neolucani sp. n., representing the first beetle-associated Pristionchus species from China. Surprisingly, samplings of millipedes in Japan revealed a previously unknown association of Pristionchus nematodes with these arthropods. Specifically, the authors found three previously known Pristionchus species, P. arcanus, P. entomophagus, and P. fukushimae on Japanese millipedes. In addition, the authors found three new Pristionchus species on millipedes, which are described as P. riukiariae sp. n., P. degawai sp. n., and P. laevicollis, sp. n., the latter of which was also found on stag beetles. These species are most closely related to P. maxplancki, P. japonicus, and P. quartusdecimus and belong to the pacificus species-complex. The authors describe all species based on morphology, morphometrics, and genome-wide sequence analysis. Mating experiments indicated that all species are reproductively isolated from each other and in contrast to the species of the "pacificus species-complex sensu stricto" they do not form F1 hybrids. The authors describe five new species of Pristionchus from Japan and Hongkong. Scarab beetle samplings in Hongkong identified P. hongkongensis sp. n. and P. neolucani sp. n., representing the first beetle-associated Pristionchus species from China. Surprisingly, samplings of millipedes in Japan revealed a previously unknown association of Pristionchus nematodes with these arthropods. Specifically, the authors found three previously known Pristionchus species, P. arcanus, P. entomophagus, and P. fukushimae on Japanese millipedes. In addition, the authors found three new Pristionchus species on millipedes, which are described as P. riukiariae sp. n., P. degawai sp. n., and P. laevicollis, sp. n., the latter of which was also found on stag beetles. These species are most closely related to P. maxplancki, P. japonicus, and P. quartusdecimus and belong to the pacificus species-complex. The authors describe all species based on morphology, morphometrics, and genome-wide sequence analysis. Mating experiments indicated that all species are reproductively isolated from each other and in contrast to the species of the “pacificus species-complex sensu stricto” they do not form F1 hybrids.
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Affiliation(s)
- Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute, Fushimi, Kyoto 612-0855, Japan
| | - Matthias Herrmann
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Kohta Yoshida
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Christian Weiler
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Christian Rödelsperger
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Ralf J. Sommer
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
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Jay Burr AH, Baldwin JG. The nematode stoma: Homology of cell architecture with improved understanding by confocal microscopy of labeled cell boundaries. J Morphol 2016; 277:1168-86. [DOI: 10.1002/jmor.20567] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/24/2016] [Accepted: 05/26/2016] [Indexed: 11/08/2022]
Affiliation(s)
- A. H. Jay Burr
- Department of Biological Sciences; Simon Fraser University; Burnaby British Columbia V5A 1S6 Canada
- Department of Nematology; University of California; Riverside California 92521
| | - James G. Baldwin
- Department of Nematology; University of California; Riverside California 92521
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Serobyan V, Ragsdale EJ, Sommer RJ. Adaptive value of a predatory mouth-form in a dimorphic nematode. Proc Biol Sci 2015; 281:20141334. [PMID: 25080344 DOI: 10.1098/rspb.2014.1334] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Polyphenisms can be adaptations to environments that are heterogeneous in space and time, but to persist they require conditional-specific advantages. The nematode Pristionchus pacificus is a facultative predator that displays an evolutionarily conserved polyphenism of its mouthparts. During development, P. pacificus irreversibly executes either a eurystomatous (Eu) or stenostomatous (St) mouth-form, which differ in the shape and number of movable teeth. The Eu form, which has an additional tooth, is more complex than the St form and is thus more highly derived relative to species lacking teeth. Here, we investigate a putative fitness trade-off for the alternative feeding-structures of P. pacificus. We show that the complex Eu form confers a greater ability to kill prey. When adults were provided with a prey diet, Eu nematodes exhibited greater fitness than St nematodes by several measures, including longevity, offspring survival and fecundity when followed by bacterial feeding. However, the two mouth-forms had similar fecundity when fed ad libitum on bacteria, a condition that would confer benefit on the more rapidly developing St form. Thus, the two forms show conditional fitness advantages in different environments. This study provides, to our knowledge, the first functional context for dimorphism in a model for the genetics of plasticity.
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Affiliation(s)
- Vahan Serobyan
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Spemannstraße 37, 72076 Tübingen, Germany
| | - Erik J Ragsdale
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Spemannstraße 37, 72076 Tübingen, Germany Department of Biology, Indiana University, 1001 East 3rd Street, Bloomington, IN 47405, USA
| | - Ralf J Sommer
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, Spemannstraße 37, 72076 Tübingen, Germany
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14
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Kanzaki N, Giblin-Davis RM. Rhabditidoides humicolus n. sp. associated with arthropods from rotting palm tissue in Florida, USA. NEMATOLOGY 2015. [DOI: 10.1163/15685411-00002883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Rhabditidoides humicolus n. sp. is described and illustrated from arthropods associated with decaying tissue from the crown shaft of a living spindle palm, Hyophorbe verschaffeltii, in southern Florida, USA. In addition to its generic character, i.e., the arrangement of male genital papillae, ⟨v1, v2, v3d, CO, v4, (ad, v5, ph, v6), (pd, v7)⟩, the new species is characterised by its small stomatal flaps, a secretory pore-like opening, a pair of deirids, two pairs of post-deirids and small subventral vulval papillae located just anterior to the vulva. Besides those newly found characters, there are only a few typological differences between R. humicolus n. sp. and several previously described species in the genus. However, based on the biological characters, e.g., gonochoristic reproduction, association as dauers with the crane fly, Limonia (Rhipidia) schwarzi (Diptera: Limoniidae), millipedes, an immature cockroach, and staphylinid beetle adults, and distribution in southern Florida, the new species was considered to be different from others in the genus.
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Affiliation(s)
- Natsumi Kanzaki
- Fort Lauderdale Research and Education Center, University of Florida/IFAS 3205 College Avenue, Davie, FL 33314, USA
| | - Robin M. Giblin-Davis
- Fort Lauderdale Research and Education Center, University of Florida/IFAS 3205 College Avenue, Davie, FL 33314, USA
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15
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Ye W, Yu Q, Kanzaki N, Adams PR, Cardoza YJ. Characterisation of, and entomopathogenic studies on, Pristionchus aerivorus (Cobb in Merrill & Ford, 1916) Chitwood, 1937 (Rhabditida: Diplogastridae) from North Carolina, USA. NEMATOLOGY 2015. [DOI: 10.1163/15685411-00002891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
During a survey of entomopathogenic nematodes in North Carolina, USA, aPristionchusspecies was recovered using theGalleriabait method. Morphological studies with light microscopy and scanning electron microscopy, mating tests with reference strains, as well as molecular analyses of the near-full-length small subunit rRNA gene (18S) and D2-D3 expansion segments of the large subunit rRNA gene (28S) identified this isolate asPristionchus aerivorus. ExposedGallerialarvae were killed within 48 h and high numbers of nematodes were recovered from the cadavers about 5 days later. Preliminary tests revealed that this nematode is capable of infecting at least two other insect species (Helicoverpa zeaandTenebrio molitor) under laboratory conditions. The status of the genusChroniodiplogasteris discussed and confirmed as a junior synonym ofPristionchusbased on morphological observation and molecular phylogenetic analysis.
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Affiliation(s)
- Weimin Ye
- Nematode Assay Section, Agronomic Division, North Carolina Department of Agriculture & Consumer Services, 4300 Reedy Creek Road, Raleigh, NC 27607, USA
| | - Qing Yu
- Agriculture and Agri-Food Canada, Environmental Health Program/Invertebrate Biodiversity, Ottawa, ON, Canada K1A 0C6
| | - Natsumi Kanzaki
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Paul R. Adams
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
| | - Yasmin J. Cardoza
- Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC 27695-7613, USA
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Kanzaki N, Giblin-Davis R, Ragsdale E. Allodiplogaster josephi n. sp. and A. seani n. sp. (Nematoda: Diplogastridae), associates of soil-dwelling bees in the eastern USA. NEMATOLOGY 2015. [DOI: 10.1163/15685411-00002908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Two commensal associates of bees,Allodiplogaster josephin. sp. from the Dufour’s gland of a cellophane bee (Colletes thoracicus) from Maryland, USA, andA. seanin. sp. from the abdominal glands of an andrenid bee (Andrena alleghaniensis) from New York, USA, are described and illustrated. Both species were collected as dauers from their respective hosts and cultured on bacteria on tryptic soy broth (TSB) or NGM agar.Allodiplogaster josephin. sp. andA. seanin. sp. are morphologically closer to each other than to other species ofAllodiplogaster, which was recently revised to include 37 valid species. However, the two new species are distinguished by reproductive isolation, shape of the spicule manubrium, host associations and molecular characters, the latter in sequences of the near-full length small subunit (SSU) rRNA gene, D2-D3 expansion segments of the large subunit (LSU) rRNA gene and partial mitochondrial COI. Morphological characterisation was supplemented by scanning electron microscopy (SEM), which revealed furcation of both v5 and v6 male genital papillae, consistent with previous reports for species of thehenrichaegroup ofAllodiplogaster.
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Affiliation(s)
- Natsumi Kanzaki
- Fort Lauderdale Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 3205 College Avenue, Fort Lauderdale, FL 33314-7799, USA
| | - Robin M. Giblin-Davis
- Fort Lauderdale Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 3205 College Avenue, Fort Lauderdale, FL 33314-7799, USA
| | - Erik J. Ragsdale
- Department of Biology, Indiana University, 915 E. 3rd Street, Bloomington, IN 47405, USA
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Kanzaki N, Ragsdale EJ, Giblin-Davis RM. Revision of the paraphyletic genus Koerneria Meyl, 1960 and resurrection of two other genera of Diplogastridae (Nematoda). Zookeys 2014:17-30. [PMID: 25349487 PMCID: PMC4205494 DOI: 10.3897/zookeys.442.7459] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/26/2014] [Indexed: 12/04/2022] Open
Abstract
Recent inferences of phylogeny from molecular characters, as well as a reexamination of morphological and biological characters, reject the monophyly of the nematode genus Koerneria Meyl, 1960 (Diplogastridae). Here, Koerneria sensu lato is revised. The genus, which previously consisted of 40 species, is separated into three genera. Almost all of the transferred species are moved to the resurrected genus Allodiplogaster Paramonov & Sobolev in Skrjabin et al. (1954). Koerneria and Allodiplogaster are distinguished from each other by a weakly vs. clearly striated body surface, an undivided vs. divided stomatal cheilostom, and arrangement of the terminal ventral triplet of male genital papillae, namely in that v5 and v6 are paired and separated from v7 vs. v5–v7 being close to each other. Allodiplogaster is further divided into two groups of species, herein called the henrichae and striata groups, based on both morphological and life-history traits. The henrichae group is characterized by papilliform labial sensilla and male genital papillae, a conical tail in both males and females, and an association with terrestrial habitats and insects, whereas the striata group is characterized by setiform labial sensilla and male genital papillae, an elongated conical tail in both sexes, and an association with aquatic habitats. A second genus, Anchidiplogaster Paramonov, 1952, is resurrected to include a single species that is characterized by its miniscule stoma and teeth, unreflexed testis, and a distinct lack of male genital papillae or stomatal apodemes. Lastly, one further species that was previously included in Koerneria sensu lato is transferred to the genus Pristionchus Kreis, 1932. The revision of Koerneria sensu lato is necessitated by the great variability in its subordinate taxa, which occupy a variety of habitats, in addition to the increased attention to Diplogastridae as a model system for comparative mechanistic biology.
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Affiliation(s)
- Natsumi Kanzaki
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan ; Fort Lauderdale Research and Education Center, University of Florida/IFAS, 3205 College Avenue, Davie, FL 33314-7719, USA
| | - Erik J Ragsdale
- Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA
| | - Robin M Giblin-Davis
- Fort Lauderdale Research and Education Center, University of Florida/IFAS, 3205 College Avenue, Davie, FL 33314-7719, USA
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Ragsdale EJ, Müller MR, Rödelsperger C, Sommer RJ. A developmental switch coupled to the evolution of plasticity acts through a sulfatase. Cell 2014; 155:922-33. [PMID: 24209628 DOI: 10.1016/j.cell.2013.09.054] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/01/2013] [Accepted: 09/16/2013] [Indexed: 10/26/2022]
Abstract
Developmental plasticity has been suggested to facilitate phenotypic diversity, but the molecular mechanisms underlying this relationship are little understood. We analyzed a feeding dimorphism in Pristionchus nematodes whereby one of two alternative adult mouth forms is executed after an irreversible developmental decision. By integrating developmental genetics with functional tests in phenotypically divergent populations and species, we identified a regulator of plasticity, eud-1, that acts in a developmental switch. eud-1 mutations eliminate one mouth form, whereas overexpression of eud-1 fixes it. EUD-1 is a sulfatase that acts dosage dependently, is necessary and sufficient to control the sexual dimorphism of feeding forms, and has a conserved function in Pristionchus evolution. It is epistatic to known signaling cascades and results from lineage-specific gene duplications. EUD-1 thus executes a developmental switch for morphological plasticity in the adult stage, showing that regulatory pathways can evolve by terminal addition of new genes.
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Affiliation(s)
- Erik J Ragsdale
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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Ragsdale EJ, Ragsdale EJ, Kanzaki N, Ragsdale EJ, Kanzaki N, Sommer RJ. Levipalatum texanum n. gen., n. sp. (Nematoda: Diplogastridae), an androdioecious species from the south-eastern USA. NEMATOLOGY 2014. [DOI: 10.1163/15685411-00002798] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A new species of diplogastrid nematode, Levipalatum texanum n. gen., n. sp., was isolated from scarab beetles (Coleoptera: Scarabaeidae) in Texas and baited from soil in Virginia, USA. Levipalatum n. gen. is circumscribed by stomatal and pharyngeal morphology, namely a long, hooked dorsal tooth connected to a ‘palate’ projecting anteriad and mediad, subventral telostegostomatal ridges of denticles, and the dorsal radius of the pharynx bulging anteriad. The males of the new species are distinguished from most other Diplogastridae by the frequent presence of ten pairs of genital papillae. Phylogenetic relationships inferred from 11 ribosomal protein-coding genes and a fragment of the small subunit rRNA gene strongly support L. texanum n. gen., n. sp. to be a sister group to Rhabditolaimus, which lacks all the stegostomatal and pharyngeal characters diagnosing the new genus. The new species expands comparative studies of the radiation of feeding morphology that are anchored on the model organism Pristionchus pacificus. The phylogenetic position of L. texanum n. gen., n. sp. indicates a new case of convergent evolution of hermaphroditism in Diplogastridae.
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Affiliation(s)
- Erik J. Ragsdale
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Erik J. Ragsdale
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Natsumi Kanzaki
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Erik J. Ragsdale
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
| | - Natsumi Kanzaki
- Forest Pathology Laboratory, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Ralf J. Sommer
- Max Planck Institute for Developmental Biology, Department of Evolutionary Biology, Spemannstraße 37, Tübingen, Germany
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