Pristionchus is a genus of nematodes (roundworms) in the family Diplogastridae that currently includes more than 50 described species. They are known mainly as non-parasitic associates of insects, especially beetles, while others have been reported from soil, organic matter, or rotting wood. The genus includes P. pacificus, a satellite model organism to the well-studied nematode Caenorhabditis elegans.
| Pristionchus | |
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| Pristionchus pacificus | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Chromadorea |
| Order: | Rhabditida |
| Family: | Diplogastridae |
| Genus: | Pristionchus Kreis 1932[1] |
Ecology and mouth dimorphism
editIn Pristionchus species associated with insects, the nematodes usually live on their hosts in a dormant stage (the dauer larva). After the death of the host insect, the nematodes resume development, feeding and reproducing on the decaying host carcass.[2] Most species of Pristionchus show a polyphenism in their feeding structures, which allows the nematodes to access different food resources in this rapidly changing environment. In one form (the "stenostomatous" form), the mouth is elongated, narrow, and equipped with one small tooth, whereas in the other ("eurystomatous" form) it is short, wide, and with two large teeth.[3] The emergence of a particular form depends on specific environmental conditions and the availability of food. Whereas the stenostomatous form feeds primarily on microorganisms, the eurystomatous form can feed additionally on other nematodes.[4] In the laboratory, Pristionchus species can be cultured on bacteria such as Escherichia coli.
Reproduction
editMost known species of Pristionchus have males and females, although several species are androdioecious, consisting of males and self-fertilizing hermaphrodites. Sex determination in Pristionchus species is by an X0 system, whereby males have one sex (X) chromosome and females/hermaphrodites have two.
Species
editThe following are all Pristionchus species that have been sequenced (most of them are kept in culture and available as frozen strains):
- Pristionchus aerivorus —from termites in North America[5]
- Pristionchus americanus —from scarab beetles in North America[5]
- Pristionchus arcanus —forms a cryptic species complex with P. pacificus and P. exspectatus; known from termites in Japan[6]
- Pristionchus atlanticus —known from soil in the eastern United States[7]
- Pristionchus auriculatae —from rotting fruits of the fig Ficus auriculata in Shanghai, China[8]
- Pristionchus boliviae —androdioecious; from scarab beetles in South America[7]
- Pristionchus borbonicus —from Réunion Island; notable for developing one of five different mouth forms depending on available food sources.[9][10]
- Pristionchus brevicauda —from Eastern Europe[11]
- Pristionchus bucculentus —associated with shining mushroom beetles and pleasing fungus beetles in Japan[12]
- Pristionchus bulgaricus —from the rose chafer in Eastern Europe[11]
- Pristionchus chinensis —from the scarab beetle Mimela sp. in Bubeng field station CAS, China[8]
- Pristionchus clavus —from Eastern Europe[11]
- Pristionchus degawai —from millipedes in Japan[13]
- Pristionchus dorci —from the stag beetle Dorcus davidis in Ganquan, China[8]
- Pristionchus elegans —from dung beetles in Japan[14]
- Pristionchus entomophagus —hermaphroditic (males rare); cosmopolitan, common in Europe, especially on scarab beetles[2]
- Pristionchus exspectatus —the putative sister species of P. pacificus; reported from stag beetles[6]
- Pristionchus fukushimae —from scarab beetles in Japan[15]
- Pristionchus fissidentatus —androdioecious; from Nepal and La Réunion Island[14]
- Pristionchus hongkongensis —from stag beetles in Hong Kong[13]
- Pristionchus hoplostomus —collected from soil in Japan[15]
- Pristionchus japonicus —from soil around a dead earthworm in Japan[6]
- Pristionchus kurosawai —from Lucanus kurosawa in Songquangang, Taiwan[16]
- Pristionchus laevicollis —from millipedes in Japan[13]
- Pristionchus lheritieri —common in Europe; reported from soil, organic material, and dung beetles[2]
- Pristionchus lucani —from stag beetles in France[11]
- Pristionchus magnoliae —from fruit of Magnolia grandiflora in Shanghai, China[8]
- Pristionchus marianneae —from Popilia japonica near Geneva, New York, USA[5]
- Pristionchus maupasi —androdioecious; from Europe and North America, especially in association with May beetles[2][5]
- Pristionchus maxplancki —from stag beetles in Japan; closest known outgroup to the P. pacificus species complex[17]
- Pristionchus mayeri —androdioecious; from scarab beetles on La Réunion and Mauritius[7]
- Pristionchus musae —from banana "Musa, sp." in Yuanyang, China[8]
- Pristionchus neolucani —from stag beetles in Hong Kong[13]
- Pristionchus nudus —from a longhorn beetle, Cerambycidae, in Xishuangbanna, China[8]
- Pristionchus occultus —from Taiwan[18]
- Pristionchus pacificus —cosmopolitan distribution, most commonly in association with scarab beetles; an established laboratory model species[19][20]
- Pristionchus paranudus —from rotting water hyacinth bulbs in Yuanyang, China[8]
- Pristionchus passalidorum —from Passalidae sp. in Ailaoshan field station CAS, China[8]
- Pristionchus pauli —from scarab beetles in the eastern United States[5]
- Pristionchus paulseni —from Lucanus taiwanensis in Taroko National Park, Taiwan[21]
- Pristionchus pseudaerivorus —from North America[5]
- Pristionchus purgamentorium —from Mimela sp. in Ganquan, China[8]
- Pristionchus quartusdecimus —from the Oriental beetle in Japan[17]
- Pristionchus racemosae[9]
- Pristionchus riukiariae —from millipedes in Japan[13]
- Pristionchus sikae —from the stag beetle Dorcus titanus sika in Huisun, Taiwan[16]
- Pristionchus sycomori —from Ficus sycomorus fig fruit in South Africa[9]
- Pristionchus taiwanensis[18]
- Pristionchus triformis —androdioecious; associated with dung beetles and other scarab beetles; reported from Europe, La Réunion, and Canada[15]
- Pristionchus uniformis —associated with the Colorado potato beetle in Europe and North America[2][22]
- Pristionchus yamagatae —from Holotrichia kiotoensis in Mamurogawa, Yamagata, Japan[21]
Molecular phylogeny
edit
References
edit- ^ "Pristionchus Kreis, 1932". GBIF.org. Retrieved 6 September 2014.
- ^ a b c d e Herrmann M, Mayer WE, Sommer RJ (2006). "Nematodes of the genus Pristionchus are closely associated with scarab beetles and the Colorado potato beetle in Western Europe". Zoology. 109 (2): 96–108. doi:10.1016/j.zool.2006.03.001. PMID 16616467.
- ^ Fürst von Lieven A, Sudhaus W (2000). "Comparative and functional morphology of the buccal cavity of Diplogastrina (Nematoda) and a first outline of the phylogeny of this taxon". Journal of Zoological Systematics and Evolutionary Research. 38: 37–63. doi:10.1046/j.1439-0469.2000.381125.x.
- ^ Serobyan V, Ragsdale EJ, Sommer RJ (2014). "Adaptive value of a predatory mouth-form in a dimorphic nematode". Proceedings of the Royal Society of London B. 281 (1791): 20141334. doi:10.1098/rspb.2014.1334. PMC 4132687. PMID 25080344.
- ^ a b c d e f Herrmann M, Mayer WE, Sommer RJ (2006). "Sex, bugs and Haldane's rule: the nematode genus Pristionchus in the United States". Frontiers in Zoology. 3: 14. doi:10.1186/1742-9994-3-14. PMC 1578557. PMID 16968539.
- ^ a b c Kanzaki N, Ragsdale EJ, Herrmann M, Mayer WE, Sommer RJ (2012). "Description of three Pristionchus species (Nematoda: Diplogastridae) from Japan that form a cryptic species complex with the model organism P. pacificus". Zoological Science. 29 (6): 403–417. doi:10.2108/zsj.29.403. PMID 22639812. S2CID 4502687.
- ^ a b c Kanzaki N, Ragsdale EJ, Herrmann M, Susoy V, Sommer RJ (2013). "Two androdioecious and one dioecious new species of Pristionchus (Nematoda: Diplogastridae): new reference points for the evolution of reproductive mode". Journal of Nematology. 45 (3): 172–194. PMC 3792836. PMID 24115783.
- ^ a b c d e f g h i j Kanzaki N, Herrmann M, Weiler C, Röseler W, Theska T, Berger J, Rödelsperger C, Sommer RJ (2021). "nine new Pristionchus species (Nematoda, Diplogastridae)from China". Zootaxa. 4346 (1): 001–066. doi:10.11646/zootaxa.4943.1.1. PMID 33757041.
- ^ a b c Susoy V, Herrmann M, Kanzaki N, Kruger M, Nguyen CN, Rödelsperger C, Röseler W, Weiler C, Giblin-Davis RM, Ragsdale EJ, Sommer RJ (2016). "Large-scale diversification without genetic isolation in nematode symbionts of figs". Science Advances. 2 (1): e1501031. Bibcode:2016SciA....2E1031S. doi:10.1126/sciadv.1501031. PMC 4730855. PMID 26824073. S2CID 6564647.
- ^ "New Worm Species Has Five Faces : DNews". DNews. 2016-01-04. Retrieved 2016-01-05.
- ^ a b c d Kanzaki N, Ragsdale EJ, Herrmann M, Sommer RJ (2014). "Two new and two recharacterized species from a radiation of Pristionchus (Nematoda: Diplogastridae) in Europe". Journal of Nematology. 46 (1): 60–74. PMC 3957573. PMID 24644372.
- ^ Kanzaki N, Ragsdale EJ, Herrmann M, Röseler W, Sommer RJ (2013). "Pristionchus bucculentus n. sp. (Rhabditida: Diplogastridae) Isolated from a Shining Mushroom Beetle (Coleoptera: Scaphidiidae) in Hokkaido, Japan". J. Nematol. 45 (1): 78–86. PMC 3625135. PMID 23589663.
- ^ a b c d e Kanzaki N, Herrmann M, Yoshida K, Weiler C, Rödelsperger C, Sommer RJ (2018). "Sampling of Millipedes in Japan and Scarab beetles in Hong Kong result in five new species of Pristionchus (Nematoda: Diplogastridae)". Journal of Nematology. 50 (4): 587–610. doi:10.21307/jofnem-2018-044. PMC 6909306. PMID 31094161.
- ^ a b Kanzaki N, Ragsdale EJ, Herrmann M, Sommer RJ (2012). "Two new species of Pristionchus (Rhabditida: Diplogastridae): P. fissidentatus n. sp. from Nepal and La Réunion Island and P. elegans n. sp. from Japan". Journal of Nematology. 44 (1): 80–91. PMC 3593256. PMID 23483847.
- ^ a b c Ragsdale EJ, Kanzaki N, Röseler W, Herrmann M, Sommer RJ (2013). "Three new species of Pristionchus (Nematoda: Diplogastridae) show morphological divergence through evolutionary intermediates of a novel feeding-structure polymorphism". Zoological Journal of the Linnean Society. 168 (4): 671–698. doi:10.1111/zoj.12041.
- ^ a b Yoshida K, Herrmann M, Kanzaki N, Weiler C, Rödelsperger C, Sommer RJ (2018). "Two New Species of Pristionchus (Nematoda: Diplogastridae) from Taiwan and the Definition of the pacificus Species-Complex Sensu Stricto". Journal of Nematology. 50 (3): 355–368. doi:10.21307/jofnem-2018-019. PMC 6909367. PMID 30451420.
- ^ a b Kanzaki N, Ragsdale EJ, Herrmann M, Röseler W, Sommer RJ (2013). "Two new species of Pristionchus (Nematoda: Diplogastridae) support the biogeographic importance of Japan for the evolution of the genus Pristionchus and the model system P. pacificus". Zoological Science. 30 (8): 680–692. doi:10.2108/zsj.30.680. PMID 23915163. S2CID 22055918.
- ^ a b Herrmann M, Weiler C, Rödelsperger C, Kanzaki N, Sommer RJ (2016). "Two New Pristionchus Species (Nematoda: Diplogastridae) from Taiwan are Part of a Species-cluster Representing the Closest Known Relatives of the Model Organism P. pacificus". Zoological Studies. 55 (55): e48. doi:10.6620/ZS.2016.55-48. PMC 6511970. PMID 31966193.
- ^ Sommer RJ, Carta LK, Kim SY, Sternberg PW (1996). "Morphological, genetic and molecular description of Pristionchus pacificus n. sp. (Nematoda: Neodiplogastridae)". Fundamental and Applied Nematology. 19: 511–521.
- ^ Sommer RJ (2009). "The future of evo-devo: model systems and evolutionary theory". Nature Reviews Genetics. 10 (6): 416–422. doi:10.1038/nrg2567. PMID 19369972. S2CID 4494832.
- ^ a b Herrmann M, Kanzaki N, Weiler C, Yoshida K, Rödelsperger C, Sommer RJ (2019). "Two new Species of Pristionchus (Nematoda: Diplogastridae) include the Gonochoristic Sister Species of P. fissidentatus". Journal of Nematology. 51: 1–14. doi:10.21307/jofnem-2019-024. PMC 6930957. PMID 31088036.
- ^ Fedorko A, Stanuszek S (1971). "Pristionchus uniformis sp. n. (Nematoda, Rhabditida, Diplogasteridae), a facultative parasite of Leptinotarsa decemlineata Say and Melolontha melolontha L. in Poland. Morphology and biology". Acta Parasitologica. 19: 95–112.