''Pasteuria'' is a genus of mycelial and endospore-forming, nonmotile gram-positive bacteria that are obligate parasites of some

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...

s and

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s. The genus of ''Pasteuria'' was previously classified within the family

Alicyclobacillaceae The Alicyclobacillaceae are a family of Gram-positive bacteria. All members of this family are aerobic and form endospores. The family contains four genera: ''Alicyclobacillus'', ''Effusibacillus'', '' Kyrpidia'', and '' Tumebacillus''. When or ...

, but has since been moved to the family

Pasteuriaceae The Pasteuriaceae are a family of nonmotile Gram-positive bacteria. They are moderately to strongly resistant to heat. Species in this family produce a septate mycelium with one refractile endospore. The mycelium grows bigger on one end to form s ...

Steps of infection

Animals that are susceptible to ''Pasteuria'' become infected when they are exposed to spores in soil or water. Therefore, ''Pasteuria'' are transmitted horizontally between hosts and when an infected host dies, it releases spores to the soil or sediment. The likelihood of infections is related to the spore density in the environment and can be affected by temperature. After contact with the host, ''Pasteuria'' spores are activated, attach to their host, penetrate the host's cuticle, proliferate within the host, and kill the host. In water fleas, the ability of the spore to successfully attach during the infection process is related to the genotype of the host and the parasite. Spore cells that do not infect animals and pass through a resistant host can still remain viable and infectious.

Effects of parasite

Following infection with ''Pasteuria'', the parasite interferes with the reproduction of their female hosts. Hosts can live with the parasite for a prolonged period of time after infection. In ''

Daphnia ''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembl ...

'', ''P. ramosa'' induces gigantism. ''P. penetrans'' parasitized females of the nematode ''

Meloidogyne javanica ''Meloidogyne javanica'' is a species of plant-pathogenic nematodes. It is one of the tropical root-knot nematodes and a major agricultural pest in many countries. It has many hosts. ''Meloidogyne javanica'' reproduces by obligatory mitotic part ...

,'' on the other hand, were smaller than healthy individuals.

Potential as biocontrol

Due to the effect of ''Pasteuria'' on reproduction, especially on nematode pests of important crops, there is an interest to develop ''Pasteuria'' as a biological control agent. In 2012,

Syngenta Syngenta AG is a provider of agricultural science and technology, in particular seeds and pesticides with its management headquarters in Basel, Switzerland. It is owned by ChemChina, a Chinese state-owned enterprise. Syngenta was founded in 2 ...

acquired a company named Pateuria Bioscience to commercialize ''Pasteuria'' as a biological control. In 2013, Syngenta launched CLARIVA™ pn, which has the active ingredient of ''Pasteuria nishizawae'' to combat the soybean cyst nematode. The effectiveness of ''Pasteuria'' as a biocontrol may depend on the biotypes of the nematode host that are present since they can vary in their susceptibility to ''Pasteuria''.

Species of ''Pasteuria'' and their hosts

Currently, four species of ''Pasteuria'' and two candidate species are described, all of which are obligate parasites with specific hosts. The described species and their hosts include: * '' P. nishizawae'' Sayre et al. 1992: parasite of cyst-forming nematodes in the genera ''

Heterodera ''Heterodera'' is a genus of nematodes in the family Heteroderidae. Members of the genus are obligate parasites and different species attack different crops, often causing great economic damage. The genus is unique among nematode genera because o ...

'' and '' Globodera.'' * ''P. penetrans'' Thorne 1940 ex Sayre & Starr 1986: parasite of root knot nematodes in the genus ''

Meloidogyne Root-knot nematodes are plant-parasitic nematodes from the genus ''Meloidogyne''. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause appro ...

'' spp. * '' P. ramosa'' Metchnikoff 1888: parasite of

Cladocera The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more ...

ns, including ''

.'' * ''P. thornei'' Starr & Sayre 1988: parasite of root-lesion nematodes in the genus ''

Pratylenchus ''Pratylenchus'' is a genus of nematodes known commonly as lesion nematodes.Crow, W. TAmaryllis lesion nematode, ''Pratylenchus hippeastri''.EENY-546. University of Florida IFAS. 2012. They are parasitic on plants and are responsible for root le ...

.'' Candidate species and their hosts include: * ''P. aldrichii'' Giblin-Davis et al. 2011: parasite of bacterivorous nematodes in the genus ''Bursilla'' spp. * ''P. usage'' Giblin-Davis et al. 2003: parasite of the sting nematode'', Belonolaimus longicaudatus'' Additional species of ''Pasteuria'' have been named but are yet to be formally described, including: * "''P. hartismeri''" Atibalentja et al. 2002b * "''P. goettingianae''" Bishop et al. 2007.

References

{{Taxonbar, from=Q16987565 Gram-positive bacteria Bacteria genera