Pasteuria Penetrans

''Pasteuria'' is a genus of mycelial and endospore-forming, nonmotile gram-positive bacteria that are obligate parasites of some nematodes and crustaceans. The genus of ''Pasteuria'' was previously classified within the family Alicyclobacillaceae, but has since been moved to the family Pasteuriaceae.

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'', ''P. ramosa'' induces gigantism. ''P. penetrans'' parasitized females of the nematode '' Meloidogyne javanica,'' 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 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'' and ''Globodera.''
* ''P. penetrans'' Thorne 1940 ex Sayre & Starr 1986: parasite of root knot nematodes in the genus '' Meloidogyne'' spp.
* '' P. ramosa'' Metchnikoff 1888: parasite of Cladocerans, including ''Daphnia.''
* ''P. thornei'' Starr & Sayre 1988: parasite of root-lesion nematodes in the genus ''Pratylenchus.''

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