Pythium

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For the ancient city named Pythium, see Pythion.

Pythium
Negative phase contrast image of Pythium sp.
Negative phase contrast image of Pythium sp.
Scientific classification Edit this classification
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Oomycota
Order: Peronosporales
Family: Pythiaceae
Genus: Pythium
Pringsheim, 1858
Species

See text

Pythium is a genus of parasitic oomycetes. They were formerly classified as fungi. Most species are plant parasites, but Pythium insidiosum is an important pathogen of animals, causing pythiosis. The feet of the fungus gnat are frequently a vector for their transmission.[1]

Morphology

Hyphae
Pythium species, like others in the family Pythiaceae, are usually characterized by their production of coenocytic hyphae without septations.
Oogonia
Generally contain a single oospore.
Antheridia
Contain an elongated and club-shaped antheridium.

Ecological importance

Pythium

Pythium-induced

genetic host resistance, but no crop has ever developed adequate resistance to Pythium.[3] This disease complex usually involves other pathogens such as Phytophthora and Rhizoctonia. Pythium wilt is caused by zoospore infection of older plants, leading to biotrophic infections that become necrotrophic in response to colonization/reinfection pressures or environmental stress,[2][4][5] leading to minor or severe wilting caused by impeded root functioning.[2][6]

Many Pythium species, along with their close relatives Phytophthora, are plant pathogens of economic importance in agriculture. Pythium spp. tend to be very generalistic and unspecific in their large range of hosts,[7] while Phytophthora spp. are generally more host-specific.

For this reason, Pythium spp. are more devastating in the root rot they cause in crops, because crop rotation alone often does not eradicate the pathogen as Pythium spp. are also good saprotrophs, and survive for a long time on decaying plant matter.

In field crops, damage by Pythium spp. is often limited to the area affected, as the motile zoospores require ample surface water to travel long distances. Additionally, the capillaries formed by soil particles act as a natural filter and effectively trap many zoospores. However, in

mefenoxam since the 1980s[9] and metalaxyl since 1984.[10]

Several Pythium species, including P. oligandrum, P. nunn, P. periplocum, and P. acanthicum, are mycoparasites of plant pathogenic fungi and oomycetes, and have received interest as potential biocontrol agents.

Species

Globisporangium sylvaticum was formerly placed here as Pythium sylvaticum

See also

References

  1. ^ "Ecogrow Fungus Gnat". 17 March 2014.
  2. ^
    ISBN 978-0-89054-122-7.[page needed
    ]
  3. ISSN 0100-5405
    .
  4. OCLC 271429383.[page needed
    ]
  5. S2CID 86573443
    .
  6. ^
    OCLC 216915405.[page needed
    ]
  7. ^
    OCLC 55510696
    .
  8. ^
    S2CID 85004809
    .
  9. PMID 30688597
    .
  10. ISSN 0191-2917
    .

Further reading

Wikimedia Commons has media related to Pythium.
  • A. J. van der Plaats-Niterink (1981). "Monograph of the genus Pythium". Studies in Mycology. 21: 1–242.
  • C. André Lévesque & Arthur W. M. de Cock (2004). "Molecular phylogeny and taxonomy of the genus Pythium".
    PMID 15757173
    .
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