Pythium

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Pythium
Negative phase contrast image of Pythium sp.

Negative phase contrast image of Pythium sp.

Systematics
Sub-kingdom : Stramenopile (Chromista)
Department : Egg mushrooms (Oomycota)
Class : Oomycetes
Order : Peronosporales
Family : Pythiaceae
Genre : Pythium
Scientific name
Pythium
Pringsheim , 1858

Pythium is a genus of parasitic egg fungi . They used to beplaced with mushrooms , but are more related to brown algae and golden algae . Most species are plant parasites, but Pythium insidiosum is a major pathogen in animals that causes pythiosis. Sciarid gnats' feetare often vectors for their transmission.

morphology

Hyphae
Pythium species are - like other representatives of the Pythiaceae - usually characterized by the fact that they develop coenocytic hyphae without septa .
Oogonia
They generally contain a single oospore .
Antheridia
They contain an elongated and club-shaped antheridium .

Ecological importance

Pythium

Pythium -induced root rot is a common disease among crops. The term seedling rot is common for the death of the seedlings and saplings caused by the egg fungus , a common problem with outdoor and greenhouse crops. This complex of diseases usually also includes other pathogens such as Phytophthora species and Rhizoctonia solani . The wilt triggered by Pythium follows a zoospore infection of older plants, which leads to biotrophic infections, which in turn become necrotrophic as a result of colonization / reinfection pressure or various external stress factors and lead to more or less serious wilting, triggered by the damaged root functions.

Many Pythium species, like the closely related Phytophthora species, are phytopathogens of economic importance in agriculture. Pythium species are generally not very host-specific, in contrast to the Phytophthora species. For this reason, the representatives of the genus Pythium have a more disastrous effect due to their root rot in cultivated plants, because crop rotation alone does not eliminate the pathogens, which are also good saprobionts and can still live on dead organic matter for a long time.

For crops, the extent of destruction by Pythium spp. often restricted to the infested fields, as the freely moving zoospores depend on abundant surface water in order to be able to spread. In addition, the bottom capillaries serve as effective natural filters that hold back many zoospores. In hydroponics within greenhouses, in which intensive plant monocultures are raised in nutrient solutions (with nitrogen , potassium , phosphates and micronutrients ) and which are continuously fed to the cultures in a circulatory system, Pythium species can cause intense and destructive root rot, which is often severe are to be prevented or combated. The root rot affects the entire system (tens of thousands of plants in many units) within two to four days down to the depths of the hydroponics, in which the bare roots are exposed to the solutions with the freely moving zoospores.

Several Pythium species, including Pythium oligandrum , P. nunn , P. periplocum and P. acanthicum , are mycoparasites of phytopathogenic fungi and egg fungi. They have therefore moved into the interest of biological pest control .

species

  • Pythium acanthicum
  • Pythium acanthophoron
  • Pythium acrogynum
  • Pythium adhaerens
  • Pythium amasculinum
  • Pythium anandrum
  • Pythium angustatum
  • Pythium aphanidermatum
  • Pythium apleroticum
  • Pythium aquatile
  • Pythium aristosporum
  • Pythium arrhenomanes
  • Pythium attrantheridium
  • Pythium bifurcatum
  • Pythium boreale
  • Pythium buismaniae
  • Pythium butleri
  • Pythium camurandrum
  • Pythium campanulatum
  • Pythium canariense
  • Pythium capillosum
  • Pythium carbonicum
  • Pythium carolinianum
  • Pythium catenulatum
  • Pythium chamaehyphon
  • Pythium citrinum
  • Pythium coloratum
  • Pythium conidiophorum
  • Pythium contiguanum
  • Pythium cryptoirregulare
  • Pythium cucurbitacearum
  • Pythium cylindrosporum
  • Pythium cystogenes
  • Pythium debaryanum
  • Pythium deliense
  • Pythium destruens
  • Pythium diclinum
  • Pythium dimorphum
  • Pythium dissimile
  • Pythium dissotocum
  • Pythium echinulatum
  • Pythium emineosum
  • Pythium erinaceum
  • Pythium flevoense
  • Pythium folliculosum
  • Pythium glomeratum
  • Pythium graminicola
  • Pythium grandisporangium
  • Pythium guiyangense
  • Pythium helicandrum
  • Pythium helicoides
  • Pythium heterothallicum
  • Pythium hydnosporum
  • Pythium hypogynum
  • Pythium indigoferae
  • Pythium inflatum
  • Pythium insidiosum
  • Pythium intermedium
  • Pythium irregular
  • Pythium iwayamae
  • Pythium jasmonium
  • Pythium kunmingense
  • Pythium litorale
  • Pythium longandrum
  • Pythium longisporangium
  • Pythium lutarium
  • Pythium macrosporum
  • Pythium mamillatum
  • Pythium marinum
  • Pythium marsipium
  • Pythium mastophorum
  • Pythium megacarpum
  • Pythium middletonii
  • Pythium minus
  • Pythium monospermum
  • Pythium montanum
  • Pythium multisporum
  • Pythium myriotylum
  • Pythium nagaii
  • Pythium nodosum
  • Pythium now
  • Pythium oedochilum
  • Pythium okanoganense
  • Pythium oligandrum
  • Pythium oopapillum
  • Pythium ornacarpum
  • Pythium orthogonon
  • Pythium ostracodes
  • Pythium pachycaule
  • Pythium pachycaule
  • Pythium paddicum
  • Pythium paroecandrum
  • Pythium parvum
  • Pythium pectinolyticum
  • Pythium periilum
  • Pythium periplocum
  • Pythium perniciosum
  • Pythium perplexum
  • Pythium phragmitis
  • Pythium pleroticum
  • Pythium plurisporium
  • Pythium polar
  • Pythium polymastum
  • Pythium porphyrae
  • Pythium prolatum
  • Pythium proliferatum
  • Pythium pulchrum
  • Pythium pyrilobum
  • Pythium quercum
  • Pythium radiosum
  • Pythium ramificatum
  • Pythium regulare
  • Pythium rhizo-oryzae
  • Pythium rhizosaccharum
  • Pythium rostratifingens
  • Pythium rostratum
  • Pythium salpingophorum
  • Pythium scleroteichum
  • Pythium segnitium
  • Pythium spiculum
  • Pythium spinosum
  • Pythium splendens
  • Pythium sterum
  • Pythium stipitatum
  • Pythium sulcatum
  • Pythium terrestris
  • Pythium torulosum
  • Pythium tracheiphilum
  • Pythium ultimum
  • Pythium uncinulatum
  • Pythium undulatum
  • Pythium vanterpoolii
  • Pythium viniferum
  • Pythium violae
  • Pythium volutum
  • Pythium zingiberis
  • Pythium zingiberum

Globisporangium sylvaticum was previously listed as Pythium sylvaticum in this genus.

Individual evidence

  1. ↑ Fungus Gnat Bradysia spp Order Diptera . In: Ecogrow . Retrieved May 14, 2019.
  2. ↑ a b c d W. R. = Jarvis: Managing diseases in greenhouse crops . APS Press, Saint Paul (Minnesota) 1992, ISBN 978-0-89054-122-7 .
  3. ↑ Tony Nathaniel Owen-Going: Quantitative investigations of phenolic compounds associated with root rot of hydroponic pepper, Capsicum annuum L., caused by Pythium aphanidermatum (Edson) Fitzp. . University of Guelph , 2005, ISBN 978-0-494-17779-2 .
  4. ↑ = TN Owen-Going, CW Beninger, JC Sutton, JC Hall: Accumulation of phenolic compounds in plants and nutrient solution of hydroponic peppers inoculated with Pythium aphanidermatum . In: Canadian Journal of Plant Pathology . 30, No. 2, 2008, pp. 214-225. doi : 10.1080 / 07060661.2008.10540537 .
  5. ↑ a b c Roger Bagnall: Control of Pythium wilt and root rot of hydroponically grown lettuce by means of chemical treatment of the nutrient solution . University of Pretoria , 2007.
  6. ↑ a b c Tony Nathaniel Owen-Going: Etiology and epidemiology of Pythium root rot in bell pepper (Capsicum annuum L.) in commercial-scale and small-scale hydroponic systems . University of Guelph , 2002, ISBN 978-0-612-71820-3 .
  7. ^ A b T. N. Owen-Going, JC Sutton, B. Grodzinski: Relationships of Pythium isolates and sweet pepper plants in single-plant hydroponic units . In: Canadian Journal of Plant Pathology . 25, No. 2, 2003, pp. 155-167. doi : 10.1080 / 07060660309507064 .

Other sources

  • AJ van der Plaats-Niterink: Monograph of the genus Pythium . In: Studies in Mycology . 21, 1981, pp. 1-242.
  • C. André Lévesque, Arthur WM de Cock: Molecular phylogeny and taxonomy of the genus Pythium . In: Mycological Research . 108, No. 12, 2004, pp. 1363-1383. doi : 10.1017 / S0953756204001431 .