Oomycetes


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Oomycetes

A class of fungi in the subdivision Mastigomycotina. They comprise a group of heterotropic, funguslike organisms that are classified with the zoosporic fungi (Mastigomycotina) but in reality are related to the heterokont algae. They are distinguished from other zoosporic fungi by the presence of biflagellate zoospores. Some taxa are nonzoosporic. Asexual reproduction involves the release of zoospores from sporangia; in some taxa the sporangium germinates with outgrowth of a germ tube. Sexual reproduction occurs when an oogonial cell is fertilized by contact with an antheridium, resulting in one or more oospores.

Oomycetes are cosmopolitan, occurring in fresh and salt water, in soil, and as terrestrial parasites of plants. Many species can be grown in pure culture on defined media. There are four orders: The Saprolegniales and Leptomitales are popularly known as water molds. Some species are destructive fish parasites. Many Lagenidiales are parasites of invertebrates and algae. The Peronosporales are primarily plant parasites attacking the root, stem, or leaf, and include some of the more destructive plant pathogens. See Eumycota, Fungi

Oomycetes

[‚ō·ə·mī′sēd·ēz]
(mycology)
A class of the Phycomycetes comprising the biflagellate water molds and downy mildews.
References in periodicals archive ?
Horizontal gene transfer facilitated the evolution of plant parasitic mechanisms in the oomycetes.
Does Immunotherapy Protect Equines from Reinfection by the Oomycete Pythium insidiosum?
Los autores reconocen que actualmente todos los taxa pertenecientes a los Oomycetes (hongos acuaticos inferiores) estan actualmente ubicados dentro del reino Chromista (=Straminipila) (Adl et al.
Pythium insidiosum is a microorganism classified as belonging to the Stramenopila kingdom, Pseudofungi phylum, Oomycetes class, Pythiales order, Pythiaceae family and Pythium genus, so that the members of the Oomycetes class are phylogenetically distant from the kingdom of the fungi and closest to algae (7).
Occurrence and characterization of fungi and oomycetes transmitted via potting mixtures and organic manures.
Most plant diseases are caused by fungal pathogens which contain chitin as their major cell wall component except Oomycetes.
Propineb (polymeric-Zinc propylen-bisdithiocarbamate) is one of the broad spectrum fungicide currently widely used as a protective treatment for several crops to control various fungi, especially Oomycetes, Ascomycetes and fungi imperfecti [1].
Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants.
It afflicts successive generations of almonds and stone fruit planted at the same location and is associated with poor health of the trees' fine roots and incidence of several plant-parasitic fungi and oomycetes.
These are oomycetes, which cause blights in plants such as the Irish potato famine; protozoan parasites of humans, including Plasmodium, which causes malaria; and fungi that cause diseases in animals and plants.