MicroBiology

Oomycetes is also referred as water molds. They are a group of unicellular and filamentous Heterokonts that physically resemble fungi. They are the absorptive and microscopic organisms composed of mycelia. Mycelia are tube like vegetative body and they are also known by the term thalamus. The reproduction of Oomycetes takes place either sexually or asexually.

Oomycetes are also referred as water molds due to the fact that they were earlier classified as fungi. And fungi exist from conditions like high humidity and running water surface. Water molds have a relation to the organisms like diatoms and brown algae. Water molds are very significant scientifically as well as economically as they are the aggressive plant pathogens.

There are about five hundred species of Oomycetes that includes water molds and downy mildews. The absorption of food of these filamentous protists takes place from the adjoining soil or water or they may attack another organisms’ body to feed themselves. These Oomycetes play a very crucial role in the process of recycling and decomposition of the decaying matter.

Oomycota refers to the egg fungi and it is a structure that contains the female gametes. The Oomycetes are oogamous that produces non-mobile and big gametes known as eggs and the smaller gametes are known as sperms. The fossil record of the Oomycota is very sparse. Oomycetes that comprises of a big group of aquatic and terrestrial organisms resemble superficially to the fungi in terms of growth and mode of nutrition. But, discrete morphological features and molecular studies position them under the Stramenopila kingdom having golden and brown algae along with diatoms.

The terrestrial Oomycetes are basically the scroungers of the vascular plants and they contain different types of very imperative plant pathogens. For instance, Aphanomyces results in a root rot of a number of hosts that includes snap bean, pea, and sugar beet.

Oomycetes refers to a large collection of some significant species, including both the parasites and the saprophytes of plants, insects and animals. However, they lack the taxonomic similarity with what we refer to as fungi. But, instead they are categorized along with the brown algae and diatoms in a group named as Stramenopiles. The largest group of these Stramenopiles comprises of the Oomycetes that are found throughout the world in salt and fresh water habitats.

Oomycetes are not only plant pathogens, but studies have revealed that they are animal pathogens, as well. There are instances that show that the Oomycetes are pathogenic on species other than the pants. These are the Pythium insidiosum; this is a species infecting animals and results in swamp cancer. Then there is Lagenidium giganteum that parasitizes the larval stage of a mosquito and are utilized as a probable control agent. And lastly, there is Saproilegnia that causes infection in different species of fish.

There are some terrestrial Oomycetes that are considered as significant plant pathogenic organisms. These organisms are found in stagnant water as well as well aerated streams and they get their energy through anaerobic respiration. These members are filamentous and they lack septa with the only exception where the production of the reproductive cells takes place.

copyright@microbiology4all.blogspot.com