Descriptions

Outline

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Saprolegnia parasitica CBS 223.65

The oomycete Saprolegnia parasitica, and related pathogens in the class Saprolegniomycetidae attack a wide variety of fish, amphibians and crustaceans important to aquaculture and to aquatic ecosystems. Saprolegnia parasitica is economically one of the most important fish pathogens, especially on catfish, salmon and trout species. It causes millions of dollar losses to the aquaculture business worldwide, notably in the USA, Scotland, Scandinavia, Chile, Japan, and Canada . Saprolegnia species have also been linked to declining wild fish stocks and amphibian populations around the world. Over the past ten years, aquaculture production has increased on average by 11% per year worldwide (FAO Fishery Information), and at this rate it will overtake beef as a protein source by 2010. The high density of fish in aquaculture farms and the recent loss of the fungicide malachite green have exacerbated disease problems. Water molds (oomycetes) are destructive pathogens of aquatic animals and terrestrial plants. Members of the genus Saprolegnia (class Saprolegniomycetidae) cause Saprolegniosis, a disease that is characterized by visible white or grey patches of filamentous mycelium on the body or fins of freshwater fish. Besides mycelium, S. parasitica generates primary and secondary zoospores whereby the latter type is infectious on fish. Also fish eggs are infected by Saprolegnia spp, resulting in abundant mycelial growth and ultimately cell death. At present, oomycete genome sequencing projects have focused on plant pathogenic species from the order Peronosporomycetidae (Phytophthora and Hyaloperonospora), and have yielded dramatic insights into the pathology of these species. Saprolegnia parasitica is the first Saprolegniomycetidae and oomycetes animal pathogen to be sequenced.

Saprolegnia declina VS20

Saprolegnia declina (or Saprolegnia diclina) is a pathogen of amphibians, fish and insects. It is an aquatic watermould or oomycete that plays an important role in the decline of natural populations of amphibian. Several outbreaks, leading to severe reductions and even extinction of amphibians have been attributed to S. declina and other closely related Saprolegniales. It is also a large problem in fish hatcheries where it infects eggs of salmon and trout. Egg losses of 10% are commonplace.

Phytophthora infestans

Phytophthora infestans is a devastating pathogen of critical food crops, causing late blight of potato and tomato.

Phytophthora sojae and P. ramorum

Phytophthora sojae and P. ramorum were sequenced by JGI as model species for the Phytophthora genus, whose members attack a wide variety of plant species. More details about these species can be found here.