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Nat. Methods 12, 698–699 (2015); published online 30 July 2015; corrected after print 24 September 2015 In the version of this article initially published, a funding source was omitted. The authors acknowledge additional funding from the Medical Research Council (program MC_U142684171). The error has been corrected in the HTML and PDF versions of the article.

Oomycetes in the class Saprolegniomycetidae of the Eukaryotic kingdom Stramenopila have evolved as severe pathogens of amphibians, crustaceans, fish and insects, resulting in major losses in aquaculture and damage to aquatic ecosystems. We have sequenced the 63 Mb genome of the fresh water fish pathogen, Saprolegnia parasitica. Approximately 1/3 of the assembled genome exhibits loss of heterozygosity, indicating an efficient mechanism for revealing new variation. Comparison of S. parasitica with plant pathogenic oomycetes suggests that during evolution the host cellular environment has driven distinct patterns of gene expansion and loss in the genomes of plant and animal pathogens. S. parasitica possesses one of the largest repertoires of proteases (270) among eukaryotes that are deployed in waves at different points during infection as determined from RNA-Seq data. In contrast, despite being capable of living saprotrophically, parasitism has led to loss of inorganic nitrogen and sulfur assimilation pathways, strikingly similar to losses in obligate plant pathogenic oomycetes and fungi. The large gene families that are hallmarks of plant pathogenic oomycetes such as Phytophthora appear to be lacking in S. parasitica, including those encoding RXLR effectors, Crinkler's, and Necrosis Inducing-Like Proteins (NLP). S. parasitica also has a very large kinome of 543 kinases, 10% of which is induced upon infection. Moreover, S. parasitica encodes several genes typical of animals or animal-pathogens and lacking from other oomycetes, including disintegrins and galactose-binding lectins, whose expression and evolutionary origins implicate horizontal gene transfer in the evolution of animal pathogenesis in S. parasitica.

Nature 537, 508–514 (2016); doi:10.1038/nature19356 In this Article, the author Wolfgang Wurst was erroneously omitted from the author list. They are associated with the affiliations: HelmholtzZentrum Munich, Institute of Developmental Genetics, 85764 Munich-Neuherberg, Germany; Technical Universityof Munich, Chair of Developmental Genetics, 85764 Munich-Neuherberg, Germany; German Center for Neurodegenerative Diseases (DZNE) Site Munich, 81377 Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany.

DIAGNOSIS Spinal epidural varix DISCUSSION Epidural varix is an uncommon entity originally reported in the literature by Cohen in 1941.1 The incidence has been reported to be .07% to 1.3%.2,3,4 The lumbar vertebral venous plexus consists of a retrovertebral plexus framed by paired anterior internal vertebral veins. The etiology of the symptoms is unknown; however, an increase in intra-abdominal pressure with compression of the inferior vena cava and resulting venous engorgement and nerve root compression is repeatedly suggested in the literature.

Oomycetes in the class Saprolegniomycetidae of the Eukaryotic kingdom Stramenopila have evolved as severe pathogens of amphibians, crustaceans, fish and insects, resulting in major losses in aquaculture and damage to aquatic ecosystems. We have sequenced the 63 Mb genome of the fresh water fish pathogen, Saprolegnia parasitica. Approximately 1/3 of the assembled genome exhibits loss of heterozygosity, indicating an efficient mechanism for revealing new variation. Comparison of S. parasitica with plant pathogenic oomycetes suggests that during evolution the host cellular environment has driven distinct patterns of gene expansion and loss in the genomes of plant and animal pathogens. S. parasitica possesses one of the largest repertoires of proteases (270) among eukaryotes that are deployed in waves at different points during infection as determined from RNA-Seq data. In contrast, despite being capable of living saprotrophically, parasitism has led to loss of inorganic nitrogen and sulfur assimilation pathways, strikingly similar to losses in obligate plant pathogenic oomycetes and fungi. The large gene families that are hallmarks of plant pathogenic oomycetes such as Phytophthora appear to be lacking in S. parasitica, including those encoding RXLR effectors, Crinkler's, and Necrosis Inducing-Like Proteins (NLP). S. parasitica also has a very large kinome of 543 kinases, 10% of which is induced upon infection. Moreover, S. parasitica encodes several genes typical of animals or animal-pathogens and lacking from other oomycetes, including disintegrins and galactose-binding lectins, whose expression and evolutionary origins implicate horizontal gene transfer in the evolution of animal pathogenesis in S. parasitica.

The oomycete Pythium oligandrum can parasitize phytopathogenic fungi and oomycetes providing protection to crop plants. Limited molecular tools were currently available to study this organism. The work set out to develop basic tools, and to acquire the first significant DNA sequencing data for this organism. P. oligandrum expressed sequence tags derived from vegetative mycelia and a P. oligandrum-P. infestans interaction were analysed in an attempt to find sequences that may be involved in its biotic interactions. Many sequences with similarity to previously described effectors from fungi, oomycetes and bacteria were revealed. A transformation protocol was adapted for use in P. oligandrum, which was used to heterologously express green fluorescent protein (gfp), producing fluorescent hyphae that could be used to follow the interaction with a plant and oomycete host. Several genes were identified from the EST libraries that were similar to nematode eggshell protein-encoding genes. Using the transformation protocol, it was possible to silence the expression of these genes by homology-dependent gene silencing. Oospores from silenced strains displayed major ultrastructural abnormalities and were sensitive to degradative enzyme treatment. From the EST libraries three sequences were identified that were similar to sea slug pheromones. Similar sequences were found to form a large gene family in the genomes of Phytopthora infestans, P. sojae and P. ramorum. One of these genes in P. infestans was shown to be up-regulated in the motile zoospore stage, leading to the hypothesis that this gene may be acting as a pheromone in zoospore autoaggregation. An initial characterisation found no evidence to support this hypothesis.