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1. Expressed sequence tags from the oomycete fish pathogen Saprolegnia parasitica reveal putative virulence factors

Author

van West Pieter, Waugh Mark E, Gajendran Kamal, Tian Miaoying, Torto-Alalibo Trudy, and Kamoun Sophien

Subjects
Microbiology, QR1-502
Abstract

Abstract Background The oomycete Saprolegnia parasitica is one of the most economically important fish pathogens. There is a dramatic recrudescence of Saprolegnia infections in aquaculture since the use of the toxic organic dye malachite green was banned in 2002. Little is known about the molecular mechanisms underlying pathogenicity in S. parasitica and other animal pathogenic oomycetes. In this study we used a genomics approach to gain a first insight into the transcriptome of S. parasitica. Results We generated 1510 expressed sequence tags (ESTs) from a mycelial cDNA library of S. parasitica. A total of 1279 consensus sequences corresponding to 525944 base pairs were assembled. About half of the unigenes showed similarities to known protein sequences or motifs. The S. parasitica sequences tended to be relatively divergent from Phytophthora sequences. Based on the sequence alignments of 18 conserved proteins, the average amino acid identity between S. parasitica and three Phytophthora species was 77% compared to 93% within Phytophthora. Several S. parasitica cDNAs, such as those with similarity to fungal type I cellulose binding domain proteins, PAN/Apple module proteins, glycosyl hydrolases, proteases, as well as serine and cysteine protease inhibitors, were predicted to encode secreted proteins that could function in virulence. Some of these cDNAs were more similar to fungal proteins than to other eukaryotic proteins confirming that oomycetes and fungi share some virulence components despite their evolutionary distance Conclusion We provide a first glimpse into the gene content of S. parasitica, a reemerging oomycete fish pathogen. These resources will greatly accelerate research on this important pathogen. The data is available online through the Oomycete Genomics Database 1.

Published
2005
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10. Prevalence and seasonal variation of Olpidiopsis porphyrae (Oomycota) infecting red algal Bangiales from the Southern Pacific.

Author

Murúa, Pedro, Muñoz, Liliana, Badis, Yacine, van West, Pieter, and Gachon, Claire M.M.

Subjects
PORPHYRA, MARINE algae, AQUACULTURE, FISHERIES, PARASITES
Abstract

The Bangiales are one of the most common seaweeds in sub-Antarctic and Southeastern Pacific upper intertidal habitats. Here we report records of an 'olpidioid' marine obligate parasite infecting Bangiales between 39°20′–41°44′S in the Southeastern Pacific for the first time. The disease resembles the 'Olpidiopsis blight disease' reported for farmed Bangiales in Japan and Korea and wild Pyropia from Scotland morphologically and developmentally. The Chilean isolate infects commercial Chilean laver or 'luche' (Porphyra sensu lato) and Bangia sensu lato from wild populations in the Southeastern Pacific. Phylogenetic markers (cox2, 18S) identify it as Olpidiopsis porphyrae. We relate the occurrence of this pathogen to both 'luche' fisheries in Chile and the potential consequences for its emergent aquaculture in the Southeastern Pacific. Highlights: The parasite Olpidiopsis porphyrae (Oomycota) is reported in Chile and the Southeastern Pacific for the first time. O. porphyrae infects Chilean Porphyra and Bangia sensu lato. The prevalence of O. porphyrae is very variable between populations, and highly seasonal in a locality of Southern Chile. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Genome sequence of the necrotrophic plant pathogen, Pythium ultimum, reveals original pathogenicity mechanisms and effector repertoire

Author

Lévesque, C André, Brouwer, Henk, Cano, Liliana, Hamilton, John P, Holt, Carson, Huitema, Edgar, Raffaele, Sylvain, Robideau, Gregg P, Thines, Marco, Win, Joe, Zerillo, Marcelo M, Beakes, Gordon W, Boore, Jeffrey L, Busam, Dana, Dumas, Bernard, Ferriera, Steve, Fuerstenberg, Susan I, Gachon, Claire MM, Gaulin, Elodie, Govers, Francine, Grenville-Briggs, Laura, Horner, Neil, Hostetler, Jessica, Jiang, Rays HY, Johnson, Justin, Krajaejun, Theerapong, Lin, Haining, Meijer, Harold JG, Moore, Barry, Morris, Paul, Phuntmart, Vipaporn, Puiu, Daniela, Shetty, Jyoti, Stajich, Jason E, Tripathy, Sucheta, Wawra, Stephan, van West, Pieter, Whitty, Brett R, Coutinho, Pedro M, Henrissat, Bernard, Martin, Frank, Thomas, Paul D, Tyler, Brett M, De Vries, Ronald P, Kamoun, Sophien, Yandell, Mark, Tisserat, Ned, and Buell, C Robin

Abstract

Abstract Background Pythium ultimum is a ubiquitous oomycete plant pathogen responsible for a variety of diseases on a broad range of crop and ornamental species. Results The P. ultimum genome (42.8 Mb) encodes 15,290 genes and has extensive sequence similarity and synteny with related Phytophthora species, including the potato blight pathogen Phytophthora infestans. Whole transcriptome sequencing revealed expression of 86% of genes, with detectable differential expression of suites of genes under abiotic stress and in the presence of a host. The predicted proteome includes a large repertoire of proteins involved in plant pathogen interactions, although, surprisingly, the P. ultimum genome does not encode any classical RXLR effectors and relatively few Crinkler genes in comparison to related phytopathogenic oomycetes. A lower number of enzymes involved in carbohydrate metabolism were present compared to Phytophthora species, with the notable absence of cutinases, suggesting a significant difference in virulence mechanisms between P. ultimum and more host-specific oomycete species. Although we observed a high degree of orthology with Phytophthora genomes, there were novel features of the P. ultimum proteome, including an expansion of genes involved in proteolysis and genes unique to Pythium. We identified a small gene family of cadherins, proteins involved in cell adhesion, the first report of these in a genome outside the metazoans. Conclusions Access to the P. ultimum genome has revealed not only core pathogenic mechanisms within the oomycetes but also lineage-specific genes associated with the alternative virulence and lifestyles found within the pythiaceous lineages compared to the Peronosporaceae.

Published
2010

26. Macroalgal eukaryotic microbiome composition indicates novel phylogenetic diversity and broad host spectrum of oomycete pathogens.

Author

Timanikova, Natalia, Fletcher, Kyle, Han, Jon‐Wong, van West, Pieter, Woodward, Steve, Kim, Gwang‐Hoon, Küpper, Frithjof C., and Wenzel, Marius

Subjects
OOMYCETES, MARINE algae, MARINE ecology, PARASITIC diseases, PATHOGENIC microorganisms, GENETIC variation
Abstract

Seaweeds are important components of marine ecosystems with emerging potential in aquaculture and as sources of biofuel, food products and pharmacological compounds. However, an increasingly recognised threat to natural and industrial seaweed populations is infection with parasitic single‐celled eukaryotes from the relatively understudied oomycete lineage. Here we examine the eukaryomes of diverse brown, red and green marine macroalgae collected from polar (Baffin Island), cold‐temperate (Falkland Islands) and tropical (Ascension Island) locations, with a focus on oomycete and closely related diatom taxa. Using 18S rRNA gene amplicon sequencing, we show unexpected genetic and taxonomic diversity of the eukaryomes, a strong broad‐brush association between eukaryome composition and geographic location, and some evidence of association between eukaryome structure and macroalgal phylogenetic relationships (phylosymbiosis). However, the oomycete fraction of the eukaryome showed disparate patterns of diversity and structure, highlighting much weaker association with geography and no evidence of phylosymbiosis. We present several novel haplotypes of the most common oomycete Eurychasma dicksonii and report for the first time a cosmopolitan distribution and absence of host specificity of this important pathogen. This indicates rich diversity in macroalgal oomycete pathogens and highlights that these pathogens may be generalist and highly adaptable to diverse environmental conditions. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Emerging oomycete threats to plants and animals

Author

Derevnina, Lida, Petre, Benjamin, Kellner, Ronny, Dagdas, Yasin F., Sarowar, Mohammad Nasif, Giannakopoulou, Artemis, De la Concepcion, Juan Carlos, Chaparro-Garcia, Angela, Pennington, Helen G., van West, Pieter, and Kamoun, Sophien

Published
2016

43. Hook, Line and Infection

Author

Stewart, Alexander, primary, Jackson, Joseph, additional, Barber, Iain, additional, Eizaguirre, Christophe, additional, Paterson, Rachel, additional, van West, Pieter, additional, Williams, Chris, additional, and Cable, Joanne, additional

Published
2017
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48. Presence/absence, differential expression and sequence polymorphisms between PiAVR2 and PiAVR2-like in Phytophthora infestans determine virulence on R2 plants

Author

Gilroy, Eleanor M., Breen, Susan, Whisson, Stephen C., Squires, Julie, Hein, Ingo, Kaczmarek, Maciej, Turnbull, Dionne, Boevink, Petra C., Lokossou, Anoma, Cano, Liliana M., Morales, Juan, Avrova, Anna O., Pritchard, Leighton, Randall, Eva, Lees, Alison, Govers, Francine, van West, Pieter, Kamoun, Sophien, Vleeshouwers, Vivianne G. A. A., Cooke, David E. L., and Birch, Paul R. J.

Published
2011

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