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Kämper J, Kahmann R, Bölker M, Ma LJ, Brefort T, Saville BJ, Banuett F, Kronstad JW, Gold SE, Müller O, Perlin MH, Wösten HAB, de Vries R, Ruiz-Herrera J, Reynaga-Peña CG, Snetselaar K, McCann M, Pérez-Martín J, Feldbrügge M, Basse CW, Steinberg G, Ibeas JI, Holloman W, Guzman P, Farman M, Stajich JE, Sentandreu R, González-Prieto JM, Kennell JC, Molina L, Schirawski J, Mendoza-Mendoza A, Greilinger D, Münch K, Rössel N, Scherer M, Vranes M, Ladendorf O, Vincon V, Fuchs U, Sandrock B, Meng S, Ho ECH, Cahill MJ, Boyce KJ, Klose J, Klosterman SJ, Deelstra HJ, Ortiz-Castellanos L, Li W, Sanchez-Alonso P, Schreier PH, Häuser-Hahn I, Vaupel M, Koopmann E, Friedrich G, Voss H, Schlüter T, Margolis J, Platt D, Swimmer C, Gnirke A, Chen F, Vysotskaia V, Mannhaupt G, Güldener U, Münsterkötter M, Haase D, Oesterheld M, Mewes HW, Mauceli EW, DeCaprio D, Wade CM, Butler J, Young S, Jaffe DB, Calvo S, Nusbaum C, Galagan J, Birren BW. Insights from the genome of the biotrophic fungal plant pathogen Ustilago maydis. Nature 2006; 444:97-101. [PMID: 17080091 DOI: 10.1038/nature05248] [Citation(s) in RCA: 907] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Accepted: 09/15/2006] [Indexed: 01/30/2023]
Abstract
Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. This basidiomycete fungus does not use aggressive virulence strategies to kill its host. U. maydis belongs to the group of biotrophic parasites (the smuts) that depend on living tissue for proliferation and development. Here we report the genome sequence for a member of this economically important group of biotrophic fungi. The 20.5-million-base U. maydis genome assembly contains 6,902 predicted protein-encoding genes and lacks pathogenicity signatures found in the genomes of aggressive pathogenic fungi, for example a battery of cell-wall-degrading enzymes. However, we detected unexpected genomic features responsible for the pathogenicity of this organism. Specifically, we found 12 clusters of genes encoding small secreted proteins with unknown function. A significant fraction of these genes exists in small gene families. Expression analysis showed that most of the genes contained in these clusters are regulated together and induced in infected tissue. Deletion of individual clusters altered the virulence of U. maydis in five cases, ranging from a complete lack of symptoms to hypervirulence. Despite years of research into the mechanism of pathogenicity in U. maydis, no 'true' virulence factors had been previously identified. Thus, the discovery of the secreted protein gene clusters and the functional demonstration of their decisive role in the infection process illuminate previously unknown mechanisms of pathogenicity operating in biotrophic fungi. Genomic analysis is, similarly, likely to open up new avenues for the discovery of virulence determinants in other pathogens.
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Affiliation(s)
- Jörg Kämper
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse, D-35043 Marburg, Germany.
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Zauner S, Greilinger D, Laatsch T, Kowallik KV, Maier UG. Substitutional editing of transcripts from genes of cyanobacterial origin in the dinoflagellate Ceratium horridum. FEBS Lett 2005; 577:535-8. [PMID: 15556642 DOI: 10.1016/j.febslet.2004.10.060] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 10/20/2004] [Accepted: 10/21/2004] [Indexed: 11/28/2022]
Abstract
Peridinin-containing dinoflagellates, a group of alveolate organisms, harbour small plasmids called minicircles. As most of these minicircles encode genes of cyanobacterial origin, which are also found in plastid genomes of stramenopiles, they were thought to represent the plastid genome of peridinin-containing dinoflagellates. The analyses of minicircle derived mRNAs and the 16S rRNA showed that extensive editing of minicircle gene transcripts is common for Ceratium horridum. Posttranscriptional changes occur predominantly by editing A into G, but other types of editing including a previously unreported A to C transversion were also detected. This leads to amino acid changes in most cases or, in one case, to the elimination of a stop-codon. Interestingly, the edited mRNAs show higher identities to homologous sequences of other peridinin-containing dinoflagellates than their genomic copy. Thus, our results imply that transcript editing of genes of cyanobacterial origin is species specific in peridinin-containing dinoflagellates and demonstrate that editing of genes of cyanobacterial origin is not restricted to land plants.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Base Sequence
- Codon, Terminator/chemistry
- Cyanobacteria/genetics
- DNA, Circular/genetics
- Dinoflagellida/classification
- Dinoflagellida/genetics
- Dinoflagellida/growth & development
- Genes, Bacterial
- Molecular Sequence Data
- Plasmids
- Protein Processing, Post-Translational
- RNA Editing
- RNA, Messenger/analysis
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Ribosomal, 16S/analysis
- Sequence Deletion
- Sequence Homology, Amino Acid
- Species Specificity
- Transcription, Genetic
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Affiliation(s)
- Stefan Zauner
- Cell Biology, Philipps-University Marburg, Karl-von-Frisch Strasse, D-35032 Marburg, Germany.
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