Prof. Dr. Jörg Kämper (Karlsruhe): Plant Infection by the smut fungus Ustilago maydis: A tale of regulatory cascades, cell cycle control, and secreted effectors |
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| Startdatum/-zeit: | 26.06.2012 17:15 |
| Enddatum/-zeit: | 26.06.2012 |
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| Adresse: | apl. Prof. Dr. Hans Merzendorfer,
Fachbereich Biologie/Chemie
Barbarastr. 11 49076 Osnabrück |
| Telefon: | 0541/969-3502 |
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| E-Mail: | merzendorfer@biologie.uni-osnabrueck.de |
| Homepage: | http://www.biologie.uni-osnabrueck.de/Fachbereich/?x=ac,dt,eb |
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| Adresse: | Hörsaal 35/E01 FB Biologie/Chemie, Barbarastr. 11 49076 Osnabrück |
| Karte: | Bei Google Maps anzeigen |
| Beschreibung: | Ustilago maydis is a ubiquitous pathogen of maize and a well-established model organism for the study of plant-microbe interactions. The basidiomycete fungus does not use aggressive virulence strategies to kill its host, but depends on living tissue for proliferation and development. This biotrophic life-style requires highly dynamic mechanisms to adapt to the host and to respond to the various lines of plant defense reactions. The master control instance for pathogenic development are two transcription factors, bE and bW, encoded by the b-mating type locus. A heterodimeric complex of bE/bW orchestrates a regulatory network consisting of different transcription factors that control cell morphology, cell cycle and the expression of secreted effector proteins. These effectors have pivotal functions during the infection process, e.g. in plant defense suppression or to reprogram the plant metabolism to nourish the fungal cells. Interestingly, the b-regulatory network connects directly to the "unfolded protein response" (UPR) pathway. In general, UPR regulates gene expression in response to the demands of increased protein secretion, which, in U. maydis, may be required for the delivery of effector proteins. Another adaptation to the plant host is reflected by the highly specialized carbon uptake system of Ustilago: unlike other fungi, U. maydis is capable to directly import sucrose via a recently discovered high affinity sucrose transporter. The direct uptake copes with the plant defense at two distinct front lines: it avoids the invertase-mediated generation of glucose, which serves as a trigger for plant defense, and the high affinity U. maydis transporter can outcompete plant sucrose transporters that are induced as a defense reaction to "starve" pathogens. |
| Kategorie: | Biologisches Kolloqium |
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