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Jörg Kämper MPI für terrestrische Mikrobiologie Marburg

Zeae maydis morbus ad ustilaginem vulgo relatus F.J.Imhof, 1784. Regulating networks and pathogenicity in Ustilago maydis. Jörg Kämper MPI für terrestrische Mikrobiologie Marburg. Economical losses by smut fungi: - high annual losses, local losses sometimes more than 25%

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Jörg Kämper MPI für terrestrische Mikrobiologie Marburg

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  1. Zeae maydis morbus ad ustilaginem vulgo relatus F.J.Imhof, 1784 Regulating networks and pathogenicity in Ustilago maydis Jörg Kämper MPI für terrestrische Mikrobiologie Marburg

  2. Economical losses by smut fungi: - high annual losses, local losses sometimes more than 25% Ustilago hordei: 0.7 - 1,4% loss/year (Canada) appr. 17.6 Mio US $/year Ustilago maydis: usually less than 2%, but up to 70% 2% in USA equals about 380 Mio US $!!!

  3. Economical losses by smut fungi: - high annual losses, local losses sometimes more than 25% Ustilago hordei: 0.7 - 1,4% loss/year (Canada) appr. 17.6 Mio US $/year Ustilago maydis: usually less than 2%, but up to 70% 2% in USA equals about 380 Mio US $!!! Related to rust fungi (obligat biotroph) • extremly high annual losses • Epidemics

  4. Life cycle of Ustilago maydis Life cycle of Ustilago maydis saprophytic phase

  5. Life cycle of Ustilago maydis Life cycle of Ustilago maydis saprophytic phase Saprophytic phase: Simple cultivation under lab conditions Various molecular techniques: - gene replacement - ARS plasmids - regulatable promoters - GFP reporter - REMI - transposon tagging - fast infection model

  6. Pant infection with Ustilago maydis 4 days

  7. Pant infection with Ustilago maydis 7 days

  8. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  9. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  10. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  11. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  12. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  13. Life cycle of Ustilago maydis Life cycle of Ustilago maydis

  14. a: pheromone signalling a: autocrine response b: filamentous growth plant signals? pathogenic development sexual development Nuclear fusion Spore formation b: Function of the a and b mating type loci a1b1 a2b2 a1b1 a2b2 a1a2b1b2

  15. Problems in mating populations sexual reproduction 50 % 50 %

  16. Problems in mating populations sexual reproduction 50 % 50 %

  17. Problems in mating populations sexual reproduction 50 % 50 %

  18. Problems in mating populations • sexual reproduction • some restrictions • may apply..... 50 % 50 %

  19. Problems in mating populations a1b1 a2b1 sexual reproduction a1b2 a2b2 25 % 25 %

  20. Problems in mating populations a1b1 a2b1 sexual reproduction self/nonself recognition systems Fungi: tetrapolar mating systems vegetative incompatibility Plants: pollen rejection Animals: MHC a1b2 a2b2 25 % 25 %

  21. sexual reproduction self/nonself recognition systems Fungi: tetrapolar mating systems vegetative incompatibility Plants: pollen rejection Animals: MHC Podospora anserina

  22. Problems in mating populations sexual reproduction self/nonself recognition systems Fungi: tetrapolar mating systems vegetative incompatibility Plants: pollen rejection Animals: MHC

  23. Problems in mating populations sexual reproduction self/nonself recognition systems Fungi: tetrapolar mating systems vegetative incompatibility Plants: pollen rejection Animals: MHC < 50 % < 50 %

  24. Two component self/nonself discrimination systems self non-self

  25. Two component self/nonself discrimination systems Mutation Consequences: plants: self-pollination fungi: cell death self-fertility Recognition as: non-self

  26. Two component self/nonself discrimination systems Mutation ? Recognition as: non-self

  27. The b mating type encodes the central regulator for pathogenic development

  28. The b mating type encodes the central regulator for pathogenic development • specificity is determined within the variable domains • variable domains are sufficient for dimerization • mutations within the variable domain alter dimerization AND specificity

  29. - sequencing: 18 strains from ATCC - screening of > 200 field isolates for novel RFLP - identification of one novel specificity 342

  30. b4b b2 b10 b2 b2 b10 b2

  31. b5 b8 b16 b8

  32. bW3 bE3 bW4 bE4

  33. Genetic manipulations: gene replacement resistence gene PCR-based system*: homologous recombination up to 100% *Schreier, P und Kämper, J: European Patent 1 279 741 A1

  34. PCR-knockout

  35. PCR-knockout a resistance cassette a SfiI: ggccnnnn nggcc

  36. PCR-knockout

  37. PCR-knockout

  38. rb2.1n rb2.2n

  39. lb hph rb

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