1. Announcements Next week – no lab Wednesday evening –Lab closes 5pm for Biol 203 exam –Lab will be open Tuesday 5-10 pm Biol 204 notes –www.usask.cawww.usask.ca –Biology –Class notes -- Biol 204 – kaminskyj –2004 lectures

2. Cytoplasmic migration in tip growth

3. Fungal cell walls Thin Fiber reinforced –Taxonomically relevant Plastic/extensible at tip Elastic/inextensible at maturity

4. Wall vesicle exocytosis at Saprolegnia hyphal tip

5. Hydrophobins Without hydrophobins, hyphae cannot break through the surface tension of water Hydrophobins are essential for mold sporulation and mushroom formation

6. Hydrophobin rodlets

7. Diverse features of Protista (P), Chromista (C), Eumycota (F) Walls in vegetative phase –Lacking (P) –Having (C, F)

8. Diverse features of Protista (P), Chromista (C), Eumycota (F) Walls in vegetative phase Mode of nutrition (always heterotrophic) –Ingestive (P) –Absorptive (C, F)

9. Protistan fungi – three taxa Myxomycota – “acellular” slime molds

10. Dictyosteliomycota – cellular slime molds

11. Plasmodiophoromycota – endoparasitic slime molds

12. Common features of Protistan fungi Nutrition by ingestion –Possible because vegetative stages do not have walls

13. Common features of Protistan fungi Nutrition by ingestion Lifestyle –Individual cells or colonies –Dictyosteliomycota -> Alternating individual and colonial stges

14. Common features of Protistan fungi Nutrition by ingestion Lifestyle –Individual cells or colonies –Alternating individual and colonial stges (Dictyosteliomycota) Sexual reproduction by spore formation –Only walled stage –Fibrils of peptidoglycan, cellulose, chitin

15. Myxomycete plasmodia

16. Physarum – nuclear behaviour

17. Myxomycete plasmodia can distinguish nonself and self

18. Physarum on heterogeneous substrate – food preference

19. Myxomycete spores in sporangia Physarum Stemonitis

20. Myxomycete spore walls contain peptidoglycan

22. Dictyosteliomycota – “cellular” slime molds

23. Dictyostelium Aggregation of amoebae uses chemical signals

24. Dictyostelium cell differentiation model system www2.mrc-lmb.cam.ac.uk

25. Dictyostelium spore walls contain cellulose niko.unl.edu

26. Plasmodiophoromycota – endoparasitic slime molds

27. Plasmodiophora in cabbage root hair

28. Plasmodiophora resting spores

29. Chromistan fungi – Oomycetes Saprobes, parasites/pathogens

30. Chromistan fungi – Oomycetes Saprobes, parasites/pathogens Obligate parasites – must have a living host to complete life cycle – aggressive Facultative parasites – parasitism is optional – less aggressive

31. Saprophytes and facultative parasites Asexual zoospores of Achlya biusexualis

32. Attachment, infection, colonization In nature, infective stage is motile flagellated zoospores – primary and secondary Heterokont flagella Zoospores find a food source by chemotaxis

33. Attachment, infection, colonization In nature, infective stage is motile flagellated zoospores – primary and secondary Heterokont flagella Zoospores locate a food source by chemotaxis

35. Attachment, infection, colonization In nature, infective stage is motile flagellated zoospores – primary and secondary Zoospores find food a source by chemotaxis Attachment is followed by shedding flagella Infection requires growth of a penetrating hypha

36. Saprophyte attachment and germination

37. 1° zoospore 1° cyst 2° zoospore 2° cyst germination and infection Morphology and parasitic aggressiveness

39. Parasitism The joy of slime

40. Oomycetes as plant pathogens Phytophthora infestans www.scisoc.org/feature/lateblit/ chapter1/epidemic.htm

41. Understanding late blight disease attributed to –excess water in the plants, –effects of the newly introduced steam locomotives Reverend M.J. Berkeley –Early 1850’s –Fungal pathogen

42. Phytophthora sporangia and zoospores www.scisoc.org/feature/lateblit/chapter1/epidemic.htm Drier soils -> direct germination Wet soils -> zoospores

43. Social consequences of Phytophthora infestans riots, eviction, emigration

44. Sexual spores of oomycetes Major significance in genetic recombination -> development of new pathotypes

45. Next time: it’s not easy being green