1 / 46

Filamentous fungi - a background

Filamentous fungi - a background. Lecture 2. Fungi are important in nature As decomposers As pathogens of plants, animals and humans, and in food spoilage As producers of secondary metabolites, e. g. penicillin In cheese, bread and wine making. Four phyla of fungi.

olympe
Download Presentation

Filamentous fungi - a background

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Filamentous fungi -a background Lecture 2

  2. Fungi are important in nature • As decomposers • As pathogens of plants, animals and humans, and in food spoilage • As producers of secondary metabolites, e. g. penicillin • In cheese, bread and wine making

  3. Four phyla of fungi • Chytridiomycota - no sexual spore • Zygomycota - zygospore • Ascomycota - ascospore • Basidiomycota - basidiospore

  4. Fungal reproduction • Asexually, by forming conidia • Sexually (three steps): • Plasmogami (dikaryon) • Karyogami (zygote forms) • Meiosis (sexual spore forms): • Zygospore • Ascospore • Basidiospore

  5. Chytridiomycota

  6. Zygomycota

  7. Gametangia fuse to produce a zygospore (Rhizopus stolonifer)

  8. Ascomycota

  9. Ascomycota -32 300 described species • Powdery mildews • Nectria cankers of trees (Nectria galligena) • Brown rot of stone fruit (Monilia fructicola) • Chestnut blight (Cryphonectria parasitica) • Dutch elm disease (Ophiostoma ulmi) • Most yeasts • Morels and truffles

  10. Characteristics of Ascomycota • Septate hyphae • Uninucleate or multinucleate hyphae • Heterothallic or homothallic • Sexual spore = ascospore, produced in sac called ascus. Usually 8 ascospores per ascus. • Ascocarp (fruiting body) can be of three different types: cleistothecium, perithecium or apothecium.

  11. Botrytis cinerea - a fungus -causes grey mold

  12. Powdery mildew of cucumber

  13. Cleistothecia of powdery mildew

  14. Anthracnose of cucurbits Anthracnose of melon caused by Colletotrichum orbiculare

  15. Eye spot disease of strawberryRamularia grevilleana, Mycosphaerella fragariae

  16. Canker, Nectria galligena

  17. Perithecium of Nectria galligena

  18. Penicillium and Aspergillus

  19. Examples of conidiophores of other imperfect fungi or Deuteromycetes

  20. Wilts caused by Fusarium oxysporum Darkened vascular tissue of cucumber caused by F. ox. f.sp. cucumerinum Wilt of field grown melon caused by F. ox. formae speciales melonis

  21. Life cycles of fusarium wilts

  22. Basidiomycota -22 300 described species • Mushrooms, stinkhorns, puffballs (Basidiomycetes) • Rusts (Teliomycetes) • Smuts (Ustomycetes) Basidiospores (sexual spore) made on club-like structure, called basidium.

  23. Basidiomycota

  24. Characteristics of Basidiomycota • Mycelium is septate • Septa are perforated - sometimes with dolipore (doughnut shaped)

  25. Characteristics of Basidiomycota • Mycelium passes two phases - monokaryotic and dikaryotic. • Two hyphal ends of the monokaryotic mycelium (of different mating types) fuse and produce the dikaryotic mycelium. • The dikaryotic mycelium can divide at the apical cell and form clamp connections.

  26. Basidiomycetes have clamp connections

  27. “Fairy ring” Fruiting bodies

  28. Fly agaric(flugsvamp)

  29. Hallocinogenic fungi • Mushrooms are part of many religious ceremonies in Mexico and Central America. Psilocybe mexicana is a fungus that contains the hallucinogenic drug psilocybin, which is related to LSD and mescaline. Psilocybe mexicana Psilocybin

  30. Rhizoctonia solani • It is a basidiomycete; teliomorph (Thanatephorus cucumeris) is rare. • Has very characteristic mycelium; typical of basidiomycete. • Differentiated into anastomosis groups (AG) (fusion of hyphae only occur if same anastomosis group)

  31. The disease cycle of Rhizoctonia solani

  32. Characteristics of the rusts (Teliomycetes) • Sori, in which uredospores are formed. • Were thought to be obligate parasites, but some can be grown in the laboratory. • Can live on one host - autoecious, or two hosts - heteroecious. • New races appear constantly; difficult to control. • Spore forms: basidiospore (n), aeciospore (n+n), uredospore (n+n) and teliospore (2n).

  33. Rusts

  34. Wheat stem rust (Puccinia graminis)

  35. Stem rust of wheat

  36. Rust of roen (rönn)

  37. Rust of raspberry

  38. Disease cycle of cedar-apple rust

  39. Rust of rose

  40. Uredospores of rose rust

  41. Teleutospores, rose rust

  42. Corn smut

  43. Corn smut

  44. Teliospores (2N) (sexual spores) Infection Meiosis Mating Budding cells (1N) Filamentous Dikaryon (N+N) The life cycle of smut fungi Chlamydospores (1N) (asexual spores)

More Related