Kingdom Fungi: A Vital Ecosystem Component

1. Luke 13:20, 21 20 And again he said, Whereunto shall I liken the kingdom of God? 21 It is like leaven, which a woman took and hid in three measures of meal, till the whole was leavened.

2. Kingdom Fungi Timothy G. Standish, Ph. D.

3. Fungi Plantae Animalia . . . . . . . . . . . . . . . Protista . . . . . . . . . Monera Fungi In The Scheme Of Life

4. Why Fungi Are Important • Important as decomposers • Spoil food • Produce antibiotics • Produce substances used as drugs (“magic mushrooms, ethanol etc.) • Cause disease in plants • Cause disease in animals (Athletes foot, yeast infections etc.) • Poison humans and animals (afflotoxin, toadstools etc.) • Important food source • Produce important fuels and industrial chemicals (ie ethanol)

5. Fungal Characteristics • Eukaryotic • Multicellular • Heterotrophic • Absorb nutrients - may be saprobes (absorb from dead material), parasites, or mutualistic symbionts (with algae make lichen). • Secrete powerful hydrolytic enzymes • Cell walls contain chitin, an amino sugar polysaccharide also found in arthropod exoskeletons • Lack flagella

6. The Body Plan of Fungi • Vegetative body consists of mycelia made up of networks of hyphae • Hyphae - Long treads of cells designed to maximize surface area and also transport nutrients • Fungus-like protists: • Lack this body structure • Lack cell walls of chitin

7. Hyphae • Hyphae are designed to increase the surface area of fungi and thus facilitate absorption • May grow fast, up to 1 km per day, as they spread throughout a food source • Haustoria - Specialized structures budding off hyphae of parasitic fungi which penetrate host cells to absorb nutrients • May be coenocytic, having no septa between cells, or septa may be present with pores through which cytoplasm can flow moving nutrients through out the fungus

8. Pores Septa Hyphae Coenocytic

9. Classification of Fungi • Lichens represent a mutualistic (?) relationship between fungi and algae • Classification of fungi is based on life cycle, specifically reproductive structures • Three major phyla, all end with mycota: • Zygomycota - Zyg = yolk - Zygote forming fungi, the black bread molds • Ascomycota - Asc = sack - Truffles, yeasts, many plant pathogens • Basidiomycota - Basidium = club - Mushrooms

10. Zygomycota • Zygomycota - Zyg = yolk - Zygote forming fungi, the black bread molds etc. • About 600 described species • Mostly terrestrial • Mycrorrhizae - Zygomycetes that form a mutualistic relationship with tree roots increasing root surface area and thus water and mineral uptake while benefiting from sugar sent down from leaves • Hyphae are coenocytic, septa are only found in reproductive cells

11. Ascomycota • Ascomycota - Asc = sack - Truffles, yeasts, many plant pathogens • Over 60,000 described species • Some associate with algae to form lichen • Some, including truffles, form mycrorrhizae • Some live on mesophyll cells producing toxins to protect leaves from insects • Hyphae have septa • Important marine saprobes • Important tool for studying genetic recombination

12. Basidiomycota • Basidiomycota - Basidium = club - Mushrooms • About 25,000 described species • Important decomposers of wood because of their ability to hydrolyze lignin • Some form mycrorrhizae including half the mushroom formers • Few are strictly plant parasites, but of those that are, the smuts and rusts are especially bad • Form long lived dikaryotic mycelia • Asexual reproduction is uncommon

13. Lichens • Lichens - Mutualism (?) between fungi and algae • Over 25,000 species described • Ascomycetes are usually the fungal component although some basidiomycetes lichens are known • Filaments green algae usually make up the algal component although some use cyanobacteria • Scientific names are the names of the fungus • Hyphae account for most mass • Fungus provides moist environment protection and minerals • Algae provide fixed carbon • Cyanobacteria may provide fixed nitrogen

14. Deuteromycota Imperfect Fungi • Deuteromycota - Deuter = second - The imperfect fungi • These organisms exhibit all the characteristics of fungi, but have not been observed reproducing sexually • As classification is based on sexual reproduction, Deutoeromycetes cannot be definitively placed in any phylum

15. Chytridiomycota:Protists or Fungi? • Chytrids have flagellated zoospores and thus do not fit perfectly with the fungi • Other characteristics are very fungus-like: • Cell walls with chitin • Unicellular or coenocytic hyphae • Enzymes common to fungi which are lacked by fungus-like protists

16. The End