Plant Bio Day 7

Intro to Fungi

Characteristics of Fungi

* Heterotrophs 
* Eukaryotic
* Multicellular or Unicellular
* Cell wall: chitin
* External digestion of food

Main body of Fungi is:

Haploid

Unicellular Fungi

Yeast

What part of fungi is reproductive

Top

2 kinds of hyphae

Septate & Coenocytic

Specialized hyphae

* Hyphae adapted to trap / kill prey
* Haustoria

4 main events of fungi life cycle

1. Plasmogamy
2. Karyogamy
3. Meiosis
4. Germination

Spores in Fungi

* Haploid (1n)
* Small
* Each contain nucleus, dehydrated cytoplasm & protective coat
* Some remain dormant for long periods

Spores produced by

* Mitosis (Asexual)
* Meiosis (Sexual)

Spores functions

* Move to new food source
* Avoid / wait out adverse environment
* New genetic combination (sexual reproduction)

How does Asexual reproduction in fungi work

1. Spores in sporangia

* Black bread mold


2. Conidia (spores) in conidiophores

* Penicillium


3. Budding

* Yeast

5 phyla of Fungi

* Chytrids
* Zygomycetes
* Glomeromycetes
* Ascomycetes
* Basidiomycetes

Phylum Chytridiomycota

* 1K species
* Single cells or colonies w hyphae
* Flagellated spore
* Aquatic, soil
* Decomposers, parasites, commensals (digestive tract of sheep & cattle)

Flagellated Spore (zoospore)

Haploid, Asexually produced

Zoo = swims

Spore release in Chytrid

Converts entire contents of flasked shaped body (thallus) into flagellated asexual zoospores

Amphibian Decline Worldwide

* ⅓ amphibian pop serious decline
* One major cause: chrytrid. Infects skin

Phylum Zygomycota

* 1000 species
* Coenocytic (non-seperate) hyphae
* Decomposers, parasites, commensals
* Lives in cow shit

Insect Destroyer

* Spore infects, fungus grows
* Death at dusk
* Mind control: summiting, head glued

Phylum Glomeromycota

* 160 species
* Arbuscules
* Non-septate hyphae
* ASEXUAL ONLY
* Obligate symbionts: mycorrhizae

Site of nutrients exchange between plant & fungi

Arbuscules

Phylum Basidiomycota

* 30K species
* Decomposers & ectomycorrhizal
* Long-lived dikaryotic mycelium
* Multicelluar (& some yeasts)
* Septate mycelia
* Asexual / sexual
* Decomposers

Multicellular sexual reproduction (Basidiomycota)

* Fruiting body = basidiocarp (mushroom, puffball, bracket)

Multicellular Asexual Reproduction (Basidiomycota)

conidia formed by hyphae

Phylum Ascomycota

* “Sac fungi”
* 65K species
* Multicellular or unicellular (yeast)
* Asexual / sexual

Multicellular asexual reproduction (Ascomycota)

Conidia

Multicellular Sexual Reproduction

Fruiting body = ascocarp

Truffles

* Ectomycorrhizae with trees

Penecillium examples

* Blue cheese
* Source of penicillin (antibiotic)

Unicellular Asexual Reproduction in Ascomycota

Yeast → Budding

Multicellular Asexual Reproduction in Ascomycota

Formation of Conidia (spores) on conidiophores

Sexual Reproduction: Multicellular Ascomycota

Formation of Ascospores in Ascus

\# of spores in each ascus

8

Ergot Alkaloids

* Several kinds
* Restrict blood flow: gangrenous ergotism
* St. Anthony’s Fire
* Salem witch trials
* Medical uses
* LSD

Fungi that hurts lungs (unavoidable)

Aspergillus fumigatus

Distinguishing Ft. of Chytridiomycota

Flagellated spores

Distinguishing Ft. of Zygomycota

Resistant zygosporangium as sexual stage

Distinguishing Ft. of Glomeromycota

Form arbuscular mycorrhizae with plants

Distinguishing Ft. of Ascomycota

Sexual spores (ascospores) borne internally in sacs

Produce vast # of asexual spores (conidia)

Distinguishing Ft. of Basidiomycota

Elaborate fruiting body containing many basidia that produce sexual spores

Plasmogamy

Fusion of cytoplasm

Karyogamy

Fusion of nuclei

Heterokayotic stage

unfused from different parents (n+n)

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basidiocarp life cycle: 2 mating types