III. Fungal Reproduction

A. Spores B. Sexual Reproduction C. Asexual Reproduction

Spores

• Haploid Reproductive Cells

• Produced by hyphae or fruiting body

• Sexual or asexual

• Non- motile, needs transport mechanism (water, wind, insects, released as puff of air)

• Land in moist place with food (spores can last a while until landing) -> germinate -> new mycelium 

Sexual Reproduction

• Mating types instead of male/female

• Mating type genes encode pheromones and pheromone receptors

• # of mating types depends on # of alleles (there can be anywhere from 2 to 1000 alleles on the loci of a hyphae)

Steps for reproduction

1. Hyphae release and detect pheromone

2. Hyphae extend toward source of pheromone

3. Plasmogamy: Cytoplasmic Fusion, If Different mating types, meet and fuse cytoplasm, but not nuclei forming Gametangia (nutrient resources shared)

4. Heterokaryon: Fused mycelium with different nuclei n+n, forms Zygosporangium

Growth after plasmogamy 

5. Cells grow and divide, nuclei divide without fusing

6. Later Karyogamy (nuclear fusion) occurs -> diploid zygote, introduces genetic variation

7. Meiosis restores haploid condition, Results in genetically unique spores

8. Spores continue cycle

Asexual Reproduction

• 20k species are asexual 

• Two main types

  • Filamentous fungi -> spores via mitosis 

  • Single Celled Yeast -> Cell Division/ Budding