Fungal Diversity

Fungal Reproduction alternates between - sexual and asexual

Fungi produce spores - spores carried by wind/water and germinate to form new mycelia

Fungi Asexual Reproduction - molds produce haploid spores by mitosis

How do yeasts reproduce - asexually without spores, simple mitosis or pinching of bud cells

Benefits and Costs of Asexual Reproduction - Benefit: can be done independently Cost: no genetic variation

Benefits and Costs of Sexual Reproduction - Benefit: genetic variation Cost: need another organism

Fungi Sexual Reproduction - fusion of hyphae from different mating types, pheromones communicate mating type

Fungal nuclei and spores - usually haploid, some nuclei are transient diploid

Plasmogamy - Step 1 on fungal sexual reproduction, union of cytoplasm from two parent mycelia, nuclei fusion delayed

Heterokaryon - mycelium with multiple coexisting genetically different nuclei

Dikaryotic - 2 nuclei in a cell, one from each parent

Karyogamy - Step 2 of fungal sexual reproduction, fusion of nuclei after heterokaryotic stage

Karyogamy produces - a zygote that undergoes meiosis to make haploid spores

Fungal Phyla -

1. chytrids
2. zoopagomycetes
3.mucoromycetes
4. ascomycetes
5. basidiomycetes

How were phyla established - according to mode of sexual reproduction and molecular data

Sixth basal fungi group - reproduce without a sexual cycle

Cryptomycetes - unicellular basal fungi, flagellated spores found in soils, marine, and freshwater

Microsporidians - unicellular basal fungi, intracellular parasites, reduced mitochondria with small genomes, spores infect cells via polar tubule

Polar tubule - harpoon like organelle that microsporidians use to infect cells

Chytridiomycota - true fungal phyla, simplest most primitive, have zoospores, aquatic habitat, similar to protists

Zoospores - flagellated spores found in chytrdiomycota

Zoopagomycota - coenocytic hyphae, asexual reproduction with non flagellated spores, sexual reproduction with zygosporangium

zygosporangium - durable structure that houses and protects zygote

Asexual Reproduction Zoopagomycota/Mucuromycota - plasmogamy --> karyogamy --> meiosis results in sporangium disperses spores that make hyphae that make up coenocytic mycelia

Zoopagomycota/Mucuromycota Plasmogamy - mating type mycelia meet and fuse producing zygosporangium, whole mycelium fuses

Zoopagomycota/Mucuromycota Karyogamy - nuclei fuse and undergo meiosis to produce unique non flagellated spores, (non flagellated adaption to life on land), (6 nuclei --> 12 spores)

Zygosporangia - metabolically inactive and resistant to freezing and drying, hyphae extend out

zygosporangium when conditions are good - undergo meiosis and germinates into a sporangium

Sporangium - develop at the tips of upright hyphae and release spores

Ascomycota - true phyla, 1st group with septate hyphae with pores, vary in size and complexity (uni or multicellular), make ascocarps during sexual stage, sac fungi

Ascomycete Asexual reproduction - through asexual spores called conidia, produced at tips of conidiophores (specialized hyphae)

Ascomycete Plasmogamy - only tips of mycelium fuse, forms dikaryotic cells, asci forms tip of dikaryotic hyphae,

Ascomycete Karyogamy - karyogamy and meiosis occurs within the asci inside of ascocarp that makes ascospores (2 nuclei --> 8 spores)

Zoopagomycota and Mucuromycota cell type - coenocytic

Ascumycota and Basidiomycota cell type - septate results in distinct dikaryotic stage, diverse fruiting body structures

Ascomycete cell life - diploid --> haploid --> dikaryotic --> haploid

Basiciomycota - true phyla, basidium, mushrooms, long lived dikaryotic mycelium produces basidiocarps (fruting structures)

Basidium - cell in basiciomycota in which karyogamy and meiosis occur, club shaped, stops after 4 haploid spores are made

Basiciomycota Sexual Reproduction - mycelia produce basidiocarps (fruiting bodies), not fused nuclei but 2 haploid nuclei (n+n)

Sapotrophic Fungi - breaks down and digests decayed organic matter

Parasitic fungi - absorb nutrients from living hosts, may take over host motor functions, 30% of fungi mostly in plants, destroy fruit harvests

Mutualistic Fungi - absorb nutrients from hosts, actions to benefit host

Decomposer Fungi - decompose organic material such as cellulose and lignin, because they are absorptive heterotrophs.

Fungi Plant Mutualisms other than mycorrhizae - Plants have endophytes (fungi or bacteria) that live inside leaves, most are ascomycetes, nutrient transfer to fight pathogens, tolerate heat, drought, heavy metals

Fungi Animal Mutualisms - fungi help break down plant material in animal guts, ex. ants provide leaves and ants eat hyphae tips

Lichens - symbiotic associations between photosyntynthetic organisms and fungi, photosynthetic cells are held in a mass of fungal hyphae

Lichens Reproduction - Asexually with fragmentation or formation of soredia, the fungal partner can reproduce sexually

Soredia - small clusters of hyphae with embedded algae

Cytridiomycocis - disease from chytrid species that has zoospores that infect amphibian host's skin, amphibian can't do gas/water exchange

Fungi Practical Uses - cheese, alc, soy sauce, penicillin

Septa - have pores that allow organelles and cytoplasm to pass

mycelium - multiple hyphae, underground, wide area

hypha - septa never present

coenocytic hyphae - organized into reproductive fruiting structure

basidiocarp - fruiting structure