Plants Lesson 7 Flashcards
Are fungi diploid or haploid?
Haploid for most of their lives. Expect for when they do sexual reproduction.
Who are the fungi closest relative?
Us, rather than plants.
Examples of fungi & their products?
Bread (the yeast)
Pizza crust (yeast)
Mushrooms
Black bread mold
Athlete’s foot (closely related with …)
Ringworm (both are very contagious and will keep spreading if not treated).
Beer (yeast)
Wine (yeast)
Characteristics of Fungi
Heterotrophs (big difference from plants). Eukaryotic. Main body is haploid (so are mosses). Multicellular or unicellular. Cell wall made of chitin (Polysaccharide and in Arthropod shells, cephalopod beaks, fish
scales). External digestion of food. ~120,000 species described.
Yeast
Unicellular without flagella
Multicellular fungi
The basic unit of it is hypha. They have a network underneath called mycelium.
Mycelium
A mass of hyphae. The grow in the structures it eats, it digests it.
Two kinds of hyphae?
Septate: have septums which are divisions in this. There are holes in it to allow material to flow through it.
Coenocytic: No septum, the nuclei just float around the cell.
2 specialized types of hyphae?
- A predator. It makes a snare and catches the worm (nematode).
- Fungal hypha. It grows into a plant cells and wrapped around fingers of nymph. Good thing for both parties in the relationships.
Growth
Straight forward. Digest outside of it, then bring in in.
Fungi lifecycle (asexual reproduction)?`
Starts at mycelium, then produces spores (that have a protected coat and grows in a fungus). Then they germinate. Then back to mycelium.
Fungi lifecycle (sexual reproduction)?
Starts with mycelium, then plasmogamy (the fusion of cytoplasm), then the heterokarytoic stage (it has two haploid nuclei from both parties). Then karyogamy (fusion of nuclei) and this creates a diploid nucleus. Then a zygote goes through meiosis makes 4 spores. These spores then germinate then it’s back to mycelium. It has to unite DNA with another thing for this to occur.
Spores in fungi?
Haploid (1n). Most <20 μm (rarely >100 μm). Each contains nucleus, dehydrated cytoplasm & protective coat. Some can remain dormant for long periods to wait out the environment.
Produced by:
Mitosis: Asexual reproduction
Meiosis: Sexual reproduction
Spore in fungi purpose?
Move to new food source. Avoid or “wait out” adverse environment because of protected coat. New genetic combination (sexual repro.).
Is there male and females in fungi sexual reproduction?
No, because they are the same size. They are + and -. Opposites are needed to unite.
Fungi that reproduce asexually?
- Spores in sporangia (sticking out of fungi).
- Conidia in conidiophores (penicillium)
- Budding (Baker’s yeast)
Opisthokonts
Includes animals (and their close protistan relatives), nucleariids, chytrids, other fungi. The last two are fungi. They all came from a unicellular flagellated ancestor 1 bya.
5 Phyla of Fungi (in order they split)
Chytids, zygomyctes, glomeromyctes, ascomycetes, basidiomyctes.
Phylum Chytridiomycota
1,000 species. Single cells or colonies with hyphae.
Flagellated spore (“zoospore”) that’s haploid, asexually produced and “zoo” because swims. Aquatic, soil (wet areas). Decomposers, parasites, commensals (digestive tract of sheep & cattle).
Spore release in Chytrid
Has converted the entire contents of its flasked-shaped body, or thallus, into flagellated asexual
zoospores. Inside of it is a lot of copies of itself about to release them.
Amphibian decline worldwide
1/3 amphibian populations serious decline. One major cause: chrytrid. Infects skin. Caused by fungi to make them not able to reproduce. Get in skin and digest the animal from the inside.
Phylum Zygomycota
1,000 species. Coenocytic (non-septate) hyphae. Decomposers, parasites, commensals (live happy with the host. Ie. Black bread mold.
Entomophthora
Spore infects, fungus grows. Death at dusk. Mind control: summiting, head glued. Kills insects by covered with spores then reproduces itself. Then it gets on the inside and infects the brain.
Pilobolus
Sporangium on a stalk. It sits in sun and when it get too hot it bursts and then spores travel to other plants.
Zygomycota life cycle
A spore, then mycelium, then asexual reproduction on the sporangia, then back to spore. For sexual reproduction the spore disperses and germinates. Then the + and - mating types look foreach other in the bread and meet up. It’s then a gametangia with haploid nuclei with formed walls. Then plasmogamy happens and produces a young zygosporangium, then the nuclei pair off and karyogmy happen to produce many diploid nuclei. Then it goes through meiosis, to sporangium, and back to spores.
Phylum Glomeromycota
160 species. Non-septate hyphae. Asexual only (!!). Obligate symbionts: mycorrhizae (fungi roots). Small but important. Associated with plants, have to do it to live. Live on plants roots. Goes around cell walls and doesn’t break the membrane, just wraps around it and exchange minerals and stuff. Helps the plant bring in water and minerals.
Phylum Basidiomycota
30,000 species. Decomposers & ectomycorrhizal. Long-lived dikaryotic mycelium. Multicellular (& some yeasts). Septate mycelia. Multicellular sexual reproduction. Fruiting body = “basidiocarp” (Mushroom, puffball, bracket). Multicellular asexual repro.: conidia formed by hyphae. Sits on outside of roots of plants but not on inside.
Bracket (shelf fungi)
Digest dead woody plants
Puffball
Spores on inside. Step on it and spores are released.
Stinkhorns
Smell bad. Has nets that makes smell distribution better.
Fairy ring
Where reproduction occurs. Started in the middle and grows in ground and eats ground.
Basidiomycete spores on gills
4 spores ends like a chair.
Basidium lifecycle
Basidiospores then dispersal and germination. Haploid mycelia with the - and + mating types. Then plasmogamy. Results in dikaryotic mycelium (2 set of nuclei). Gils lined with basidia, basidiocarp (n+n). Then each cell through fertilization results in diploid (karyogamy). Causing diploid nuclei. Then it goes through meiosis. Then basidium containing four haploid nuclei.
Leaf-cutter ants
Fungus farmers. They feed the leaves to the fungi.
Phylum Ascomycota
“Sac” fungi. 65,000 species. Multicellular or unicellular (yeast). Multicellular asexual repro.: conidia. Multicellular sexual reproduction. Fruiting body = “ascocarp” (cup fungi, morels, truffles)
Truffles (ascomycota)
Ectomycorrhizae with trees. Sell for a lot of money. Grown under grown with specific species of tree.
Penicillium roqueforti
Blue cheese are fungi. The blue part made from blue spores.
Penicillium
Source of penicillin. Isolation of antibiotic penicillin by
Alexander Fleming (1928); clinical treatment 1941.
Asexual reproduction in Ascomycota
Unicellular: Yeast by budding. It leaves scar every time it buds, so it can only bud so many times.
Multicellular: Formation of conidia (spores) on conidiophores.
Sexual Reproduction: Asci
In multicellular ascomycota. 8 spores in each ascus (a sac). With 8 nuclei in each (meiosis followed by mitosis). They have ascocarp in it, which is a fruiting body, this is where meiosis and mitosis occurs.
Ascomycota lifecycle
For asexual reproduction, the mycelia then germination, then the conidiophore puts coat around it and send of the haploid spores (conidia), then they germinate then the hypha goes back to mycelia. For sexual reproduction, the mycelium (+) combine with the conidia (-). Then they go through plasmogamy occurs in cup, resulting in ascus (eukaryotic) and eukaryotic hyphae. Then it goes through karyogamy, resulting in a diploid nucleus (zygote). Then it goes through meiosis. Then the four haploid nuclei goes through mitosis resulting in 8 ascocpores. They then release into the environment, to start 8 new fungi.
Ergot Alkaloids
Several kinds. Restrict blood flow: gangrenous ergotism. St. Anthony’s Fire *extreme feels of heat). Salem (Massachusetts) Witch Trials (???). Others: medical uses. LSD: Lysergic acid diethylamide (ergot alkaloid derivative) and Synthesized by Albert Hofmann, 1938, “LSD-25,” Sandoz Pharmaceuticals, ingested 1943, took bike ride (lived to age 102).
Ergot on rye
Causes seeds of rye to turn into ergot. Grows on rye and can b e eaten by some people.
Botrytis
Causes strawberries to rot and it’s hard to control. Same with grapes and can make wines from it.
Budding/brewer’s/baker’s yeast
Gives off CO2 which makes bread rise.
Aspergillus fumigatus
Inhabits soils worldwide (esp. compost). Wide thermal tolerance. Conidia exposure constant & unavoidable.
We inhale >100 conidia daily. Concentration in the air
indoors or outdoors is 1–100 conidia/m3. Spores small so can reach deep into respiratory pathways. Normally cleared from respiratory pathways. Invasive aspergillosis: disease in immunocompromised
individuals (chemotherapy, organ transplant). Difficult to treat.
Candida albicans
Normal part of human gut flora. Also on skin & in oral cavity, urogenital tract. Transmitted from mother to child during childbirth. 2 morphlogical forms: yeast (looks like a single cell) & hyphal (stretch of fungi bodies and the harmful part). Subcutaneous, oral thrush, heat tissue.
Fungi: the future
Evolution: Phylogenetic relationships. Relation to animals. Multicellularity: how many times arose?Diploidy vs. haploidy. No sex in Glomeromycota-how?
Medicine: Aspergillosis, … and Evolution & genetics of
resistance.
