The document provides information about the characteristics of fungi. It discusses that fungi can have unicellular, filamentous, or multicellular body forms. It also describes that fungi are heterotrophic and can be saprophytes, symbionts, or parasites. Key characteristics of fungi include their hyphal growth, reproduction through spores, and roles in decomposition, symbiosis, and as pathogens. The major phyla of fungi are also introduced based on characteristics of their sexual structures and spore motility.
38. Zygomycota (Rhizopus) the Common Molds -are primarily decomposers -asexual spores may be produced in sporangia -sexual reproduction occurs between + and – strains forming a 2n zygote; a zygospore develops and may lie dormant for a long period of time; meiosis occurs just before germination -only the zygote is diploid; all hyphae and asexual spores are haploid
39. Zygomycota – common molds The fungal mass of hyphae, known as the MYCELIUM penetrates the bread and produces the fruiting bodies on top of the stalks Mycelia = a mass of hyphae or filaments
40. Rhizoids = root-like hyphae The zhizoids meet underground and mating occurs between hyphae of different molds (SEXUAL REPRODUCTION)
50. Truffles are round, warty, fungi that are irregular in shape. They vary from the size of a walnut to that of a man's fist. Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods, often commanding as much as $250 to $450 per pound. Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. The female pig becomes excited when she sniffs a chemical that is similar to the male swine sex attractant. The use of dogs to find truffles is also and option.
55. Mushroom Life Cycle Nuclear fusion in basidium Meiosis Hyphal fusion of haploid mycelia haploid mycelium young basidia - the only diploid cells mycelium and fruiting body are dikaryotic N 2N N+N
56. Bracket Fungi Puff Balls Mushrooms Jelly Fungi Basidiomycete Fungi that all produce Basiospores
57. Other Basidiomycetes Rusts and Smuts Rust infecting wheat leaves Rust infecting a Leaf Whitrot Smut digesting old wood
61. Deuteromycota (Imperfect Fungi) -Regarded as imperfect because they exhibit no sexual stage has been observed in their life cycle -Members are not closely related and are not necessarily similar in structure or appearance; do not share a common ancestry, polyphyletic = coming from many ancestors – hmm weird
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63. Water Molds -- Oomycota The water molds are better known as the MILDEWS. Fish tank fuzz is an example. Protist-like mold because share common characteristics with plant-like protists, such as the cell wall
66. Irish Potato Famine of 19 th Century Devastated potato crops, causing devastating starvation in Ireland
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68. Phylum Ex’s Characteristics Asexual Sexual Oomycota Mildew Spud blight Cellulose cell walls, 2N hyphae Flagellated oospores from sporangia Gametes fuse in gametangia creating oospores Zygomycota Rhizopus a dung fungus Chitin cell walls Coenocytic = hyphae lack crosswalls Unflagel. spores drop from sporangia Gametangia fuse to create zygospore Ascomycota Yeast, morels, truffles Conidia on conidophores Hyphae + & - fuse to create ascospores in ascus
69. Basidiomycota Mushrooms Puffballs, rusts, smuts Cross walls in hyphae Asexual by way of Conidophores which produce conidiospores Sexual when hyphae fuse in BASIDIA to produce basidiospores Fungi Imperfecti Deuteromycota Penicillium, Athlete’s Foot fungus, Tomato Blight Similar To Basidio and Zygomy Asexual by conidia which produce conidophores Sexual repro Not known
70. Cross Walls of Hyphae Coenocytic hyphae where the nucleis of each cell is embedded in the cytoplasm without a cell wall Eg. Zygomycota, Oomycota Hyphae with cross walls Eg. Basidiomycota, Ascomycota coenocytic having multiple nuclei embedded in cytoplasm without cross walls; nonseptate
71. Lichens are mutualistic symbiotic organisms. They have an ____________ fungus and a _________ or cyanobacterial portion. There are three lichen growth forms which are predominant in nature: _____________________ _____________________________ Lichens
74. Soredia are the asexual reproductive part of lichens, containing both symbionts. Rhizines may be present to anchor the lichen. Notice the distinctive algal layer and the fungal layer present in the above illustration.
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Editor's Notes
Most enzyme release (and absorption) at tips Proteins and other materials synthesized by the entire mycelium are channeled by cytoplasmic streaming to the tips of the extending hyphae.
Chitin is the same material used by Arthropods (Insects, crabs, etc.) in their exoskeletonsa Nuclei of fungi are hard to see without stains
Half of the mushroom-forming fungi (basidiomycota) form mycorrhizas with trees Some people think that the spongy tissue in roots evolved as a place where fungi could invade to form early links with plants that helped them survive the harsh life on early earth
4 of the regions where mycorrhizas are found are circled. These are “ecto” because the hyphae remain outside the root cells (though they extend inside the root)
Thallus is a plant-like body that doesn’t have roots, stems or leaves Thallus doesn’t look like either partner Dual nature of thalli was not fully understood until early 1900’s Fungus gives the name to the lichen (by agreement) Fungus usually, but not always, an Ascomycote (in 8+ independent orders) Algae green. If bluegreen bacteria present, lichens fix nitrogen (turn atmospheric nitrogen into amino acid nitrogen in proteins)
The nature of lichen symbiosis is may also be described as mutual exploitation instead of mutual benefit. Lichens live in environments where neither fungi nor algae could live alone. While the fungi do not not grow alone in the wild, some (but not all) lichen algae occur as free-living organisms. If cultured separately, the fungi do not produce lichen compounds and the algae do not “leak” carbohydrate from their cells. In some lichens, the fungus invades algal cells with haustoria and kills some of them, but not as fast as the algae replenish its numbers by reproduction. Lobaria oregana prefers old-growth conifer canopies in forests with clean air.
Fungi reproduce by releasing spores that are produced either sexually or asexually. The output of spores from one reproductive structure is enormous, with the number reaching into the trillions. Dispersed widely by wind or water, spores germinate to produce mycelia if they land in a moist place where there is food.
Fungal mycelia can be huge, but they usually escape notice because they are subterranean. One giant individual of Armillaria ostoyae in Oregon is 3.4 miles in diameter and covers 2,200 acres of forest, It is at least 2,400 years old, and weighs hundreds of tons. (Actually noone has seen this of this extent – but cultures have been taken from soil over that area and all isolates have been found to be the same individual) Ten cubic centimeters of rich organic soil may have fungal hyphae with a surface area of over 300 cm 2
Molecular studies indicate that animals, not plants, are the closest relatives of fungi. Both Animals and Fungi are related most closely to a group of Protists known as the choanoflagellates (collar flagellates) Kingdom began in ocean during Precambrian (Late Proterozoic era) More than 100,000 species of fungi are known and mycologists estimate that there are actually about 1.5 million species worldwide.
The phyla of fungi are determined by 1. motility of spores 2. nature of sexual stage Fungi moved onto land with the plants in the Early Paleozoic Much of the evolution of fungi was in conjunction with the evolution of plants and plant parts For example, when roots evolved, fungi were there and helped (mycorrhizas) When wood evolved, fungi evolved to take advantage of it Other evolutionary changes related to animals
Classified in CMR as true fungi (because of their molecular relationships) Remainder of the phyla are almost exclusively terrestrial (a few molds on wet plant material)
Most of the 600 zygomycote, or zygote fungi , are terrestrial, living in soil or on decaying plant and animal material. Asexual reproduction in sporangia One zygomycote group form mycorrhizas , mutualistic associations with the roots of plants.
Mycologists have described over 60,000 species of ascomycetes, or sac fungi . Ascomycota tend to grow from spore to spore in one year and relate well to living plant tissues There is diverse form in the growth and fruiting structures – yeasts to morels, many intermediate (and small) Asexual reproduction by conidia (externally produced, not in sporangia) Half of the Ascomycota form lichens (evolved 8 or more times in different orders) but not all lichens are Ascomycotes
This begins the first of several photographic reviews of fungal diversity. Enjoy the pictures and try and get a feeling of some of the different forms these fungi take and their roles in the environment.
Bread and wine yeast, the budding yeast, Saccharomyces Easily cultured. For a time, this was the most important organism for studying the molecular genetics of eukaryotes Thus, Saccharomyces is arguably the most important organism known to humans Candida causes diseases of humans, usually experiencing chemical imbalance or immune problems
Asexual spores conidia Ecologically important on wood as decomposers and parasites Half the mushrooms form mycorrhizas
A mold is a rapidly growing, asexually reproducing fungus. The mycelia of these fungi grow as saprobes or parasites on a variety of substrates. Also used in foods (Blue cheese, Tempeh) and in industrial production of drugs Early in life, a mold, a term that applies properly only to the asexual stage, produces asexual spores. Later, the same fungus may reproduce sexually, producing zygosporangia, ascocarps, or basidiocarps Some molds go through a “fake sex” process
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