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Intro to fungi

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Intro to fungi

  1. 1. Kingdom Fungi
  2. 2. The Characteristics of Fungi <ul><li>Body form </li></ul><ul><ul><li>unicellular </li></ul></ul><ul><ul><li>filamentous (tube-like strands called hypha (singular) or hyphae (plural) </li></ul></ul><ul><ul><li>mycelium = aggregate of hyphae </li></ul></ul><ul><ul><li>sclerotium = hardened mass of mycelium that generally serves as an overwintering stage. </li></ul></ul><ul><ul><li>multicellular, such as mycelial cords, rhizomorphs, and fruit bodies (mushrooms) </li></ul></ul>
  3. 3. mycelium fruiting bodies both are composed of hyphae
  4. 4. The Characteristics of Fungi <ul><li>Heterotrophy - 'other food' </li></ul><ul><ul><li>Saprophytes or saprobes - feed on dead tissues or organic waste (decomposers) </li></ul></ul><ul><ul><li>Symbionts - mutually beneficial relationship between a fungus and another organism </li></ul></ul><ul><ul><li>Parasites - feeding on living tissue of a host.  </li></ul></ul><ul><ul><ul><li>Parasites that cause disease are called pathogens. </li></ul></ul></ul>
  5. 5. Heterotrophic by Absorption <ul><li>Fungi get carbon from organic sources </li></ul><ul><li>Hyphal tips release enzymes </li></ul><ul><li>Enzymatic breakdown of substrate </li></ul><ul><li>Products diffuse back into hyphae </li></ul>Enzymes Enzymatic breakdown Products Product diffuses back into hypha and is used Nucleus hangs back and “directs”
  6. 6. Hyphae <ul><li>Tubular </li></ul><ul><li>Hard wall of chitin </li></ul><ul><li>Crosswalls may form compartments ( ± cells) </li></ul><ul><li>Multinucleate </li></ul><ul><li>Grow at tips </li></ul>
  7. 7. Hyphal growth <ul><li>Hyphae grow from their tips </li></ul><ul><li>Mycelium = extensive, feeding web of hyphae </li></ul><ul><li>Mycelia are the ecologically active bodies of fungi </li></ul>This wall is rigid Only the tip wall is plastic and stretches
  8. 8. Modifications of hyphae
  9. 9. Fungi as Saprobes and Decomposers
  10. 10. Fungi as Symbionts (Mutualism)
  11. 11. Mycorrhizae <ul><li>“ Fungus roots” </li></ul><ul><li>Mutualism between: </li></ul><ul><ul><li>Fungus (nutrient & water uptake for plant) </li></ul></ul><ul><ul><li>Plant (carbohydrate for fungus) </li></ul></ul><ul><li>Several kinds </li></ul><ul><ul><li>Zygomycota – hyphae invade root cells </li></ul></ul><ul><ul><li>Ascomycota & Basidiomycota – hyphae invade root but don’t penetrate cells </li></ul></ul><ul><li>Extremely important ecological role of fungi! </li></ul>
  12. 12. “ Ecto”mycorrhizae Russula mushroom mycorrhizas on Western Hemlock root Fungal hyphae around root and between cells Mycorrhiza cross sections
  13. 13. Lichens <ul><li>“ Mutualism” between </li></ul><ul><ul><li>Fungus – structure </li></ul></ul><ul><ul><li>Alga or cyanobacterium – provides food </li></ul></ul><ul><li>Three main types of lichens: </li></ul><ul><ul><li>Crustose lichens form flat crusty plates.  </li></ul></ul><ul><ul><li>Foliose lichens are leafy in appearance, although lobed or branched structures are not true leaves. </li></ul></ul><ul><ul><li>Fruticose lichens are even more finely branched and may hang down like beards from branches or grow up from the ground like tiny shrubs. </li></ul></ul>
  14. 14. Lichen internal structure Lobaria <ul><li>Lichens are nature’s biological monitors of pollution and air quality </li></ul><ul><ul><li>Thalli act like sponges </li></ul></ul><ul><ul><li>Some species more sensitive to pollution </li></ul></ul><ul><ul><li>Which species are present can indicate air quality </li></ul></ul><ul><ul><li>Most resistant species can also be analyzed for pollutants, including bioaccumulation of heavy metals and radioactive isotopes </li></ul></ul>
  15. 15. Fungi as Parasites & Pathogens
  16. 16. Fungi are Spore-ific!!! <ul><li>Spores - asexual (product of mitosis) or sexual (product of meiosis) in origin. </li></ul><ul><li>Purpose of Spores </li></ul><ul><ul><li>Allows the fungus to move to new food source. </li></ul></ul><ul><ul><li>Resistant stage - allows fungus to survive periods of adversity. </li></ul></ul><ul><ul><li>Means of introducing new genetic combinations into a population </li></ul></ul>
  17. 17. Reproduce by spores <ul><li>Spores are reproductive cells </li></ul><ul><ul><li>Sexual (meiotic in origin) </li></ul></ul><ul><ul><li>Asexual (mitotic in origin) </li></ul></ul><ul><li>Formed: </li></ul><ul><ul><li>Directly on hyphae </li></ul></ul><ul><ul><li>Inside sporangia </li></ul></ul><ul><ul><li>Fruiting bodies </li></ul></ul>Amanita fruiting body Pilobolus sporangia Penicillium hyphae with conidia
  18. 18. Hyphal growth from spore <ul><li>Mycelia have a huge surface area </li></ul>mycelium germinating spore
  19. 19. The Characteristics of Fungi <ul><li>Fungus is often hidden from view. It grows through its food source (substratum), excretes extracellular digestive enzymes, and absorbs dissolved food. </li></ul><ul><li>Indeterminate clonal growth. </li></ul><ul><li>Vegetative phase of fungus is generally sedentary. </li></ul>
  20. 20. The Characteristics of Fungi <ul><li>Cell wall present, composed of cellulose and/or chitin. </li></ul><ul><li>Food storage - generally in the form of lipids and glycogen. </li></ul><ul><li>Eukaryotes - true nucleus and other organelles present. </li></ul><ul><li>All fungi require water and oxygen (no obligate anaerobes). </li></ul><ul><li>Fungi grow in almost every habitat imaginable, as long as there is some type of organic matter present and the environment is not too extreme. </li></ul><ul><li>Diverse group, number of described species is somewhere between 69,000 to 100,000 (estimated 1.5 million species total). </li></ul>
  21. 21. Generalized Life Cycle of a Fungus
  22. 22. Evolution of the fungi
  23. 23. Classification & Phylogeny motile spores zygosporangia asci basidia
  24. 24. <ul><li>The phyla of fungi are determined by </li></ul><ul><li>1. motility of spores </li></ul><ul><li>2. nature of sexual stage </li></ul><ul><li>Fungi moved onto land with the plants in the Early Paleozoic </li></ul><ul><li>Much of the evolution of fungi was in conjunction with the evolution of plants and plant parts </li></ul><ul><li>For example, when roots evolved, fungi were there and helped (mycorrhizas) </li></ul><ul><li>When wood evolved, fungi evolved to take advantage of it </li></ul><ul><li>Other evolutionary changes related to animals </li></ul>
  25. 25. <ul><li>At present ,the major phyla (sometimes called divisions) of fungi have been classified mainly on the basis of characteristics of their sexual reproductive structures. Currently, seven phyla are proposed: Microsporidia, Chytridiomycota, Blastocladiomycota, Neocallimastigomycota, Glomeromycota, Ascomycota, and Basidiomycota. </li></ul>
  26. 26. Microsporidia – “microsporan” <ul><li>Microsporidia are eukaryotic, unicellular organisms belonging to the phylum Microspora. All microspoidia are obligate, spore-forming, intracellular parasites that invade vertebrates and invertebrates. </li></ul><ul><li>A characteristic feature of microsporidia is the polar tube or polar filament found in the spore used to infiltrate host cells. They are widely distributed in nature with over 1200 species characterized. </li></ul>
  27. 27. <ul><li>However, microsporidia have only recently been documented to parasite humans, and more research is needed to understand this emerging infectious disease. Infection in humans, Microsporidiosis, is primarily found in patients with compromised immune systems, especially those infected with Human Immunodeficiency Virus (HIV) or have undergone organ transplantspest management. </li></ul><ul><li>. Some species, however, have also been known to parasite those with health immune systems. Beyond the human realm, Microsporidia are important parasites in fisheries, veterinary medicines and </li></ul>
  28. 29. Blastocladiomycota <ul><li>Blastocladiomycota is one of seven currently recognized phyla within the kingdom Fungi . These zoosporic fungi are found in soil and fresh water habitats and are mostly detritivores , subsisting on decaying organic matter. </li></ul><ul><li>Three of the five families within Blastocladiomycota exclusively contain pathogens . These infect species such as water bears , the plankton Daphnia , nematodes , various aquatic and semi-aquatic plants, and mosquito larvae. </li></ul><ul><li>Blastoclades were originally included in the phylum Chytridiomycota until DNA sequencing in 2006 elevated it and its &quot;sister phyla&quot; Neocallimastigomycot a . </li></ul>
  29. 30. <ul><li>The blastocladiomycetes are saprotrophs , feeding on decomposing organic matter, and they are parasites of all eukaryotic groups. Unlike their close relatives, the chytrids, which mostly exhibit zygotic meiosis , the blastocladiomycetes undergo sporic meiosis . </li></ul>
  30. 31. Neocallimastigomycota <ul><li>Neocallimastigomycota (NE-o-ka-li-go-ma-sti-go-mi-KO-ta] is made of four Greek roots that mean new (neos- νεός), good or beautiful (kalos- καλός), whips (mastigio- μαστίγιο), and fungus (mykes - μύκης), respectively.  The reference may be to the multiflagellate zoospore of the fungus </li></ul>
  31. 32. <ul><li>The anaerobic rumen fungi inhabit the rumens of large ungulate mammals.  They form small mycelia of coenocytic hyphae (Figure A) that disperse through the production of multiflagellated, posteriorly-directed flagella (Figure B), sometimes with an associated barren basal body .  </li></ul>A. Mycelium of Neocallimastix B. A multiflagellate zoospore of Neocallimastix . 
  32. 33. <ul><li>The sporangia can be clustered  (Figure C) on small compact mycelia or dispersed.  They are notable in that they have hydrogenosomes rather than mitochondria.  </li></ul><ul><li>Indeed, it was through examination of the hydrogenosomes of Neocallimastix particiarum that van der Giezen et al. (1997) were able to demonstrate that hydrogenosomes were reduced mitochondria, which were adapted to an anoxic environment. </li></ul>C. Small mycelium of Caecomyces with multiple sporangia.
  33. 34. <ul><li>This group as a separate phylum was established by Hibbett et al. (2008). </li></ul><ul><li>  SYNONYMS: rumen fungi </li></ul><ul><li>NUMBER: few known, but likely very many species in anaerobic environments. </li></ul><ul><li>PHYLUM CHARACTERISTICS: </li></ul><ul><li>A. ASEXUAL REPRODUCTION: </li></ul><ul><li>Zoospores .  </li></ul><ul><li>B. SEXUAL REPRODUCTION: </li></ul><ul><li>None known. </li></ul><ul><li>C. VEGETATIVE HYPHAE: </li></ul><ul><li>Coenocytic; with a few cross walls. </li></ul><ul><li>D. CELL WALLS: Chitin and chitosan. </li></ul><ul><li>E. ECOLOGY: Mostly known from the rumen flora of mammalian ungulates; however, they may occur in other anaerobic environments. </li></ul>
  34. 35. Chytridiomycota – “chytrids” <ul><li>Simple fungi </li></ul><ul><li>Produce motile spores - zoospores </li></ul><ul><li>Mostly saprobes and parasites in aquatic habitats </li></ul><ul><li>Could just as well be Protists </li></ul>Chytridium growing on spores Chytriomyces growing on pine pollen
  35. 36. <ul><li>. Chytrids produce zoospores that are capable of active movement through aqueous phases with a single flagellum . </li></ul><ul><li>Classified in CMR as true fungi (because of their molecular relationships) </li></ul><ul><li>Remainder of the phyla are almost exclusively terrestrial (a few molds on wet plant material) </li></ul>
  36. 37. Zygomycota – “zygote fungi” <ul><li>Sexual Reproduction - zygosporangia </li></ul><ul><li>Asexual reprod. – common (sporangia – bags of asexual spores) </li></ul><ul><li>Hyphae have no cross walls </li></ul><ul><li>Grow rapidly </li></ul><ul><li>Decomposers, pathogens, and some form mycorrhizal associations with plants </li></ul>Rhizopus on strawberries Rhinocerebral zygomycosis
  37. 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
  38. 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
  39. 40. Rhizoids = root-like hyphae The zhizoids meet underground and mating occurs between hyphae of different molds (SEXUAL REPRODUCTION)
  40. 41. Zygomycota ( Rhizopus )
  41. 43. Lifecycle of a Zygomycete Fungi – Asexual then Sexual
  42. 44. Life cycle of Rhizopus Asexual sporangium with spores inside Sexual zygsporangium with one zygospore
  43. 45. Ascomycota – “sac fungi” <ul><li>Sexual Reproduction – asci (sing. = ascus) </li></ul><ul><li>Asex. Reprod. – common </li></ul><ul><li>Cup fungi, morels, truffles </li></ul><ul><li>Important plant parasites & saprobes </li></ul><ul><li>Yeast - Saccharomyces </li></ul><ul><li>Decomposers, pathogens, and found in most lichens </li></ul>A cluster of asci with spores inside
  44. 46. Sac fungi diversity
  45. 47. Ascomycota – Cup Fungi Life Cycle
  46. 48. Yeast is an Ascomycete Fungus
  47. 49. Yeasts <ul><li>Single celled fungi </li></ul><ul><li>Adapted to liquids </li></ul><ul><ul><li>Plant saps </li></ul></ul><ul><ul><li>Water films </li></ul></ul><ul><ul><li>Moist animal tissues </li></ul></ul>Candida Saccharomyces
  48. 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.
  49. 51. Morels are Ascomycete Fungi
  50. 52. Basidiomycota – “club fungi” <ul><li>Sexual Reproduction – basidia </li></ul><ul><li>Asexual reprod – not so common </li></ul><ul><li>Long-lived dikaryotic mycelia </li></ul><ul><li>Rusts & smuts –plant parasites </li></ul><ul><li>Mushrooms, polypores, puffballs, boletes, bird’s nest fungi </li></ul><ul><li>Enzymes decompose wood, leaves, and other organic materials </li></ul><ul><li>Decomposers, pathogens, and some form mycorrhizal associations with plants </li></ul>SEM of basidia and spores
  51. 53. Basidiomycete or Club Fungi
  52. 54. Life Cycle of Basidiomycete Fungi
  53. 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
  54. 56. Bracket Fungi Puff Balls Mushrooms Jelly Fungi Basidiomycete Fungi that all produce Basiospores
  55. 57. Other Basidiomycetes Rusts and Smuts Rust infecting wheat leaves Rust infecting a Leaf Whitrot Smut digesting old wood
  56. 58. Bioluminescence in Mycena
  57. 59. Some fungi have more than one scientific name – Why? <ul><li>Teleomorph : the sexual reproductive stage (morph), typically a fruiting body (e.g., Morchella esculenta , Agaricus brunescens ). </li></ul><ul><li>Anamorph : an asexual reproductive stage (morph), often mold-like (e.g. Aspergillus flavus , Fusarium solani ). When a single fungus produces multiple morphologically distinct anamorphs, they are called synanamorphs . </li></ul><ul><li>Holomorph : the whole fungus, including all anamorphs and the teleomorph. </li></ul>
  58. 60. Deuteromycota – Form Phylum “Imperfect Fungi” <ul><li>Fungi that seldom or never reproduce sexually. </li></ul><ul><li>Asexual reproduction by vegetative growth and production of asexual spores common. </li></ul>
  59. 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 
  60. 62. Deuteromycota – the Fungi Imperfecti <ul><li>Resemble Ascomycetes, but their reproductive cycle has never been observed </li></ul><ul><li>Different from Ascomycetes because there is a definite lack of sexual reproduction, which is why they are called Imperfect Fungi </li></ul>Penicillium fungi Up Close
  61. 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
  62. 64. LifeCycle of Oomycota
  63. 65. Things to Know about Oomycete Fungi <ul><li>Water molds or mildews </li></ul><ul><li>Cause diseases such as potato blight </li></ul><ul><li>Cell walls made of cellulose (like plant) </li></ul><ul><li>Hyphae have multiple nuclei! Because the cell walls do not fully close off. </li></ul><ul><li>Spore swims away like a flagellate, which is why it is protist like (think of Euglena) </li></ul>
  64. 66. Irish Potato Famine of 19 th Century Devastated potato crops, causing devastating starvation in Ireland 
  65. 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
  66. 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
  67. 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
  68. 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
  69. 72. Crustose Foliose Fruticose
  70. 73. Mycorrhizae Mycorrhizae means “fungus-root”; mutualistic relationship between plant and fungi The plant photosynthesizes while the fungus more efficiently takes up nutrients and water from the rhizosphere than the roots would alone. <ul><li>Plant benefits include: </li></ul><ul><ul><li>Improved nutrient/water uptake </li></ul></ul><ul><ul><li>Improved root growth </li></ul></ul><ul><ul><li>Improved plant growth and yield </li></ul></ul><ul><ul><li>Improved disease resistance </li></ul></ul><ul><ul><li>Reduced transplant shock </li></ul></ul><ul><ul><li>Reduced drought stress </li></ul></ul>
  71. 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.
  72. 75. Molds <ul><li>Rapidly growth </li></ul><ul><li>Asexual spores </li></ul><ul><li>Many human importances </li></ul><ul><ul><li>Food spoilage </li></ul></ul><ul><ul><li>Food products </li></ul></ul><ul><ul><li>Antibiotics, etc. </li></ul></ul>Noble Rot - Botrytis
  73. 76. HUMAN-FUNGUS INTERACTIONS <ul><li>Beneficial Effects of Fungi </li></ul><ul><ul><li>Decomposition - nutrient and carbon recycling. </li></ul></ul><ul><ul><li>Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms). </li></ul></ul><ul><ul><li>Model organisms for biochemical and genetic studies. </li></ul></ul><ul><li>Harmful Effects of Fungi </li></ul><ul><ul><li>Destruction of food, lumber, paper, and cloth. </li></ul></ul><ul><ul><li>Animal and human diseases, including allergies. </li></ul></ul><ul><ul><li>Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.). </li></ul></ul><ul><ul><li>Plant diseases. </li></ul></ul>

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