BIOL 108 Introduction to Biological Diversity - Topic 18: Fungi PDF

BIOL 108 Introduction to Biological Diversity Topic 18: Fungi Lecture A2 Yan-yin Wang Introduction to Fungi # Phylogeny of protists leading to fungi and...

BIOL 108 Introduction to Biological Diversity Topic 18: Fungi Lecture A2 Yan-yin Wang Introduction to Fungi # Phylogeny of protists leading to fungi and animals. Fungi are diverse and widespread. Amorphea Most fungi are found in soil, and they function as decomposers. Fungi are phylogenetically closer to Animalia than to land plants. Molecular phylogenetic analyses place fungi in Opisthokonts of Amorphea, which also includes animals. Fungi and animals may have a shared common ancestor among protists, which was unicellular and had posterior flagella. Jirsová, D., & Wideman, J. G. (2022). Evolution: divergent trajectories predate the origins of animals and fungi. Current Biology, 32(21), R1242-R1244. Shared, Derived Traits of Fungi # hyphae and mycelium (top), and materials strength of mycelium (middle), and chitinous cell wall in the pathogenic yeast (bottom). Three synapomorphies: 1. Absorptive nutrition 2. Presence of hyphae and mycelium 3. Presence of chitinous cell walls Gow, N. A., & Lenardon, M. D. (2023). Architecture of the dynamic fungal cell wall. Nature Reviews Microbiology, 21(4), 248-259. Islam, M. R., Tudryn, G., Bucinell, R., Schadler, L., & Picu, R. C. (2017). Morphology and mechanics of fungal mycelium. Scientific reports, 7(1), 13070. Hotz, E. C., Bradshaw, A. J., Elliott, C., Carlson, K., Dentinger, B. T., & Naleway, S. E. (2023). Effect of agar concentration on structure and physiology of fungal hyphal systems. Journal of Materials Research and Technology, 24, 7614-7623. Absorptive nutrition # Process of absorptive nutrition. Fungi are absorptive chemoheterotrophic eukaryotes Absorptive nutrition: Fungi obtain nutrients by absorbing organic molecules from outside of their bodies. Organic compounds are used as sources of carbon and energy. https://www.nagwa.com/en/explainers/727196329684/ Absorptive nutrition # Process of absorptive nutrition. Fungi achieve absorptive heterotrophy by external digestion. Typical process of external digestion: Large and complex organic molecules are broken down in the environment by enzymes (i.e., exoenzymes) secreted by fungi. Simple organic molecules (e.g., amino acids) are absorbed by the fungal bodies. Fungi can digest cellulose and lignin from plants, as well as chitin and keratin from https://www.nagwa.com/en/explainers/727196329684/ animal tissues. The versatility of the enzymes contributes to the ecological success of fungi.  # Hyphae (top) as well as growth and spread of fungal hyphae (bottom). Anatomy of the Fungi Fungi are non-motile. Nutrients are located and acquired by growing. Most fungi are characterised by the presence of numerous hyphae. Hyphae: cylindrical, branched, and multicellular filaments that absorb nutrients. Hyphae are present in the fruiting body Hyphae form a filament network called mycelium. Bauer, Y., Knechtle, P., Wendland, J., Helfer, H., & Philippsen, P. (2004). A Ras-like GTPase is involved in hyphal growth guidance in the filamentous fungus Ashbya gossypii. Molecular biology of the cell, 15(10), 4622-4632. Anatomy of the Fungi # Independent evolutionary origin of toolkits for yeast development. Fungi are non-motile. Nutrients are located and acquired by growing. Most fungi are characterised by the presence of numerous hyphae. Hyphae: cylindrical, branched, and multicellular filaments that absorb nutrients. Hyphae are present in the fruiting body Hyphae form a filament network called mycelium. Unicellular fungi called yeasts do not produce hyphae. Yeasts have evolved independently multiple times from a hyphae-forming ancestor. Nagy, L. G., Ohm, R. A., Kovács, G. M., Floudas, D., Riley, R., Gácser, A.,... & Hibbett, D. S. (2014). Latent homology and convergent regulatory evolution underlies the repeated emergence of yeasts. Nature communications, 5(1), 4471. Anatomy of the Fungi # Micrograph of fungal spores, asexual conidiophores, and hyphae. The multicellular hyphal morphology enhance nutrient absorption in fungi. Hyphae are thin, tubular cells range from 2 – 10 µm filled with cytoplasm and organelles. Tips of hyphae grow in length but not in girth. The filamentous structure of mycelium greatly increases the surface-area-to-volume ratio, which increases efficiency for enzyme secretion and nutrient absorption. Cell walls of hyphae are composed of chitin, which is a glucosamine polymer. Elegbede, J. A., & Lateef, A. (2018). Valorization of corn-cob by fungal isolates for production of xylanase in submerged and solid state fermentation media and potential biotechnological applications. Waste and Biomass Valorization, 9, 1273-1287. Anatomy of the Fungi Two types of internal arrangements of hyphae: Hyphae of septate (left) and coenocytic (right) fungi (required!). The hyphae exhibit a coenocytic structure: They form a continuous compartment without division. These fungi are coenocytic (aseptate) fungi. Numerous nuclei are dispersed throughout the hyphae. A condition seen in the earliest fungal lineages called coenocytic fungi. The hyphae develops wall-like structures called septa along with nuclear division. These fungi are septate fungi. Cytoplasm is divided into separate, uninuclear cells. Pores are present for cell-to-cell movements of molecules and small organelles. https://microbiologynotes.org/fungi-distribution-morphology-reproduction-classification/ A condition seen in most fungi. https://www.medical-labs.net/fungi-hyphae-1522/ Reproduction in Fungi # A fruiting body releasing spores. Fungi reproduce by creating and dispersing high quantity of spores. Spores can be produced asexually or sexually. Many fungi use sexual and asexual reproduction at different stages of the life cycle, while others rely on asexual reproduction (e.g., Penicillium). Fungal spores are produced by mitosis (e.g., haploid mycelia) and meiosis (e.g., fruiting bodies). Plant spores are produced only by meiosis. Spores are dispersal stage of the life cycle. Fungal spores have cell walls rich in chitin for rigidity and protections. https://northspore.com/blogs/the-black-trumpet/mushroom-spores-mushroom-spawn-what-is-the- difference Reproduction in Fungi # spores of fungi in extant (top) and fossil taxa (bottom). Fungi reproduce by creating and dispersing high quantity of spores. Spores can be produced asexually or sexually. Many fungi use sexual and asexual reproduction at different stages of the life cycle, while others rely on asexual reproduction (e.g., Penicillium). Fungal spores are produced by mitosis (e.g., haploid mycelia) and meiosis (e.g., fruiting bodies). Plant spores are produced only by meiosis. Spores are dispersal stage of the life cycle. Fungal spores have cell walls rich in chitin for rigidity and protections. Guarín, F. A., Abril, M. A. Q., Alvarez, A., & Fonnegra, R. (2015). Atmospheric pollen and spore content in the urban area of the city of Medellin, Colombia. Hoehnea, 42(1), 09-19. van Geel, B., Gelorini, V., Lyaruu, A., Aptroot, A., Rucina, S., Marchant, R.,... & Verschuren, D. (2011). Diversity and ecology of tropical African fungal spores from a 25,000-year palaeoenvironmental record in southeastern Kenya. Review of Palaeobotany and Palynology, 164(3-4), 174-190. Life Cycle of Fungi The life cycle in fungi resemble Typical life cycle of fungi (required!). those of haploid-dominant eukaryotic organisms. Diploid stage is transient. Unique steps in fungi: Plasmogamy with fusion of cytoplasm but not nuclei. Karyogamy with fusion of nuclei. The zygotic stage after karyogamy is transient, and fungi lack a diploid, multicellular stage. Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Origin of Fungi Phylogeny of Opisthokonts (required!), # an opisthokont protist (bottom left) and a nucleariid (bottom right). Fungi and animals are related protists from the opisthokonts of the Amorphea cluster. The opisthokont ancestor of fungi was an aquatic, unicellular, flagellated protist. Molecular phylogenetic analyses suggest: Kingdom Fungi is a monophyletic group. Fungi are closely related to the unicellular nucleariids, which are non-flagellated, spherical or flat amoebae. Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Paps, J., & Ruiz-Trillo, I. (2010). Animals and their unicellular ancestors. http://skepticwonder.fieldofscience.com/2009/10/sunday-protist-nucleariids.html Phylogeny of Fungi Approximately 100,000 fungal species have Phylogeny of Kingdom Fungi (required!). been identified, but an estimated 1.5 million species may exist. Fungi likely formed mutualistic relationship with earliest land plants. Fungi are classified int five diverse phyla: Chytrids from the phylum Chytridiomycota Zygomycetes from the phylum Zygomycota Glomeromycete from the phylum Glomeromycota Ascomycetes from the phylum Ascomycota Basidiomycetes from the phylum Basidiomycota Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Chytrids Chytrids form a paraphyletic group of about # Anatomy of the zoospores (left) and hyphae of a chytrid (right). 1000 species that inhabit aquatic or moist environment. The most basal group of fungi Characteristics: Presence of motile, flagellated asexual spores called zoospores (unique among fungi). Absence of a true mycelium, but hyphae may be produced. Most chytrids are unicellular and others have coenocytic bodies. Presence of chitin in cell wall. Chytrids use external digestion as in other fungi. Margulis, L., Melkonian, M., Chapman, D. J., & Corliss, J. O. (2017). Handbook of the Protists (Vol. 10, pp. 978-3). J. M. Archibald, A. G. Simpson, & C. H. Slamovits (Eds.). Cham, Switzerland: Springer. Ecological roles Letcher, P. M., & Powell, M. J. (2018). Morphology, zoospore ultrastructure, and phylogenetic position of Polyphlyctis willoughbyi, a new species in Chytridiales (Chytridiomycota). Fungal biology, 122(12), Decomposers, parasites, or mutualists. 1171-1183. Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Zygomycetes Zygomycetes form a paraphyletic group of # zygosporangia (top) and hyphae (bottom) in the black bread mould Phizopus stolonifera. fungi, comprising of less than 1% of fungal species. Examples: Black bread mould Phizopus stolonifera. Characteristic: Presence of coenocytic hyphae. Presence of zygosporangia. Liu, Q., Chen, Q., Liu, H., Du, Y., Jiao, W., Sun, F., & Fu, M. (2024). Rhizopus stolonifer and related control strategies in postharvest fruit: A review. Heliyon. https://www.plantsdiseases.com/p/rhizopus-stolonifer.html Diversity of Fungi - Zygomycetes Zygomycetes life cycle: # Typical life cycle of zygomycetes. Asexual sporangia produce haploid spores that are dispersed through the air. Sexual reproduction occurs through the formation of zygosporangia, which form after the fusion of specialised hyphae. Karyogamy occurs within zygosporangia. Zygosporangia are resistant to harsh environment. Some zygomycetes such as Pilobolus aim and shoot their sporangia at high velocity towards bright light sources. Ecological roles Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Parasites and commensal symbionts Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Glomeromycetes Envomychorrhizae between the plant Hieracium pilosella and the glomeromycetes Rhizophagus intraradices. Glomerohycetes form a small monophyletic group and are known for their symbiotic relationship with plant roots. Characteristic: Only asexual reproduction by soil spores has been documented. A form of endomycorrhizae called arbuscular mycorrhizal associations with over 80% of extant plant species. Ecological roles Important symbiont facilitating minerals and nutrients exchange for host plants. https://www.researchgate.net/post/Can-anyone-identify-these-fungal-structures-stained-with- Trypan-Blue Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Dikarya Phylogeny of Dikarya (required!). Most fungi species belong to the monophyletic Dikarya. Chitin cell wall Hyphae and mycelia Absorptive nutrition Dikarya contains about 98% of fungal species Characteristics: Dikarya Presence of septate hyphae. hyphae Septate Development of dikaryotic hyphae after Complex, multicellular plasmogamy. fruiting bodies Typical life cycle of fungi (required!). Economic significance: Dikaryotic stage Edible mushroom Yeasts for making bread, beer, and cheese Pathogens Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Ascomycetes # Ascomycetes (top) and hyphae fusion (bottom). Ascomycetes form the most diverse group that inhabit a wide range of environments (e.g., marine, freshwater, and terrestrial). Ascomycetes range from unicellular yeast to fungi with multicellular, complex structures. Characteristics: Sexual reproduction The dikaryotic stage is brief with plasmogamy and karyogamy taking place in quick succession. Presence of sac-like sexual spores called asci. Asci is in the fruiting body called ascocarp. Asexual reproduction by vast quantities of spores called conidia inside of the specialised hyphae called conidiophores. Ecological roles Roper, M., Ellison, C., Taylor, J. W., & Glass, N. L. (2011). Nuclear and genome dynamics in multinucleate ascomycete fungi. Current biology, 21(18), R786-R793. Honegger, R., Edwards, D., Axe, L., & Strullu-Derrien, C. (2018). Fertile Prototaxites taiti: a Decomposers, mutualists, and pathogens. basal ascomycete with inoperculate, polysporous asci lacking croziers. Philosophical Transactions of the Royal Society B: Biological Sciences, 373(1739), 20170146. Diversity of Fungi - Ascomycetes Ascomycetes form the most diverse group that inhabit a wide range of environments (e.g., Life cycle of a typical ascomycete. marine, freshwater, and terrestrial). Ascomycetes range from unicellular yeast to fungi with multicellular, complex structures. Characteristics: Sexual reproduction The dikaryotic stage is brief with plasmogamy and karyogamy taking place in quick succession. Presence of sac-like structures called asci. Asci is in the fruiting body called ascocarp. Asexual reproduction by vast quantities of spores called conidia inside of the specialised hyphae called conidiophores. Ecological roles Decomposers, mutualists, and pathogens. Campbell, N. A., Reece, J. B., Urry, L. A., Cain, M. L., Wasserman, S. A., Minorsky, P. V., & Jackson, R. B. (2024). Campbell biology (4th Canadian ed.). Pearson. Diversity of Fungi - Basidiomycetes # Diversity of basidiomycetes. Basidiomycetes include many familiar fungi known for the production of sexual spores called basidiospores on specialized structures called basidia. Characteristics: Sexual reproduction is most common but asexual reproduction is also known. The dikaryotic stage is elongated compared to ascomycetes. The presence of a club-like structures called basidiocarp. “basidium” means pedestal. Ecological role Significant decomposer, known for their Mowna Sundari, T., Alwin Prem Anand, A., Jenifer, P., & Shenbagarathai, R. (2018). Bioprospection of capacity to breakdown lignin. Basidiomycetes and molecular phylogenetic analysis using internal transcribed spacer (ITS) and 5.8 S rRNA gene sequence. Scientific Reports, 8(1), 10720. Fungi Lifestyles # The black bread mould Rhizopus (top) and Penicillium (bottom). Fungi can be categorised by lifestyles: Moulds are fast-growing, filamentous fungi. Characteristics Primarily reproduce asexually. Fuzzy growths of hyphae are often formed on the surface or organic materials. Mould taxa are found in zygomycetes (e.g., Rhizopus) and ascomycetes (e.g., Penicillium). https://www.britannica.com/science/Rhizopus Fungi Lifestyles Fungi can be categorised by lifestyles: # Hyphae growing in a yeast colony in Candida citri. Yeasts are unicellular fungi found in liquid or moist environments. Characteristics: Yeasts reproduce asexually by budding off daughter cells after mitosis. Yeasts have evolved independently multiple times from a hyphae-forming ancestor. Some taxa can flexibly shift between yeast and hyphal forms based on environmental conditions. Yeasts are commonly found in ascomycetes (e.g., Saccharomyces) and basiciomycetes. Sipiczki, M. (2011). Dimorphic cycle in Candida citri sp. nov., a novel yeast species isolated from rotting fruit in Borneo. FEMS yeast research, 11(2), 202-208. Fungi Lifestyles # Comparison between ectomycorrhiza (top) and Fungi can be categorised by lifestyles: endomycorrhiza (bottom). Mycorrhizae are mutualistic symbiotic relationship between fungi and roots of vascular plants. Ectomycorrhiza: The fungus forms a hyphal sheath surrounding the roots but does not cause invagination of the plasma membrane of the host plant cells. Endomycorrhiza: The fungus penetrates the host plant cells to form arbuscules and vesicles. Characteristics Multiple fungal groups can contribute to ectomycorrhiza but approximately 10% of vascular plants (e.g., conifers) can form ectomycorrhizal associations. Arbuscular mycorrhizae are found in a monophyletic group in glomeromycetes, and about 85% of vascular plants can form arbuscular mycorrhizal associations. https://www.researchgate.net/post/Can-anyone-identify-these-fungal- structures-stained-with-Trypan-Blue Kaldorf, M., Renker, C., Fladung, M., & Buscot, F. (2004). Characterization and spatial distribution of ectomycorrhizas colonizing aspen clones released in an experimental field. Mycorrhiza, 14, 295-306. Fungi Lifestyles – Two Types of Mycorrhizae # Comparisons between ectomycorrhiza and endomycorrhizaa (left) and connection between fungal and plant tissues (right). Bonfante, P., & Genre, A. (2010). Mechanisms underlying beneficial plant–fungus interactions in mycorrhizal symbiosis. Nature communications, 1(1), 48. Some Reflective Questions (Not an Exhaustive List for Exam!) How do fungi fit in the grand evolutionary scheme of life? On a phylogeny, how may we locate the origin of fungi from protists? What are the anatomical and physiological characteristics of fungi? How are fungi classified? How can we identify main groups of fungi?