Presentation on theme: "Introductory Mycology BOT 461/561. What are fungi? Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their."— Presentation transcript:
What are fungi? Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their nutrition.
Body Plan unicellular (yeast), filamentous, or both (=dimorphic) Hypha (pl. hyphae) is the basic “cellular” unit in filamentous fungi; they may be septate or coenocytic (aseptate); collectively a mycelium limited tissue differentiation and division of labor somatic & reproductive structures plectenchyma: all organized fungal tissue, somatic & reproductive
Nuclear Status Eukaryotic; uni, bi- or multinucleate Haploid, diploid (less frequent) Monokaryon (1 nucleus per hyphal compartment) Dikaryon (2 nuclei per hyphal compartment) Homokaryotic Heterokaryotic
Mitosis –intranuclear: nuclear membrane doesn't breakdown during mitosis –centric in flagellated forms; typical centrioles of eukaryotes –noncentric in nonflagellated forms; possess spindle pole bodies (SPBs); differ from centrioles in lacking microtubular component
Organelles typical eukaryote assemblage of organelles + fungal specific ones mitochondria endoplasmic reticulum Golgi equivalents single cisternal elements vacuoles microbodies funx in fatty acid degradation, N metabolism
Cell Wall well defined chitin 1-4 n-acetyal glucosamine -glucans polymers of glucose 1-3 glucose cellulose in some 1-4 glucose chitin -glucans Chitin Cellulose 1-3 glucan
fungal specific organelles involved in cell wall growth Spitzenkorper associated with growing hyphal tips in septate fungi chitosome microvesicles transporting chitin synthases to growing cell wall
Spores - a minute propagative unit functioning as a seed, but differing from it in that a spore does not contain a preformed embryo Fruiting body - any complex fungal structure that contains or bears spores; a sporocarp
Reproduction Sexual reproduction: spores meiotically derived nuclei Homothallic (selfing) Heterothallic (outcrossing) Monoecious or dioecious Genetic mating system –MAT loci –1 to hundreds of “sexes” Asexual reproduction –Spores with mitotically derived nuclei
Misc. Life cycle: simple to complex; wide variety Sporocarps: microscopic or macroscopic, limited tissue differientiation Habitat: ubiquitous Studied by mycologists!!!!!!
What are fungi? Eukaryotic, spore-bearing, heterotrophic organisms that produce extracelluar enzymes and absorb their nutrition.
Fungi vs. "fungi" Based on the phenotypic definitions or traits attributed to fungi, fungi do not comprise a single monophyletic group of organisms more than one evolutionary origin not all "fungi" are members of the Kingdom Fungi
FUNGI (e.g., mushrooms, yeasts) MICROSPORIDIA METAZOA (Animals) DICTYOSTELIDAE MYXOGASTRIDAE LOBOSA ANGIOSPERMAE (Green Plants) CHLOROPHYCEAE RHODOPHYTA GLAUCOPHYTA OOMYCETES PHAEOPHYCEAE (Brown algae) CILIOPHORA APICOMPLEXA KINETOPLASTIDA EUGLENOIDEA ACRASIDAE VAHLKAMPFIIDAE PARABASALLA DIPLOMONADIDA Slime molds Phylogeny Of Eukaryotes (some water molds Sudden Oak Death) based on DNA sequence data
Some characters that separate the the Kingdom Fungi from “protistan fungi” Kingdom Fungi Protistan fungi mitochondria: cristae flattened cristae tubular motile cells: no motile cells or motile cells with anterior posterior flagellumor lateral heterokont flagella cell wall carbohydrate: glucans, chitin glucans, cellulose lysine biosynthesis:alpha-aminoadepic acid (AAA) diaminopimelic (DAP) storage compoundglycogenmycolaminarins sterolsergosterolfucosterol Phyla: Chytridiomycota Oomycota (emphasizedZygomycotaMyxomycota in class)Glomeromycota Dictyosteliomycota Basidiomycota Ascomycota
General characteristics of the Phyla of the Kingdom Fungi basal lineages Chytridiomycota: (800) unicellular to mycelial (coenocytic) zoospore with single posterior whiplash flagellum aquatic & terrestrial no sporocarp production Zygomycota: (1000) generally coenocytic mycelium production of zygosporangia & zygospores no sporocarp production Glomeromycota: (200) formerly part of Zygomycota coenocytic mycelium no known sexual reproduction arbuscular mycorrhizae (Glomerales) no sporocarp production
Basidiomycota: (22500) septate mycelium clamp connections complex dolipore septa dikaryotic, haploid mycelium production of exospores (basidiospores) on a basidium production of complex sporocarps Ascomycota: (35000) septate mycelium simple septa monokaryotic, haploid mycelium production of endospores (ascospores) in an ascus production of complex sporocarps often dominant asexual reproduction
Chytridiomycota + Zygomycota Ascomycota Basidiomycota Glomeromycota Chytridiomycota Phylogeny of Kingdom Fungi Regularly septate hyphae Multiple losses of flagellum X X chitin* glycogen* mito cristae* ergosterol post smooth flagellum* *share with animals asci + ascospores basidia + basidiospores dolipore + clamp connections