Introductory Mycology BOT 461/561

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

Nutrition• Heterotrophic• Secrete extracellular enzymes • Absorptive nutrition• Saprobes: decay dead organic matter• pathogens: biotroph, necrotroph • symbionts: parasites - commensals - mutualists

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)

M ICROSPORIDIA

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 moldsSudden Oak Death)

based onDNAsequencedata

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 anteriorposterior flagellum or lateral

heterokont flagella cell wall carbohydrate: glucans, chitin glucans, cellulose lysine biosynthesis: alpha-aminoadepic acid (AAA) diaminopimelic (DAP)

storage compound glycogen mycolaminarins

sterols ergosterol fucosterol

Phyla: Chytridiomycota Oomycota(emphasized Zygomycota Myxomycotain class) Glomeromycota Dictyosteliomycota

Basidiomycota Ascomycota

General characteristics of the Phyla of the Kingdom Fungibasal 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 septatehyphae

Multiple lossesof flagellum

X

X

chitin*glycogen*mito cristae*ergosterolpost smooth flagellum**share with animals asci + ascospores

basidia + basidiosporesdolipore + clamp connections

http://ocid.nacse.org/research/aftol/

Silurian 440 hypha, spores ?Ascomycota

Devonian 410 wood decay Basidiomycotamycorrhizae Glomeromycotazoosporangia Chytridiomycota

Carboniferous 360 zygospores Zygomycotaclamp connections Basidiomycota?fruit bodies

Permian 286 white rot Basidiomycota

Triassic 245 wood decay Basidiomycotamycorrhizae Glomeromycota

Jurassic 208 shelf fungus Basidiomycota

Cretaceous 144 rusts Basidiomycotapolyporesconidia Ascomycota

Tertiary 65 extant morphologies

Fossil Record of Kingdom Fungi - How old are fungi?

Hymenomycetesmushrooms, shelf fungijelly fungi, coral crusts, puffballs

Ustilaginomycetessmuts

Urediniomycetesrusts, marine yeastscrusts

3 Major Clades - Classes - of the Basidiomycota

Kingdom - Fungi Phylum - Basidiomycota

Class - HymenomycetesOrder - Agaricales

Family - AmanitaceaeGenus - Amanita

Species - A. muscaria

Amanita muscaria

Nomenclature

Introductory Mycology BOT 461/561 http://ocid.nacse.org/classroom/fungi/bot461/