bis2c. biodiversity and the tree of life. 2014. l14. fungi

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014

Lecture 14

!

Lecture 14 !

Fungi !!

BIS 002C Biodiversity & the Tree of Life

Spring 2014 !

Prof. Jonathan Eisen

1


Where we are going and where we have been

• Previous Lecture: !13: Fungi

• Current Lecture: !14: Fungi and Symbioses

• Next Lecture: !15: Fungi and humans

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Lecture 22 Outline

• What are Fungi?

• Diversity of form

• Phylogenetic diversity

• Symbioses

!3

Slides by Jonathan Eisen for BIS2C at UC Davis Spring 2014 4

Microsporidia


Microsporidia

Microsporidia are unicellular fungi, obligate intracellular parasites of animals; 1,500 species.

Among the smallest eukaryotes known.

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Microsporidia

• Host cell is penetrated by a polar tube of the microsporidian spore, and contents of spore are injected into host.

• The sporoplasm replicates in the host cell and produces new infective spores.

• The life cycle of some species is complex and involves multiple hosts.

• Microsporidia have cell walls with chitin, and lack true mitochondria; they have reduced structures called mitosomes.

• Misclassified as protists for many years.6


Chytrids


Chytridiomycosis: Batrachochytrium dendrobatides

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Chytrids: Only Fungi with Swimming Spores

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Chytrids

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• General !Mostly aquatic; <1,000 species. !May be parasitic or saprobic !Some are unicellular, others have

rhizoids, still others are coenocytic. !Multicellular diploid stage of some

includes a structure that can withstand freezing and drying.

• Reproduction !Flagellated spores and gametes. !Have alternation of generations, but

haploid stage produces independent male and female gametes.

!Reproduce both sexually and asexually. !The cytoplasms of individuals of different

mating types fuse (plasmogamy) before their nuclei fuse (karyogamy).

• Evolution !May be polyphyletic. !Once classed as protists.


Figure 30.14 Sexual Life Cycles of Chytrids & Zygospore Fungi

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Figure 30.14 Sexual Life Cycles of Chytrids

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Study this life cycle


Figure 30.14 Sexual Life Cycles of Chytrids

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Flagellated spores

Flagellated gametes


Zygospore fungi (Zygomycota):

Animation 30.1 Life Cycle of a Zygospore Fungus



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Figure 30.14 Sexual Life Cycles of Zygospore Fungi

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• General !>1000 species described; includes

Rhizopus stolonifer, black bread mold. !Terrestrial fungi—saprobes on soils,

parasites of insects & spiders, mutualists w/ other fungi and invertebrates.

!Reproduction !Zygospore can be dormant for months,

then the nuclei undergo meiosis to form haploid spores which disperse.

!Hyphae of different mating types release pheromones, which cause them to grow toward each other.

!Zygote is the only diploid cell.

• Evolution !Likely paraphyletic.


Glomeromycota


Figure 30.11 Mycorrhizal Associations (B)

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Glomeromycota

• General !Mutualistic symbiosis with plant roots. !<200 species, but 80 to 90 percent of plants have associations

with them !Glucose from plant partner is primary energy source for fungus. !Essential to almost all vascular plants to increase water and

mineral uptake. !Hyphae are coenocytic. !Enter root and penetrate cell walls, but not the plasma membrane. !As in ectomycorrhizae, the fungus forms a vast web of hyphae in

the surrounding soil and increases surface area for water and mineral uptake.

!Only asexual reproduction

• Evolution !Evolution of mycorrhizal associations may have been an important

step for plants to colonize land. !Seen in some liverworts

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Taylor et al. 1995 - mycorrhizal fungi in Rhynie Chert!Hyphae, vesicles, arbuscules


Dikarya


Dikarya

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Figure 30.16 Sexual Life Cycles among the Dikarya

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Dikaryon

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• Dikaryon—hypha with two haploid nuclei. • Also called a heterokaryon (n + n).

• Karyogamy (fusion of nuclei) occurs long after plasmogamy (fusion of cytoplasm), so that two genetically different haploid nuclei coexist and divide within the same hypha.


Dikaryon continued

• Unusual aspects of dikaryon life cycle: ! No gamete cells, only gamete nuclei ! No true diploid tissue; zygote is the only

true diploid ! Hypha is neither diploid (2n) nor haploid

(n); rather, it is dikaryotic (n + n)

• Duration spent in dikaryon varies ! Short lived in sac fungi ! In club fungi it may last months or years—

opportunity for more than two mating types to fuse, and more genetic recombination.

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Ascomycota - Sac Fungi

• Marine, freshwater, and terrestrial.

• 64,000 species, half as lichens

• Produce sacs called asci (singular ascus), which contain sexually produced haploid ascospores

• Hyphae are septate, pores in septa allow movement of cytoplasm and organelles

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Figure 30.16A Sexual Life Cycles among the Dikarya

HAPLOID (n)

Sac fungi (Ascomycota)Hyphae of – mating type

Hyphae of + mating type


HAPLOID (n)

Sac fungi (Ascomycota)Mating structureHyphae of

– mating type



HAPLOID (n)

DIKARYOTIC (n + n)

Plasmogamy

Sac fungi (Ascomycota)Mating structureHyphae of

– mating type



HAPLOID (n)

DIKARYOTIC (n + n)

Plasmogamy

Sac fungi (Ascomycota)Mating structure

Dikaryotic mycelium

(n + n)

Hyphae of – mating type



HAPLOID (n)

DIKARYOTIC (n + n)

Plasmogamy


Dikaryotic mycelium

(n + n)

Haploid hyphae (n)




HAPLOID (n)

DIKARYOTIC (n + n)

Plasmogamy

Ascoma (fruiting structure)


Dikaryotic mycelium

(n + n)

Haploid hyphae (n)




HAPLOID (n)

DIKARYOTIC (n + n)

Plasmogamy


Dikaryotic asci (n + n)


Dikaryotic mycelium

(n + n)

Haploid hyphae (n)




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy


Sac fungi (Ascomycota)

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



MEIOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei

Ascus




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



Ascospores

MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei

Ascus




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



Ascospores

MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei

Ascus

Ascus




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



Ascospores

Ascospores (n)

MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei

Ascus

Ascus




HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

Plasmogamy


Karyogamy



Ascospores

Ascospores (n)

Germinating ascospores

(n)

MEIOSIS

MITOSIS

FERTILIZATION

Mating structure

Dikaryotic mycelium

(n + n)

Haploid hyphae (n)

Fused nuclei

Ascus

Ascus




Figure 30.16 Sexual Life Cycles of Ascomycota

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Yeasts

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! Saccharomyces cerevisiae is baker’s or brewer’s yeast. It metabolizes glucose to ethanol and CO2 by fermentation.

! Some yeasts live on fruits such as grapes and are important in wine making.

! Some live in the guts of insects and help break down cellulose.

! Reproduce asexually by budding

! Sexual reproduction—cells of different mating types fuse, zygote nucleus undergoes meiosis to form ascospores, the whole cell is the ascus.

! Lost the dikaryon stage.


Cup FungiCup fungi

• The inner surfaces of the cups are covered with specialized hyphae and asci, and produce huge numbers of spores.

! Many species are edible, including morels and truffles.

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Molds and Mildews

! Filamentous hyphae that do not form large ascomata

! Reproduce asexually by conidia which give molds characteristic colors.

! Sexual reproduction includes relatively brief dikaryon.

! Plant parasites (e.g, chestnut blight and Dutch elm disease)

! Many used in food production (Aspergillus tamarii for soy sauce; A. oryzae to brew sake) (Penicillium camembertii and P. roquefortii in Camembert and Roquefort cheeses)

! Some Penicillium species produce the antibiotic, penicillin

! Aflotoxin form an Aspergillus

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Club fungi (Basidiomycota)

• Fruiting structures are basidiomata

• 30,000 species, includes mushrooms, puff balls, bracket fungi

• Plant pathogens such as rusts and smuts infect cereal grains.

• Other club fungi species are fungal partners in ectomycorrhizae.

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Figure 30.19 Club Fungus Basidiomata

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Figure 30.18 Club Fungus Fruiting Structures

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Puffballs

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HAPLOID (n)

Basidiomycota


Basidium

HAPLOID (n)

Basidiomycota


Basidiospores

Basidium

HAPLOID (n)

Basidiomycota


Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

Basidiomycota


In club fungi, the products of meiosis are borne exposed on pedestals called basidia. Fruiting bodies consist solely of dikaryotic hyphae, and the dikaryotic phase can last a long time.

Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

+ Mating type

– Mating type

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

+ Mating type

– Mating type

Mycelial hyphae

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Dikaryotic mycelium

(n + n)

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Dikaryotic mycelium

(n + n)

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Dikaryotic mycelium

(n + n)

Gills

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Dikaryotic mycelium

(n + n)

Gills

Gills lined with basidia

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Dikaryotic mycelium

(n + n)

Gills

Developing basidium

(n + n)


Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Dikaryotic mycelium

(n + n)

Gills

Developing basidium

(n + n)


Nuclei

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Karyogamy

Fertilization

Dikaryotic mycelium

(n + n)

Gills

Developing basidium

(n + n)


Nuclei

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Karyogamy

Fertilization

Dikaryotic mycelium

(n + n)

Gills

Developing basidium

(n + n)

Fused nuclei


Nuclei

Basidiomycota



Basidiospores

Basidium

Basidium50 µm

HAPLOID (n)

DIKARYOTIC (n + n)

DIPLOID (2n)

+ Mating type

– Mating type

Mycelial hyphae

Plasmogamy

Basidioma (fruiting

structure)

Karyogamy

Fertilization

Meiosis

Dikaryotic mycelium

(n + n)

Gills

Developing basidium

(n + n)

Fused nuclei


Nuclei

Basidiomycota


Basidiomycota

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Symbioses

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Parasites

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Zombie Ants

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from @zombieantguy

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Cordyceps species


Cordyceps sinensis


30.2 How Do Fungi Interact with Other Organisms?

• Parasitic fungi

• Mycologists recognize two classes: !Facultative—can grow on living organisms

but also grow on their own !Obligate—grow only on specific host

species

• Insects and plants are the most common hosts.

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Example: Invading a Leaf

• Fungal hyphae are well-suited to invade plant tissues through stomata, wounds, or by penetrating epidermal cell walls.

• Some hyphae produce haustoria, projections that press into cells without breaking through the plasma membranes, and absorb nutrients.

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Example: Trichophyton rubrum

• Ascomycota

• Feeds on keratin

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http://microbewiki.kenyon.edu/index.php/Trichophyton_rubrum

http://microbewiki.kenyon.edu/index.php/Trichophyton_rubrum


Trichophyton rubrum

• Causes ! Ringworm ! Jock itch ! Athlete’s foot ! Nail infections ! Many other irritating maladies

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Pathogenic Fungi

• A major cause of death in people with compromised immune systems, such as AIDS patients.

• Fungi cause other human diseases such as ringworm and athlete’s foot.

• The worldwide decline of amphibian species has been linked to a chytrid fungus.

• The chytrid is endemic to southern Africa and probably spread with exports of the African clawed frog.

• Fungi are the most important pathogens in plants, causing crop losses amounting to billions of dollars.

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Stachybotrys chartarum

• Ascomycota

• Feeds on cellulose

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Stachybotrys chartarum

• Likes wet building materials like drywall, floors, ceilings

• Causes ! allallergic rhinitis (cold-

like symptoms,) ! dermatitis (rashes,) ! sinusitis ! conjunctivitis ! aggravation of asthma. ! inability to concentrate ! fatigue.

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Paper on wallboard


White Nose Syndrome

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Geomyces destructans White Nose syndrome


Aspergillus flavus

• Ascomycota

• Feeds on lots of things

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Aspergillus flavus

• Grows well on stored grains

• Produces aflotoxin, which can cause short and long term problems (e.g., liver cancer)

56


The brown mold Aspergillus:

• Aspergillus tamarii acts on soybeans to make soy sauce; A. oryzae is used to brew sake

• Other Aspergillus species grow on grains and nuts and produce extremely carcinogenic aflatoxins

• Aspergillus fumigatus was cause of the primary case in the steroid-injection outbreak

57


Photo 30.15 Conidiophores with numerous conidia of Aspergillus

58


Other fungal human pathogens

• Cryptococcus species (Basidiomycota) (HIV associated) • Encephalitozoon cuniculi (Microsporidia) (HIV associated) • Enterocytozoon bieneusi (Microsporidia) (usually in pigs) • Pneumocystis carinii (Ascomycota) (HIV associated) • Candida albicans (Ascomycota) (yeast infections) • Coccidiodes immitis (Ascomycota) (Central Valley fever)

59Encephalitozoon cuniculiPneumocystis carinii Candida albicans


Mutualisms

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Lichens

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Figure 30.7 Lichen Body Forms

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30.2 How Do Fungi Interact with Other Organisms?

Lichens: fungus + photosynthetic microorganism

Together they can survive some of the harshest environments on Earth, such as Antarctica.

About 30,000 “species” are named for the fungal component.

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Figure 30.8 Lichen Anatomy

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Lichens for dyes

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Human uses of lichens: dyes

bis2c. biodiversity and the tree of life. 2014. l14. fungi

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