Mycology Lecture 4 Ascomycota

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Lecture 4 Ascomycota, ascomycetes

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Lecture 4 Ascomycota, ascomycetes

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Ploidy level of most fungi?

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Haploid

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Group of Fungi that thickens the neck of frogs?

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Chytridiomycota

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What are the upright lichens commonly called?

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Fruticose lichens

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The net formed by ectomycorrhizae

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Hartig net

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Cells without septa are called?

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Coenocytic

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What to be weary of in peanuts?

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Aflatoxins

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More than one in the cytoplasm

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Heterokaryopsis(n+n)

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Parenthetical in forming a pore?

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Dolipore

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Genus used for naming the Phylum glomeromycota?

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Glomerus

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What asexual spores are produced in some ascomycota?

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Phialides

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Telomorph+anamorph=?

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Holomorph

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The name of the person called the father of Mycology?

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Elias Fries

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Fungal wall component?

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Chitin

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What pushes a chytrid?

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Flagellum

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The dikaryotic Fungi: Ascomycota and Basidiomycota

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Dikaryotic means? 2 haploid nuclei in each 'cell' or hyphae segment

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What are some characteristics that Ascomycota and Basidiomycota have in common?

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-Maintained for length of time

-Cross walls with pores= Septa

-Can anastomose= fuse hyphae together: sexually compatible nuclei are brought together with leads to dikaryotic condition(n+n)

-Nuclei remain separate and go on dividing synchronously(eventually fuse)

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What are some characteristics Ascomycota and Basidiomycota not have in common?

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-Dikaryon is maintained much longer in Basidiomycota(years in some species)

-Restricted Dikaryon in ascomycota(only occur in ascogenous hyphae of the ascocarp)

-Extended dikaryon in basidiomycota

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What are some other characteristics ascomycota and basidiomycota not have in cmmon?

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Their septa are different.

-Septa in ascomycota have a simple pore(Woronin bodies=act as plugs)

-Septa in basidiomycota are complex(parenthesomes or pulleywheel plugs=dolipore)

-Multilayered walls in basidiomycota, double layered in ascomycota

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What are some other characteristics ascomycota and basidiomycota not have in common?

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-Clamp connections are found in cells of many groups of Basidiomycetes, where as its only found in the reproductive structure in Ascomycota(crosier)

-Sporangia: A sac like structure in ascomycota(called an ascus); a club shaped structure with external spores in basidiomycota

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left= ascomycota pore(simple, woronin body)

right=basidiomycota pore(complex, parenthesomes)

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asdf

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What are the two main groups of Dikaryotic fungi?

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Ascomycota and Basidiomycota

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What are their sexual frutifications?

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Ascocarps and basidiocarps

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What is the sporangia of ascomycetes and basidiomycetes?

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asci and basidia

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What happens in the asci and basidia?

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Karogamy and meiosis

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What happens at the end of the dikaryotic phase?

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The production of haploid spores

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The telomorph stage is the what stage? What about the anamorph stage?

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Sexual reproductive stage(usually the fruiting body). The anamorph stage is the asexual reproduction stage(usually mold-like). Holomorph is the whole fungus including telomorph and anamorph.

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How are the walls layered in ascomycota and basidiomycota?

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ascomycota= double-layered

Basidiomycota=multilayered

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General characteristics of zygomycota and chtridiomycota?

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-Coenocytic

-larger hyphae

-mostly humid conditions

-simple sugars and starches used

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General characteristics of Ascomycota and Basidiomycota?

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-Septate with central septal pore for cytoplasmic flow including nuclei.

-smaller hyphae(5mm); can anastomose

-can grow in dry conditions, much greater range of environments than zygomycetes

-complex nutrients such as cellulose and lignin used

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General characteristics of only Ascomycota

General Characteristics:

Largest group of fungi

-18,000 as independent species (teleomorphs) -16,000 as lichens

-30,000 as anamorphs ??

-Mostly haploid throughout life history

-Sexual stage: teleomorph; dikaryon stage ---Asexual stage: anamorph; condia

-Holomorph: anamorph + teleomorph

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What kind of organisms are ascomycetes?

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They are unspecialized saprotrophs to very specialized parasitic or mutualistic organisms.

Times are a changing so is the classification.

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The typical telomorph cycle in some ascomycetes are triggered by what?

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It is triggered by a lack of carbohydrates.

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Are the ascomycetes fungi self-sterile or self-fertile?

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they can be either or. If self-sterile, two strains are required.

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What happens when two strains come together?

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Sex organ formation

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What are the sex organ formations called?

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Globose ascogonium, and Elongated antheridium. Both are multinucleate.

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The ascogonium have a projection called the trichogyne. What is it and what does it do?

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It is a hyphal extension that grows towards the antheridium.

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What happens when the hyphal extension grows towards the antheridum?

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They fuse and nuclei from the antheridium flow into the ascogonium.

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What grows out of the ascogonium after this?

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Ascogenous hyphae grow out from ascogonium with pairs of + and – nuclei in pairs

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What does the tip of the ascogenous hyphae turn into?

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A crosier

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What happens to the two nuclei in the tip of the crosier?

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They divide to form four nuclei

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What happens after this?

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Septa form leaving a + and - nuclei in the cell

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What happens to these two differing nuclei?

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They fuse and undergo meiosis right away

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What happens after meiosis?

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They form 4 nuclei which migrate into the ascus

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Each of these spore undergoes a mitotic division leaving how many spores in the ascus?

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8

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How is each ascus interspersed?

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With a sterile hyphae called paraphyses.

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What do paraphyses do?

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Builds pressure up in the ascus.

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In some ascomycetes a cap forms called what?

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operculum

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If mutate strains, can get idea about outcome right away as there is no hidden alleles. If we cross a wild-type with mutant strain, would expect what?

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Four wild type spores and four mutant strain spores in the ascus(8 total)

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The different types of asco carps:

Athecia: ?

Apothecium: ?

Perithecium: ?

Pseudothecium: ?

Chasmothecium: ?

Cleistothecial(cleisoto=closed)?

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Athecia: without surrounding fungal tissue

Apothecia: cup shaped, open top, all asci can be released at same time

Perithecia: flask shaped, narrow opening, only few asci can be released at a time

Pseudoperithecial: uniloculate ascostroma, similar to perithecium

Chasmothecium: closed ascocarp with characteristic appendages, similar to powdery mildews, ascomycota)

Cleistothecial: small and closed ascocarp with external layer of cells

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Types of asci:

Atunicate- ?

Unitunicate- ?

Bitunicate- ?

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Atunicate= no coat

unitunicate= one coat

bitunicate= two coats

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How does a unitunicate asci work?(it can either be operculate or inoperculate)

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It has an opening(operculate) which is a built in lid which pops open when spores are mature.

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How does a unitunicate asci work?(inoperculate)

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It has no opening but instead a special elastic ring which breaks when the pressure inside the asci becomes to great

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How does a bitunicate asci work?

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Has two layers, one thin elastic layer and one thick inelastic layer. When spores mature the thin elastic layer ruptures and the thick layer absorbs water and expands. This causes pressure to build up, which carries the spores up and out of the ascocarp. (like a jack in the box)

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What is a protunicate asci?

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Means first or primative. Since its mostly in cleisothecial/hypogeous fungi, there is no need to be elongated and aim the ascus towards any object. In the case of truffles, evolved from unitunicate asci.

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What is the asexual reproduction stage of ascomycetes called?

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Anamorphs

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What are condiophores?

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Aerial hyphae that rise about the substratum. Ends of hyphae bleb off into elipsoidal spores containing one to several nuclei-macrocondia

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What color are macrocondia

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Pink, due to carotenoids in spores, readlily dispatched by air currents.

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What are microcondia?

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Tiny uninucleate

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What also participates in the sexual process?

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Arthospores. Chunks of hyphae break into spores, if touch the opposite strain, promotes ascogonial formation

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Many teleomorph stages of ascomycetes unknown

-Some may not have a sexual stage

-Thus:Many ascomycetes have two scientific names:

- One for the anamorph

-One for the teleomorph

-Only with DNA and RNA analysis are the two being linked

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In zygomycetes mitospores are all produced from a common mass of cytoplasm inside a chamber called what? produced at same time as meiospores as well

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Mitosporangium

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In ascomycetes mitospores are produced from? do not occur at same time as meiospores

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The tips of hyphae called conidia

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In zygomycetes the anamorph and teleomorp generally occuyr when?

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Together and have the same binomial

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In ascomycetes the anamorph and teleomoph generally occur when?

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At different times, with different binomials.

-Develop at different times on different substrates

-2000 genera of anamorphs have been keyed out of 30,000 described species

-collected at different times without knowledge of other phasel perfectly okay with rules of taxonomy

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Anamorph stage

-Several thousand anamorphs (5,000 spp.) and teleomorphs have now been connected because of DNA analysis (total 30,000)

-Former category Deuteromycota, Fungi Imperfecti are obsolete; should be classified as ascomycetes.

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Anamorph stage

Where are we today?

- ~15% of teleomorphs connected to their anamorphs

- Members of single genus of anamorphs probably have teleomorphs in many teleomorph genera

-Members of several genera of anamorphs may well be in one teleomorph genus

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conidia: are asexual,[2] non-motile spores of a fungus

CONIDIOPHORE. : a structure that bears conidia; specifically : a specialized hyphal branch that produces successive conidia

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First anamorphs described in late 1800’s based on:

-Conidia

-Colour of conidia

-Septa of conidia

-Shape of condia

-Conidiophore aggregation (+ or - )

-Enclosures of conidia (+ or - )

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What are hypomycetes?

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Conidiophores and conidia not enclosed in condioma

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What are coelomycetes?

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Conidiophores and conidia enclosed in conidioma

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What are acervuli coelomycetes?

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form their conidiophores in conidioma just beneath the surface of their plant substrate, covered by hosts cuticle, epidermal layer, subepidermal tissue

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What are pycnidial coelomycetes?

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fungus that provides the enclosing wall with an ostiole

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There are three forms of hypomycetes:

solitary conidiomata, synnemata conidiomata, sporodochial condiomata

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There are three types of conidiogenesis:

Arthic: hyphae stop growing, then split into arthroconidia

Alternate arthric: every other cell breaks away as conidia

Solitary: released one spore at a time; phragmophitic at the end of process

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Why identify/study conidial anamorphs?

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Many plant diseases and human mycoses(fungal infection) are caused by the conidial stage of ascomycetes

-Keratin attacking species: ringworm (scalp); jock itch; athlete’s foot

-Southern corn blight: wiped out the Texas corn crop in 1970

-Food spoilage: even on jams

-Aflatoxin on peanuts: extremely carcinogenic

-Mycotoxins of feed for pigs and other animals

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Major colonizers and decomposers of plant debris

-Major recyclers of carbon and nitrogen

-Hyphomycetes dominate forest soil flora

-Aquatic hyphomycetes break down dead leaf litter in cold streams of north: important to invertebrates in stream

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Soil predatory fungi: control pests in soil; biological controls, nematodes, rotifers, amoeba, springtails

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Enzymes of fungi

-Soften cheese: Cambert, brie

-Flavour cheese: Roquefort, Danish blue

-Changes soy protein into soy sauce

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Secondary metabolites against bacteria: medicine

-Penicillin: fight bacterial infections

-Cyclosporine: least toxic of the immune suppressants

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Major groups of non-lichens:

Atunicate

- O. Taphinales

-Four unique characteristics

- Dikaryotic assimilative hyphae

-Exposed asci (no surrounding hyphae

-Ascospores bud like yeastAsci split at end

-Diseases of plants in Rose Family (Rosaceae)

-Peach Leaf Curl

cause ringworm and atheletes foot