Lecture 5a: Fungal diversity Flashcards
which fungal species are easier to discover
Species that produce spore-bearing structures, because they are visible
What do taxonomists do
They have the task to uncover and name new fungal species
What is the basis for describing fungi
Morphological, anatomical and chemical characteristics
What is the importance of molecular technology-based fungal studies?
They provide a better understanding of fungal diversity and DNA-based data
What do Fungal DNA-based studies use
Internal Transcribed Spacer Region (ITS)
What is ITS
It is a nuclear ribosomal repeat unit composed of 3 parts, flanked by the SSU and LSU
What can ITS do?
they can identify fungi at a species level (fungal barcode)
What is the secondary barcode?
Translation elongation factor 1 (tef1)
What is the largest group of fungi?
Ascomycota
What is the sexual state of Ascomycota characterised by
Ascocarp (fruiting body) containing asci that produce ascospores (1n)
How does asexual reproduction occur in Ascomycota?
it takes place through conidia
When is the dikaryophase produced?
Shortly before ascus production through the formation of crozier
What is a crozier?
An anatomical feature that forms at the base of the ascus, it maintains the dikaryotic state in the ascus
How are croziers formed?
See slides, too long to type
Types of ascocarps and their scientific names
- Naked ascus- Neolecta spp.
- Cleisothecium- Uncinula spp.
- Pseudothecium- Venturia
- Perithecium- Sordaria
- Apothecium- peziza
Unitunicate-Operculate asci
They are single-celled with built-in lids, and the lip pops open at maturity to eject spores. (found in apothecium)
Unitunicate-Inoperculate asci
Have a single cell wall with no lid. They have a special elastic ring mechanism built into their tip
the ring stretches momentarily or turns inside out to shoot spores out (found in perithecium)
Bitunicate asci
Have double cell walls (outer-thin, inner- thick & elastic)
At maturity, the thin outer wall splits and the outer wall absorbs water to expand upwards.
allows ascus to stretch into the neck of perithecium to expel spores
Protunicate asci
Observes no active spore shooting, rather the wall dissolves at maturity and releases the ascospores which then ooze out of the ascocarp
These are found in Ceistothecium
South African Ascomycetes
kalaharituber pfeilbi (‘Kalahari truffel’)
What does the class of Basidiomycota consist of
Mushrooms, rusts and smuts
What is the sexual state of Basidiomycota characterised by
Its characterised by a basidiocarp containing basidium-producing basidiospores
What is the extended dikaryophase maintained by?
It is maintained throughout most of the life cycle of hyphae through clamp connection
What do secondary hyphae result from?
Fusion between 2 primary hyphae
What happens after plasmogamy?
The dolipore septum breaks down to allow nuclear migration
What is a clamp connection?
A structure formed by growing hyphal cells to ensures that each cell or segment of hyphae receives a set of different nuclei obtained through mating
What is the significance of clamp connections?
They create genetic variation within the hyphae
What is the largest organism in the world?
Mushrooms (honey fungus-Armillaria)
Basidiomycota
Are Armillaria mushrooms safe to eat raw
No, they are slightly poisonous if eaten raw
