Lecture 2 Flashcards
What are the levels of classification. What is placing organisms into different groups called?
7 levels
Taxomomy
- Kingdom
- phylum/division
- class
- order
- family
- genus
- species
What are the 6 kindoms
What cell types are in them
- Plantae : multicellular, eukaryotic
- Animalia: multicellular, eukaryotic
- Fungi : multicellular, eukaryotic
- Protista : multicellular, eukaryotic, unicellular
- Eubacteria : unicellular, prokaryotic
- archaebacteria: unicellular, prokaryotic
list the 5 phyla/lineages of fungi
+ an informal group and what makes it informal
- Chytridiomycota (Chytrids)
- Zygomycota
- Ascomycota
- Basidiomycota
- Glomeromycota
informal group: Deuteromycota
- all sharing common character of reproduction asexually
General characteristics of Fungi
- eukaryotic, mostly microscopic organisms.
- no chlorophyll
- lacks vascular system unlike
- filamentous (possessing a mycelium or hyphae.
- reproduce sexually and asexually (unlike bacteria that reproduce by fission)
- cell walls contain chitin or cellulose or both
- strictly heterotrophic (depends on
other organisms for food and energy) - Fungi or even plant pathogenic fungi are not always harmful.
What is hyphae
- mass of mycelial threads
- Hyphae grow at the tip as cell wall is rigid
- carry organelles and cell structure just like most eukaryotes
Why is the cell wall of the fungi most important
3 things
- Because it makes the first contact with the host
- its structure determins the form of the fungi
- functional &metabolic roles for getting nutrition from host plant/dead matter
How does the fungus get nutrition from polysaccharides Lignin lipids (cutin) & proteins
fungi produce a variety of enzymes to break down these polymers into smaller units or monomers which can easily pass the cell wall and cell membrane
SpitzenkÖrper
structure, consisted of very small
vesicles, found in fungal hyphae that is the center for
fungal hyphal growth and morphogenesis
structure, consisted of very small
vesicles, found in fungal hyphae that is the center for
fungal hyphal growth and morphogenesis
SpitzenkÖrper
what makes up cell wall structure
**carbohydrate polymers **
- chitin
- glucan
- cellulose
Whats chitin and what role does it play in the fungi
- a carbohydrate polymer thats part of the cell wall
- forms chitin chains -> making microfibril and microfibrils to confer strength to the fungi
what is composed in a complex fibrillar network of fungi
what proteins
polysaccharides and glycoproteins
What are fungi and plant pathodenic fungi used/important for?
- important industrial, food,
and pharmaceutical uses. (corn smut is a delicacy in Mexico, ergot is used in pharmaceutical industry to develop drugs that helps stop bleeding, Tulip Break Virus (‘tulip mania’) helped Dutch growers in Netherland in late 18th century (google and read the story yourself!), and many
more examples.
List the modes of nutrition for Fungi and the 3 classified levels
2 modes, 3 levels
Saprophytic vs parasitic
1. biotrophic
2. hemibiotrophic
3. necrotrophic
Biotrophic Fungi
how nutrition is obtained, what type of host do they look for. Examples
- obtain nutrition from living host or organism
- cannot survive on dead plant tissue.
- Mostly, biotrophs are host specialized and therefore have narrow host range.
- cannot culture biotrophs on growth media in lab.
- eg: rusts, smuts, mildews.
Hemibiotrophic Fungi
- attacks living host similar to biotrophic fungi, however, continue
to grow and develop on dead tissue. - eg: Fusarium graminearum, most
of the leaf spotting fungi.
Necrotrophic Fungi
- kills the host prior for penetration and feeding.
- not host specialized
- secretes cell wall degrading enzymes and toxins.
- can easily be cultured axenically.
- eg: Botrytis cinerea causing
grey molds on plants or plant parts.
please review general fungi structure
Thallus
Vegetative body of the fungus lacking stems, roots, or leaves unlike plants
Mycelium
- Network of hyphae collectively makes mycelium.
Aseptate mycelium & aseptate hyphae
- Aseptate mycelium are not divided by cross-walls (septa) at certain intervals.
- Aseptate hyphae are generally present in lower fungi.
Septate mycelium & Septate hyphae
- Septate mycelium is divided by cross-walls (septa) at certain
intervals - Septate hyphae are found in higher fungi
septal pore
minute hole In the septa (singular septum)
Sclerotia
dense aggregates of fungal mycelia which often serves as overwintering structure.
What are the endings for:
- phyla
- sub-phylum
- class
- order
- family
- phyla: ___mycota
- sub-phylum: ___mycotina
- class: ___mycetes
- order: ___ ales
- family: ___ aceae
how are the phyla’s grouped into sub-kingdoms
zoosporic fungi
- Chytridiomycota
zygomycetous fungi
- Zygomycota, Glomeromycota
dikarya
- Ascomycota, Basidiomycota
ZOOSPRIC FUNGI
All fungi in this class descend from an organism that was single-celled and at least at some point in its life cycle, able to swim with the use of posterior flagella
Chytridiomycota (chytrids)
Its form, spores, what type of enviroment. what role do they play
- simple, primitive fungi
- only true fungi with motile
(swimming) zoospores) - Zoospores: pear or kidney shaped, naked, motile (uni or biflagellate). produced in sporangium (zoosporangium).
- mostly saprophytic, parasitic in aquatic habitats.
- important pathogens of plants (e.g. Synchytrium), animals, algae, as well decomposers of organic matter.
- Parasitic chytrids play a role in aquatic environments by controlling algal bloom and act as food for very small animals
ZYGOMYCETOUS FUNGI
- Loss of flagellar apparatus
- development of hyphal growth allowed a particular group of fungi to cover the land.
- type of terrestrial fungi along with Dikarya fungi.
Zygomycota
and exampels
‘Zygospores’.
- sexual spores, Black in color, rough walled, warty in appearance.
sporangiospores
- Asexual spores, produced in sporangia.
Hyphae have no septa or cross-walls. Nowadays, Glomeromycota
covers Zygomycota.
Eg: Soft rots of fruits are mostly caused by zygote fungi.
Glomeromycota
its role, how it feeds
- friends of plants
- forming mycorrhizae: symbiotic relationship. All known members are obligate symbionts.
- live in soil
- endomycorrhizae (endo means ‘within’) the relationship with the roots: aseptate hyphae enter roots
- arbuscule: When The hyphal tips branch repeatedly in the host cells at intervals. (‘little tree’).
- fungus does not penetrate through the plant cell membrane but rather the arbuscule surrounds and coats every hypha in it. This close contact helps fungus
draw nutrients and in return fungus helps plant draw nutrition from the soil.
How many wild plants are estimated to have such fungal partners?
> 80%
DIKARYA
- so-called ‘higher fungi’.
- characterized for a sexual
cycle that includes production of dikaryons.
(dikaryon: a cell in which the two nuclei—one from each parent cell—share a single cytoplasm for a period of time without undergoing nuclear fusion.)
Ascomycota (sac fungi)
- pathogenic fungi and saprophytic fungi.
sexual spores ascospores:
- Mating -> formation of short lived dikaryon hyphae -> formation of ‘ascus’ (sac-like structure), carries meiosis-derived sexual spores (usually eight in number).
Asexual spores:
- produced for propagation and sexual stages
- Not well known
model organism
- due to the high diversity & ease of culturing in a lab setting
eg: yeast
(Saccharomyces cerevisiae)
- The most valuable fungi in this group is yeast, used in baking and brewing industry.
Human related diseases
- ~58 genera of fungi in this group
- eg: Athlete’s foot, jock itch, and ringworm.
- ~95% of the infections are cured without treatment
- rarely fatal infections
List the Different types of ascocarps/fruiting bodies due to sexual outcome
3
- Cleistothecia
- Perithecia (-um)
- Apothecia (-um)
Cleistothecia (-um)
ascocarps/fruiting bodies due to sexual outcome
- Completely closed
- spherical in shape
- black
- hard structure inside which asci scattered.
- Asci come out by rupturing the cleistothecium.
Perithecia (-um)
ascocarps/fruiting bodies due to sexual outcome
- Flask shaped
- natural opening “ostiole”,
- sometime having long neck
- Asci produced in perithecium at basal region in a hymenium layer.
- Paraphyses may also be present in between the asci. (sterile, filament-like support structures)
Apothecia (-um)
ascocarps/fruiting bodies due to sexual outcome
- open disc/ cup shaped structure called apothecium where the ascospores are produced.
- exposed structure allows formation of a layer of the asci in a hymenium.
-
Paraphyses may be
present. (sterile, filament-like support structures)
List the Different types of fruiting bodies due to asexual outcome by ascomycetes
4
- Pycnidia
- Acervuli
- Sporodochia
- Synnemata
Pycnidia
fruiting bodies due to asexual outcome by ascomycetes
- Spehrical or flask shaped structures.
- natural opening called ostiole through which conidia are released.
- causes plant dead tissue
- never biotrophic
Acervuli
fruiting bodies due to asexual outcome by ascomycetes
- Mat or cushion like saucer shaped structure formed below cuticle or epidermis of the host.
Sporodochia
fruiting bodies due to asexual outcome by ascomycetes
- Cushion shaped stcructures from which the condiophores are produced.
Synnemata
fruiting bodies due to asexual outcome by ascomycetes
- conidiophores are grouped together at the base and free towards apex.
Basidiomycota
- 2nd largest groupd with the most complex structure
- Hymenomycetes: mushrooms
basidimata:
- nsexual fruiting body
- spores : basidospores
almost always biotrophic
difference between ascomycota vs basidiomycota
they’re both in the dikarya group
- Ascomycota fungi (sexual fruiting bodies and thallus) are much smaller in size, dikaryon hyphae in Ascomycota are short-lived.
