Early Diverging Lineages Flashcards
What is another way that heterokaryons are formed?
Anastomosis
What is anastomosis?
The fusion between branches of the same or different hyphae, and is a common method for gene exchange
What does the septum in Ascos and Basidios allow for?
Traffic along the mycelium
How can fungi have even more free traffic in the mycelium?
By having coenocytic hyphae (like Zygos) that have no septa
What are the 6 phyla of the early diverging lineages?
Glomeromycota = another group of mycorrhizal fungi
Mucoromycota = molds
Zoopagomycota = fly and animal pathogens
Blastocladiomycota
Sanchytriomycota
Chytridiomycota
What are the main characteristics of Glomeromycota?
Inhabit herbaceous plant roots
Are obligate symbionts
Abundant - more than 80% of plants are in a relationship with Glomeromycota
Why are Glomeromycota obligate symbionts?
They require plant roots to grow, they cannot be cultured without them
What are the major differences between Glomeromycota and Dikarya?
Glomeromycota hyphae are coenocytic and no sexual fruiting bodies are formed
What is coenocytic hypha?
The hypha cells are multinucleate, there are no cell walls dividing nuclei
What type of hyphae does Dikarya have?
Septate
Which types of hyphae are present in Glomeromycota?
Absorptive and distributive
What is the function of arbuscles in root cells?
The major site of exchange between the fungus and the host
What is the function of vesicles between root cells?
They developed to accumulate storage products in arbuscular mycorrhizal fungi
Vesicles are hyphal swellings in the root cortex that contain lipids and cytoplasm
What is understood about the sexual and asexual life cycles of AM fungi?
The sexual stage is unknown
They reproduce via large asexual spores called chlamydospores
What are the main characteristics of Zygomycota?
Coenocytic hyphae
Produce zygospores
Lack a motile stage (unlike earlier diverging lineages)
How do Mucoromycota sexually reproduce?
Conjugation
What is the zygosporangium and what does it contain?
A warty-walled structure in the Mucoromycota life cycle
It contains a single zygospore
Which sporangium is associated with the asexual/sexual life cycle of Mucoromycotina?
Mitosporangium = asexual
Meiosporangium = sexual
What are spores in Thamnidium produced on?
Spores are produced on sporangia and sporangioles
What is a sporangiole?
A specialized spherical sporangium produced by some species of fungi, smaller than or secondary to the typical sporangium
What is unique about Pilobolus?
It is phototropic and tilts towards a light source as it has a light-sensitive “retina”
What is unique about Entomophthoromycetes in Zoopagomycota?
Includes many species that attack and kill insects
Which genus’ are serious human pathogens in Zygopagomycota?
Basidiobolus and conidiobolus
What are the main characteristics of Chytridiomycota?
Are one of the groups that still has a motile life stage (posterior flagella)
Motility is an ancestral state lost in later diverging fungi
Zoospores with a single whiplash flagellum (opisthokonts)
The thallus can be holocarpic or eucarpic, mono- or polycentric, heteropolar
Saprotrophic or parasitic
What is the direction of movement of opisthokonts?
Posterior to anterior
What does it mean for a thallus to be holocarpic?
The entire fungal body is transforming, the entire thallus of fungus becomes changed into a reproductive cell
What does it mean for a thallus to be monocentric?
Only one sporangium forms
What does it mean for a monocentric thallus to be endobiotic?
The reproductive structure is entirely inside the substrate or the host
What does it mean for a monocentric thallus to be epibiotic?
The reproductive structure is outside of the substrate or the host
What does it mean for a thallus to be polycentric?
It produces many sporangium
What are the main characteristics of blastocladiomycota?
Saprotrophs in soil, water, some parasites
Mostly eucarpic (produce something mycelia-like)
Irregular or heteropolar
Zoospores mostly with one whiplash flagellum
Produce extensive mycelium; chytrids do not
What is unique about the blastocladiomycota life cycle?
Alternation of generations
What are the main characteristics of Sanchytriomycota?
Algal parasites (freshwater brown algae)
Monocentric and epibiotic
Amoeboid zoospores with anterior filopodia and posterior pseudocilium
What is pseudocilium?
A posterior flagellum that drags behind the cell and is not involved in active locomotion
What is filopodia?
Plasma membrane protrusions that function as antennae for cells to probe their environment
What are the 3 early diverging lineages that have non-motile sporangiospores and well-developed mycelium that is coenocytic?
Glomeromycota
Mucoromycota
Zoopagomycota
What are the 3 early diverging lineages that have motile sporangiospores (zoospores) and rarely have well-developed mycelium?
Blastocladiomycota
Sanchytriomycota
Chytridiomycota
