Early Diverging Lineages

Question 1

What is another way that heterokaryons are formed?

Answer 1

Anastomosis

Question 2

What is anastomosis?

Answer 2

The fusion between branches of the same or different hyphae, and is a common method for gene exchange

Question 3

What does the septum in Ascos and Basidios allow for?

Answer 3

Traffic along the mycelium

Question 4

How can fungi have even more free traffic in the mycelium?

Answer 4

By having coenocytic hyphae (like Zygos) that have no septa

Question 5

What are the 6 phyla of the early diverging lineages?

Answer 5

Glomeromycota = another group of mycorrhizal fungi
Mucoromycota = molds
Zoopagomycota = fly and animal pathogens
Blastocladiomycota
Sanchytriomycota
Chytridiomycota

Question 6

What are the main characteristics of Glomeromycota?

Answer 6

Inhabit herbaceous plant roots
Are obligate symbionts
Abundant - more than 80% of plants are in a relationship with Glomeromycota

Question 7

Why are Glomeromycota obligate symbionts?

Answer 7

They require plant roots to grow, they cannot be cultured without them

Question 8

What are the major differences between Glomeromycota and Dikarya?

Answer 8

Glomeromycota hyphae are coenocytic and no sexual fruiting bodies are formed

Question 9

What is coenocytic hypha?

Answer 9

The hypha cells are multinucleate, there are no cell walls dividing nuclei

Question 10

What type of hyphae does Dikarya have?

Answer 10

Septate

Question 11

Which types of hyphae are present in Glomeromycota?

Answer 11

Absorptive and distributive

Question 12

What is the function of arbuscles in root cells?

Answer 12

The major site of exchange between the fungus and the host

Question 13

What is the function of vesicles between root cells?

Answer 13

They developed to accumulate storage products in arbuscular mycorrhizal fungi
Vesicles are hyphal swellings in the root cortex that contain lipids and cytoplasm

Question 14

What is understood about the sexual and asexual life cycles of AM fungi?

Answer 14

The sexual stage is unknown
They reproduce via large asexual spores called chlamydospores

Question 15

What are the main characteristics of Zygomycota?

Answer 15

Coenocytic hyphae
Produce zygospores
Lack a motile stage (unlike earlier diverging lineages)

Question 16

How do Mucoromycota sexually reproduce?

Answer 16

Conjugation

Question 17

What is the zygosporangium and what does it contain?

Answer 17

A warty-walled structure in the Mucoromycota life cycle
It contains a single zygospore

Question 18

Which sporangium is associated with the asexual/sexual life cycle of Mucoromycotina?

Answer 18

Mitosporangium = asexual
Meiosporangium = sexual

Question 19

What are spores in Thamnidium produced on?

Answer 19

Spores are produced on sporangia and sporangioles

Question 20

What is a sporangiole?

Answer 20

A specialized spherical sporangium produced by some species of fungi, smaller than or secondary to the typical sporangium

Question 21

What is unique about Pilobolus?

Answer 21

It is phototropic and tilts towards a light source as it has a light-sensitive “retina”

Question 22

What is unique about Entomophthoromycetes in Zoopagomycota?

Answer 22

Includes many species that attack and kill insects

Question 23

Which genus’ are serious human pathogens in Zygopagomycota?

Answer 23

Basidiobolus and conidiobolus

Question 24

What are the main characteristics of Chytridiomycota?

Answer 24

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

Question 25

What is the direction of movement of opisthokonts?

Answer 25

Posterior to anterior

Question 26

What does it mean for a thallus to be holocarpic?

Answer 26

The entire fungal body is transforming, the entire thallus of fungus becomes changed into a reproductive cell

Question 27

What does it mean for a thallus to be monocentric?

Answer 27

Only one sporangium forms

Question 28

What does it mean for a monocentric thallus to be endobiotic?

Answer 28

The reproductive structure is entirely inside the substrate or the host

Question 29

What does it mean for a monocentric thallus to be epibiotic?

Answer 29

The reproductive structure is outside of the substrate or the host

Question 30

What does it mean for a thallus to be polycentric?

Answer 30

It produces many sporangium

Question 31

What are the main characteristics of blastocladiomycota?

Answer 31

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

Question 32

What is unique about the blastocladiomycota life cycle?

Answer 32

Alternation of generations

Question 33

What are the main characteristics of Sanchytriomycota?

Answer 33

Algal parasites (freshwater brown algae)
Monocentric and epibiotic
Amoeboid zoospores with anterior filopodia and posterior pseudocilium

Question 34

What is pseudocilium?

Answer 34

A posterior flagellum that drags behind the cell and is not involved in active locomotion

Question 35

What is filopodia?

Answer 35

Plasma membrane protrusions that function as antennae for cells to probe their environment

Question 36

What are the 3 early diverging lineages that have non-motile sporangiospores and well-developed mycelium that is coenocytic?

Answer 36

Glomeromycota
Mucoromycota
Zoopagomycota

Question 37

What are the 3 early diverging lineages that have motile sporangiospores (zoospores) and rarely have well-developed mycelium?

Answer 37

Blastocladiomycota
Sanchytriomycota
Chytridiomycota