Lab 6: Plants + Fungal Diversity

What are Fungi?

Fungi are heterotrophic eukaryotes with absorptive nutrition

What group are fungi part of?

Opisthokonts

describe absorptive nutrition

in which enzymes are secreted into the environment to break down organic substrates and nutrients are absorbed across the cell wall

what is the body of a fungus known as?

mycelium or thallus

life cycle of most fungi

haplontic

fungi can be unicellular or multicellular. multicellular fungi are composed of what>

hyphae (filaments that are a single cell thick)

hyphae in many fungi may be divided by what?

septa (cross walls) to create individual cells

what do we call hyphae that do not have septae

aseptate or coenocytic

what are fruiting bodies?

multicellular reproductive structures (e.g. mushroom)

hyphae may differentiate into what 3 possible structures?

spores, resting structures, nutrient acquisition structures

many fungi are dimorphic. what does this mean?

they are capable of switching between two forms: mycelial and yeast (unicellular) forms

Fungi are recognized into 6 phyla:

• Ascomycota

• Basifiomycota

• Glomeromycota

• Zygomycota

• Chytridomycota

• Microsporidia

However, what problem remains?

uncertainty. therefore, they are usually presented as a polytomy

What fungi phyla accounts for the majority of all described fungal species? What group are they sister taxa to?

Ascomycota and Basifiomycota. They are sister taxa in Dikarya group.

specific characteristic in Dikarya group

at one stage in their life cycle, two haploid nuclei are present in a single cell

most fungi spend the majority of their life as what?

foraging hyphae

Does the dikaryotic fungi have both a haplontic and diplontic stage?

no. only a haplontic stage

what is special about fungi reproduction?

fungi lack gametes. they instead have mating types (compatibility of hyphae)

plasmogamy

the plasma membrane of two hyphae fuse and form a dikaryon (a single cell with two haploid nuclei)

karyomary

in which the two haploid nuclei fuse to form a single diploid nucleus

defining structure of Ascomycota

ascus (a sac that encloses eight haploid spores)

defining structure of Basidiomycota

basidium (a club-like structure with four external spores)

how are spores dispersed?

via fruiting bodies

what are special about lichens?

they have a symbiotic relationship between fungus, green alga, cyanobacteria, or both.

what does mold refer to?

refers to fungi with microscopic reproductive structures (mostly saprobes)

5 morphological features most helpful in the identification of fungi

• gills, pores, or spines (on underside of cap)

• honeycomb-like cap with singular pits or saddle-like cap with fluted stalk or cap with no stalk

how do all fungi get their nutrients?

from decomposing matter

Ascomycota: habitat, cell type, characteristic(s), reproduction

terrestrial, unicellular or filamentous with septate hyphae, sexual reproduction via asocarps that bear asci

basidiomycota: habitat, cell type, characteristic(s), reproduction

mostly terrestrial, filamentous with septate hyphae, sexual reproduction via basidiocarps

what is the fungal component of a lichen referred to? what is the algal and bacterial component known as?

mycobiont; photobiont

most lichening forming fungi are obligately (independent/dependent) on their photobiont

dependent

there are 3 main growth forms of lichens: foliose, fruticose, crustose.

what is the growth form of foliose?

lichens are leaf-like in shape and tend to be flattened

there are 3 main growth forms of lichens: foliose, fruticose, crustose.

what is the growth form of fruticose?

lichens are erect or pendent and cylindrical. they have a distinct three-dimensional structure

there are 3 main growth forms of lichens: foliose, fruticose, crustose.

what is the growth form of crustose?

lichens are flattened and fused very tightly to their substrate

what type of lichen (foliose, fruticose, crustose) would be found on rocks or bark?

crustose lichens

in some lichens, what forms to get the nutrients from algae?

haustoria

what do we call a mass of woven hyphae that provide the structure of the lichen?

medulla

this structure is present on the lower cortex of a lichen and serves to anchor the lichen to a substrate

rhizines