Lecture 7b: Fungal Ecology Flashcards
How do decomposing fungi spread?
- spore
- scelortia
- mycelia
Mycelial cords
Aggregations of predominantly parallel, longitudinally aligned hyphae
Short-range branching patterns of mycelium
Dense hyphae and mycelia
Long-range branching patterns of mycelia
When a new recourse is encountered there is a reallocation of mycelia biomass
‘Sit-and-wait’ strategy
Waits for leaves and branches to fall on the network
‘Active-search’ strategy
Grow from one leaf to the next
Foraging strategies vary among species and can alter depending on:
- Resource quantity and quality
- Presents of other organisms
- Microclimatic conditions
Fungal spores and/or mycelia will colonise, establish and grow until:
- Outcompeted by another fungus
- Encounter adverse abiotic conditions
- Used the available resources
Abiotic conditions
Fungi alter the physical and chemical properties of the environment; they metabolise the resource and alter the chemistry of wood which leads to a change in pH and the water content
Exploitatoin competition
They use up the resources
Interference competition
Inhibit access
Competition at a distance VOCs
Volatile organic compounds can act over greater distances
Competition at a distance DOCs
Diffusible organic compounds accumulate and diffuse through the substrate
What do VOCs and DOCs do?
They can alter sporulation, mycelia morphology and enzyme production of its target species
Mycoparasitism
One mycelia gains nutrition from another mycelium
Necrotrophy
Cause death of the mycelia and utilise nutrients from dead or decaying hyphae
Biotrophy
Derive nutrients from living mycelia
Non-invasive necrotrophs
Grow close to host hyphae which they attack by secreting nonenzymatic diffusible toxins
Result of non-invasive necrotrophs on the host hyphae
- Loss of membrane function
- Lysis of organelleses
- Deaths of hyphal compartments
- Multiple contacts= whole mycelia die
Invasive necrotrophs
Coil around and penetrate host hyphae and produces antifungal
Results of invasive necrotrophs on the host
- Lysis of hyphal walls and organelles
- disrupts host cytoplasm
Intracellular biotrophs
- entire thallus enter and develop within host cells
- obtain nutrients directly from the cytoplasm
Haustoria biotrophs
- Penetrate host cell by production of appresoria
- Develop abortive branches that invades the host plasma membrane
Fusion or contact biotrophs
Specialised hyphae forms channels of microspores in the cell wall that absorbs nutrients
Gross mycelium contact
A way in which mycelium maximise territory by replacing other mycelium and defending themselves from replacement
Hyphae stained with CMFDA
This accumulates in fungal vacuoles and shows as bright green fluorescence
Hyphae treated with Cellufluor
This binds to chitin in fungal walls and fluoresces blue
Hyphae stained with Dil and DiO
Give green or red fluorescence of fungal membranes
Hyphae stained with CMAC
Give blue fluorescence of the vacuoles
Hyphae stained with Nile red
Show intense yellow fluorescence of lipid droplets, while the cytoplasm fluoresces orange
Fungal Ecology using PCR method
- Isolate DNA/RNA directly from soil
- Target specific core and/or housekeeping genes using fungal specific primers
- Profile the community using electrophoresis methods or cloning and DNA-sequencing
Fungal ecology using Next generation sequencing
- Isolate DNA/RNA directly from soil
Target specific core and/or housekeeping genes using fungal specific primers - Sequencing in the illumine platform
- Assemble sequence reads
- Analyse the sequence data
