Q8: Endophyte/Animal Symbiosis & Community Ecology Flashcards
Neutral symbioses in which one partner benefits and the other is neither benefitted or harmed.
Commensalism
Ways endophytes are disseminated.
(1) Vertically in seed and (2) horizontally by spore.
The food source of fungus-cultivating termites.
Modified cellulose
Ways that plants benefit from endophytes.
(1) Herbivore resistance, (2) protection from pathogens, (3) drought tolerance, (4) growth enhancement, (5) heavy metal tolerance, and (6) thermotolerance.
Endophytes of woody plants are dispersed only by (vertical/horizontal) dissemination.
Horizontal
(T/F) The symbiosis between termites and fungus has evolved many times.
False.
Gongylidia
Swollen hyphal tips that form as a result of mycelial pruning by ants. The main source of food for leafcutter ants.
(T/F) Leafcutter ants are often highly specialized with only one cultivated strain of a specific fungal species.
True; some species are more generalist, and can reform relationships with free-living fungi.
In what stage of the symbiosis between Leucoagaricus spp. and leafcutter ants does the fungus usually fruit?
After the ants abandon the nest.
C-selective fungi.
Combative fungi, characterized by slow growth rate; good competitors.
What do chytrid endosymbionts provide for ruminants?
The mycelium can break down larger material to make it more available for other microbes.
S-selected fungi.
Stress tolerant fungi adapted to specific extreme environments.
Fungal community succession generally proceeds from communities dominated by (R/C/S)-selected species to (R/C/S)-selected species.
R-selected to C-selected
Fungal community succession generally proceeds from communities (with/without) dominant species to communities (with/without) dominant species.
Without dominant species to with dominant species.
The major drawback of direct observation of a fungal community.
Non-fruiting fungi can be missed or unidentifiable.
Antibiosis in which secondary compounds are used to kill competing hyphae.
Fungicidal antibiosis
Examples of direct effects of animals on fungal communities.
Fungivory, grazing.
(T/F) Fungal commensals can be free-living.
True, requiring a host for only a stage in life cycle. Others, however, are never free-living.
R-selecting fungi.
Ruderal/pioneer species selected for short lifespans and high rate of production in disturbed environments.
Ruderal/pioneer species selected for short lifespans and high rate of production in disturbed environments.
R-selecting fungi.
The fungus that is cultivated by termites.
Termitomyces
Fungal community succession generally proceeds from communities dominated by (many/fewer) species to (many/fewer) species.
Many species to fewer species.
Most endophytes belong to which group?
Ascomycota
Direct antagonism.
A contact phenomenon that leads to the destructions of hyphae. Aggressive behavior by one or both fungi that requires hyphal contact.
Endophytes
Fungi that live within plants but cause no outward symptoms.
The negative influence of one fungus on another via production of secondary compounds, such as antibiotics.
Antibiosis.
Endophytic dissemination in which spores are produced on dead/dying plant tissue, going on to infect and colonize tissues of a new plant.
Horizonal dissemination
The FOUR broad influences on the composition and diversity of fungal communities.
(1) Substrate/nutrient availability, (2) physical environmental factors, (3) interspecific interactions, (4) impacts of animals.
The range of leafcutter ants.
South America to southern United States.
How do endophytes protect plants from pathogens?
(1) Production of toxins, (2) competitive exclusion, or (3) stimulating host defense.
Combative fungi, characterized by slow growth rate; good competitors.
C-selective fungi
What do leafcutter ants get out of the symbiosis with fungi?
The ability to use cellulose as a food source.
Endosymbionts
Symbionts that live most of their life cycle within another organism.
A contact phenomenon that leads to the destructions of hyphae. Aggressive behavior by one or both fungi that requires hyphal contact.
Direct antagonism.
Aggressive behavior by one or both competitor that does not require hyphal contact.
Indirect antagonism.
Ruderal
The term for pioneer/R-selected species.
Agricultural activities practices by leafcutter ants.
(1) Cultivation, (2) fertilization, (3) weed/pest control, (4) pruning, (5) specialized labor forces, (6) domestication of new crops/crop improvement.
(T/F) The symbiosis between leafcutter ants and Leucoagaricus spp. has evolved multiple times.
False
Fungicidal antibiosis.
Antibiosis in which secondary compounds are used to kill competing hyphae.
(R/C)-selective fungi tend to use more complex substrates.
C-selective
Mycorrhizal fungal communities tend to become (more/less) host-specific as a forest matures.
More
Commensalism
Neutral symbioses in which one partner benefits and the other is neither benefitted or harmed.
Swollen hyphal tips that form as a result of mycelial pruning by ants. The main source of food for leafcutter ants.
Gongylidia
Fungi that live within plants but cause no outward symptoms.
Endophytes
Antibiosis.
The negative influence of one fungus on another via production of secondary compounds, such as antibiotics.
What do ambrosia beetles and Ambrosiella get out of their symbiosis?
The beetles get food (the fungus) and the fungus receives transmission and refuge from competitors.
The genus of fungus that is primarily cultivated by leafcutter ants.
Leucoagaricus
The term for pioneer species.
Ruderal
The key difference between endophytes and mycorrhizae.
Endophytic fungi live entirely within plant tissue with no external connections.
Horizontal dissemination.
Endophytic dissemination in which spores are produced on dead/dying plant tissue, going on to infect and colonize tissues of a new plant.
The specialized structure on the thorax of female ambrosia beetles for carrying fungi.
Mycangium
Approaches to characterize and quantify fungal communities.
(1) Direct observation, (2) isolation, (3) molecular methods.
Indirect antagonism.
Aggressive behavior by one or both competitor that does not require hyphal contact.
The genus of snail that has been found to cultivate fungi.
Littoria
Mycangium
The specialized structure on the thorax of female ambrosia beetles for carrying fungi.
Vertical dissemination.
Endophytic dissemination in which the infection is passed from parent to progeny via seed.
How do endophytes provide herbivore resistance to plants?
Production of toxins that reduce herbivory.
(Vertical/horizonal) dissemination is found primarily in the endophyte-grass symbiosis.
Vertical.
Fungistatic antibiosis.
Antibiosis in which secondary compounds are used to slow the growth of other fungi.
Examples of indirect effects of animals on fungal communities.
Inputs of dung/urine, changing composition of plant communities.
The term for pioneer/R-selected species.
Ruderal.
The fungus cultivated by ambrosia beetles.
Ascomycota -> hyphomycetes -> Ambrosiella
Endophytic dissemination in which the infection is passed from parent to progeny via seed.
Vertical dissemination.
Major drawbacks to using isolation to study fungal communities.
Many fungi do not grow well in culture, have very specific requirements for growth in culture, or are not good competitors on artificial media.
(T/F) Endophytes are parasitic.
False, most are mutualistic.
R-selecting fungi are primarily (sexual/asexual).
Asexual
What do the fungi get out of the symbiosis with leafcutter ants?
A readily available food supply.
Broad possible outcomes of interspecific interactions within a fungal community.
(1) Stimulation of one or both species, (2) mutual tolerance, or (3) intolerance/antagonism.
Most endosymbionts tend to be (mutualistic, commensal, parasitic).
Commensal.
The alternate name for leafcutter ants.
Attine ants
What is the endophyte Neotyphodium known for?
Reducing grass herbivory by producing alkaloids
What is a common example of a commensal endosymbiont that can become a parasite under certain conditions?
Candida albicans
How does the Littoria snail cultivate fungus?
It creates wounds that weak parasitic fungi can exploit, then it eats the fungi.
What type of insect is Dutch Elm Disease spread by?
Bark beetles
What is the Mycangium of an Ambrosia beetle used for?
Carrying fungi!
What is the nutrient aquisition strategy for most C-selected / combative fungi?
Wood decay
What is the character trait of Xerophilic fungi?
Drought loving
T or F. Mycoparasitism includes both necrotrophs and biotrophs.
True.
What compound does Trichoderma, and other mycoparasites, use to break down host fungal cell walls?
Chitinases
Why are R-selected pioneers not good competitors?
They can’t handle antibiotics.
