exam 3 (25,26,27) Flashcards
mycorrhiza
symbiotic assoc essential for one OR both partners - fungus and root of living plant
may be present with plants that do not for true roots
arbuscular mycorrhiza
dominant in roots tree like vesicles, tubular structure, stain roots
ecotmycorrhizal
no penetration in cell
fungal hyphae wrap around root cell
other mycorrhizas
mixtureee of arbuscular and ecto
ecoectendo, arbutoid, ericoid
both penetratin and less developed mantle (outside)
occurences of mycorrhiza
90% of all land plant belong to families that are commonly mycorrhizal
2% of plants form ECM associations BUT 60% of trees globally have ECM fungi on roots
non-mycorrhizal plant species
families with ruderals (brassicaceae, first colonizers) or diff root struct (Proteaceae)
plant succession mycorrhizas
None > AM > ECM > ERM (mix)
changes in nutrient type and availability: mineral to organic
AM and ECM trends
AM - more abundant in terms of plant species, common in P limited areas
ECM - more abundant in terms of land area, common in N limited areas
Benefits of mycorrhiza symbiosis
For fungi: C from plant For plants: 1. nutrients and water 2. protection from root pathogens 3. enhanced tolerance of heavy metals
mycoheterotrophs
plants don’t make out photosynthates, get CNP from fungi
nutrient content in mycorrhizal plants
higher than non-mycorrhizal
due to
1. extension of root system through fungal mycelium allows for larger area of soil to be exploited
2. hyphal diameter smaller than roots so access to smaller soil pores (inc soil volume exploited)
3. fungi have enzymes that allow them to capture nutrients from soil organic matter not normally accesible by plants
mycorrhiza plant diversity and productivity
inc diversity, inc biomass, inc hyphae, P used and put in plants more
mycorrhiza succession
common mycorrhizal network –> share ECM, same benefits, share hyphal connections
larger trees need the willow occurence first because of established ECM
mycorrhizal cost to plants
net cost = extra C gained from interaction - C expended
typically overall C gain is higher with M+ plants
15% of total plant C expended
environments for colonization ranked (light, P)
best low light, low P high light, low P high light, high P low light, high P
Past interaction between early-diverging mucuromycotan fungi and basal land plants (liverworts)
high thallus colonization (no roots)
fungal struct formed include arbuscules
Marchantia-colonizing fungi are AM, but called AML due to plant struct (AM-like)
photosynthesis with liverworts + early-diverging fungi
higher photosyn with AML colonization regardless of CO2 level
AML fungi and liver wort growth and reproduction
both in past and now
higher dry mass with AML
better growth by AML fungi regardless of nutrient level
more reproduction
fungi as disease agent
more common in plants
not common in animal
fungi disease in humans
300 species
worst associated with weakened immune systems
Fungi agricultural pathogens
crops - puccina (rust) and magnaporthe
spoilage - cladosporium and aspergillus
oomycetes:
phytophthora (potato blight), pythium, plasmopara
wheat rust
puccinia graminis
resistant varieties in 1960s. Ug99 is new rust that 90% of wheat is susceptible to
borlaug
pathogen spread
long distance spores dispersal (wind, atmosphere)
human transport
natural movement
attine ants
in american tropics, they cultivate basidiomycota as anti-bacterial covering that limits pathogen
leaves feed the fungus and the fungus prod nutrients that ants eat
ant-microbial network
ants and fungus
ants to antibiotic producing bacteria (pseudonocardia) to parasitic fungus (escovopsis) to fungus
2 diff basid cultivars (agaricaceae, pterulaceae. convergent evol)
endophytic fungi in plants
leaf cutter ants clean due to chemical cues in antennae
gomerella cingulata
mycoparasites
muellerella thalamita parasite in apothescium
power cups
filled with parasitizing fungi spores
Why increase in plant-infecting fungi?
dependent on plant disease triangle (enviro, pathogen, host susceptibility)
what is pathogen of prunus in JC?
oomycete fungus in pythium
pythium
fungus for JC prunus trees
new JC study in chinese forests
looked at heat impact
chamber –> less survival during warming, inc JC pathogenicity
prunus
fungal abundance inc in killer pathogen at closer distance and higher temp
fungal service soil formation
soil generated from rock weathering - abiotic and abiotically
lichen colonization facilitates rock weathering via water condensation and acid production
ECM fungal hyphae tunnel into rock minerals to extract nutrients like P
fungal service soil accumulation
net to keep soil
physical ‘meshing’ of nutrients and organic matter via mycelium
extraction of polysacch, ‘glue’
soil fertility fungi service
breakdown CNP
decomposition
proteases (N), peptidases (N) and phosphatase (P)
fungal service primary production
mycorrhizal symbioses stimulate plant primary production
endophytic symbiosis can stim primary prod by suppressing herbivory
fungal service secondary production
fungal hyphae are base of soil microfood-webs
mushrooms consumed by animals (lean proteins, low fat, carbs)
flying squirrel eats when more shrooms avail
deer each lichens when avail
fungal service pop regulation
bd chytrid pathogen on frogs ascomycota rust on wheat, rice bat ascomycota white nose syndrome on bats puccinia on wheat aspergillus on corals nosema on bees
saprotophic fungi forest effect
does not decompose wood
C is stuck, no cycling
forest without mycorrhizal fungi
dec health, less access to nutrients, inc herbivory
forest without plant parasitic fungi
dec div b/c JC hypoth
fungal service degradation of pollutants
wood rot fungi use oxygen radicals to breakdown lignin (wood)
non-specific process that can be used on other complex molecules like human-made pollutants
fungal service mycofiltration
pigfarm with methane released
cleans emissions
Ganoderma and pluerotus
schilling lab
fungal service phytoremediation
extraction of Zinc or other toxic material in soil
mychorrizal plants have better survival b/c of fungi
lichens and atmospheric pollutants
sulfur dioxide caused loss of lichens but returned after scrubbing
atmospheric pollutants and mycorrhizal fungi
effect of deposition both direct on fungi and indirect (through plant host)
