Microbial Symbiosis Flashcards
what are the types of symbiosis?
Commensal, Parasitic, Mutualistic
why do super nodulating soybean plants have stunted growth?
too much energy is invested in creating nodules
what are the sponge specific marine bacteria?
Poribacteria, spongibacter
what mutualistic properties do marine bacteria have?
photosynthesis, nitrogen fixation, denitrification, toxic metabolites, CHEMICAL DEFENSE
what symbiotic benefits does Arbuscular Mycorrhizal Fungus and Plants have?
Provides fungus with carbs (glucose/sucrose)
Plant get more water/nutrients absorption - larger surface area, phosphate uptake and translocation
Underground hyphal networks connect plants and transport water, carbon, nutrients between plants
mechanism of Arbuscular Mycorrhizal fungal replication in plants
Strigolactone released by roots signals to AMF Fungus response produces myc factors Symbiosis signalling pathway activated Hyphopodium forms - fungus enters Fungus colonises plant root cortex Abruscules formed
types of abruscules formed
Endomycorrhizal - inside root
Ectomycorrhizal - outside root
mechanism of Rhizobium replication and Plants
Flavonoids are released by plant root signals to rhizobia
Bacteria produce nodulation factors and activate symbiosis signalling pathway
Rhizobia enter plant root through root hair cells
Bacteria become trapped in root hair curl
Nodules initiate below site of infection and Infection grows
Bacteria released into membrane bound compartments where bacteria become nitrogen fixing
how does Rhizobium compensate for the lack of oxygen present?
Longitudinal oxygen gradient - central nitrogen fixing zone
High concentration of Hb facilitates oxygen diffusion
