Fungal Pathogens of Plants Flashcards
What 3 factors influence fungal infection in plants?
Environmental severity, host susceptibility, and pathogen virulence/abundance.
What are the main methods of arrival and entry on a plant?
Spores (via many vectors), some fungi germinate or mycelia can enter the plant.
What are some preformed plant defences against fungal infection?
Thick cell walls.
Cutin/Suberin/Wax outer layer.
Bark.
Phyanticipins (inhibitory compounds).
What are the main infection courts on a plant?
Wounds and natural openings eg stomata.
How do fungi penetrate plant tissues?
Using an appressorium.
Insertion by animal vectors feeding or ovipositing.
Natural openings.
What is an appressorium and how does it work?
It is a specialised cell - a flattened hyphal “pressing” organ. It uses mechanical pressure and enzymes to get into the plant.
What are some rapid plant defences to fungal infection?
Oxidative burst, nitrous oxide production, cross-linking of cell wall proteins and callose production.
What are some slower plant defences to fungal infection?
Phytoalexins, lignification, suberisation, HGRPs, pathogenesis related proteins and systemic resistance.
Define inoculum potential.
The amount of energy available for the fungus to infect the host at the site of infection (Garrett 1960).
What are necrotrophs?
Species that extract nutrients from dead cells killed before or during colonization, using enzymes.
What are some symptoms of necrotroph infection?
Soft, watery tissue.
Discoloured with discrete slow spreading lesions.
What are biotrophs?
Species that establish a long-term feeding relationship with the host’s living cells, without killing the plant.
What are hemibiotrophs?
Pathogenic fungi that keep their hosts alive and establish themselves in the host tissue. They can then go on to live a necrotrophic lifestyle.
What are the main methods of exiting the host plant?
Sexual or asexual spores are released. Survival spores are released if the plant dies. Necrotrophs can send out mycelium.
What is the benefit of being a necrotroph?
They are initially free from competition.
