How do Plants Defend Against Infection Flashcards
What is an incompatible interaction in plant immunity?
When a resistant host detects an avirulent pathogen and stops the infection
What historical event was caused by plant disease?
The Irish Famine
What does the gene for gene hypothesis state?
For every plant resistance gene there is a matching avirulence gene in the pathogen
What happens when R and Avr match?
The plant recognises the pathogen and activates a defence response
What happens if there’s no match between R and Avr?
The pathogen escapes detection and causes disease
What is an effector?
A molecule secreted by the pathogen to help it infect the plant
What is Effector-Triggered Immunity?
A strong specific immune response triggered by recognising pathogen effectors
What kind of proteins detect effectors in ETI?
NLRs - Nucleotide binding Leucine rich repeat proteins
What are the three domains of a typical NLR?
- N terminal
- NB-ARC domain
- LRR domain
What does the NB-ARC domain do?
It binds and hydrolyses ATP to activate the NLR
What does the LRR domain do?
It recognises pathogen effectors or their effect
What is direct recognition in ETI?
The NLR binds the effector directly like a lock and key
What is indirect recognition in ETI?
The NLR monitors a host protein that gets changed by the effector
What is the integrated decoy strategy?
The NLR includes a fake target of the effector to trap it and trigger immunity
What is the hypersensitive response?
Localised cell death around the infection site to stop pathogen spread
What is pattern triggered immunity?
A broad immune response triggered by detection of PAMPs
What detects PAMPs in plants?
Pattern recognition receptors on the plasma membrane
What are the two types of PRRs in plants?
- Receptor like kinases RLKs
- Receptor like proteins RLPs
What happens when a PRR detects a PAMP?
Pattern triggered immunity is triggered leading to various immune responses
What are five effects triggered by pattern triggered immunity in plants?
- Calcium influx
- Reactive oxygen species burst
- MAPK activation
- Callose deposition
- Defence gene expression
What are the two layers of the plant immune system?
- PTI first layer
- ETI second stronger layer
What is the zig-zag model in plant immunity?
A model describing the ongoing arms race between pathogens and plants as they evolve PTI, effectors, ETI in response to one another
