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Plant responses to pathogens - Coggle Diagram
Plant responses to pathogens
passive defences
physical barriers
thick cuticle cell walls and small stomatas
prevent pathogen entry
Thicker cuticles are able to prevent pathogen entry
Bark offers plants extra protection against pathogens
Vertical hanging leaves
reduce water reservoirs
pathogens cannot accumulate
Stomata tend to open during humid weather / rainstorms
Potential port of entry of pathogens
Chemical barriers
Chemical barriers
reduce fungal and bacterial growth
ware off vectors of viruses
Produce enzymes that break down pathogen-derived toxins
Chemical receptors on plant cells
detect the presence of a pathogen
activate the next stage of defence
Active defences
pathogen recognition
Able to recognise pathogens by detecting certain physical / chemical signals
such as fragments from the cells walls of bacteria and fungi
genes within the cells are known to regulate plant responses
Rapid response
Recognition of a pathogen by proteins cause changes in the permeability of the plant cell membrane
Allows for movement of certain ions into the cell
Triggers defense responses by activating the expression of certain genes.
Second response
is reinforcement of the cell wall with aggregates of materials in the cytoplasm
Third response
is programmed cell death
Causes a cluster of dead plant cells to accumulate around a pathogen to isolate it
Followed by secretion of antimicrobial compounds
Dalayed response
Delayed active responses limit the spread of the pathogen
Important strategy is to repair wounds in the bark via cork cell production / gum section
Lysozyme-like chemicals
are released and have an antimicrobial action
Salicylic acid
acts as a signaling agent of infections
plays a role in memory of certain pathogens